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BACKGROUND: Computational models of atrial fibrillation (AF) help clarify arrhythmia mechanisms, but the contribution of left atrial (LA) epicardial adipose tissue (EAT) is rarely included.
OBJECTIVE: To assess whether incorporating EAT-associated effects into fibrosis-based atrial models alters reentrant arrhythmia inducibility, and to characterize the pro-arrhythmic properties of EAT-affected tissue.
METHODS: LA fibrosis and EAT were quantified by LGE and Dixon MRI in 19 patients with persistent AF. For each patient, three anatomically identical image-personalized models were built (fibrosis only; fibrosis plus half-epicardial EAT effects, 0.5 mm; fibrosis plus full-epicardial EAT effects, 1.0 mm), yielding 855 simulations. In EAT regions, inward rectifier K+ current was reduced by 35%, intracellular K+ by 50%, and conduction velocity by 25%.
RESULTS: Sustained reentry occurred in 370 simulations (43.3%), of which 306 had a functional (rotor-driven) component. Functional reentry inducibility rose from 22.8% (fibrosis only) to 41.4% (half-EAT) and 43.2% (full-EAT). At least one functional reentry was inducible in 12/19 fibrosis-only models, 18/19 half-EAT models, and 19/19 full-EAT models. Median inducible simulations per patient increased from 4 to 6 (p=0.004) and 7 (p=0.003), without significant difference between half- and full-EAT (p=0.895). Fibrosis/EAT overlap regions comprised only 2.1% of the LA wall but were the most arrhythmogenic, with a median 65.5% of their volume harboring reentry versus 8.8% (non-substrate), 37.3% (fibrosis), and 42.8% (EAT) (all p<0.001). In an exploratory analysis of PVI-only ablation patients (n=13), fibrosis-EAT overlap outside the PVI region was associated with 1-year recurrence (log-rank p=0.007).
CONCLUSION: Adding EAT effects to fibrosis-based models increased sustained functional reentry, with transmural depth contributing only modestly. Reentry anchored preferentially where fibrosis and EAT effects coexisted.

BACKGROUND: Atrial fibrillation (AF) remains a common outcome after catheter ablation, with recurrence observed in up to 50% of patients within 5 years. Despite extensive research, challenges remain in optimizing observation and prediction windows for AF recurrence assessment. Therefore, we developed and validated a novel deep learning model that reclassifies sinus rhythm based on past and future AF events using single-lead ECG strips from handheld devices.
METHODS: Of the 558 participants, 308 with no documented recurrence during study follow-up contributed Benign Sinus strips, while 250 with documented recurrence contributed sinus rhythm strips recorded within ±3 days of an AF event, defined as Severe Sinus strips. Both clinical feature-based models and a deep learning model were used to classify these ECGs according to their proximity to AF recurrence events. Performance was evaluated using area under the receiver operating characteristic curve, accuracy, sensitivity, specificity, and F1-score.
RESULTS: The strip-level pretrained deep learning model achieved an area under the receiver operating characteristic curve of 0.86, with sensitivity of 0.79, and specificity of 0.76. The complementary participant-level clinical feature-based Random Forest benchmark achieved an area under the receiver operating characteristic curve of 0.71, sensitivity of 0.58, and specificity of 0.69. Feature-based analyses identified associations involving heart-rate variability, mean R-R interval, female sex, left atrial volume, and mean P-wave duration.
CONCLUSIONS: Our dynamic deep learning model reclassifies 30-second single-lead sinus rhythm ECGs based on AF events within ±3 days, transforming a brief ECG snapshot into a summarized indicator of short-term AF risk.

AIMS: Atrial fibrillation (AF) is the most frequently diagnosed cardiac arrhythmia. Catheter ablation using radiofrequency cauterization (CA-RFC) performed in the left atrium (LA) aims to isolate electrical sources of AF. This intervention is accompanied by frequent AF recurrences affecting 10% of patients at 30 days and 50% at one-year post-procedure. It has been suggested that inflammation could contribute to AF-recurrence post-CA-RFC. Given its anti-inflammatory and cardioprotective properties, colchicine has been proposed as a potential treatment to prevent AF recurrence post-CA-RFC.
HYPOTHESIS: RFC can lead to atrial fibrosis, inflammation, and new-onset AF, which may be mitigated by colchicine.
METHODS AND RESULTS: Male and female Wistar rats (225-275 g) were divided into four groups: Sham or RFC, with or without colchicine (0.25 mg/kg/8 h, intraperitoneally) starting 8 h before surgery until D1 post-procedure. Sham animals underwent surgery without RFC. Electrophysiology and echocardiography assessments were performed on days 1 (D1) and 3 (D3) post-RFC. Colchicine significantly lowered RFC-induced AF vulnerability, improved LA conduction velocity, reduced LA fibrosis, and attenuated LA inflammation post-procedure. Colchicine also prevented RFC-induced CD11c+ macrophages while promoting CD206+ recruitment in the LA.
CONCLUSION: Colchicine started before RFC may be an innovative strategy to prevent the development of LA arrhythmogenic substrate post-procedure.

AIMS: Evidence supporting the use of pulsed field ablation (PFA) for ventricular arrhythmia (VA) ablation remains limited and heterogeneous, and the relationship between preclinical lesion characteristics and clinical outcomes is incompletely defined. We sought to systematically summarize preclinical lesion metrics and clinical outcomes of ventricular PFA.
METHODS AND RESULTS: We performed a systematic review and meta-analysis of preclinical and clinical studies of ventricular PFA. Preclinical studies reporting lesion depth or transmurality and clinical studies detailing procedural efficacy and safety were included. Random-effects models were used to pool lesion characteristics and clinical outcomes. Seventy-five studies were included (33 preclinical, 43 clinical; 355 patients). In preclinical models, mean lesion depth was 5.96 mm(95%CI, 5.07-6.84) in healthy endocardium and 5.19 mm (95%CI, 2.58-7.79) in healthy epicardium. Notably, lesion depth was quantitatively similar in models of scarred myocardium (5.96 mm; 95%CI, 5.39-6.53). Lesion transmurality was variable in healthy tissues (32%; 95%CI, 15-52%) but higher within scar (53%; 95%CI, 36-70%). Consistently, lesion depth was similar between PFA and RF in healthy myocardium, but greater with PFA in scarred models (within-study mean depth difference, 2.09 mm; 95%CI, 0.84-3.34). Greater contact force, repeated applications, and higher energy/duration settings were associated with increased lesion depth. Clinically, acute success was high for both premature ventricular complexes (PVCs,90%; 95%CI, 83-96%) and ventricular tachycardia (VT;92%; 95%CI, 87-96%) in studies with ≥3patients. Over a mean follow-up of approximately 5months, recurrence rates were 19% (95%CI, 12-28%) for PVCs and 21% (95%CI, 10-35%) for VT. The overall complication rate was 10% (95%CI, 5-17%) in studies with ≥3patients, with coronary artery spasm and conduction disturbances representing the most frequent adverse events.
CONCLUSION: Ventricular PFA demonstrates high acute efficacy and encouraging mid-term outcomes, supported by preclinical evidence of favourable lesion penetration within scarred myocardium. Safety considerations-particularly coronary and conduction system effects-and the heterogeneity of preclinical evidence highlight the need for further investigation.

BACKGROUND: Redo ablation for persistent atrial fibrillation (AF) that recurs after pulmonary vein isolation (PVI) has had limited durable success, and adjunctive substrate strategies have not consistently improved outcomes. The STAR Apollo mapping system is a Food and Drug Administration-cleared technology that applies stochastic trajectory analysis of ranked signals to identify repetitive patterns of activation and early sites of activation (ESAs) that may indicate regions sustaining AF.
OBJECTIVE: The purpose of this study was to evaluate the procedural feasibility and safety and to describe the 12-month rhythm outcomes of STAR Apollo-guided redo ablation in patients with recurrent persistent AF after prior PVI.
METHODS: In this prospective, multicenter, observational study, patients with persistent AF recurring after 1 prior PVI (prior extrapulmonary vein ablation excluded) underwent pulmonary vein re-isolation, STAR Apollo mapping, and operator-directed adjunctive ablation. Because mapping of stochastic trajectory analysis of ranked signals (STAR) requires ongoing AF, the analysis was confined to the 50 patients (of 64 enrolled) in whom a STAR map was obtained; the 14 without a STAR map, because they were not in AF during the procedure, were excluded. Procedural parameters, safety, and rhythm at the 3-, 6-, and 12-month visits were recorded.
RESULTS: All 50 patients had 1 prior PVI and recurrent persistent AF; they were 68.8 ± 8.7 years old, 35 (70.0%) were male, with a body mass index of 31.3 ± 5.5 kg/m2. Pulmonary vein reconnection was found and re-isolated in 46 of 50 (92.0%). The system identified a median of 3 (2-3) ESAs per patient, and STAR mapping added a median of 16 (13-21) minutes to a median total procedure time of 125 (91-166) minutes. Sinus rhythm was restored without cardioversion in 23 of 50 (46.0%; AF terminated during ablation in 19/50 [38.0%] and spontaneously in 4/50 [8.0%]); 26 of 50 (52.0%) required cardioversion and 1 of 50 (2.0%) was not restored in the laboratory. Adjunctive lines included a roof line in 30 of 50 (60.0%) and a mitral isthmus line in 11 of 50 (22.0%). A procedural complication occurred in 1 of 50 patients (2.0%) (pericardial effusion). Among the 40 patients assessed at 12 months, 33 (82.5%) were in sinus rhythm, and symptom class improved to European Heart Rhythm Association I in 23 of 30 (76.7%). By Kaplan-Meier estimation (single procedure; recurrence, repeat ablation, or cardioversion counted as failure), freedom from AF was 95.3% (95% confidence interval [CI]: 82.5-98.8) at 6 months and 75.3% (95% CI: 59.0-85.9) at 12 months.
CONCLUSION: In conclusion, in recurrent persistent AF after prior PVI, STAR Apollo-guided redo ablation was feasible and safe, added a modest mapping step, and was associated with sinus rhythm and symptom improvement in most patients at 12 months. Designed as a feasibility and safety study, and being single arm, these data cannot establish the incremental efficacy of STAR guidance; the encouraging rhythm outcomes are hypothesis generating and support a randomized comparison with PV re-isolation alone.
GOV IDENTIFIER: NCT05826665.

BACKGROUND: Pulsed field ablation (PFA) is an emerging modality for atrial fibrillation (AF) ablation. However, adequate sedation of patients during treatment is imperative.
OBJECTIVE: Our aim was to compare safety and outcome after deep sedation (DS) managed by electrophysiology staff (EP-DS), DS by an anaesthesia nurse (AN-DS), and general anaesthesia (GA) during PFA AF ablation.
METHODS: All Danish patients undergoing first-time AF ablation with pentaspline PFA technique from 2021 to 2024 were included. Patients were stratified according to sedation strategy. EP-DS and AN-DS were defined as sedation without assisted ventilation managed by EP staff and an anaesthesia nurse, respectively. Patients in GA underwent endotracheal intubation and were monitored by anaesthesia staff. Patient selection for the sedation strategy was based on the institutional practice.
RESULTS: Of 1269 patients, 661 (52%) underwent EP-DS, 173 (14%) underwent AN-DS, and 435 (34%) underwent GA. Overall, sedation complications were few, and no procedures were abandoned due to adverse effects of sedation. In the EP-DS group, the anaesthesiologist was unexpectedly called for back-up in 1 (0.2%) patient due to prolonged hypotension during the procedure. In the AN-DS group, the anaesthesiologist was called due to desaturation in 1 patient (0.6%) but without the need for escalation to intubation. In the GA group, no periprocedural sedation complications occurred. We found no difference in 1-year atrial tachycardia recurrence between sedation groups.
CONCLUSION: In this nationwide cohort, EP staff-administered deep sedation was feasible and associated with few clinically significant sedation-related adverse events during PFA. No significant differences in observed atrial tachyarrhythmia recurrence rates were identified between sedation strategies.

AIMS: Atrial fibrillation (AF) ablation by pulmonary vein isolation (PVI) and left atrial appendage closure (LAAC) are increasingly performed as standalone procedures. Given that PVI and LAAC share the same access route, a combined approach of pulsed field ablation (PFA)-based PVI and LAAC might be beneficial. The COCONUT study focused on safety, efficacy, and outcomes combining PVI by PFA with LAAC in one procedure.
METHODS: This is a retrospective, multinational registry study. The primary endpoints were the following: (1) primary safety endpoint: serious adverse events; and (2) primary efficacy endpoint: success of PVI and LAA closure defined as the ability to isolate all pulmonary veins and the successful closure of the LAA. For secondary endpoints, peri-procedural data and follow-up data were collected.
RESULTS: A total of 155 patients from 22 centres of nine European countries were treated by concomitant pentaspline catheter PFA-based PVI and LAAC. The mean CHA2DS2-VA score was 3.1 ± 1.4. The primary efficacy endpoint was achieved at 97.4% with successful PVI at 100% and successful LAAC in 151/155 patients (97.4%). The primary safety endpoint was observed in 3/155 patients (1.9%). Transoesophageal echocardiography and/or CCTA 67 ± 26 days after the procedure showed no device embolization and no device-related thrombus, 24/151 (15.9%) patients showed peri-device gaps of <5 mm while gaps of >5 mm have been observed in 3/151 (2.0%). Among 137/155 patients with available arrhythmia, a follow-up >6 months at 78.1% showed sinus rhythm.
CONCLUSION: In this large multicentre study, concomitant PFA-based AF ablation and LAA closure proved to be feasible, effective, and safe and overall procedure duration was short.

BACKGROUND: Clinical recognition of multifocal premature ventricular complexes (PVCs) poses diagnostic and therapeutic challenges. Despite their morphological diversity, these arrhythmias may originate from a confined anatomical region, allowing a systematic mapping and ablation strategy.
OBJECTIVE: To describe clinical characteristics and propose a stepwise approach to mapping and ablation of multifocal PVCs originating from the basal septal left ventricular (LV) ostium.
METHODS: Patients with multifocal septal PVCs who underwent coronary venous mapping were included. Ablation targeted the basal LV septum from the anterolateral LV ostium to the posterior LV process.
RESULTS: Twenty-four patients (mean age, 64.5 ± 9.2 years; 92% male) were included. Baseline electrocardiogram showed PR prolongation of >200 ms in 50%, QRS of >100 ms in 75%, absent septal R waves in 63%, and QRS fractionation in inferior leads in 38%. LV ejection fraction was preserved or mildly reduced (median, 45%). Cardiac magnetic resonance showed delayed gadolinium enhancement in 71%, and intracardiac echocardiography revealed septal abnormalities in 83%. Intramural coronary venous mapping was feasible in 75%, revealing fractionated electrograms; intramural activation preceded endocardial activation by 10 ms (P < .01). Thirteen patients (54%) received an implantable cardioverter-defibrillator. PVC burden decreased from 18.7% to 2.8% (P < .01), with ≥80% reduction in 83%. During 1.7 years of follow-up, 4 patients (31%) received appropriate therapies.
CONCLUSION: Multifocal septal PVCs are consistently associated with abnormalities on electrocardiogram, cardiac magnetic resonance and/or intramural septal electrograms. A stepwise ablation approach substantially reduces PVC burden, although damage to the conduction system remains clinically relevant. The risk of malignant ventricular arrhythmias remains high despite preserved or mildly reduced LV ejection fraction.

BACKGROUND: The Sphere-9 lattice-tip catheter (Affera, Medtronic) enables delivery of both radiofrequency ablation (RFA) and pulsed field ablation (PFA) for ventricular arrhythmia (VA) ablation. Data on its impact on cardiac implantable electronic devices (CIEDs) are limited.
OBJECTIVES: This study sought to evaluate changes in CIED function following VA ablation using the Sphere-9 catheter.
METHODS: We reviewed 65 consecutive patients (median age 71 years, 94% male, 63% ischemic cardiomyopathy, median left ventricular ejection fraction 31%) with pre-existing CIEDs who underwent VA ablation (62 ventricular tachycardia [95%], 3 premature ventricular contraction [5%]) using the Sphere-9 catheter (combined RFA/PFA (53 [82%]), RFA alone (6 [9%]), PFA alone (6 [9%])). Device interrogation was performed within 30 days preprocedure, within 7 days postprocedure, and at 3-month (+/- 30 days) follow-up.
RESULTS: At 3-months, right ventricular leads demonstrated reduced sensing amplitude (11.7-10.0 mV, P = 0.04), pacing impedance (441-422 Ω, P < 0.001), shock impedance (64-59 Ω, P = 0.01), and increased capture threshold (0.9-1.0 V at 0.4-0.5 milliseconds, P = 0.03). Left ventricular (LV) leads demonstrated reduced pacing impedance (544-475 Ω, P = 0.04), whereas LV capture threshold remained elevated (1.0-1.4 V, P = 0.08). Right atrial lead parameters remained stable. No patient required CIED revision. One patient experienced cardiac resynchronization therapy-D pulse generator failure during PFA delivery 7.5 mm from an LV lead tip electrode, requiring generator replacement.
CONCLUSIONS: Ventricular arrhythmia ablation using the Sphere-9 dual-energy lattice-tip catheter was associated with small but persistent changes in right and left ventricular lead parameters. Serious CIED interactions were uncommon, and further studies are needed to better understand the underlying mechanisms.

BACKGROUND: Multipolar electrogram is designed to improve near-field (NF) signal clarity by subtracting far-field (FF) components using adjacent electrodes.
OBJECTIVE: To assess the performance of multipolar electrogram mapping in identifying critical activation pathways and substrates in ventricular tachycardia (VT).
METHODS: Scar-related VT maps created using the CARTO™3 system and Optrell™ catheter were analyzed. Bipolar VT activation maps were created using wavefront algorithm (annotating unipolar maximum -dV/dt), while substrate maps employed late annotation mapping (LAM). Bipolar maps were converted into multipolar maps offline using the CARTOREPLAY TM module. Electrograms with both NF and FF components-including local abnormal ventricular activities (LAVA), late potentials (LP), and diastolic signals-were compared between bipolar and multipolar maps. Auto-annotation accuracy was evaluated.
RESULTS: A total of 3,636 electrograms from 53 maps (45 patients, age 64±9 years, 87% male, 57% ischemic) were analyzed. Multipolar signals showed higher NF/FF amplitude ratio than bipolar signals (1.50 [0.61-3.08] vs. 1.19 [0.52-2.60], p<0.0001). Multipolar activation mapping more accurately identified diastolic potentials than bipolar wavefront mapping (76% vs. 46%, p<0.0001). However, multipolar substrate mapping was less sensitive in detecting LAVA/LP than bipolar LAM (80% vs. 92%, p<0.0001). Of 30 maps with LPs, 87% had LPs missed by the multipolar algorithm but captured by LAM. Smaller NF / larger FF amplitudes and perimeter electrodes predicted multipolar annotation errors.
CONCLUSIONS: Multipolar activation mapping enhances diastolic potential detection but reduces sensitivity for VT substrate identification compared to bipolar LAM. These findings inform optimal electrogram annotation approaches for VT activation and substrate mapping.

AIMS: This retrospective analysis of our extensive experience focuses on idiopathic premature ventricular contractions (PVC) ablation guided by robotic magnetic navigation (RMN). Critical evaluation is given to the causes and impact of acute procedural failure.
METHODS: This retrospective cohort study enrolled 824 patients (mean PVC burden 21.0 ± 6.6%) undergoing first-time RMN-guided PVC ablation. Acute failure was defined as recurrent clinical PVC during the observation period after the last radiofrequency (RF) application. The Navigation Index was calculated as the ratio of RF delivery time to total ablation time. Multivariate logistic regression was used to detect the impact factors of acute failure from patient demographics, PVC characteristics, and procedural parameters.
RESULTS: The mean procedure and fluoroscopic times were 73.8 ± 38.3 and 2.6 ± 2.9 min, respectively. The overall acute procedural failure rate was 11% (90/824). Acute procedure failure was strongly dependent on the PVC origin: lowest in the right ventricular outflow tract (2.7%) and highest in the left ventricular summit (44%). The primary mechanisms were determined to be intramural origins (50%, 45/90) and proximity to high-risk structures (24%, 22/90). Multivariate analysis identified PVC origin and Navigation Index (OR = 0.1, 95% CI 0.05-0.20; p < 0.001) as independent predictors of failure. A higher Navigation Index, reflecting greater procedural efficiency, correlated with procedural success. No major complications occurred, and minor complications were observed in 0.6% of patients.
CONCLUSIONS: RMN-guided idiopathic PVC ablation demonstrated excellent safety and a relatively low acute procedural failure rate. Procedural outcomes are critically determined by the anatomical origin of the PVC and the procedural efficiency measured by the Navigation Index.

BACKGROUND: Vagal response (VR) was thought to the successful rate in catheter ablation of atrial fibrillation (AF). However, little is known about VR during pulmonary vein isolation (PVI) in AF and heart failure (HF). This study aims at investigating the incidence, risk factors and clinical outcomes of VR during PVI in paroxysmal AF with HF.
METHODS: A total of 551 paroxysmal AF patients were enrolled and classified according to HF status: without HF, HF with preserved, reduced and mildly reduced ejection fraction. The VR was defined as atrioventricular block, asystole or an increase in the R-R interval by 50% during ablation.
RESULTS: VR had the same occurrence rate between patients without HF and those with HFpEF (63 [20.5%] vs. 22 [18.9%], p = 0.722). However, VR were less frequently observed in HFmrEF and HFrEF(3 [5.0%] and 2 [2.9%], p = 0.004 and < 0.001 compared with without HF, respectively). Left ventricular EF ≥ 50% was independently associated with intraprocedural VR by multivariable analysis (p = 0.007). Patients with HFrEF or HFmrEF showed a higher mean and slower heart rate with decreased heart rate variability than those without HF. After 18.3 ± 7.4 months' follow-up, 2 of 22 (9.0%) HFpEF patients with VR and 12 of 94 (12.8%) without VR had AF recurrence (p = 0.942). Four HFrEF or HFmrEF patients with VR maintained sinus rhythm during 18.3 ± 4.9 months' follow-up.
CONCLUSION: Intraprocedural VR is not uncommon in HFpEF but is rarely observed in HFmrEF and HFrEF. Autonomic nervous system remodeling in HF, manifesting as a decrease in heart rate variability, might be the underlying reason. VR does not indicate a better clinical outcome in HFpEF.

INTRODUCTION: Atrial fibrosis is an adverse factor for arrhythmia recurrences and thromboembolic events in atrial fibrillation (AF). Cardiac magnetic resonance imaging (CMRi) has emerged as a noninvasive tool for its assessment, though evidence remains conflicting.
METHODS AND RESULTS: Sixty ablation-naïve patients with AF scheduled for first-time catheter ablation were enrolled (78% men, 67% paroxysmal AF, 73% heart failure reduced ejection fraction [HFrEF]). Prior to the procedure, CMRi was performed in sinus rhythm (SR) on a 1.5T system using a high-resolution (1.3 mm isotropic) free-breathing 3D LGE sequence with echo-navigator end-expiratory gating and whole-heart coverage. Left atrium (LA) fibrosis was quantified using the commercially available ADAS 3D software, with fibrosis defined at four image intensity ratios (IIR) thresholds (0.97, 1.2, 1.32, and 1.61 times mean blood-pool signal intensity). High-density electroanatomical mapping (EAM) was performed in SR, and low-voltage substrates (LVS) were quantified at three bipolar voltage thresholds (0.5, 0.25, and 0.1 mV). LVS-EAM were identified in 97%, 88%, and 45% of patients at 0.5, 0.25, and 0.1 mV, respectively. LGE-CMRi was detected in 100%, 97%, 63%, and 17% of patients at IIR thresholds of 0.97, 1.2, 1.32, and 1.61, respectively. Quantitative correlation between CMR- and EAM-derived fibrosis was negligible to weak across all threshold combinations. When fibrosis was analyzed dichotomously, agreement was highest between EAM 0.5 mV and CMR IIR 0.97 (0.97, 95% CI [0.92, 1.00]; p < 0.001) and IIR 1.2 (1, 95% CI [1.00, 1.00]; p < 0.001), and between EAM 0.25 mV and CMR IIR 0.97 (0.87 95% CI [0.76, 0.97]; p < 0.001) and IIR 1.2 (0.9, 95% CI [0.81, 0.99]; p < 0.001).
CONCLUSIONS: In an ablation-naïve AF population with a predominance of HFrEF patients, CMR- and EAM-derived measures of atrial fibrosis showed poor quantitative correlation across multiple threshold combinations. Although agreement improved when fibrosis was analyzed dichotomously (presence vs. absence of fibrosis), the highest agreement was observed at the most sensitive threshold combinations. The findings of our study highlight the need for standardized, validated, and reproducible CMR protocols for native atrial fibrosis assessment in order to provide a noninvasive alternative to EAM.

BACKGROUND: Drug-refractory ventricular tachycardia (VT) after failed radiofrequency (RF) ablation remains a clinical challenge. Pulsed-field ablation (PFA) is expanding to ventricular applications, but United States experience with focal pulsed-field-only catheters in VT is sparse, and pulsed-field platforms are not equivalent across manufacturers. Here we describe the first United States experience of FARAPOINT focal PFA in patients with refractory VT.
METHODS AND RESULTS: We retrospectively reviewed ten consecutive patients who underwent VT ablation with the FARAPOINT (Boston Scientific) focal PFA catheter at a single VA Health Care System between July 2025 and May 2026. All patients had drug-refractory sustained monomorphic VT. Median age was 77 years with a mix of ischemic and nonischemic cardiomyopathy. Six of ten had at least one prior failed catheter ablation. Acute non-inducibility was achieved in all nine patients who underwent formal post-ablation stimulation testing. No procedural complications occurred. Over a median follow-up of 95.5 days, sustained VT recurred in four of ten patients. No patient underwent repeat ablation, required mechanical circulatory support, or died.
CONCLUSIONS: In this initial United States experience, FARAPOINT was safe and acutely effective in patients with ischemic cardiomyopathy within a high-risk cohort with refractory VT and prior failed ablations, including challenging substrates. Prospective multicenter studies are warranted to expand these observations.

BACKGROUND: Catheter ablation is an essential tool for ventricular arrhythmia management, yet sustained procedural success is hindered by the limited ability to identify nonendocardial arrhythmogenic substrates during the procedure. Although delayed enhancement cardiac magnetic resonance imaging is the reference standard for detecting myocardial fibrosis, barriers including cost, workflow complexity, and artifacts in patients with implantable devices limit its preprocedural use. We hypothesized that intracardiac electrograms provide sufficient information to infer scar beyond the endocardial surface and that this information can be harnessed by machine learning techniques.
METHODS: This retrospective study included a total of 131 584 cardiac contact electrogram (EGM) signals collected from 46 patients undergoing ventricular arrhythmia ablation. A stratified patient-wise split was used to create the training/validation set (N=37) and the testing set (N=9), while ensuring a similar distribution of scar types. We developed a novel image-processing workflow to create scar labels using coregistered cardiac magnetic resonance imaging and electroanatomic mapping surface meshes. We developed a transformer-based self-supervised model, EGM2Scar-AI, alongside basic convolutional neural network models using either EGM waveforms or EGM-derived short-time Fourier transform spectrograms.
RESULTS: The average task-specific area under the receiver operating characteristic curve of both the basic and short-time Fourier transform-based convolutional neural networks was 0.729 (0.725-0.732) and 0.729 (0.726-0.733), respectively, while EGM2Scar-AI performed significantly better with an average area under the receiver operating characteristic curve of 0.822 (0.819-0.825) across all 3 scar types. All models performed better on endocardial and mid-myocardial fibrosis identification, with a modest reduction in performance for epicardial fibrosis. Sensitivity improved significantly with the transformer-based architecture without appreciable changes in specificity.
CONCLUSIONS: Our study demonstrates that routine intracardiac electrograms enable the identification of endocardial, mid-myocardial, and epicardial scar using a transformer-based self-supervised deep learning model. Ultimately, our model has the potential to provide magnetic resonance imaging-like fibrosis maps during EP procedures without the need for external imaging and to increase the data set size for patient-specific models in ventricular arrhythmia research.

BACKGROUND: Slowly conducting anatomical isthmuses (SCAI) represent the main substrate for ventricular arrhythmias (VAs) in tetralogy of Fallot (TOF). However, the optimal conduction velocity (CV) threshold and the best approach for measurement remain to be determined.
OBJECTIVE: This study aimed at evaluating a new method for CV analysis.
METHODS: This single-center retrospective study included consecutive patients with TOF undergoing right ventricular electroanatomic activation mapping. CV across anatomical isthmus 3 was assessed using both automated Local Activation Time Velocity Vector (LVV) analysis and conventional manual measurements. The primary outcome was the inducibility of sustained monomorphic ventricular tachycardia (VT; SMVT).
RESULTS: A total of 44 patients were included (mean age 44.6±13.8 years, 56.8% males). Overall, a SMVT was inducible in 23 (52.3%) patients, including 12/14 (85.7%) patients referred for catheter ablation of VT (history of clinical VT) and 11/30 (36.7%) patients referred for EPS without spontaenous VT. LVV-CV showed a strong correlation with manual measurements (r = 0.81). The optimal cutoff value of LVV-CV based on the Youden index was 0.5 m/s. AUC, sensitivity, and specificity were 0.81, 0.96, and 0.71 using LVV-CV vs 0.75, 0.57, and 0.81 using manual CV measurements, respectively. LVV analysis reduced the number of classification errors from 14 (31.8%) cases with manual CV measurement to 7 (15.9%) cases when LVV-CV was used.
CONCLUSION: This novel, reproducible, and easy-to-use LVV-based approach to CV measurement for substrate evaluation in patients with TOF suggests that LVV-CV provides superior discriminative performance compared with manual CV measurements for identifying SCAIs associated with SMVT inducibility. Further studies are warranted to evaluate this approach in larger populations.

INTRODUCTION: Pulmonary vein isolation remains central to atrial fibrillation (AF) ablation, yet right atrial substrate modification remains incompletely defined. The crista terminalis (CT) region lies close to the right phrenic nerve and may exhibit anisotropic conduction and native or functional conduction block, while also serving as a potential non-pulmonary-vein trigger site. We evaluated the acute feasibility and electroanatomic endpoint of the Crista Caval Line (CCL), a CT-guided, sinoatrial node (SN)-sparing lesion set created with lattice-tip pulsed field ablation (PFA).
METHODS AND RESULTS: We prospectively enrolled 36 consecutive patients undergoing CCL creation during repeat AF ablation or ablation for non-paroxysmal AF. Pre-CCL sinus-rhythm high-density right atrial activation mapping was performed in all patients. CT-related conduction delay or block was observed in 27 patients (75.0%). In 14 patients (38.9%) with an apparent CT block line, the inferior application-set edge was aligned to the block line; in the remaining 22 patients without an apparent block, placement was primarily guided by intracardiac echocardiography. The CCL was positioned posterior to the CT, with the lateral margin of its superior application set kept approximately 15 mm posterolateral to the earliest mapped sinus activation site for SN protection. The CCL measured 78.8 [66.4-86.0] mm from first to last tag and required 26 [22-30] PFA applications over 370 [282-481] s. First-pass bidirectional transverse conduction block was confirmed in all patients by postablation activation mapping and differential pacing from both sides of the CCL. Next-day inspiratory/expiratory chest radiography showed no abnormality suggestive of phrenic nerve palsy; no pacemaker-requiring SN dysfunction or other clinically apparent collateral injury occurred.
CONCLUSIONS: A CT-guided, SN-sparing CCL can be reproducibly created with lattice-tip PFA, producing a first-pass bidirectional transverse conduction block without clinically apparent phrenic nerve palsy. These findings establish acute feasibility and an electroanatomic endpoint; lesion durability, arrhythmia recurrence, and incremental clinical benefit require further study.

BACKGROUND: Atrial fibrillation below age 30 is rare; ablation outcome data is scarce.
OBJECTIVE: The multicenter AF-YOUNG registry analyzed clinical, procedural, and outcome data of consecutive patients ≤30 years undergoing first-time catheter ablation.
METHODS: Two high-volume German centers retrospectively included patients ≤30 years undergoing first-time pulmonary vein isolation (PVI) for atrial fibrillation (2005-2025). Recurrence: documented atrial fibrillation after a 90-day blanking period.
RESULTS: Of 140 patients (mean age 29.1±3.1 years; 28.6% female), 104 with outcome analysis (paroxysmal 83.6%, persistent atrial fibrillation 16.4%; 18.6% with family history of atrial fibrillation). PVI: Radiofrequency 49.3%, Cryoballoon 45.7%, Pulsed-Field ablation 5%. Mean procedure duration 117 ± 66 min. Over a median follow-up of one year (IQR 0.25-1.74), 10 patients had recurrences. Freedom from atrial fibrillation was 93.6/ 88.2/ 82.1% at 1/ 2/ 3 years; 94.9% at one year after up to two procedures. Paroxysmal vs persistent atrial fibrillation showed better outcome: 98.5% vs. 67.7% at 1 year and 87.8% vs. 50.8% at 3 years (log-rank p<0.001). Three in-hospital complications (2.1%) occurred: one vascular complication requiring surgical repair; a pericarditis and a mild pulmonary-vein stenosis without need for intervention.
CONCLUSION: In adults below 30 years, catheter ablation for atrial fibrillation delivers high rhythm control with low complication rates. Benefit is lower in persistent than paroxysmal atrial fibrillation. Atrial fibrillation subtype is the strongest determinant which may argue for early referral to ablation as first-line rhythm control in young adults.

BACKGROUND: Implantable cardioverter defibrillators rely primarily on electrical signals to guide therapy. Hemodynamic sensing may provide complementary information about the immediate physiological consequences of arrhythmias.
OBJECTIVE: In this study, we evaluated the acute feasibility and performance of a 3-dimensional substernal shock lead that integrates hemodynamic sensing, electrical sensing, and ventricular pacing.
METHODS: This prospective first-in-human feasibility study enrolled 5 patients undergoing cardiac surgery or epicardial ventricular tachycardia (VT) ablation. A substernal shock lead was temporarily placed through a percutaneous subxiphoid approach using a dedicated delivery system. Lead placement and removal, adverse events, synchronized sensor signals, surface electrocardiograms, substernal electrograms, and pacing thresholds were assessed.
RESULTS: Lead placement and removal were successful in all patients without device- or procedure-related acute adverse events. Interpretable hemodynamic signals were obtained in all 5 patients and showed stable beat-to-beat temporal correspondence with the electrocardiogram and distinct rhythm-associated patterns across sinus rhythm, atrial fibrillation, VT, and ventricular fibrillation. All 147 VT episodes had interpretable hemodynamic-index recordings. The hemodynamic index decreased abruptly during VT and recovered after arrhythmia termination. Corresponding changes in the hemodynamic index were observed during transitions among VT, ventricular fibrillation, and sinus rhythm. Ventricular capture was achieved in all 5 patients at 11-17 V (mean, 13.8 V) at 0.5 ms.
CONCLUSION: Acute placement of this multifunctional substernal lead was feasible and enabled integrated hemodynamic and electrical sensing with acute ventricular capture. These findings provide preliminary human support for further development of physiology-guided extravascular implantable cardioverter defibrillator systems; chronic performance and clinical validation of the hemodynamic sensing algorithm require further study.

INTRODUCTION: Unlike most pulsed-field ablation (PFA) systems, Affera (Medtronic) delivers unipolar energy between a lattice-tip catheter and a cutaneous return patch, potentially generating a broader electric field. We hypothesized that this may attenuate voltage beyond ablated regions and tested this using spatially matched pre- and post-ablation maps.
METHODS AND RESULTS: We retrospectively studied five consecutive patients undergoing primary atrial fibrillation ablation with the Affera system. Pre- and immediate post-ablation voltage maps were generated using CARTO 3 and OCTARAY (Biosense Webster) with identical settings during right atrial pacing. Because Affera lacks point-level 3D coordinates for spatial matching, coordinates (x, y, z) and bipolar voltages were extracted from CARTO 3. Pre- and post-ablation points-outside energy delivery sites, excluding the annulus and left atrial appendage-were spatially matched using a 2 mm mutual nearest-neighbor criterion. This yielded 3772 pairs. Bipolar voltages were averaged by case. Mean bipolar voltage decreased in all cases from 1.01 ± 0.61 to 0.56 ± 0.29 mV, representing a 40.2% reduction (95% CI, 24.6%-55.8%; p = 0.044). In a distance-stratified analysis, residual bipolar voltage (post/pre × 100) was lowest just beyond the ablated zone and increased progressively with distance from the nearest application tag center (16.5% at 10-15 mm to 57.8% at 25-30 mm; all p < 0.001), becoming numerically comparable to baseline beyond approximately 30 mm.
CONCLUSIONS: Affera-based unipolar ablation produced acute bipolar voltage attenuation that extended into non-ablated myocardium adjacent to the lesion set but diminished with distance and was largely confined within approximately 30 mm of the application sites.

AIMS: Data on long-term durability of pulmonary vein isolation (PVI) with newer pulsed field ablation (PFA) platforms and incremental value of electroanatomic mapping (EAM) guidance remain limited. This study evaluated chronic PVI durability following ablation with a balloon-in-basket PFA catheter and compared outcomes of fluoroscopy-only vs. fluoroscopy plus EAM workflows.
METHODS AND RESULTS: In this prospective, single-centre trial, consecutive patients with paroxysmal or persistent atrial fibrillation (AF) underwent de novo PVI with a balloon-in-basket PFA catheter. Patients were randomized 1:1 to fluoroscopy-only or fluoroscopy plus EAM workflow. Systematic invasive remapping was planned >30 days after the index procedure. The dual primary efficacy endpoint was the proportion of pulmonary veins (PVs) and of patients with all PVs durably isolated. The prespecified secondary endpoint was the comparison of procedural characteristics and PVI durability between workflows. Safety outcomes included major adverse events within 30 days of index or remapping procedures. Ninety-six patients (67.4 ± 9.2 years, 44.8% female, 57.3% with paroxysmal AF) underwent index ablation. Fluoroscopy time and number of applications were 3.4 [2.4-4.6] minutes and 15 [13-16], respectively. Systematic remapping was performed in 86 patients at a median of 41 days, with per-vein and per-patient durability of 341/350 (97.4%), and 79/86 (91.9%) respectively. PVI durability and chronic remapping parameters were comparable between guidance strategies. No major adverse events occurred.
CONCLUSION: A standardized balloon-in-basket PFA workflow for PVI achieved high PVI durability. EAM guidance did not confer additional procedural or durability benefit over fluoroscopy-only guidance.

BACKGROUND: The benefit of additional left atrial posterior wall ablation (LAPWA), beyond pulmonary vein isolation (PVI), in persistent atrial fibrillation (PersAF) treatment remains controversial.
OBJECTIVE: We investigated whether signals recorded with a pentaspline pulsed field ablation (PFA) catheter can identify PersAF patients with rapid LAPW activity who may benefit from LAPWA. We additionally evaluated whether PFA-induced atrial fibrillation cycle length (AF-CL) prolongation predicts arrhythmia-free survival.
METHODS: In this multicenter observational study, consecutive PersAF patients undergoing first-time PVI plus-LAPWA with a pentaspline PFA catheter were included. AF-CL was measured using the FARS-10 method at three time points: baseline, post-PVI, and post-LAPWA, using distal CS signals. LAPW-CL was measured post-PVI from multiple LAPW positions. Any atrial tachyarrhythmia (ATA) lasting >30 seconds beyond the 2-month blanking period was recorded.
RESULTS: 270 patients were included. The overall 12-month ATA-free survival was 72.6%. "Fast LAPW activity" was defined as a LAPW-CL value shorter than the mean LAPW-CL of the entire cohort (191.4±2.4 msec; ≤ 190 msec). Fast LAPW activity was not associated with arrhythmia recurrence (HR 1.263, 95% CI: 0.739-2.160; p=0.393). In contrast, a greater CS-CL prolongation was independently associated with lower arrhythmia recurrence risk (HR 0.298, 95% CI: 0.017-0.520; p<0.001). A CS-CL increase >23.5% from baseline had a sensitivity of 0.65 and specificity of 0.72 for predicting ATA-free survival.
CONCLUSION: Post-PVI fast LAPW activity does not predict recurrence after LAPWA in PersAF patients. CS-CL prolongation >23.5% after LAPWA may serve as a useful real-time marker of effective substrate modification and arrhythmia control.

BACKGROUND: Long-term rhythm outcomes following cryoballoon ablation (CBA) in early persistent atrial fibrillation (AF) remain incompletely characterized.
OBJECTIVE: To evaluate 3-year atrial fibrillation (AF) burden trajectories, subsequent recurrence patterns detected by implantable loop recorder (ILR), and their association with healthcare resource utilization (HCRU).
METHODS: The COOL-PER trial was a prospective, multicenter, single-arm study that enrolled patients with early persistent AF (duration ≤ 3 years). An ILR was implanted 7-90 days before CBA for continuous rhythm monitoring.
RESULTS: Among 130 enrolled patients, 123 completed the 3-year follow-up (mean age, 60.5 ± 8.4 years; 25.2% women). Median AF burden decreased from 99.9% (interquartile range, 53.1-100.0) at baseline to 0.1% (0.0-4.2), 0.5% (0.0-9.1), and 0.7% (0.0-9.5) at 1, 2, and 3 years (all P < .001). Of 47 patients who were recurrence-free at 1 year, 25 (53.2%) developed subsequent recurrence, and 20 (80.0%) were detected by ILR alone. Compared with first-year recurrence, subsequent recurrence was less often persistent (4.0% vs 28.9%; P = .001) and was associated with a lower AF burden (0.1% [0.0-1.6] vs 2.8% [0.4-18.7]; P = .010). Both persistent-type recurrence and AF burden ≥ 10% were associated with more additional rhythm control interventions (78.3% vs 30.8% vs 0%; 78.6% vs 39.1% vs 0%; both P < .001) and cardiovascular hospitalization (17.4% vs 3.8% vs 0%, P = .045; 14.3% vs 4.3% vs 0%, P = .029).
CONCLUSION: CBA achieved durable AF burden suppression over 3 years in early persistent AF. Subsequent recurrence after the first year was common and was predominantly detectable by ILR only. Subsequent recurrences were often paroxysmal, with a lower AF burden and associated with lower HCRU, supporting the value of continuous long-term rhythm monitoring for characterizing rhythm status beyond the first post-ablation year.

BACKGROUND: Recurrence rates of atrial arrhythmias after catheter ablation in patients with congenital heart disease (CHD) remain substantial. Given the high prevalence of peritricuspid flutter, systematic cavotricuspid isthmus (CTI) ablation may represent a rational preventive strategy.
OBJECTIVES: The objective of this study was to assess the impact of empirical CTI ablation in CHD patients.
METHODS: This prospective nationwide study included all CHD patients referred for a first catheter ablation of an atrial arrhythmia between 2020 and 2024. Empirical ablation comprised probabilistic (noninducible arrhythmia with prior documentation) and prophylactic (no prior documentation) ablation. The primary endpoint was freedom from any atrial arrhythmia recurrence. Secondary endpoints included arrhythmia-related hospitalizations, redo ablations, and complications.
RESULTS: Among 575 patients undergoing a first catheter ablation for atrial arrhythmia, 345 (60.0%) had CTI-dependent flutter. The remaining 230 patients formed the study population (mean age: 48.2 ± 16.4 years; 50.9% male). CHD complexity was predominantly moderate (57.4%). Targeted arrhythmias were atrial macro-re-entry (53.0%), atrial fibrillation (47.0%), and focal atrial tachycardia (17.4%), with multiple arrhythmias in 16.5%. Empirical CTI ablation was performed in 71 patients (30.9%) and was associated with significantly higher freedom from any atrial arrhythmia at 1 year (78.1% vs 65.6%, P = 0.010) and 2 years (71.2% vs 56.1%, P = 0.025), remaining independently associated with lower risk of recurrence after multivariable adjustment (HR: 0.47, 95% CI: 0.24-0.92, P = 0.027). This benefit was primarily observed in patients without atrial fibrillation history (interaction P = 0.005). Arrhythmia-related hospitalization was also significantly reduced (14.1% vs 25.8%, P = 0.048).
CONCLUSIONS: Empirical CTI ablation is associated with improved freedom from atrial arrhythmia and reduced rehospitalization in CHD patients.

BACKGROUND: Functional substrate mapping identifies areas of decremental conduction, which are critical targets for ventricular tachycardia (VT) ablation. The evidence for this observation is derived from unblinded studies.
OBJECTIVES: In a blinded study, we evaluated the correlation between areas of decremental conduction unveiled with functional substrate mapping and VT critical sites identified using traditional substrate mapping.
METHODS: We studied consecutive patients with structural heart disease undergoing VT ablation whereby the operator simultaneously acquired 2 maps: a baseline substrate map (unblinded) simultaneous with a functional substrate map (blinded) using an extra-stimulus pacing protocol. Ablation was performed using conventional mapping techniques without access to functional mapping data. Postprocedure, blinded analyses evaluated the spatial concordance between decremental conduction areas and VT critical sites.
RESULTS: Among 33 patients who underwent the extra-stimulus protocol, 20 patients completed mapping and had inducible VT (mean age: 62 [IQR: 54-73] years; 55% ischemic cardiomyopathy [ICM]). Among 51 VTs with putative isthmi or breakthrough sites identified, these sites colocalized with decremental conduction regions in 78% and 73% using 10-milliseconds and 20-milliseconds cutoffs, respectively (P = 0.25). Although colocalization rate did not differ between thresholds, the 20-milliseconds decremental area was smaller (P < 0.01). Colocalization rate was higher in ICM compared with nonischemic cardiomyopathy (NICM) patients (93% vs 59%, P < 0.01 for 10-ms; 86% vs 55%, P = 0.03 for 20-ms).
CONCLUSIONS: In a blinded evaluation, areas of decremental conduction identified by functional substrate mapping showed a high degree of colocalization with VT critical sites, particularly in ICM patients. This relationship was less consistent in NICM patients.

BACKGROUND: Convergent hybrid ablation (HA) combines epicardial and endocardial approaches to achieve pulmonary vein isolation (PVI) and posterior wall isolation (PWI). Whether this strategy compromises left atrial (LA) mechanical function remains uncertain.
OBJECTIVE: To compare the effects of HA and endocardial-only catheter ablation (CA) on LA mechanical function.
METHODS: 50 patients with persistent atrial fibrillation (AF) were randomized (1:1) to PVI and PWI via HA or CA. Blinded speckle-tracking echocardiography was performed at baseline and 6 months. Primary mechanistic analyses were prespecified to include patients in sinus rhythm at follow-up (n = 42) to enable comparable assessment of rhythm-dependent atrial mechanics. The primary endpoint was the between-group difference in post-ablation LA reservoir strain (LASr, %), adjusted for baseline values. Secondary endpoints included LA ejection fraction (LAEF, %) and LA volume index (LAVi, mL/m2). Between-group comparisons used baseline-adjusted analysis of covariance with supporting linear mixed-effects models.
RESULTS: Baseline characteristics were balanced (mean age: 69 ± 7.5 years; median AF duration: 26 months). At baseline, all patients were in AF with impaired LA function (LASr: 8.6 ± 3.8%, LAEF: 22.9% ± 7.5%, and LAVi: 50.7 ± 10.0 mL/m2; P > .05 between groups). At follow-up, 84% were in sinus rhythm (HA: 88%, CA: 80%; P = .70). LASr, LAEF, and LAVi significantly improved in both groups (all P < .001). No significant between-group differences were detected after baseline adjustment.
CONCLUSION: Among patients in sinus rhythm at follow-up, both HA and CA were associated with favorable LA remodeling. No signal of adverse LA remodeling or impaired LA mechanical recovery was observed with HA compared with CA, despite its dual epicardial-endocardial approach.

BACKGROUND: Atrial fibrillation/flutter (AF/AFL) are increasingly seen in reproductive-aged adults, yet AF/AFL guidelines are largely based on older populations. Sex differences in this age group remain poorly defined. In this study, we examined sex-based disparities in the presentation, management, and outcomes among reproductive-aged adults with AF/AFL.
METHODS: Using the Get With The Guidelines-Atrial Fibrillation national registry, we included adults (18-50 years) with AF/AFL who were prospectively enrolled from May 2013 to March 2024. The primary exposure was sex and primary outcomes included anticoagulant prescription and rhythm control strategies (cardioversion, AF ablation, or antiarrhythmic therapy). Multivariable logistic regression estimated associations between sex and outcomes, adjusting for covariates including age, race and ethnicity, insurance, and anemia.
RESULTS: Among 14 301 patients with mean age 42.3 ± 7.3 years, women were more symptomatic and had more paroxysmal AF (57.7% vs. 49.9%, p < 0.001), while men had more persistent AF (19.9% vs. 11.6%, p < 0.001). CHA2DS2VASc scores were significantly higher in women (2.3 ± 1.2 vs. 1.4 ± 1.2 in men, p < 0.001). Despite similar use of antiarrhythmic drugs and anticoagulation, women were 9%-15% less likely to receive rhythm-control therapies overall (adjusted OR 0.91, 95% CI 0.83-0.99), driven by differences in AF ablation and cardioversion. For both sexes, the proportion of patients undergoing ablation increased while those undergoing cardioversion decreased significantly over time (all p < 0.001). Women undergoing AF ablation experienced more complications (3.7% vs. 1.9%, p = 0.01) and were more likely to have relative or absolute contraindications to anticoagulation (9.0% vs. 7.2%, p < 0.001).
CONCLUSIONS: In a large US registry, reproductive-aged women with AF/AFL were less likely to receive rhythm-control interventions, experienced more ablation complications, and had more anticoagulation contraindications. These findings highlight persistent sex-based disparities in the management and outcomes of young adults with AF/AFL, underscoring the need for targeted, sex-specific approaches to improve treatment inequities.

BACKGROUND: The arrhythmogenesis in cardiac sarcoidosis (CS) is poorly understood. The recent ability to register fluorodeoxyglucose (FDG)-avid (FDG+) areas from positron emission tomography studies enables us to correlate the location of areas containing late gadolinium enhancement (LGE+) on cardiac magnetic resonance imaging with FDG-avid areas.
OBJECTIVES: This study sought to characterize ventricular tachycardia (VT) target sites with respect to FDG uptake and to correlate with VT recurrence post-VT ablation.
METHODS: In 14 patients (4 women; age 55 ± 11 years; ejection fraction 43% ± 14%) with definite CS and active inflammation referred for VT ablation, positron emission tomography and cardiac magnetic resonance findings were registered to electroanatomic maps. VT target areas were identified with pace- and entrainment-mapping, and conduction patterns were assessed based on different stimulus-QRS intervals of VA target sites.
RESULTS: A total of 43 distinct VTs with 59 VT target sites were identified. A total of 88% of the identified VT target sites were in LGE+ areas, whereas 71% were in FDG+ areas. The LGE+ and FDG+ sites colocalized at 59% of all VT target sites. VT exit sites were identified for 42 of 59 VT target sites and nonexit sites for 17 of 59 VT target sites. VT exit sites were associated with FDG+ areas. During a follow-up time of 32 ± 33 months, 6 patients in whom only VT exit sites were identified had a higher VT recurrence rate than patients (n = 8) in whom both nonexit sites and exit sites for individual VTs were identified (100% vs 25%; P = 0.01), indicating that ablation at both exit and nonexit sites yielded superior results.
CONCLUSIONS: In patients with CS and active inflammation, most VT target sites were confined to LGE+ and FDG+ areas. VT exit sites were associated with FDG+ areas. Patients in whom only VT exit sites were identified had higher VT recurrences.

BACKGROUND: Optimal ablation strategies of pulsed field ablation (PFA) in persistent atrial fibrillation (PerAF) remain under investigation.
OBJECTIVE: This study aimed to explore an innovative electrogram (EGM)-guided PFA approach for PerAF ablation.
METHODS: This prospective cohort study used CARTO 3-dimensional mapping combined with the Farawave catheter for ablation. 85 patients with PerAF who underwent EGM-guided PFA (pulmonary vein isolation, posterior wall isolation [PWI], and target EGM ablation) were enrolled (EGM group). Another cohort of 85 patients treated with anatomic pulmonary vein isolation plus PWI using the same PFA system was also included as the control group (PWI group). The procedure end point was atrial fibrillation (AF) termination or complete ablation of all target sites. The primary efficacy end point was freedom from AF/atrial tachycardia (AT) recurrence at 12 months after a single procedure, off antiarrhythmic drugs. Safety outcomes included PFA-related adverse events.
RESULTS: 72 patients (84.7%) in the EGM group experienced intraprocedural AF termination, which was significantly higher than the PWI group (10 of 85; 11.8%; P < .001). At 12 months, the primary efficacy outcome (AF-/AT-free survival) was achieved in 82.4% of patients (70 of 85) in the EGM group vs 65.9% (56 of 85) in the PWI group (log-rank P = .017; hazard ratio .47; 95% confidence interval 0.25-0.87). Patients who reached procedural AF termination had a higher rate of AF-/AT-free survival of 84.1% than 64.8% of non-AF termination (log-rank P = .007; hazard ratio 0.40; 95% confidence interval 0.21-0.77). The primary safety end point occurred in 1 patient (1.2%) with hemolysis in the EGM group. No other PFA-related adverse event was observed.
CONCLUSION: In this single-center, nonrandomized comparative cohort study, EGM-guided PFA demonstrated preliminary efficacy and safety in PerAF ablation, suggesting promising prospects as an innovative strategy for PerAF ablation. (ClinicalTrials, NCT06729866, EGM Guided PFA for PerAF).

BACKGROUND: Hemolysis is a recognized side effect of pulsed field ablation (PFA). Severe hemolysis can lead to acute kidney injury, affecting the morbidity of patients undergoing PFA for atrial fibrillation. Here, we aimed to characterize the degree of hemolysis across different PFA technologies.
METHODS: This is a retrospective cohort study of 552 PFA procedures performed in our center, where Hp (haptoglobin) was measured both at baseline and on postoperative day 1. The PFA catheters used were Farawave (59%), Sphere-9 (19%), Pulseselect (16%), and Varipulse (5.8%).
RESULTS: Hemolysis (ie, reduction in Hp >10 mg/dL) was observed in the majority of cases (95%), with the lowest incidence observed in patients undergoing PFA with Sphere-9 (88%) compared with Farawave (97%), Varipulse (97%), and Pulseselect (100%). Significant and severe hemolysis (ie, Hp-postoperative day 1 ≤25 mg/mL and Hp-postoperative day 1 ≤10 mg/mL) occurred in 34% and 13%, with a different distribution across catheter types: Farawave 46% and 21%, Varipulse 29% and 9.7%, Pulseselect 23% and 1.2%, and Sphere-9 5.5% and 0%. Hp decreased by a mean of 76±40 mg/dL from baseline, with a significantly greater degree of reduction seen with Farawave (94±40 mg/dL) and Varipulse (85±32 mg/dL) compared with Pulseselect (62±25 mg/dL) or Sphere-9 (39±23 mg/dL). There is a linear relationship between Hp reduction and number of PFA applications, with a decrease of Hp per application of 0.47 mg/dL (95% CI, 0.22-0.71 mg/dL) for Farawave, 0.40 mg/dL (95% CI, 0.09-0.73 mg/dL) for Pulseselect, and 0.10 mg/dL (95% CI, 0.02-0.19 mg/dL) for Sphere-9.
CONCLUSIONS: PFA-induced hemolysis is common, with different PFA technologies exhibiting variable degrees of hemolysis, lower with the focal PFA catheter Sphere-9 when compared with single-shot PFA catheters.

BACKGROUND: The formation of transmural lesions is necessary for the ablation of persistent atrial fibrillation (prAF). Ablation index (AI) and generator impedance drop (ID) predict lesion size but their correlation with long-term outcomes in prAF is not known. Furthermore, we proposed a new parameter, efficacy ratio (ER) calculated as ID/AI, to gain indirect insight into the role of factors affecting ID but not considered by AI.
METHODS: We included ablations performed during the DECAAF II trial if they had uploaded lesion-by-lesion summary data and were performed with radiofrequency catheters on the CARTO system. Average patient-level parameters were calculated from all generated Vizitags.
RESULTS: A total of 427 ablations met inclusion criteria and 166 utilized AI. Analyzed as continuous variables, ID and ER predicted long-term arrhythmia-free survival but not AI. The ideal cut-off for ID was ID ≥ 10.4 ohms and had a C-index of 0.55. It predicted reduced risk of arrhythmia: hazard ratio 0.56 [0.36-0.88], p = .013 (arrhythmia-free survival of 67% vs. 52%). Similarly, an ER of 1.7 ohms/100AI had a C-index of 0.58 and predicted reduced arrhythmia recurrence: HR 0.39 [0.22-0.69], p = .001. ER < 1.7 ohms/100AI was related to just 32% arrhythmia-free survival. ER improved prognostication as compared to ID alone and identified a subset of low ID patients with even worse outcomes.
CONCLUSION: Average ID was predictive of improved outcomes following ablation of prAF. The ratio of ID/AI (ER) was postulated as a measure to summarize the overall impact of factors not considered in the AI formula and provided improved prognostication.

BACKGROUND: Recurrent ventricular tachycardia (VT) can be treated by substrate modification of the myocardial scar by catheter ablation during sinus rhythm without VT induction. Better defining this arrhythmic substrate could help improve outcome and reduce ablation burden.
OBJECTIVE: The study aimed to limit ablation within postinfarction scar to conduction channels within the scar to reduce VT recurrence.
METHODS: Patients undergoing catheter ablation for recurrent implantable cardioverter-defibrillator therapy for postinfarction VT were recruited at 5 centers. Left ventricular maps were collected on CARTO using a Pentaray catheter. Ripple mapping was used to categorize infarct scar potentials (SPs) by timing. Earliest SPs were ablated sequentially until there was loss of the terminal SPs without their direct ablation. The primary outcome measure was sustained VT episodes as documented by device interrogations at 1 year, which was compared with VT episodes in the year before ablation.
RESULTS: The study recruited 50 patients (mean left ventricular ejection fraction, 33% ± 9%), and 37 patients (74%) met the channel ablation end point with successful loss of latest SPs without direct ablation. There were 16 recurrences during 1-year follow-up. There was a 90% reduction in VT burden from 30.2 ± 53.9 to 3.1 ± 7.5 (P < .01) per patient, with a concomitant 88% reduction in appropriate shocks from 2.1 ± 2.7 to 0.2 ± 0.9 (P < .01). There were 8 deaths during follow-up. Those who met the channel ablation end point had no significant difference in mortality, recurrence, or VT burden but had a significantly lower ablation burden of 25.7 ± 4.2 minutes vs 39.9 ± 6.1 minutes (P = .001).
CONCLUSION: Scar channel ablation is feasible by ripple mapping and can be an alternative to more extensive substrate modification techniques.

BACKGROUND: The dual-energy lattice-tip catheter delivering radiofrequency (RF) or pulsed field ablation (PFA) has experienced rapid uptake in atrial fibrillation (AF) ablation, with potential trade-offs between efficiency and cost. Real-world data on clinical, operational, and economic impact remain limited.
OBJECTIVE: To report a real-world, single-center experience with the Sphere-9 catheter for AF ablation, focusing on clinical, practice management, and financial outcomes.
METHODS: Consecutive patients undergoing AF ablation were prospectively enrolled between December 2024 and January 2026. Procedural characteristics, acute outcomes, safety events, discharge status, and early follow-up were analyzed. Procedural volume, efficiency, and supply-related costs and charges were compared with a pre-implementation cohort.
RESULTS: A total of 985 patients underwent 1008 procedures (53.3% paroxysmal; 66.5% first ablation). Pulmonary vein isolation was achieved in all cases, with adjunctive lesion sets performed as indicated. Acute safety events occurred in 2.4%, including coronary vasospasm (n = 1), ventricular fibrillation during mitral PFA (n = 1), persistent atrioventricular block (n = 2), and device-related complications (n = 3). There were no deaths, strokes, tamponades, atrio-esophageal fistulas, or phrenic nerve injuries. Same-day discharge was achieved in 83.5%. Compared with pre-implementation, annual AF ablation volume increased by 26.8%, and median procedure time decreased (69 vs 116 minutes; P < .001). Supply costs and charges increased by 37% and 43%, respectively (P < .001).
CONCLUSION: AF ablation with the Sphere-9 catheter was associated with improved procedural efficiency, low complication rates, high same-day discharge, and favorable early effectiveness. These gains were offset by substantial increases in supply costs.

BACKGROUND: Pulsed field ablation (PFA) induces cell death predominantly through irreversible electroporation (IRE), a non-thermal mechanism. However, Joule heating during PFA delivery may result in clinically relevant temperature rises.
OBJECTIVES: This study aimed to characterize the thermal profiles, peak surface temperatures, and ablation lesions produced by 6 proprietary PFA catheters using an ex vivo vegetal model.
METHODS: The thermal profile of 6 PFA catheters-Farawave, PulseSelect, Volt, Varipulse, Electropulse, and Sphere-9-was evaluated in Solanum Tuberosum at recommended energy settings. Thermal imaging was performed using a high-resolution infrared camera. Standard PFA applications were delivered in 5 independent runs for each catheter. Post-ablation, specimens were stained with 0.5% triphenyl tetrazolium chloride (TTC) to delineate IRE and reversible electroporation (RE).
RESULTS: All systems demonstrated reproducible and distinct thermal signatures. Mean peak temperature rises were as follows: Varipulse low irrigation flow (4 mL/minute), 15.1°C ± 1°C; Farawave basket, 13.6°C ± 0.6°C; Farawave flower, 9.7°C ±0.4°C; Varipulse high irrigation flow (30 mL/minute), 8.5°C±0.5°C; PulseSelect, 4.1°C ± 0.6°C; Electropulse, 2.7°C ±0.7°C; Sphere-9, 2.1°C ±1.2°C; and Volt, 1.3°C ± 0.2°C (Kruskal-Wallis, P < .0001). PFA catheters demonstrated either localized or distributed thermal hotspot patterns. Localized hotspot catheters confined heating within 1 mm of the electrode margin, whereas distributed hotspot catheters exhibited additional peripheral hotspots beyond 5 mm, as observed with the Farawave catheter. All catheters produced well-demarcated TTC-unstained IRE lesions surrounded by a rim of TTC-stained RE tissue.
CONCLUSION: PFA systems exhibit distinct thermal signatures and can be categorized as low (0°C-6°C), moderate (6°C-12°C), or high (12°C-18°C°C) heating profile catheters.

BACKGROUND: Pulsed field ablation (PFA) of atrial fibrillation has been rapidly adopted, partly because of safety expectations compared with thermal ablation. Comparative safety data between the 2 modalities remain limited.
METHODS: We conducted a prospective registry analyzing consecutive atrial fibrillation ablations at a high-volume US academic center between 2022 and 2026. The primary end point was stroke or transient ischemic attack (TIA) within 30 days, independently adjudicated by blinded neurologists. Secondary end points included death and other procedural complications. Propensity score methods with inverse probability of treatment weighting were used to balance differences in patient characteristics. Differences in the procedural workflow of PFA versus radiofrequency ablation (RFA) were evaluated with exploratory mediation analyses.
RESULTS: A total of 4221 ablation procedures (2077 RFA and 2144 PFA: 68.7% Farawave, 23.3% Sphere 9, 6.9% Varipulse, 0.7% PulseSelect) was performed by 12 operators. Patients receiving PFA and RFA had similar baseline characteristics (mean age, 67 years; 31% female; 47% persistent atrial fibrillation; 7% previous stroke/TIA), which were balanced after inverse probability of treatment weighting. Compared with RFA, PFA procedures were shorter (108 versus 144 minutes) and included more frequent posterior wall isolation (57% versus 31%). The 30-day rate of stroke/TIA was significantly higher for PFA cases (10 events; 0.47%) compared with RFA (2 events; 0.10%) in both unweighted and propensity score-weighted analyses (weighted risk difference, 0.36% [95% CI, 0.03%-0.70%]; P=0.03). Stroke/TIA events were evenly distributed throughout the study period with no clustering around the time of PFA adoption or operators (with no operator associated with ≥2 events). Exploratory mediation models were limited by the low event rates and did not identify more extensive ablation as an independent risk factor for stroke. Weighted rates of other procedural complications were low (<1%) and similar between PFA and RFA groups.
CONCLUSIONS: In a high-volume, single-center registry with high clinical granularity and systematic patient follow-up, PFA was associated with a significantly higher risk of stroke/TIA at 30 days compared with RFA. These results call for enhanced postmarket surveillance and dedicated prospective evaluation as the PFA procedural volume continues to exponentially increase.

BACKGROUND: Catheter ablation of ventricular arrhythmias (VAs) with conventional small-tip radiofrequency ablation (RFA) catheters is limited by inadequate lesion size and small footprint design.
OBJECTIVES: This early U.S. experience investigated procedural and clinical outcomes of VA ablation with a lattice-tip wide footprint catheter that allows toggling between RFA and pulsed field ablation (PFA).
METHODS: The Cleveland Clinic VT (CLEAR-VT) Registry is a prospectively maintained registry of consecutive patients undergoing catheter ablation of VAs. Patients undergoing catheter ablation of VA with an RFA/PFA lattice-tip catheter (Sphere-9; Medtronic) between January and September 2025 were analyzed.
RESULTS: A total of 59 patients (median age 70 years; mean left ventricular ejection fraction 36.3% ± 12.3%) underwent ablation of VA using the lattice-tip catheter during the study period. Of these, 50 (85%) had scar-related ventricular tachycardia (VT) (28 with ischemic, 19 with nonischemic, and 3 with mixed cardiomyopathy), and 9 (15%) had frequent premature ventricular contractions (PVCs). Acute procedural success, defined as non-inducibility of any VT (excluding nonclinical VTs with cycle length ≤240 milliseconds) or complete PVC suppression, was achieved in 78% and 100% of patients, respectively. After a median follow-up of 100 days (Q1-Q3: 51-172 days), VT recurred in 9 patients (18%), and death/heart transplantation/left ventricular assist device implantation occurred in 6 patients (12%). At 6 months, the Kaplan-Meier-estimated VT-free survival was 69.8% (95% CI: 54.0%-90.3%); the Fine-Gray cumulative incidence of VT recurrence, accounting for competing risks, was 28.4% (95% CI: 11.0%-45.8%). No patient with PVCs had recurrence after a median follow-up of 54 days (Q1-Q3: 40-71 days). Three major procedure-related complications occurred, including 2 major bleeding events and 1 implantable cardioverter-defibrillator system failure after PFA application approximately 7.5 mm from the tip of a left ventricular pacing lead (which required intra-operative device generator change).
CONCLUSIONS: In this first U.S. series, catheter ablation of VAs with a lattice-tip RFA/PFA catheter appeared effective and generally safe. Caution should be exercised when applying PFA in proximity to exposed conductors of implantable cardiac devices.

BACKGROUND: Achieving a durable mitral line block using radiofrequency as a part of an anatomical approach for ablation in patients with persistent atrial fibrillation or for treating peri-mitral flutter has always been challenging due to the complex anatomy of the mitral isthmus. Epicardial ablation via the coronary sinus and the vein of Marshall has been proposed to help create durable lesions. Recently, a novel lattice-tip catheter using pulsed field ablation has shown promising results for creating mitral lines, despite limited data.
METHODS AND RESULTS: We present a case demonstrating the recovery of connection through the mitral isthmus after a waiting period, despite initial clear isolation achieved by creating an endocardial linear lesion. This necessitated further epicardial lesions, performed via ethanol infusion into the vein of Marshall, due to the presence of a coronary sinus CRT lead in this patient.
CONCLUSION: Despite the high rates of acute mitral line block with PFA the rate of recurrence might be significant. Considering its novelty, our experience with point-by-point PFA is more limited. The present case report highlights the risk of delayed reconnection treated with EI-VOM. Further studies are warranted to explore additional outcomes and recurrence patterns among these patients.

BACKGROUND: High-density three-dimensional (3D) mapping in the Triangle of Koch during sinus rhythm (SR) has demonstrated low amplitude, late activating, multi-component signals suggestive of the AV nodal (AVN) right inferior extension (RIE). Ablation at the site of these signals has been successful for the treatment of typical AV nodal reentrant tachycardia (AVNRT). The leftward inferior extension (LIE) of the AVN has been proposed as a participatory limb in AVNRT and described in the inferoseptal region of the left atrium (LA). We present the use of Ripple mapping of the LA in sinus rhythm to identify low amplitude, late-activating multi-component atrial electrograms similar to those seen at the RIE.
METHODS AND RESULTS: Patients undergoing first-time ablation for paroxysmal atrial fibrillation at one institution over a 1-year period were included. High-density mapping of the entire LA was performed in SR using multi-spline mapping catheter & CARTO-3 (Biosense Webster Inc.). Left atrial activation was recorded and displayed using CARTO Ripple mapping, and local electrograms manually reviewed in areas with delayed and multi-component activation. Thirty-two patients underwent LA mapping; in 26 patients, low amplitude, late activating, multi-component electrograms were recorded in the inferoseptal region with discrete, late far-field signal similar in profile to previously described RIE slow pathway potential. Of the six remaining cases, the annotated LA activation was posterolateral in five and in the superior septum in one case. The mapping technique was also utilized in a case of "slow/fast" typical AVNRT in which ablation at the typical slow pathway site in the Triangle of Koch and within the coronary sinus did not elicit junctional response and tachycardia remained inducible. Mapping the LA septum in SR was performed. Ablation at the inferoseptal site with late-activating, multi-component electrogram resulted in junctional beats with non-inducibility of tachycardia without recurrence through 31 months post-procedure.
CONCLUSION: Using high-density 3D mapping in SR, multi-component far-field electrograms can be identified at sites of late LA activation. In one case of AVNRT requiring LA ablation, ablation at this site was successful. Further study may provide additional information regarding the relationship of these signals and the LIE of the AVN.

BACKGROUND: Pulsed field ablation (PFA) for atrial fibrillation (AF) has entered practice with a favorable safety profile from pivotal trials, but real-world post-market signals remain incompletely characterized.
OBJECTIVE: To analyze adverse events associated with 4 Food and Drug Administration-approved PFA systems using the Manufacturer and User Facility Device Experience (MAUDE) database.
METHODS: We queried MAUDE for reports involving PulseSelect, FARAPULSE, VARIPULSE, and Affera Sphere-9 from each device's approval date through May 29, 2026. Duplicates were removed by report number and narrative fingerprint. Deaths were counted using Event-Type and natural language processing (NLP) analysis. Proportional reporting ratio (PRR), corroborated by the reporting odds ratio, was used with Evans criteria.
RESULTS: After de-duplication, 7177 unique reports were identified: FARAPULSE (4541), PulseSelect (1687), Affera Sphere-9 (630), and VARIPULSE (319). Event-Type recorded 180 deaths; NLP adjudication identified 191 (κ = 0.96). Leading clinical events were pericardial effusion (14.8%), hypotension (14.1%), stroke or cerebrovascular accident (10.9%), and cardiac tamponade (9.0%). The most frequent device problem was FARAWAVE basket-catheter entrapment (1026 FARAPULSE reports). Brand-specific signals included FARAPULSE for acute kidney injury (PRR, 11.70), hemolysis (PRR, 6.59), and coronary occlusion or myocardial infarction (PRR, 4.25); VARIPULSE for stroke or cerebrovascular accident (PRR, 8.72), transient ischemic attack (PRR, 6.45), and cardiac tamponade (PRR, 3.06); Affera Sphere-9 for ventricular arrhythmia (PRR, 8.10), vascular-access complication (PRR, 7.89), and bradyarrhythmia (PRR, 3.03). PulseSelect generated no signal.
CONCLUSION: Real-world MAUDE reports identify clinically meaningful, brand-specific signals despite PFA's favorable overall safety profile: VARIPULSE with cerebrovascular predominance, FARAPULSE with hemolysis-acute kidney injury and basket entrapment, Affera Sphere-9 with ventricular and bradyarrhythmic events, and PulseSelect with device-integrity issues. NLP narrative review identified additional under-coded deaths, warranting continued vigilance and prospective registry confirmation.

BACKGROUND: Recent studies have identified diagonal conduction block lines at the electrophysiologically defined superior vena cava (SVC)-right atrium (RA) junction using three-dimensional mapping systems and reported the utility of SVCI using these lines. However, these block lines are not always observed, requiring the use of a conventional horizontal isolation approach.
OBJECTIVE: This study aimed to visualize the electrophysiologically defined SVC-RA junction using high-resolution mapping with atrial extrastimulus pacing.
METHODS: Twenty-five patients underwent high-resolution mapping during sinus rhythm (Sinus map) and extrastimulus pacing (S2 map) using a three-dimensional mapping system (CARTO 3, version 8). Slow conduction or conduction block along the SVC-RA junction was assessed by adjusting the lower threshold cut-off value in the "early meets late" analysis. The length of slow or conduction block lines was compared between the two maps.
RESULTS: The S2 map revealed significantly longer slow or conduction block lines compared to the Sinus map (52.5 ± 18.0 mm vs. 35.6 ± 16.1 mm, p = 0.0013). The adjusted lower threshold values were comparable between the two maps: 26.4 ± 3.7% for the S2 map and 25.2 ± 3.8% for the Sinus map (p = 0.2819). In the S2 map, a slow or block line covering more than half of the junction was observed in all patients. Furthermore, the sinus node was consistently located inferior to this line.
CONCLUSION: High-resolution mapping with atrial extrastimulus pacing more clearly visualizes the SVC-RA junction, potentially enabling more effective SVCI and estimation of the sinus node location.

BACKGROUND: The GANGLIA-AF trial showed that ectopy-triggering ganglionated plexus (ET-GP) ablation alone, without pulmonary vein isolation (PVI), can prevent paroxysmal atrial fibrillation (AF) with similar success rates to PVI alone. However, it is not known whether ET-GP mapping and ablation are feasible in persistent AF.
OBJECTIVE: This study aimed to perform mapping and ablation of left atrial ET-GP in patients with persistent AF and assess 1-year freedom from ≥30-second AF/atrial tachycardia (AT).
METHODS: Patients with persistent AF, undergoing ablation, were pretreated with amiodarone. Three-dimensional geometry (CARTO/Precision) was collected in sinus rhythm after cardioversion. ET-GPs were mapped by delivering endocardial high-frequency stimulation within the atrial refractory period and ablated until they became nonfunctional. If triggered AF became incessant, atrioventricular-dissociating GPs (AVD-GPs) were ablated. No PVI was performed. Patients were followed up for 1 year to assess the recurrence of AF/AT.
RESULTS: Forty-nine patients completed GP ablation (64 ± 9 years; 76% male; left atrial diameter 46 ± 8 mm; AF duration 3.4 ± 2.5 years; continuous AF lasting ≥12 months 41%). High-frequency stimulation was performed at a mean of 110 ± 20 sites, identifying 15 ± 9 GPs/patient (ET-GP only 12/49 [25%]; combination 31/49 [63%]; AVD-GP only 6/49 [12%]). ET-GP only ablation (12 ± 8 ET-GP) had higher freedom from persistent AF recurrence (11/12 [92%]) than combination ET/AVD-GP ablation (17 ± 9 GP; 13/31 [42%]) or AVD-GP only ablation (4 ± 0 AVD-GP; 1/6 [17%]) (P = .005). One-year freedom from ≥30-second AF/AT was 16 of 49 (33%), and freedom from persistent AF was 25 of 49 (51%) for the whole cohort.
CONCLUSION: ET-GP mapping and ablation, as a solo ablation strategy, are feasible in persistent AF and can prevent AF recurrence at 1 year.

BACKGROUND: Stereotactic arrhythmia radioablation (STAR) has been proposed to treat refractory ventricular tachycardia (VT) in patients with structural heart disease (SHD).
OBJECTIVES: The aim of the STAR-VT-2020 (Stereotactic Ablative Radiosurgery of Recurrent Ventricular Tachycardia in Structural Heart Disease) randomized trial was to compare the efficacy of STAR and catheter ablation (CA) after a failure of previous CA.
METHODS: Patients with VT recurrences were randomized at 2 centers (June 2020 to January 2024) to the STAR or CA group in a 1:1 fashion using a covariate-adaptive algorithm. In the STAR group, the arrhythmogenic substrate was irradiated by a single dose of 25 Gy delivered by a robotic system (CyberKnife). The planning target volume was delineated by coregistering the electroanatomical substrate map (CARTO 3) with the planning computed tomographic scan. In the CA group, CA was performed using substrate modification strategies. The primary endpoint was VT recurrence, while repeated CA was one of the secondary endpoints.
RESULTS: A total of 22 patients (68% men, mean age 67 ± 11 years, 27% with ischemic cardiomyopathy, mean left ventricular ejection fraction 31% ± 9%, 3.0 ± 1.3 previous CAs) were enrolled (11 in each group) and followed for 28 ± 17 months. The STAR patients exhibited a nonsignificantly higher risk for VT recurrence (HR: 2.5; 95% CI: 0.97-6.6) than those who underwent CA, and a significantly higher risk of repeated CA for VT (HR: 4.0; 95% CI: 1.2-13.8). Throughout the trial, 13 patients died, 3 underwent heart transplantation, and 3 received left ventricular assist devices, with no significant differences between the 2 groups.
CONCLUSIONS: The STAR-VT-2020 trial suggests a potential clinical benefit of repeated CA over STAR in patients with SHD, despite prior failed CA at specialized centers. Because of the small study cohort of highly selected patients and several methodological limitations, the results of the prematurely terminated trial should be considered exploratory and interpreted strictly as hypothesis generating. Larger trials with optimized design are warranted. (Stereotactic Ablative Radiosurgery of Recurrent Ventricular Tachycardia in Structural Heart Disease; NCT04612140).

INTRODUCTION: Sphere-9 is a lattice tip ablation catheter (Medtronic, USA) capable of delivering both pulsed field and radiofrequency ablation. It is approved for the treatment of atrial fibrillation. Adverse events related to this device have been reported to national databases. A systematic assessment of these reports is needed to understand the nature of device-related complications.
METHODS: We queried the FDA Manufacturer and User Facility Device Experience (MAUDE) database between October 24, 2024 and October 24, 2025 to identify reports related to the Sphere-9 catheter. A total of 222 reports were included in the final analysis.
RESULTS: Of 222 reports, 148 (67%) resulted in clinical events. Of these, 107 were suspected to be related to the Sphere-9, including: VT/VF during/following energy delivery (n = 30), Stroke/TIA (n = 25), sinus node dysfunction/AV block (n = 23), pericardial effusion (n = 7), coronary spasm (n = 9), and phrenic nerve injury (n = 2). Catheter/defibrillator (ICD) related interactions were suspected in 10 of the VT/VF reports. There were 65 catheter related reports that did not appear to be associated with adverse clinical events, which included tissue/char formation on the catheter tip (n = 24), steam pop (n = 25), and mechanical entrapment (n = 7).
CONCLUSION: This early analysis of adverse events reported for the Sphere-9 catheter highlights complications including arrhythmias, such as VT/VF and AV block, and the risks associated with ICD-catheter related interactions.

BACKGROUND: Pulsed-field ablation (PFA) is a novel ablation energy source, which leads to selective and irreversible electroporation of cardiomyocytes with no collateral damage to adjacent tissues. The presence of mechanical prosthetic valves may pose some issues related to catheter manipulation and risk of electromagnetic interference.
OBJECTIVES: The purpose of this study was to assess the feasibility of PFA in patients with mechanical prosthetic valves.
METHODS: The authors enrolled 30 consecutive patients (age 64.7 ± 11.4 years; 43% men) with mitral and/or aortic valve replacement with mechanical substitutes undergoing endocardial AF ablation via a PFA technology at 6 institutions.
RESULTS: Time between valve surgery and ablation was 6.6 ± 6.5 years; 14 (46.7%) patients had an aortic mechanical valve, 10 (33.3%) a mitral, and 6 (20.0%) both. The following PFA technologies were used: FARAWAVE in 25 patients, Sphere-9 in 2, PulseSelect in 2, and the CENTAURI System in 1. No periprocedural and 1-month postablation major and minor complications were observed. Postprocedural transthoracic echocardiography did not identify any prosthetic valve dysfunction. One patient showed electromagnetic interference of the PFA catheter adjacent to the mitral prosthesis without clinical implications. No energy delivery to the mitral edge of the isthmus was possible despite multiple attempts to reposition the catheter. Mean procedural time was 77.5 ± 29.9 minutes, whereas mean left atrial dwell and fluoroscopy times were 43.1 ± 21.4 and 14.0 ± 6.4 minutes, respectively.
CONCLUSIONS: PFA in patients with mechanical valves appears safe, but careful catheter handling is essential to avoid electromagnetic interference hindering PFA delivery.

BACKGROUND: New-onset migraine or exacerbation of pre-existent migraine has been reported following catheter ablation for atrial fibrillation (AF). We assessed the incidence of migraine following pulsed-field ablation (PFA).
METHODS: Consecutive AF patients undergoing PFA using either Farawave or Pulse Select or Sphere 9 catheter systems were included in this multicenter study and prospectively followed up for new migraine or an increase in the severity of the pre-existent headache. Migraine was labeled as "new onset" if the condition was diagnosed for the first time after the index ablation without any previous history, recent or remote. Anti-arrhythmic drugs and oral anticoagulation were prescribed for 2 months after the procedure.
RESULTS: A total of 2148 AF patients undergoing PFA procedures (Farawave: 1477; Pulse Select: 369; and Sphere 9: 392) at the participating centers were included in the analysis. A history of migraine was present in 32 (1.48%) patients, of which 6(18.75%) reported an increase in frequency of migraine in the immediate post-ablation period. New-onset migraine was diagnosed in 31 (1.4%) post-PFA patients. Of these 31 patients, 25 (80.6%) underwent PFA using the Farapulse system, Sphere 9 in 5 (16.12%), and Pulse Select in 1 (3.22%) patient. The incidence of new-onset migraine was comparable between different systems; 1.69% (95% CI 1.10%-2.49%), 1.65% (95% CI 0.54%-3.82%), and 0.27% (95% CI 0.01%-1.50%) for Farapulse, Sphere 9, and Pulse Select, respectively. Mean duration of onset was 3.08 ± 0.67 days post-procedure. In the multivariable regression analysis, BMI was found to be the only predictor of new-onset migraine (OR = 1.402; 95% CI 1.002-1.987; p-value = 0.031).
CONCLUSION: New-onset migraine was observed to be uncommon in patients undergoing PFA. Although the incidence rate was comparable among the three platforms analyzed, the Farawave system showed a higher trend. Of note, BMI was an independent predictor of new migraine.

BACKGROUND: Safety data of the latest radiofrequency (RF) technologies during atrial fibrillation (AF) ablation in real-world clinical practice are limited.
OBJECTIVES: We sought to evaluate the acute procedural safety of the four latest ablation catheters commonly used for AF ablation.
METHODS: A total of 3957 AF ablation procedures performed between January 2022 and December 2023 at 20 centers with either the THERMOCOOL SMARTTOUCH SF (STSF), TactiCath (TC), QDOT Micro (QDM), or TactiFlex (TF) were retrospectively analyzed.
RESULTS: In total, QDM, STSF, TF, and TC were used in 343 (8.7%), 1793 (45.3%), 1121 (28.4%), and 700(17.7%) procedures. Among 2406 index procedures, electrical pulmonary vein isolations were successfully achieved in 99.5%. Despite similar total procedure times in the four groups, the total fluoroscopic time was significantly shorter for QDM/STSF with CARTO than TF/TC with EnSite (18.7 ± 14 vs. 27.6 ± 20.6 min, p < .001) and longest in the TF group. The incidence of cardiac tamponade was 0.7% (0.5% and 0.9% during index and redo procedures, 0.8% and 0.3% for paroxysmal and non-paroxysmal AF) and was significantly lower for QDM/STSF than TF/TC (0.2% vs. 1.1%, p = .008) and highest in the TF group. The incidence of cardiac tamponade was higher for TF than TC and STSF than QDM. In the multivariate analysis, TF/TC with EnSite was a significant independent predictor of cardiac tamponade during both the index (odds ratio [OR] = 4.8, 95% confidence interval [CI] = 1.3-17.5, p = .02) and all procedures (OR = 3.0, 95% CI = 1.3-7.2, p = .01).
CONCLUSIONS: The incidence of cardiac tamponade and the fluoroscopic time during AF ablation significantly differed among the latest RF catheters and mapping systems in real-world clinical practice.

BACKGROUND: Cavotricuspid isthmus (CTI) ablation is frequently performed either as a standalone procedure or in combination with pulmonary vein isolation. With the rapid adoption of pulsed field ablation for atrial fibrillation, it is essential to delineate the utility of this modality in treating CTI-dependent atrial flutter (AFL). This study aims to evaluate the procedural and clinical outcomes of CTI ablation using pulsed field energy.
METHODS: We conducted a retrospective analysis of consecutive patients who underwent pulsed field ablation for CTI-dependent AFL between January 2024 and March 2025. The primary end points were acute procedural success, periprocedural complications, and CTI-dependent AFL recurrence during follow-up.
RESULTS: A total of 132 patients underwent CTI nonthermal ablation. The median age was 69.5 years, and 27.3% were female. The Farawave catheter was used in 93.9% of cases, PulseSelect in 4.5%, and Sphere-9 in 1.5%. Acute block was achieved in 99.2% of patients, although 8 required adjunctive radiofrequency ablation to complete the line. Periprocedural complications included transient ST-segment elevation in 2 patients and transient conduction disturbances in 3. During a median follow-up of 114 days (n=131), 5 patients (3.8%) experienced recurrence of typical AFL. The 6-month typical AFL-free survival estimate was 93.6%.
CONCLUSIONS: Pulsed field ablation appears to be a feasible and effective strategy for CTI-dependent AFL. However, anatomic variability may limit its universal applicability with current catheter designs. Although acute procedural success is high, the long-term durability of the CTI block and its comparative efficacy versus conventional thermal ablation remain areas requiring further investigation.

BACKGROUND: High density electroanatomical mapping (EAM) is the standard for identifying functional substrate in scar-related ventricular tachycardia (VT), but it is limited by its two-dimensional nature and increased procedural complexity. Imaging-based strategies provide anatomical characterization but lack functional information. We evaluated a novel digital twin model (CardioMat) to non-invasively predict functional substrate in three-dimensions.
OBJECTIVE: To validate a novel digital twin model for noninvasive prediction of functional substrate in scar-related ventricular tachycardia.
METHODS: Fifteen patients with ischemic or nonischemic cardiomyopathy undergoing VT ablation were retrospectively analyzed. High-density EAM, cardiac magnetic resonance (CMR) post-processing with ADAS3D, and CardioMat modeling were performed. CardioMat-generated three-dimensional activation maps were integrated into the CARTO EAM suite. Deceleration zones (DZs) identified by CardioMat were compared with EAM-derived DZs and CMR-based heterogeneous tissue channels (HTCs) and scar areas.
RESULTS: A total of 255 cardiac segments were analyzed. CardioMat-derived DZs demonstrated high diagnostic accuracy (79% sensitivity, 93% specificity, 81% PPV, 92% NPV, 89% accuracy) for predicting EAM-DZ localization, outperforming CMR scar and HTCs. Multivariate analysis confirmed CardioMat DZs are the strongest independent predictor of EAM-DZ localization (OR 17.4, 95% CI 6.9-43.8, p > 0.001).
CONCLUSIONS: This study provides preliminary evidence supporting the feasibility of a digital twin model for noninvasive functional substrate characterization. CardioMat integrates anatomical and functional information, outperforming conventional CMR-based assessment. Prospective multicenter validation is needed to establish its role in VT ablation guidance.

INTRODUCTION: Ablation targeting spatio-temporal dispersion electrograms (STDEs) in addition to pulmonary vein isolation (PVI) has been reported to reduce atrial fibrillation (AF) recurrence in patients with persistent AF.
BACKGROUND: However, STDE identification remains subjective. Complex Signal Identification (CSI), integrated into the CARTO 3 mapping system, automatically quantifies electrogram characteristics. We evaluated whether CSI parameters can accurately identify STDEs.
METHODS: We retrospectively analyzed intracardiac electrogram points from five consecutive patients who underwent catheter ablation for persistent AF using the CARTO 3 version 8 mapping system (Biosense Webster, Diamond Bar, CA, USA) between October and December 2024 to evaluate the ability of CSI parameters to identify STDEs. STDEs were identified and marked by the operator using an OCTARAY catheter.
RESULTS: A total of 4453 electrogram points obtained before ablation were analyzed. Among all CSI metrics, the fractionation score demonstrated the highest diagnostic accuracy. An optimal cutoff of 4.1 yielded an area under the curve (AUC) of 0.905 (95% CI: 0.892-0.918), with a sensitivity of 80.4%, specificity of 98.6%, positive predictive value of 94.1%, and negative predictive value of 93.1%. In contrast, complex duration (cutoff ≥ 50 ms), %cycle length (cutoff ≥ 15%), and complex onset (cutoff ≤ -32) showed AUCs of 0.613 (95% CI: 0.557-0.668), 0.599 (95% CI: 0.538-0.660), and 0.525 (95% CI: 0.461-0.589), respectively.
CONCLUSION: A CSI fractionation score cutoff of 4.1 identified STDEs with high accuracy, suggesting that CSI-guided mapping may serve as a practical tool for adjunctive ablation beyond PVI.

BACKGROUND: Hemolysis is a well-recognized consequence of microsecond pulsed-field ablation (PFA); however, its occurrence with nanosecond PFA has not been determined.
OBJECTIVES: The aim of this study was to compare hemolysis profiles across different PFA systems.
METHODS: Consecutive patients with atrial fibrillation undergoing first-time PFA with Pentaspline (FARAWAVE; Boston Scientific), Lattice tip (Sphere-9; Medtronic), or Nano PFA 360 (CellFX; Pulse Bioscience) catheters were included in this prospective analysis. Hemolysis was assessed by haptoglobin (Hp), lactate dehydrogenase, and bilirubin measured before ablation (T1) and 24 hours after the procedure (T2). Hemolysis was defined as a >10 mg/dL decrease in Hp between T1 and T2. Significant hemolysis was defined as Hp ≤ 25 mg/dL.
RESULTS: A total of 94 (67% male, mean age 58.9 ± 11.68) patients were included. No statistically significant differences in the baseline and procedural characteristics were found among the 3 systems. The catheters used were Nano PFA 360, Pentaspline, and Lattice tip in 30 (32%), 34 (36%), and 30 patients (32%), respectively. Hemolysis occurred in 88 (93.6%) patients. Significant hemolysis was observed in 21 (70%) Nano PFA 360, 27 (79.4%) Pentaspline, and 7 (23%) Lattice tip cases (P < 0.001). Multivariable analysis showed that the Nano PFA 360 and Pentaspline were associated with a similarly high risk of significant hemolysis compared with Lattice tip (P < 0.001). No statistically significant difference was observed between Nano PFA 360 and Pentaspline catheters.
CONCLUSIONS: Hemolysis commonly occurs across PFA procedures, irrespective of pulse duration, and is greater with single-shot than focal systems.

INTRODUCTION: The VARIPULSE™ variable-loop circular catheter (VLCC) is a bidirectional, multielectrode catheter that can perform electrophysiological mapping and deliver pulsed field energy through the TRUPULSE™ Generator for the treatment of atrial fibrillation. This ablation system, including the CARTO 3™ three-dimensional electroanatomical mapping system, represents a fully integrated system.
METHODS: Pulsed field ablation (PFA) is a novel, primarily cardiac tissue-selective ablation technology with a minimal thermal effect, potentially eliminating the collateral tissue damage associated with radiofrequency ablation or cryoablation. Integration of a mapping system may lead to shorter fluoroscopy times and improve the usability of the system, allowing tracking of energy density and placement to confirm no areas around the vein are left untreated.
RESULTS: This step-by-step review covers patient selection, mapping, the step-by-step ablation workflow, details on catheter repositioning and ensuring contact, considerations for ablation of specific anatomical variations, and discussion of ablation without fluoroscopy based on our initial clinical experience.
CONCLUSIONS: The VLCC is part of the fully integrated PFA system designed for pulmonary vein isolation, using mapping to guide catheter placement and lesion set creation. The current workflow, which is based on our initial clinical experience, may be further refined as the PFA system is used in real-world settings.

INTRODUCTION: In atrial fibrillation (AF) ablation procedures, the CARTO VIZIGO Bidirectional Guiding Sheath has previously shown promising results in reducing fluoroscopy times without compromising clinical effectiveness or safety compared with non-steerable sheaths.
METHODS: This non-randomized, multicenter, retrospective cohort study (INSIGHT) aimed to determine the real-world impact of the VIZIGO sheath on procedural efficiency, clinical effectiveness, and safety in paroxysmal AF (PAF) catheter ablation. Consecutive adults who underwent de novo radiofrequency (RF) ablation for PAF with a non-VIZIGO sheath (January 2019-July 2021) or VIZIGO sheath (January 2020-July 2021) were included. Procedural characteristics, primary adverse events (PAEs), and 12-month effectiveness (freedom from repeat ablation or recurrent atrial arrhythmia) were evaluated.
RESULTS: Of 199 patients included (mean age, 69.7 years; 59.3% male), 97 had ablation with a VIZIGO sheath and 102 with a non-VIZIGO sheath. Significantly shorter mean times were achieved in the VIZIGO vs. non-VIZIGO group for time to left PVI (18.1 ± 7.5 vs. 19.9 ± 5.6 min, p = 0.046), right PVI (16.5 ± 6.1 vs. 23.1 ± 9.9 min, p < 0.001), total PVI (34.6 ± 9.7 vs. 42.9 ± 11.4 min, p = 0.002), and fluoroscopy time (7.3 ± 10.4 vs. 18.3 ± 13.3 min, p < 0.001). Mean fluoroscopy dose was significantly lower (45.9 ± 112.0 vs. 139.5 ± 251.5 mGy, p < 0.001) with VIZIGO vs. non-VIZIGO sheaths. Catheter stability was comparable between groups. PAE rates were similar in the VIZIGO (3.1%) and non-VIZIGO (4.9%) groups. Freedom from repeat ablation and recurrent atrial arrhythmia at 12 months were also similar in the two groups.
CONCLUSION: These real-world data demonstrate that use of the VIZIGO sheath in PAF ablation procedures allows for significantly lower fluoroscopy time and dose with significantly shorter PVI isolation time, without compromising acute and long-term effectiveness or safety.

BACKGROUND: CARTONET is a cloud-based system for the analysis of ablation procedures using the CARTO system. The current CARTONET R14 model employs deep learning, but its accuracy and positive predictive value (PPV) remain underevaluated.
OBJECTIVE: This study aimed to compare the characteristics of the CARTONET system between the R12.1 and the R14 models.
METHODS: Data from 396 atrial fibrillation ablation cases were analyzed. Using a CARTONET R14 model, the sensitivity and PPV of the automated anatomic location model were investigated. The distribution of potential reconnection sites and confidence level for each site were investigated. We also compared the difference in the data between the CARTONET R12.1, the previous CARTONET version, and the CARTONET R14 models.
RESULTS: We analyzed the overall tags of 39,169 points and the gap prediction of 625 segments using the CARTONET R14 model. The sensitivity and PPV of the R14 model significantly improved compared with the R12.1 model (R12.1 vs R14: sensitivity, 71.2% vs 77.5% [P < .0001]; PPV, 85.6% vs 86.2% [P = .0184]). The incidence of reconnections was highly observed in the posterior area of the right pulmonary veins (98/238 [41.2%]) and left pulmonary veins (190/387 [49.1%]). In contrast, the possibility of reconnection was highest in the roof area for the right pulmonary veins (14% [5.5%-41%]) and left pulmonary veins (16% [8%-22%]).
CONCLUSION: The R14 model significantly improved sensitivity and PPV compared with the R12.1 model. The tendency for predicting potential reconnection sites was similar to that of the previous version, the R12 model.

BACKGROUND: Radiofrequency ablation of the mitral isthmus (MI) is unreliable. Vein of Marshall (VOM) ethanol infusion can improve MI ablation success and eliminate local MI autonomic innervation. The role of pulsed field ablation (PFA) in MI ablation and its autonomic effect is unclear. We evaluated the transmurality of endocardial PFA at the MI and its autonomic effects, using real-time epicardial VOM electrograms and VOM high-frequency stimulation.
METHODS: Patients undergoing atrial fibrillation ablation (n=71) were prospectively enrolled. MI ablation (endocardial to VOM) was delivered using FaraPulse (N=31), PulseSelect (N=9), or Affera (N=31) while monitoring VOM epicardial electrograms to assess transmurality, defined as VOM signal elimination after 20 minutes. MI block was assessed using differential pacing from the left atrial appendage and VOM. High-frequency stimulation from the VOM was performed before and after PFA. VOM ethanol infusion was administered when MI ablation was incomplete.
RESULTS: Endocardial PFA led to durable epicardial electrogram attenuation in 52.1% (FaraPulse in 38.7%, PulseSelect in 44.4%, and Affera in 67.7%; P<0.05). Myocardial capture with VOM pacing persisted in 43.7% (FaraPulse in 45.2%, PulseSelect in 100%, and Affera in 25.8%; P<0.05). Pseudoblock (epicardial-only MI conduction and MI delays) was present in 38%. MI block was achieved with PFA alone in 45% (32/71) of patients; VOM ethanol infusion achieved MI block in an additional 38% (27/71) of patients for a cumulative 83% (59/71); and coronary sinus ablation was required in the remaining 17% (12/71). After PFA, VOM high-frequency stimulation elicited intact parasympathetic responses evidenced as atrioventricular block.
CONCLUSIONS: Across all 3 PFA platforms, endocardial ablation of the MI is not reliably transmural and does not ablate VOM parasympathetic innervation. VOM ethanol infusion can complete transmurality and denervation of the MI.

INTRODUCTION: Pulsed field ablation (PFA) minimizes the risk of esophageal injury, pulmonary vein stenosis, and permanent phrenic nerve damage. However, when PFA is applied near coronary arteries, it has been associated with the induction of coronary vasospasm, which is typically asymptomatic but occasionally results in ventricular arrhythmias. Pre-treatment strategy with intravenous nitroglycerin can significantly reduce the occurrence of this complication.
CASE PRESENTATION: A 79-year-old male with cavotricuspid isthmus (CTI)-dependent atrial flutter and atrial fibrillation underwent catheter ablation after antiarrhythmic therapy failure. Following pulmonary vein and posterior wall isolation using a novel variable-loop biphasic circular pulsed field ablation (PFA) catheter integrated with a 3D mapping system (VARIPULSE catheter, CARTO mapping system, Johnson and Johnson, USA), CTI ablation was performed with the same system. Twenty-one applications resulted in sinus rhythm restoration and confirmed bidirectional block, with no complications.
CONCLUSION: To our knowledge, this is the first real-world reported case of CTI-dependent atrial flutter successfully treated with the mapping-integrated PFA system, with clinical and rhythm follow-up extending to 6 months. Further studies are needed to assess its role in non-pulmonary vein ablation.

BACKGROUND: This case presented the first domestic instance of ablation for persistent left superior vena cava (PLSVC)-associated atrial arrhythmia, utilizing the "Varipulse" pulsed-field ablation system.
CASE SUMMARY: The computed tomography angiography examination revealed the presence of a PLSVC. During the procedure, left atrial modeling was performed using the CARTO3D electroanatomical mapping system, and models of the pulmonary veins and PLSVC were manually constructed in conjunction with intracardiac echocardiography. A combined ablation strategy was employed intraoperatively, and after pulsed-field ablation of the earliest activation site in the middle segment of the PLSVC, the patient's rhythm converted to sinus.
DISCUSSION: The "Varipulse" pulsed-field ablation system enables circumferential ablation of atrial fibrillation trigger foci in the PLSVC, achieving rapid, uniform isolation and significantly improving ablation efficiency.
TAKE-HOME MESSAGE: The "Varipulse" pulsed-field ablation system offers a novel technical approach for the precise and safe treatment of atrial arrhythmias associated with PLSVC.

BACKGROUND: Paroxysmal atrial fibrillation (AF) and epicardial ventricular tachycardia (VT) are complex arrhythmias requiring precise, safe ablation. Zero-fluoroscopy radiofrequency ablation (RFA) minimizes radiation exposure while maintaining procedural accuracy.
FIH/EARLY REPORTS SUMMARY: A 56-year-old male with diabetes, hypertrophic cardiomyopathy, AF, and VT underwent zero-fluoroscopy, single-stage RFA for both AF and epicardial VT. Integration of intracardiac echocardiography (ICE) and CARTO 3D mapping enabled effective ablation and restored sinus rhythm with symptom relief.
DISCUSSION: This case highlights the utility of ICE and CARTO 3D in enhancing procedural precision and safety. Eliminating fluoroscopy reduces radiation risks, particularly in complex cases.
NOVELTY: This is the first report of single-stage, zero-fluoroscopy RFA for both AF and epicardial VT using ICE and 3D mapping.

INTRODUCTION: Epicardial adipose tissue (EAT) can attenuate electrograms and limit lesion formation during epicardial ventricular tachycardia (VT) ablation.
CASE PRESENTATION: We developed a simplified workflow using predefined CT attenuation values to integrate EAT into the CARTO 3 system. We applied this approach in three patients with dilated cardiomyopathy undergoing epicardial VT ablation, where EAT visualization guided target selection, avoided ineffective ablation, and informed alternative endocardial strategies.
DISCUSSION: EAT-integrated mapping improved the interpretation of epicardial substrates and influenced procedural decision-making. This workflow may facilitate efficient assessment of epicardial ablation feasibility in complex VT cases.

This case report presents the management of tachycardiomyopathy (TCM) in a patient with Friedreich ataxia, a hereditary disorder characterized by progressive neurodegeneration and associated cardiac complications. The patient exhibited severe tachycardia-induced cardiac dysfunction, complicating the clinical picture due to the overlapping neurological symptoms of Friedreich ataxia. Utilizing a 3D mapping system, catheter ablation was performed to accurately identify and target the arrhythmogenic foci contributing to the patient's TCM. The procedure resulted in significant symptom relief and improvement in cardiac function, underscoring the potential benefits of advanced electrophysiological techniques in managing complex cases. This report highlights the importance of a multidisciplinary approach in diagnosing and treating cardiac manifestations in patients with Friedreich ataxia, as well as the efficacy of 3D mapping technology in guiding successful ablation therapies.

Ventricular tachycardia (VT) is a potentially fatal arrhythmia that often requires a combination of medications and invasive procedures, including implantable cardioverter defibrillators (ICDs) and radiofrequency catheter ablation, to manage and treat. Despite these interventions, recurrence rates for VT remain high, particularly in patients with structural heart disease. Recent advancements in cardiac stereotactic body radiation therapy (SBRT) offer a promising alternative for patients with refractory VT, particularly for those whose arrhythmogenic areas are difficult to access through conventional methods. This study presents a novel approach to treating refractory VT, integrating advanced cardiorespiratory motion tracking using CyberKnife Synchrony (Accuray Incorporated, Madison, WI, USA) and a 3D heart reconstruction technology (inHeart, Pessac, France). The case involves a 66-year-old male with a history of dilated cardiomyopathy and recurrent VT, unresponsive to multiple medical and invasive interventions, including ICD implantation and catheter ablation. Using a combination of CT imaging, MRI, and electroanatomical mapping, we identified the arrhythmogenic region of the heart. He then underwent a single fraction of SBRT, 25 Gy to the target area, using real-time motion tracking via Synchrony. Six months post-treatment, the patient remained free from VT and has not required ICD therapies or further medical or procedural interventions. Our center has successfully implemented cardiac SBRT for refractory VT using inHeart technology for heart reconstruction and Synchrony for cardiorespiratory motion tracking.

BACKGROUND: Left-sided accessory pathways (APs) can be accessed with either a transaortic (TA) or transseptal approach (TS). For children with Marfan syndrome (MFS) who have aortic disease, the use of TA can aggravate the disease, making TS the best choice for these patients.
CASE SUMMARY: A 10-year-old girl was hospitalized because of intermittent heart palpitations and chest tightness. She was diagnosed with MFS, supraventricular tachycardia, Wolff-Parkinson-White syndrome, and left-sided AP was detected by cardiac electrophysiological. Catheter ablation was successfully performed via TS under the guidance of the Ensite system. During the follow-up, no recurrence or complications occurred.
CONCLUSION: The TS for catheter ablation of left-sided APs can be considered in children with MFS. Adequate evaluation and selection of the appropriate puncture site are particularly important.

This paper presents a novel approach to gap mapping in pulmonary vein isolation (PVI) for atrial fibrillation (AF) treatment, utilizing the real-time Ripple (RR) technique. Radiofrequency (RF) catheter ablation, particularly encircling PVI, is a common intervention for AF. Identifying left atrium-pulmonary vein conduction gaps is crucial for achieving PVI with minimal additional ablation if first-pass PVI is unsuccessful. However, identifying conduction gaps can be relatively challenging, often necessitating manual electrocardiogram reannotation due to the limitations of local activation time (LAT) maps. In the case of a 63-year-old patient with drug-resistant symptomatic persistent AF, the RR technique was utilized to identify conduction gaps during RF ablation. The technique involved pausing fast anatomical mapping (FAM), activating Ripple map (RM) feature on the CARTO 3 system and acquiring points with an ultrahigh-resolution mapping catheter. This approach revealed that the actual site of earliest activation differs from the LAT map indication, enabling successful PVI. The RM feature's capability to reflect actual excitation propagation without reliance on map annotations was crucial for precise conduction gap identification, overcoming inter-operator variability and inaccuracies of conventional methods. The RR technique not only facilitated real-time analysis during gap mapping but also significantly reduced the procedure time, minimizing potential complications. This case report highlights the efficacy of the RR technique in real-time gap mapping, demonstrating its value in cases where first-pass PVI is unsuccessful. The integration of this technique into PVI procedures can enhance both the accuracy and efficiency of catheter ablation for AF.

BACKGROUND: The management of malignant ventricular tachycardia (VT) in the aftermath of a myocardial infarction is a complex undertaking, particularly in cases accompanied by left ventricular aneurysm (LVA). It is frequently the case that conventional unipolar radiofrequency catheter ablation (RFCA) is inadequate.
CASE SUMMARY: A 50-year-old male patient with a medical history of myocardial infarction presented with recurrent VT due to a LVA. Initial unipolar RFCA proved to be an ineffective treatment. Bipolar RFCA guided by CARTO mapping during coronary artery bypass grafting has been demonstrated to successfully ablate the LVA. Subsequent postoperative follow-up revealed no recurrence of VT and sustained cardiac function over a 2-year period.
DISCUSSION: Refractory VT due to LVA poses significant treatment challenges. Bipolar RFCA, guided by CARTO mapping, has been shown to offer an effective solution, overcoming the limitations of unipolar RFCA by targeting both epicardial and endocardial arrhythmogenic substrates. This case demonstrates a surgical approach with the potential to yield favorable outcomes.

Idiopathic premature ventricular contractions (PVCs) most often occur under or above the semi-lunar valves from the right ventricular outflow tract and less often from the left ventricular outflow tract. Radio-frequency ablation is mostly used for patients who develop left ventricular dysfunction or intolerable symptoms. Since most of the patients are in the young age group and ablation has a high success rate with recurrence being relatively low, it can be offered to those symptomatic patients who want a definitive cure. The use of 3-dimensional (3D) electroanatomic mapping systems helps locate the ablation site. We report a case of a young man with PVCs coming from a rare site of non-coronary cusp, which was ablated successfully by using a high-density mapping system. Key Words: Catheter ablation, Left ventricular outflow tract, Non-coronary aortic cusp, Premature ventricular contractions.

BACKGROUND: Right phrenic nerve (PN) injury is a major complication of thermal ablation of atrial tachycardias (ATs) originated from the superior vena cava (SVC).
CASE SUMMARY: We report the case of a 41-year-old female patient admitted for catheter ablation of a frequent paroxysmal AT resistant to antiarrhythmic drugs. Electroanatomical activation map demonstrated a focal origin located at the lateral aspect of the SVC, ∼17 mm above the breakthrough of the sinus node wavefront. Importantly, high-output pacing from this site resulted in PN capture. To avoid PN injury, low-output radiofrequency (RF) ablation, with a power output limited to 20 W, was performed. However, this approach was insufficient to terminate AT. High-power RF applications in proximity to the PN were avoided and pulsed-field ablation (PFA) with a pentaspline catheter was chosen. The catheter was advanced into the SVC to the level of the earliest activation under fluoroscopic guidance and visualization within the mapping system. Two pairs of applications, in basket configuration, were delivered inside the SVC, rendering AT non-inducible while sinus node function was not compromised.
DISCUSSION: Phrenic nerve is vulnerable to injury during ablation within the SVC using thermal ablation modalities. Low-output RF ablation may be safe but less efficient. In contrast, non-thermal approaches such as PFA may be preferable to avoid damage to the collateral tissues as PN. Electroanatomical mapping may be important to avoid lesions in proximity to the sinus node.

Biatrial tachycardia (BiAT) is a rare arrhythmia, and identification of the re-entry circuit is often complicated. By creating an activation map of the right atrium, left atrium, and coronary sinus as a single chamber, the LUMIPOINT module of the Rhythmia mapping system (Boston Scientific, Marlborough, MA, USA) can be used in real time to make an accurate diagnosis. Ablation of the Bachmann bundle is a feasible way to terminate BiAT, but might cause interatrial conduction delay and electrical isolation of the left atrial appendage. Chemical ablation into the vein of Marshall might be the more beneficial treatment, avoiding any potential interatrial conduction delay.

BACKGROUND: Long RP supraventricular tachycardia poses a significant diagnostic challenge because of overlapping electrophysiological features among differential diagnoses. Detailed evaluation with an electrophysiological study is essential for accurate diagnosis and effective management, particularly when initial ablation attempts fail to eliminate inducibility.
CASE PRESENTATION: A 40-year-old Southeast Asian male with a 5-year history of recurrent palpitations was referred for evaluation. Baseline echocardiography was normal. During symptomatic episodes, electrocardiography demonstrated long RP tachycardia. Electrophysiology study revealed eccentric atrial activation with decremental conduction, with the earliest A recorded at DD 9-10 (coronary sinus ostium/left posteroseptal region). Tachycardia cycle length was 410 ms, with a VA interval of 215 ms, AH interval of 93 ms, HA interval of 332 ms (AH/HA < 1), a VAV response during ventricular entrainment, PPI-TCL of 225 ms, and SA-VA of 194 ms. Ventricular reset did not terminate the arrhythmia and showed no atrial delay or advancement. Ablation at the coronary sinus ostium terminated the tachycardia but did not prevent reinduction. A subsequent slow pathway ablation was performed, during which slow junctional rhythm was observed. Post-ablation testing demonstrated crossover at 320 ms, while supraventricular tachycardia remained easily inducible with atrial S1 pacing at 400 ms. Given persistent inducibility, medical therapy was optimized and the patient was scheduled for advanced three-dimensional mapping and ablation. The leading differential diagnoses were atypical atrioventricular nodal reentrant tachycardia (fast-slow variant) with a bystander accessory pathway and permanent junctional reciprocating tachycardia with coexisting dual AV nodal physiology.
CONCLUSION: This case illustrates the diagnostic complexity and management challenges of long RP supraventricular tachycardia, particularly in distinguishing atypical atrioventricular nodal reentrant tachycardia from permanent junctional reciprocating tachycardia. When initial ablation does not achieve full arrhythmia control, a stepwise strategy involving detailed electrophysiological evaluation, cautious ablation, and advanced mapping may be required to guide definitive therapy.

Premature ventricular complex (PVC) is one of the most common arrhythmias detected in young patients. We report a case of a young patient with symptomatic high-burden PVC suspected to originate from the posterior right ventricular outflow tract (RVOT) who underwent an electrophysiology study (EPS) and was subsequently successfully ablated with markedly reduced PVC burden. The following day, it was noted that there was a change in PVC morphology. A repeat 3D electroanatomical mapping localized the second PVC morphology to posterolateral RVOT and abolished it with radiofrequency ablation (RFA).

Background: Atypical atrial flutter (AFL) is a complex clinical challenge, particularly in patients with prior atrial fibrillation (AF) treated with pulmonary vein isolation (PVI). Arrhythmias involving the vein of Marshall (VOM) often require extensive lesion sets, including ethanol infusion, to effectively target the epicardial substrate. To minimize tissue damage, an alternative strategy has been proposed, emphasizing advanced electroanatomical mapping, entrainment maneuvers, and highly targeted ablation techniques. Case Presentation: We describe a 72-year-old woman with recurrent atrial arrhythmias following pulmonary vein isolation (PVI), who presented with palpitations as her primary symptom. After ineffective pharmacological therapy, she underwent a catheter ablation procedure. Electroanatomical mapping revealed significant left atrial scarring and suggested a macroreentrant circuit involving the VOM. Entrainment maneuvers confirmed the VOM's involvement. A single targeted endocardial ablation guided by the ablation index terminated the arrhythmia within 12 s, without the need for ethanol infusion or extensive lesion sets. Discussion: This case underscores the VOM's role in sustaining atypical AFL post-PVI and highlights the effectiveness of precise electroanatomical mapping combined with targeted endocardial ablation. Unlike broader ablation or ethanol infusion strategies, a focused lesion at the critical isthmus achieved arrhythmia termination with minimal tissue damage. Conclusions: Endocardial ablation at the site of entrainment can safely and effectively treat VOM-related AFL, offering symptom relief and restoration of sinus rhythm. This approach may reduce procedural risks and expand the feasibility of VOM-related arrhythmia management in centers without access to ethanol infusion.

BACKGROUND: Cardiac dextroposition involves a rightward shift of a normally configured heart, setting it apart from mirror-image dextrocardia. This anatomical variant can alter typical thoracic relationships, rendering conventional fluoroscopic reference points unreliable and increasing the complexity of electrophysiological procedures.
CASE SUMMARY: A 57-year-old man was admitted following an out-of-hospital ventricular fibrillation arrest attributed to pre-excited atrial fibrillation. Chest radiography identified rightward displacement of the heart's silhouette. Further diagnostic imaging confirmed cardiac dextroposition without abnormalities in atrioventricular or great-vessel orientation, thus distinguishing it from mirror-image dextrocardia. Electrophysiological study revealed that mapping the anteroseptal accessory pathway was complicated by altered fluoroscopic landmarks. Successful radiofrequency ablation was achieved with the aid of three-dimensional electroanatomical mapping and intracardiac echocardiography, resulting in the elimination of pre-excitation without causing atrioventricular nodal injury.
DISCUSSION: The integration of advanced imaging modalities facilitated accurate localization and ablation, despite the abnormal cardiac position. This case demonstrates that even in the setting of significant anatomical displacement, safe and effective ablation of anteroseptal pathways can be accomplished through the application of multimodal mapping techniques.

Slow pathway (SP) ablation is an established therapy for slow-fast atrioventricular nodal reentrant tachycardia (AVNRT), with high success and low recurrence rates. We report a case in which a complex signal identification (CSI) map with the CARTO system was used during slow-fast AVNRT to localize a fractionated region near the coronary sinus ostium that coincided with the successful SP ablation site.

Transcatheter aortic valve replacement (TAVR) is commonly used to treat severe aortic stenosis. Although atrial fibrillation and conduction disturbances are well-known complications, peri-mitral atrial tachycardia (PMT) post-TAVR is less frequently reported. A 75-year-old man with persistent PMT 1-year post-TAVR was managed successfully through radiofrequency catheter ablation. High-density 3-dimensional mapping identified a macro-reentrant circuit and a slow-conduction area adjacent to the transcatheter aortic valve implantation site, diagnosed as counterclockwise PMT. Ablation resulted in tachycardia termination, with no recurrence at follow-up. This case highlights structural alterations from TAVR as potential contributors to arrhythmic substrates. The rarity and successful management of PMT post-TAVR contribute significant insights, emphasizing the need for vigilant arrhythmic monitoring and tailored interventions. This case underscores the importance of recognizing and managing rare arrhythmic complications following TAVR, enhancing patient outcomes through precise diagnostic and interventional strategies.

BACKGROUND: Left variant type slow-slow atrioventricular nodal reentrant tachycardia (AVNRT) is rare, and its occurrence in patients with situs inversus totalis has not been previously reported.
CASE SUMMARY: A patient with situs inversus totalis presented with recurrent supraventricular tachycardia. Electrophysiological study excluded atrioventricular reentrant tachycardia and atrial tachycardia, supporting a diagnosis of left variant slow-slow AVNRT. Catheter ablation targeting the left atrial slow pathway at the inferolateral mitral annulus was performed using cardiac computed tomography and high-density electroanatomical mapping. Tachycardia was terminated with a single radiofrequency application and was no longer inducible.
DISCUSSION: Catheter ablation in patients with situs inversus is technically challenging because of mirror-image anatomy, but advanced imaging and electroanatomical mapping allow accurate localization of the arrhythmogenic substrate and safe ablation.
TAKE-HOME MESSAGES: Left variant slow-slow AVNRT can occur in patients with situs inversus totalis. Advanced imaging and electroanatomical mapping facilitate safe ablation despite anatomical complexity.

UNLABELLED: Pulmonary vein (PV) antrum isolation (PVAI) that involves electrically isolating PV foci is a useful treatment strategy for atrial fibrillation (AF). However, non-PV triggers during/after the PVAI are observed in approximately 30 % of AF cases, contributing to AF recurrence. We present the case of an 84-year-old woman who underwent ablation of recurrent symptomatic paroxysmal AF in our hospital. AF was easily induced following spontaneous activity (SA) from non-PV triggers even after completing the PVAI, left atrial posterior wall isolation with roof and bottom lines, and superior vena cava isolation. Interestingly, the area of the earliest activation site of the SAs initiating AF and that with a fractionation mapping score of ≥4 corresponded. AF was steadily terminated during ablation of this fractionated area, and the programmed stimulation could no longer induce any SA or AF. This case report demonstrated that the area with a score of ≥4 points on the fractionation mapping calculated by EnSite™ (Abbott, Abbott Park, IL, USA) during sinus rhythm may contribute to the initiation and maintenance of paroxysmal AF. In patients whose AF does not resolve during ablation, physicians may consider performing an additional targeted ablation of the area with a fractionation mapping score of ≥4, even in patients with paroxysmal AF.
LEARNING OBJECTIVE: The area with a fractionation mapping score of ≥4 calculated by EnSite™ during sinus rhythm might play an important role in producing spontaneous activities and initiating and maintaining paroxysmal atrial fibrillation (AF). Thus, if the AF does not terminate during ablation, physicians should consider performing an additional targeted ablation of the area with a fractionation mapping score of ≥4, even if it is paroxysmal.

INTRODUCTION: We described a rare case of an adolescent girl with paroxysmal atrial fibrillation originating from the right atrial appendage diverticulum and successfully converted to sinus rhythm after surgical intervention.
METHODS: A 19-year-old girl was referred to the hospital for a catheter ablation of paroxysmal atrial fibrillation. conventional radiofrequency ablation using 3-D mapping were ineffective. Activation mapping showed the root of the free wall atrial appendage was first excited and catheter modeling (3D Carto map) showed a sac-like structure.
RESULTS: We did selective angiography and further Computed tomography angiography (CTA) and Transesophageal echocardiography (TEE) which showed diverticulum originating from the right atrial appendage. Hence the patient was referred to cardiac surgery and had no recurrent atrial fibrillation at three months postoperative follow up.
CONCLUSIONS: Right atrial appendage diverticulum was an extremely rare malformation that can coexist with atrial tachyarrhythmia. Surgical ligation or excision of the abnormal structure with local ablation can achieve excellent results.

A 35-year-old female with sarcoidosis sought medical attention due to palpitations. The ECG showed an atrial tachycardia (AT), apparently originating in the left atrium. A 24-hour Holter monitoring revealed AT to be present during the entire day. Cardiac magnetic resonance exhibited no cardiac involvement by sarcoidosis but registered a mildly depressed left ventricular ejection fraction (LVEF). Atrial electroanatomical mapping showed the earliest activation zone on the distal portion of the left atrial appendage (LAA). Considering the high risk for perforation with catheter ablation in this region, she was sent to thoracoscopic surgical LAA exclusion with a clip device; it was possible to witness the termination of the arrhythmia during the procedure. She was safely discharged two days after surgery and has completed a one-year follow-up without recurrence of AT or symptoms, and with normalization of LVEF.

BACKGROUND: Congenital interruptions of the inferior vena cava (IVC) and persistent left superior vena cava (PLSVC) are rare. When combined with dextroversion, they pose significant challenges for catheter ablation.
CASE SUMMARY: A 65-year-old man with 2-year palpitations (worsened for half a month) had typical atrial flutter and dextroversion on ECG. Echocardiography showed PLSVC; computed tomography angiography confirmed IVC interruption. Ablation was successfully performed via a left superior venous approach with 3D mapping, targeting the cavotricuspid isthmus between the tricuspid annulus and hepatic vein.
DISCUSSION: This is the first reported case of atrial flutter ablation in a patient with coexisting dextroversion, PLSVC, and IVC interruption. It highlights the importance of anatomical recognition and adaptive strategies.
TAKE-HOME MESSAGES: Preprocedural imaging is crucial in cardiac malformation. Alternative access routes and 3D mapping are key to successful ablation in complex anatomy.

BACKGROUND: Catheter ablation of epicardial accessory pathways (APs) remains challenging, especially in patients with anatomical variations to the coronary sinus (CS).
CASE SUMMARY: We report a redo ablation case: A patient with an anomalous CS drainage into the left atrium, diagnosed with epicardial AP-mediated tachycardia, underwent successful ablation at the epicardial basal crux after failed previous endocardial ablation at the bilateral posterior septum.
DISCUSSION: This case demonstrates that ablation at the epicardial basal crux is safe and effective for epicardial APs associated with CS anatomical variations.
TAKE-HOME MESSAGE: For treating tachycardia mediated by epicardial APs in patients with anomalous CS drainage into the left atrium, meticulous mapping and ablation targeting AP potential in the epicardial posteroseptal region may be safe and effective.

INTRODUCTION: Catheter ablation for atrial tachycardia (AT) in Budd-Chiari syndrome (BCS) presents unique challenges due to altered venous anatomy. This case demonstrates an innovative approach to overcome complete inferior vena cava (IVC) occlusion.
METHODS: A 24-year-old female with BCS underwent catheter ablation via an innovative femoral vein-IVC-azygos-SVC approach, guided by preprocedural CT angiography and 3D electroanatomical mapping.
RESULTS: Successful ablation was achieved at the anterior interatrial septum with no arrhythmia recurrence during the 3-month follow-up.
CONCLUSION: This case demonstrates the successful use of an IVC-azygos-SVC approach guided by CT angiography and 3D mapping for atrial tachycardia ablation in Budd-Chiari syndrome, offering a viable solution for patients with complex venous obstruction.

A seven-year-old, male intact Newfoundland was referred for catheter ablation of supraventricular tachycardia. Activation mapping was performed using an electroanatomical mapping system to visualize the activation wavefront in a color-coded fashion on an anatomical shell. Atrial flutter with an early-meets-late signal (i.e. suspected isthmus) at the cranial vena cava was most suspected, but could not be targeted due to overlap with the phrenic nerve. On follow-up, a more complete high-density map better outlined the suspected circuit and substrate of cranial vena cava flutter. Compared to point-by-point catheters, high-density mapping catheters enhance identification and annotation of low-amplitude electrogram signals.

A case of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create a three-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia.
Wir berichten über den Fall einer erfolgreichen Katheterablation von paroxysmalem Vorhofflimmern und Vorhoftachykardie. Nach Isolation der Lungenvenen wurde eine Vorhoftachykardie durch Verwendung von Isoproterenol und „burst pacing“ durch den Katheter im rechten Vorhof ausgelöst. Wir versuchten, eine dreidimensionale Karte der Vorhoftachykardie zu erstellen, aber die Tachykardie wurde während der Kartierung beendet. Die dreidimensionale Karte war unzureichend, zeigte jedoch an, dass die obere Hohlvene in den Erregungskreis einbezogen war. Bei Überprüfung der intrakardialen Elektrogramme stellten wir fest, dass die Vorhoftachykardie mit der orthodromen Erfassung von Potenzialen der oberen Hohlvene initiiert wurde, und kamen zu dem Schluss, dass die Verbindung zwischen oberer Hohlvene und rechtem Vorhof an der Vorhoftachykardie beteiligt war. Dementsprechend wurde eine Isolation der oberen Hohlvene durchgeführt. Danach wurden weder Vorhofflimmern noch Vorhoftachykardien durch Isoproterenol und „burst pacing“ ausgelöst. Im vorgestellten Fall half ein intrakardiales Elektrogramm zum Zeitpunkt der Tachykardieinduktion, den Erregungskreis der Tachykardie zu verstehen.

UNLABELLED: Atrial tachyarrhythmias occurring after transcatheter atrial septal defect closure are not uncommon; however, those related to device stimulation are rare. Herein, a case involving a 24-year-old female, who developed drug-refractory atrial tachycardia during the early postoperative period, is reported. The results of electroanatomical mapping could eventually be obtained from both atria. They revealed a focal pattern, and the earliest site was located on the left atrial side of the superior atrial septum, between the left and right atrial discs of the device. An ablation catheter was inserted through the side of the device into the left atrial septum, and cauterization successfully achieved recovery of the sinus rhythm without device dislodgement.
LEARNING OBJECTIVE: Atrial tachyarrhythmia related to mechanical stimulation with an atrial septal defect closure device in the early perioperative period is a rare complication. Catheter ablation with transseptal approach through the side of the device might be an option, although careful attention should be paid to the risk for device dislodgement.

BACKGROUND: Congenital anomalies of the coronary sinus (CS) are rare and often overlooked on standard imaging. Among these, the unroofed coronary sinus (URCS) is the most recognized, typically involving the proximal CS and frequently associated with a persistent left superior vena cava. In contrast, fistulous communications between the distal CS and the left atrium (LA) are exceptionally uncommon. Their recognition is important during atrial fibrillation (AF) ablation, where unanticipated channels may complicate catheter manipulation and lesion delivery.
CASE SUMMARY: A 76-year-old woman with recurrent paroxysmal AF underwent catheter ablation. A lumen-equipped multipolar catheter was positioned in the CS, and transseptal access to the LA was achieved. During electroanatomical mapping with a high-density catheter, entanglement with the CS catheter suggested an anomalous connection. Contrast injection through the CS catheter opacified the left atrial appendage (LAA), and selective angiography revealed simultaneous filling of the LAA and the left inferior pulmonary vein (LIPV), confirming a fistulous tract between the distal CS, LAA, and LIPV. Pulmonary vein isolation was completed without complication. Retrospective review of pre-procedural computed tomography demonstrated a connecting vein from the distal CS to the LA at the LAA-LIPV ridge, corroborating the procedural findings.
DISCUSSION: This case highlights a rare distal CS-LA fistulous communication involving the LAA and LIPV. It broadens the anatomical spectrum between URCS and partial anomalous pulmonary venous connection. Recognition of these anomalies is critical for procedural safety during AF ablation, underscoring the value of multimodality imaging and intra-procedural venography.

The Senning operation used to be widely performed for an intracardiac repair in a complete transposition of the great arteries. During the long-term follow-up, supraventricular tachycardia (SVT) is often observed because of the complex suture lines. The typical mechanism of a Senning-related SVT is cavo-tricuspid isthmus-dependent atrial flutter. On rare occasions, complex SVTs (e.g., biatrial tachycardia (BiAT)) whose diagnosis and treatment are challenging, may occur. We report a rare case of a BiAT following a Senning operation that was successfully ablated from the superior vena cava, and the local activation time histogram module (CARTO3 V7 module [Biosense Webster, Irvine, CA, USA]) was crucial for analyzing the complex circuit.

A 56-year-old woman underwent an electrophysiological study and radiofrequency catheter ablation of a narrow QRS tachycardia. Programmed atrial extrastimulation reproducibly induced the tachycardia. During the tachycardia, differential atrial overdrive pacing exhibited no ventriculoatrial (VA) linking, and ventricular overdrive pacing exhibited VA dissociation. Entrainment of the tachycardia with atrial overdrive pacing was not demonstrable because the tachycardia cycle length varied from 262 to 320 ms. An intravenous bolus of 5 mg of adenosine reproducibly terminated the tachycardia without atrioventricular (AV) block. Based on these findings, the clinical tachycardia was diagnosed as an adenosine-sensitive atrial tachycardia (AT). Activation mapping during the AT using the EnSite Precision system and Advisor HD Grid mapping catheter (Abbott, Minneapolis, MN, USA) exhibited a centrifugal pattern with the earliest activation along the lateral mitral annulus. A radiofrequency application at the earliest activation during the AT successfully terminated the AT. Adenosine-sensitive ATs generally originate from the vicinity of the AV node and tricuspid annulus. We present a case with an unusual location of the origin of an adenosine-sensitive AT, which was successfully ablated at the lateral mitral annulus. Since the AT was sensitive to adenosine, the AT substrate appeared to have been calcium channel-dependent tissue along the mitral annulus. .

Catheter ablation for tachyarrhythmia via superior approach has been used in patients without possible inferior vena cava access such as in cases of venous occlusion or complex anomaly. Difficulty in catheter manipulation, instability, number of required vascular access, and radiation exposure of operator had been described in the procedure. Application of three-dimensional (3-D) mapping system in catheter ablation via superior approach could navigate the guiding catheter and provide more precise ablation. We reported four cases receiving catheter ablation due to atrioventricular nodal reentry tachycardia, atrial fibrillation, and right ventricular arrhythmia via superior approach facilitated by 3-D mapping system with fewer vascular access and catheters.

Catheter knotting is a rare but potentially serious complication encountered during electrophysiological procedures. We report an unusual case of catheter ablation for premature ventricular complexes (PVCs) arising from anterolateral papillary muscle, where a ThermoCool SmartTouch (ST) catheter (Biosense Webster, Irvine, CA) developed a knot within the arterial system during transaortic mapping. The knot formed after the catheter was inadvertently withdrawn into the ascending aorta and re-advanced, leading to looping and tip entrapment. Standard maneuvers to untie the knot were unsuccessful. As a novel bailout strategy, the external portion of the catheter was cut near the handle and a large-bore 8.5 SL0 sheath (Swartz Braided SL Transseptal Guiding Introducer Sheath; length 63 cm) was advanced over it. The knotted catheter was then maneuvered against the aortic valve, and controlled mechanical contact led to successful loosening of knot and sheath retrieval. This case underscores the importance of early recognition, careful manipulation, and innovative problem-solving in managing rare mechanical complications in the cardiac electrophysiology lab.

BACKGROUND: The number of transcatheter aortic valve replacement (TAVR) procedures is steadily increasing, and although its main complications are well documented, ventricular arrhythmias (VAs) following TAVR remain infrequently reported in the literature. We present a rare case of ventricular tachycardia (VT) occurring late after TAVR, originating from the lower portion of the prosthesis at the interventricular septum.
CASE SUMMARY: An 82-year-old Caucasian man presented with recurrent episodes of lipothymia and VT occurring late after undergoing TAVR. The VT persisted despite escalating medical therapy. He was referred for catheter ablation using a transseptal approach. Electroanatomical mapping of the left ventricle identified the earliest VT activation at the interventricular septum, adjacent to the lower portion of the prosthetic aortic valve. The arrhythmia was successfully treated with targeted radiofrequency ablation. At 11 months post-ablation, remote monitoring confirmed that the patient remained free of VT episodes.
DISCUSSION: This case report highlights a rare complication of TAVR. Clinicians should consider VT as a potential cause of presyncope or syncope following TAVR, rather than attributing these symptoms solely to conduction disorders. In this case, we demonstrate that catheter ablation targeting the interventricular septum near the lower portion of a 29-mm Edwards Sapien aortic valve was both feasible and effective.

During catheter ablation (CA) of tachycardia, conventional point-by-point mapping may be hindered due to hemodynamic instability. We performed open-window mapping (CARTO, Biosense Webster, USA) in a patient who developed hemodynamic instability during orthodromic atrioventricular reciprocating tachycardia (AVRT) and unwarranted induction of AVRT during attempts to map accessory pathway (AP) with ventricular pacing. With over 11,000 points acquired rapidly, the system accurately identified AP at the mitral valve (MV) annulus where the application of single radiofrequency (RF) lesion promptly eliminated AP's conduction. Our case illustrates the utility of open-window mapping for the ablation of AVRT.

UNLABELLED: Posteroseptal accessory pathways (APs) often involve epicardial connections, making radiofrequency catheter ablation (RFA) particularly challenging. We present the case of a 14-year-old boy in whom a heart murmur was detected after birth. Echocardiography revealed an isolated ductus arteriosus aneurysm with tricuspid regurgitation, while electrocardiogram (ECG) showed pre-excitation due to an AP. The aneurysm spontaneously closed during infancy. At age 13 years, the patient experienced brief monthly palpitations but did not seek medical treatment. By age 14 years, echocardiography showed reduced cardiac function, and a 12‑lead ECG revealed a posteroseptal AP. Contrast-enhanced computed tomography revealed a small middle cardiac vein (MCV) diverticulum located >5 mm from the right coronary artery. Electrophysiological study (EPS) and RFA were performed to improve cardiac function. Although EPS did not induce atrioventricular reciprocating tachycardia, intracardiac echocardiography and multipolar electrode mapping demonstrated continuous atrioventricular potentials with an AP potential at the MCV diverticulum neck. Low-power radiofrequency energy delivered with a QDOT MICRO™ catheter eliminated AP conduction within 2 s. Follow-up echocardiography confirmed resolution of left ventricular dyssynchrony and improved function. High-resolution electroanatomical mapping enabled precise localization of the AP, and low-power irrigation catheter use provided effective and safe ablation in pediatric posteroseptal AP.
LEARNING OBJECTIVE: The posteroseptal accessory pathway (AP) is a possible epicardial pathway often associated with anatomical abnormalities, such as the coronary sinus diverticula, and radiofrequency catheter ablation (RFA) is technically more challenging in such cases than in other APs. The combined use of a multispline high-resolution electroanatomical mapping catheter and a low-power irrigation catheter enables accurate and safe RFA, even in pediatric patients with an epicardial posteroseptal AP in the middle cardiac vein diverticulum.

BACKGROUND: Epicardial ventricular tachycardia (VT) ablation is an established approach in patients with epicardial arrhythmogenic foci and is most commonly performed via percutaneous access. An alternative approach is via video-assisted thoracoscopic surgery (VATS), although reports of this technique are limited to the use of catheter-based technologies for radiofrequency ablation delivery.
CASE SUMMARY: A 55-year-old man with non-ischaemic cardiomyopathy presented with recurrent VT despite medical therapy. Twelve-lead ECG and cardiac MRI were suggestive of an epicardial left ventricular lateral wall breakout. Epicardial ablation was successfully performed via VATS using a linear surgical bipolar ablation device with electroanatomical mapping (EAM) integration. Following ablation, VT was non-inducible. Other than six short episodes of non-sustained during initial follow-up (up to 6 weeks), the patient remained free of ventricular arrhythmias at 18 months with minimal anti-arrhythmic therapy.
DISCUSSION: Epicardial VT ablation via VATS is feasible and allows for integration of a surgical ablation device within an EAM system. This may serve as an alternative approach in patients with a failed percutaneous ablation, or those with adverse features for a successful percutaneous procedure.

Background: Focal atrial tachycardia (AT) originating from the right atrial appendage (RAA), often persistent and refractory, is clinically rare in pregnant woman, and the therapy is much more challenging. We report that a pregnant woman presented with hypotension due to persistent and refractory atrial tachycardia and was successfully cured by a multidisciplinary treatment (MDT) approach, consisting of a combination of zero-fluoroscopy mapping and thoracoscopic atrial appendectomy. We also carried out a literature review of this topic. Methods and Results: A 26-year-old woman in pregnancy at 21 weeks presented with severe palpitation and hypotension due to persistent rapid supraventricular tachycardia (SVT). Since adenosine triphosphate could not terminate the tachycardia, a catheter ablation procedure was planned and finally canceled when the zero-fluoroscopy mapping using Carto 3TM system revealed an atrial tachycardia originating from the RAA. Thoracoscopic RAA ectomy was recommended after multidisciplinary consultation and successfully performed without fluoroscopy. EnsiteTM velocity mapping system was used for accurately locating the origin of the arrhythmia during ectomy. The woman finally produced a healthy baby during follow-up. Conclusions: Focal AT originating from appendage in pregnant patients can be persistent, refractory, and life-threatening; traditional strategies, such as medicine or catheter ablation, are limited in this situation. MDT measures, using a thoracoscopic ectomy and zero-fluoroscopy three-dimensional electroanatomical mapping technique, is minimally invasive and a promising strategy.

BACKGROUND: Myocardial involvement in tuberculosis is exceptionally rare and may closely mimic cardiac sarcoidosis, particularly when presenting with ventricular arrhythmias.
CASE SUMMARY: A 47-year-old man from a tuberculosis-endemic region presented with sustained monomorphic ventricular tachycardia and biomarker elevation. Coronary angiography was normal. Multimodal imaging demonstrated extensive inflammatory nonischemic myocardial involvement and mediastinal lymphadenopathy. Initial lymph node biopsy showed nonnecrotizing granulomas, leading to a working diagnosis of probable cardiac sarcoidosis and initiation of corticosteroid therapy. Delayed lymph node culture later identified Mycobacterium tuberculosis, prompting revision of the diagnosis and initiation of antituberculous therapy. Despite microbiologic control, recurrent ventricular tachycardia required antiarrhythmic optimization and catheter ablation.
DISCUSSION: This case highlights the diagnostic overlap between tuberculous myocarditis and cardiac sarcoidosis and underscores the importance of microbiologic confirmation in patients from endemic regions.
TAKE-HOME MESSAGES: Tuberculosis should be considered in granulomatous myocarditis with ventricular arrhythmias. Multimodal imaging combined with extracardiac tissue culture may be decisive in establishing the correct diagnosis.

Atrial fibrillation is one of the most common supraventricular arrhythmias. It has multiple etiologies, some of which include advanced age, hypertension, valvular heart disease, hyperthyroidism, sleep apnea, ischemic heart disease, cardiomyopathy, and certain medications. Herein, we will discuss a case of extensive atrial fibrosis in a 57-year-old male with recalcitrant atrial fibrillation, the significant role extensive atrial fibrosis plays in the recurrence of atrial fibrillation, a brief pathophysiologic interplay between both pathologies based on current literature and research, and various imaging modalities and treatment options utilized in these cases. Likewise, we will also outline some challenges faced or worth keeping in mind when using the various imaging modalities pertaining to the above subject matter.

UNLABELLED: A 33-year-old man, who had undergone atriopulmonary connection Fontan procedure (AP Fontan) for double outlet right ventricle, suffered from heart failure due to atrial tachycardia at 27 years old. Atrial tachycardia was suppressed after amiodarone administration. At 32 years old, atrial tachycardia recurred, and short palpitations gradually increased. Cardiac computed tomography showed that coronary sinus (CS) was perfused into the pulmonary venous atrium, and catheter insertion to CS from the systemic venous atrium was impossible. We performed an electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA) under local anesthesia. An esophageal electrode catheter was inserted as a potential reference for ultra-high density three-dimensional (3D) mapping system. Two types of atrial tachycardia were induced by EPS. Ultra-high-density 3D mapping system revealed an intra-atrial reentrant pattern around the scar area on the lower right atrium in both atrial tachycardias; therefore, we diagnosed intra-atrial reentrant tachycardia (IART). The low voltage area and inferior vena cava during IART were ablated linearly, and IART was terminated.In conclusion, a CS electrode catheter cannot be inserted in a patient with AP Fontan, and ultra-high-density 3D mapping using the esophageal electrode catheter as a potential reference enables accurate and rapid mapping and is very effective for RFCA.
LEARNING OBJECTIVE: The incidence of intra-atrial reentrant tachycardia (IART) is high in patients with late after Fontan procedure, and the treatment may be difficult. Ultra-high-density three-dimensional mapping can perform accurate mapping of IART and rapid detection of low voltage areas effective for radiofrequency catheter ablation. An esophageal electrode catheter can be the reference potential for accurate activation mapping in Fontan patients where coronary sinus electrode catheter insertion may be impossible from a systemic venous atrium.

BACKGROUND: Premature ventricular complexes (PVCs) from the cardiac crux often have intramural or epicardial substrates, complicating localization and ablation.
CASE SUMMARY: A 53-year-old man presented with symptomatic, flecainide-refractory PVCs with a 24-hour Holter burden of 41.8%. An electrocardiogram showed frequent PVCs with 2 alternating QRS morphologies (right and left bundle branch block), both with a superior axis and subtle V1 to V2 and/or precordial differences, suggesting a single crux focus with preferential exits. Proximal coronary sinus mapping did not reveal early activation. Stepwise bilateral endocardial mapping identified the earliest basal inferoseptal activation. Standard irrigated radiofrequency catheter ablation caused only transient suppression. Half-normal saline irrigation at the earliest sites and a discrete prepotential achieved complete PVC elimination.
DISCUSSION: This case highlights idiopathic crux PVCs with variable morphologies from an intramural focus with preferential exits. A bilateral endocardial lesion-enhancement strategy may obviate epicardial access.
TAKE-HOME MESSAGES: Dual morphologies may share 1 crux focus, and bilateral endocardial mapping and lesion enhancement may be required for successful ablation.

BACKGROUND: Posterior wall isolation (PWI) is often added to pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) and at redo ablation. Still, procedural performance with the Affera pulsed field ablation (PFA) platform is not well described.
METHODS: We retrospectively analyzed consecutive patients who underwent PWI with the Affera Sphere-9 lattice-tip catheter from April to August 2025. Baseline characteristics and procedural data, including PWI time, number of lesions, and acute success, were analyzed. The primary procedural endpoint was acute PWI success. Secondary measures included time to PWI, number of applications, posterior wall area isolated, and complications.
RESULTS: Forty patients underwent PWI (paroxysmal AF 13 [32.5%], persistent AF 27 [67.5%]). First pass PWI was achieved in 97.5%; overall acute PWI success was 100%. Median time to complete PWI was 7.0 min (IQR 5.1-11.0). Mean lesions for PWI were 19.6 ± 6.6, and the mean posterior wall area isolated was 12.9 ± 4.5 cm². Two minor vascular complications occurred (5.0%): one acute and one delayed femoral hematoma, both managed conservatively. After a median follow-up of 76 [58.5-121] days, 38/40 (95%) patients remained free from atrial arrhythmia.
CONCLUSIONS: PWI with the Affera Sphere-9 system achieved 97.5% first-pass isolation with rapid, consistent procedural times. Further study of lesion durability and clinical outcomes is warranted.

BACKGROUND: Activation mapping is often used to differentiate focal from re-entrant arrhythmias. This can be challenging but is critical to ablation success. The local activation time (LAT) histogram, which depicts point distribution over isochronal segments, may help characterize arrhythmia mechanisms and identify an optimal ablation strategy.
OBJECTIVES: This study aimed to investigate features of the LAT histogram associated with the focal vs re-entrant mechanism of atrial tachycardias (ATs) and the use of the LAT histogram in the identification of target ablation sites.
METHODS: We retrospectively evaluated cases of focal and re-entrant ATs performed at a single academic tertiary care center for which activation mapping was performed using CARTO 3 version 7 software (Biosense Webster). Baseline patient, arrhythmia, and procedural characteristics as well as LAT histogram features were evaluated for each case. LAT histogram-guided ablation targets were also compared against actual ablation sites.
RESULTS: Among 52 ATs assessed, 17 were focal, and 35 were re-entrant. Tachycardia cycle length was significantly shorter in re-entrant than in focal ATs (288.2 milliseconds [Q1-Q3: 250-306.5 milliseconds] vs 370 milliseconds [Q1-Q3: 285-400 milliseconds], respectively; P = 0.006). LAT histograms contained more "valleys" in re-entrant than in focal ATs (3 [Q1-Q3: 2-4] vs 1 [Q1-Q3: 1-1]; P < 0.001). No focal ATs contained >2 and no re-entrant ATs contained <1 LAT valley(s). All successful ablation sites correlated with LAT histogram-suggested sites.
CONCLUSIONS: LAT histograms can help distinguish focal from re-entrant Ats and identify effective ablation sites.

INTRODUCTION: Pulsed-field ablation with a lattice-tip catheter has emerged as a promising technology for pulmonary vein isolation. We report a case of intraprocedural catheter malfunction with fibrin deposition potentially leading to a transient neurological deficit during ablation despite optimal anticoagulation.
CASE: A 39-year-old man with symptomatic atrial fibrillation and tachycardia-mediated cardiomyopathy underwent pulmonary vein isolation using the Affera mapping system and Sphere-9 lattice tip catheter. During the procedure, despite uninterrupted oral anticoagulation and heparin given to meet manufacturer-recommended activated clotting times, the catheter malfunctioned, and when removed, there was a white solid substance that was seen within the lattice tip. The procedure was stopped prematurely with incomplete pulmonary vein isolation. A pathologist confirmed the white substance was fibrin inside the lattice tip. The patient had symptoms of transient ischemic attack postoperatively and also suffered early recurrence of atrial fibrillation.
CONCLUSION: This case demonstrates fibrin deposition and possible embolic events using the Sphere-9 lattice tip catheter despite stringent anticoagulation protocols. This highlights the importance of meticulous catheter inspection as well as provides a post-market complication utilizing this catheter.

Despite the progress in understanding left atrial substrate and arrhythmogenesis, only little is known about conduction characteristics in atrial fibrillation patients with various stages of fibrotic atrial cardiomyopathy (FACM). This study evaluates left atrial conduction times and conduction velocities based on high-density voltage and activation maps in sinus rhythm (CARTO®3 V7) of 53 patients with persistent atrial fibrillation (LVEF 60% (55-60 IQR), LAVI 39 ml/m2 (31-47 IQR), LApa 24 ± 6 cm2). Measurements were made in low voltage areas (LVA ≤ 0.5 mV) and normal voltage areas (NVA ≥ 1.5 mV) at the left atrial anterior and posterior walls. Maps of 28 FACM and 25 no FACM patients were analyzed (19 FACM I/II, 9 FACM III/IV, LVA 14 ± 11 cm2). Left atrial conduction time averaged to 110 ± 24 ms but was shown to be prolonged in FACM (119 ms, + 17%) when compared to no FACM patients (101 ms, p = 0.005). This finding was pronounced in high-grade FACM (III/IV) (133 ms, + 31.2%, p = 0.001). In addition, the LVA extension correlated significantly with the left atrial conduction time (r = 0.56, p = 0.002). Conduction velocities were overall slower in LVA than in NVA (0.6 ± 0.3 vs. 1.3 ± 0.5 m/s, -51%, p < 0.001). Anterior conduction appeared slower than posterior, which was significant in NVA (1 vs. 1.4 m/s, -29%, p < 0.001) but not in LVA (0.6 vs. 0.8 m/s, p = 0.096). FACM has a significant influence on left atrial conduction characteristics in patients with persistent atrial fibrillation. Left atrial conduction time prolongs with the grade of FACM and the quantitative expanse of LVA up to 31%. LVAs show a 51% conduction velocity reduction compared to NVA. Moreover, regional conduction velocity differences are present in the left atrium when comparing anterior to posterior walls. Our data may influence individualized ablation strategies.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

BACKGROUND: Dextrocardia with atrial fibrillation (AF) complicates radiofrequency ablation treatment.
METHODS: A case of successful AF ablation in dextrocardia, guided by intracardiac echocardiography (ICE) and the Carto 3 high-density mapping system, is reported.
RESULTS: ICE-guided transseptal puncture and three-dimensional mapping facilitated successful pulmonary vein isolation (PVI). The patient had a good recovery with no recurrence.
CONCLUSION: ICE and Carto 3 system's high-density mapping aid in ablation for abnormal cardiac anatomy, reducing surgical complications.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

OBJECTIVE: To explore the predictive value of Real-world Cardiologist Performance (RWCP) score for atrial fibrillation (AF) recurrence risk after radiofrequency catheter ablation (RFCA).
METHODS: Patients with nonvalvular AF who underwent first-time RFCA at Luoyang Central Hospital affiliated to Zhengzhou University between October 2021 and June 2023 were included in this study. Detailed ablation data were exported from CARTO®3 system (Biosense Webster, USA), based on which, four parameters, including discharge time proportion, Catheter Contact Force Stability (C3-FOT proportion), Ablation Index Consistency (SURPOINT/TOP-4 proportion) and fragmented points proportion, were calculated. Then, the RWCP score was calculated from these parameters for each patient. Predictive value of the RWCP score for AF recurrence risk were assessed using Cox regression and Kaplan-Meier analyses.
RESULTS: A total of 148 AF patients were enrolled, including 68 males and 80 females. During follow-up, 30 patients (20.3%) experienced AF recurrence. The RWCP score was calculated using Cox regression coefficients: RWCP score = (left ring discharge time ratio × 2.853) - (left C3-FOT proportion × 0.91) + (left SURPOINT/TOP4 × 2.943) + (left fragmented points proportion × 0.423) - (right ring discharge time ratio × 4.039) - (right C3-FOT proportion × 6.159) - (right SURPOINT/TOP4 × 1.312) - (right points fragmented proportion × 4.425). It was found that patients with higher RWCP scores (-12.53 to 5.79) had higher recurrence risk than those with low scores (-28.68 to -12.76) (HR = 5.55, 95% CI: 2.23-13.80, p = 0.0002). Kaplan-Meier analysis confirmed this (plog-rank < 0.001). To simplify the operation of RWCP, an online calculator was explored using shiny platform (https://doctorwanghao.shinyapps.io/RWCP_English/).
CONCLUSION: The RWCP score shows promise as a tool for evaluating ablation completeness, assessing cardiologist performance and predicting AF recurrence risk after ablation.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

OBJECTIVES: Brugada syndrome is a life-threatening disease with an arrhythmogenic substrate located in the epicardium of right ventricle outflow tract. Therefore, the correct region identification is crucial for a successful ablation procedure. Various mapping techniques can be adopted to elaborate this issue, but they were all initially developed for endovascular use.
METHODS: In this study, we analysed 21 consecutive hybrid video-assisted thoracoscopic ablation of Brugada syndrome, performed using different mapping systems to identify the ablation target and confirm the elimination of arrhythmogenic substrate; 35 maps have been analysed.
RESULTS: Acute success of epicardial right ventricle outflow tract ablation has been achieved in 100% of procedures, no periprocedural complications have been observed; HD Grid catheter showed higher area identification speed and faster fractionated potentials visualization; Rhythmia system has demonstrated the best map density; Carto 3 system showed a significant advantage in patient preparation time, but mapping speed was reduced due to focal catheter use only.
CONCLUSIONS: All tested electro anatomical mapping systems can be used for hybrid video-assisted thoracoscopic ablation with same clinical success; however, accuracy and efficacy of mapping systems are heterogenous and highly dependent on proper patient preparation, mapping system and physician skills.

BACKGROUND: Ablation of persistent atrial fibrillation and atypical atrial flutter (AAFL) is limited by the durability of pulmonary vein isolation, progression of underlying atrial myopathy, and incomplete formation of linear and focal lesions from radiofrequency energy. Tissue characteristics and proximity to vulnerable tissue such as the esophagus and phrenic nerve play a role. Herein, we demonstrate that a focal form factor with dual-energy capability using predominantly pulsed field ablation (PFA) and integrated high-density mapping can yield improved results for complex AAFL circuits. METHODS: We analyzed data from consecutive patients at Minneapolis Heart Institute who underwent de novo or repeat ablations for AAFL or persistent atrial fibrillation between January and June 2025. Ablation was performed in all patients using the Affera (Medtronic) ablation system with the Sphere 9 dual-energy lattice tip focal form factor. Patients were followed for up to 6 months. RESULTS: Our cohort included 209 patients treated with Affera, of whom 74 patients (median age 72 [62,78], 55% male, and 99% Caucasian) underwent ablation for persistent atrial fibrillation or atypical atrial flutter. The mean procedural time was 94 min, with a median fluoroscopy time of 2.5 (0.0, 5.5) minutes and a median fluoroscopy dose of 3 (0,13) mGy. Acute procedural success was achieved in 99% of patients. No major cardiovascular and cerebrovascular events were reported within 30 days after the procedure. More than 80% of patients remained in sinus rhythm during a 6-month follow-up period. CONCLUSIONS: A significant percentage of patients presenting for ablation with the Affera system who had persistent atrial fibrillation or underwent repeat ablation demonstrated AAFL circuits. Sphere 9 is the first FDA-approved focal catheter with PFA capability for persistent atrial fibrillation, and our analysis of the Sphere 9 catheter with Affera in complex atrial flutter cases demonstrates safety, efficacy, and efficiency that may improve long-term outcomes in patients with complex atrial arrhythmias.

BACKGROUND: Functional mapping tools such as Coherent Mapping (CM) and Isochronal Late Activation Mapping (ILAM) allow visualization of conduction slowing and block during ventricular tachycardia (VT) ablation; however, their anatomical correlates within computed tomography (CT)–derived myocardial wall-thickness (WT) maps are incompletely defined. We aimed to evaluate the spatial relationship between CT-derived WT characteristics and functional electroanatomical markers and to assess the predictive value of WT-derived conduction channels (WTC) for identifying critical VT isthmuses. METHODS: Seven consecutive patients with ischemic cardiomyopathy undergoing VT ablation and pre-procedural contrast-enhanced CT were analyzed. WT maps and WTCs were reconstructed using the inHeart™ platform and integrated with CARTO 3 electroanatomical maps. CM-SCZs, ILAM-DZs, and lines of blocks (LOBs) were identified using predefined criteria and projected onto WT models. Local WT values, overlap with WT ≤ 5 mm regions, and Dice similarity coefficients were calculated to quantify anatomical–functional concordance. RESULTS: Eighteen CM-SCZs, 15 ILAM-DZs, and 12 LOBs were identified. Functional regions predominantly localized within thinned myocardium (WT ≤ 5 mm). Mean WT was 3.6 ± 0.8 mm for SCZs, 3.8 ± 0.9 mm for DZs, and 4.2 ± 1.1 mm for LOBs, compared with 6.3 ± 1.3 mm in remote myocardium (p < 0.01). SCZs overlapped with WT ≤ 5 mm areas by 74 ± 12% (Dice 0.67 ± 0.10), while DZs showed 70 ± 15% overlap (Dice 0.63 ± 0.11). Direct correspondence between WTCs and SCZs occurred in 50% of cases. CONCLUSIONS: Although CT-derived WTCs identify regions at risk, functional mapping remains essential for precise substrate delineation. Integrated CT and CM/ILAM analysis may enhance targeting efficiency during VT ablation.

The Affera system features a versatile and large footprint catheter with a lattice-tip design that is capable of delivering both pulsed field and radiofrequency energy. It provides precise mapping and ablation capabilities, demonstrating high acute success rates and durable lesion formation, with excellent safety profile in both radiofrequency and pulsed field ablation modes. Preclinical and clinical studies have shown high lesion durability, reduced procedural time, and promising outcomes in pulmonary vein isolation with minimal complications.

AIMS: Coherent mapping (CM) uses a new algorithm to identify critical conduction isthmuses of atrial tachycardias (ATs). We analysed our experience of ablation of AT in patients with congenital heart disease (CHD) with this new technology.
METHODS AND RESULTS: All patients with CHD who had CM of AT using the high-density mapping PENTARAY™ catheter and three-dimensional electroanatomic mapping system Carto3 between June 2019 and June 2021 were included retrospectively (n = 27). As a control group, 27 patients with CHD and mapping of AT without CM between March 2016 and June 2019 were included. In total, 54 ablation procedures were performed in 42 patients [median age 35 (interquartile range, IQR 30-48) years] and 64 ATs were induced and mapped (thereof 50 AT intraatrial re-entrant tachycardia and 14 AT ectopic AT). The median procedure duration was 180 (120-214) min and median fluoroscopy time was 10 (5.2-14) min. Acute success was 100% (27/27) in the Coherence group and 74% (20/27) in the non-Coherence group (P = 0.01). During follow-up [median 26 (12-45) months], AT recurred in 28/54 patients, thereof 15 patients needed a re-ablation procedure. Log-rank test showed no difference in recurrence rate between the two groups (P = 0.29). Three minor complications occurred (5.5%).
CONCLUSION: Mapping of AT in patients with CHD using the PENTARAY™ mapping catheter and the CM algorithm led to excellent acute success. All ATs were possible to map and no complications related to the PENTARAY™ mapping catheter were observed. Thus, the use of the CM algorithm represents a promising tool in patients with CHD and complex AT.

BACKGROUND: Scar-related atrial flutter (AFL) comprises complex reentrant atrial arrhythmias arising from areas of slow conduction typically in the setting of prior ablation, cardiac surgery, or atrial cardiomyopathy. Three-dimensional electroanatomic mapping is essential to define these complex circuits.
OBJECTIVE: This study evaluated the feasibility of mapping and ablation of AFL using the Affera mapping and ablation system.
METHODS: This single-center retrospective study included consecutive patients who underwent high-density mapping and catheter ablation of scar-related AFL using Sphere-9 catheter and Prism-1 software. The primary efficacy outcome was defined as termination of the AFL at the initial ablation site or within the surrounding area. Secondary efficacy outcomes were termination of AFL with ablation at any site and AFL recurrence on/off antiarrhythmic drugs during follow-up.
RESULTS: A total of 65 patients were included. Most patients had undergone ≥1 previous atrial fibrillation ablation procedure (87.7%). Median mapping time was 8 (6-10) minutes, with a median number of points acquired on activation maps of 835 (510-1175) for the right atrium and 1859 (1418-2531) for the left atrium. Termination of the clinical AFL at the initial ablation size or surrounding area was achieved in 79.4% of patients. Termination of AFL with ablation at any site was achieved in all patients. During a median follow-up of 69 (49-116) days, AFL recurrence occurred in 15% of patients.
CONCLUSIONS: The study results demonstrate the feasibility of Affera 3D-EAM System to successfully map and ablate scar-related AFLs.

AIMS: Robotic magnetic navigation (RMN) provides increased catheter precision and stability. Formerly, only the CARTO 3 mapping system was integrated with the RMN system (CARTO-RMN). Recently, a novel high-resolution non-contact mapping system (AcQMap) has been integrated with the RMN system (AcQMap-RMN) for the treatment of atrial fibrillation (AF) and atrial tachycardias (AT). We aim to compare the safety, efficiency, and efficacy of AcQMap-RMN with CARTO-RMN guided catheter ablation (CA) procedures.
MATERIAL AND METHODS: In this prospective registry, procedural safety efficiency and outcome data from total of 238 consecutive patients (147 AcQMap-RMN and 91 CARTO-RMN patients) were compared.
RESULTS: AcQMap-RMN is non-inferior in the primary endpoint of safety as compared to CARTO-RMN across the whole group (overall procedural complications in 5 (3.4%) vs. 3 (3.3%) patients, p = 1.0). Overall procedure durations were longer and associated with more fluoroscopy use with AcQMap-RMN (172.5 vs. 129.6 min, p < 0.01; 181.0 vs. 131.0 mGy, p = 0.02, respectively). Procedure duration and fluoroscopy use decreased significantly between the first 30 and the last 30 AcQMap-RMN procedures. The AcQMap-RMN system had fewer recurrences after persistent AF ablations and was non-inferior in paroxysmal AF patients compared to CARTO-RMN at 12 months (36.6% vs. 75.0%, p = 0.04, PAF 6.6% vs. 12.5%, p = 0.58; respectively). CA of AT outcomes were better using the AcQMap-RMN system (1 year recurrence 17.1% vs. 38.7%, p < 0.05).
CONCLUSION: AcQMap-RMN integration has no negative impact on the excellent safety profile of RMN guided ablations. It improves outcomes of CA procedures for persAF and AT but requires longer procedure times and higher fluoroscopy use during the initial learning phase.

BACKGROUND: Pulsed field ablation (PFA) has emerged as a nonthermal alternative for catheter ablation of atrial fibrillation (AF). However, experience on ablation in patients with a prior left atrial appendage occlusion (LAAO) device remains limited.
OBJECTIVES: This study aimed to assess the feasibility and safety of PFA in patients with an implanted LAAO device and evaluate outcomes in those undergoing a combined PFA and leak closure procedure.
METHODS: We analyzed consecutive patients with a prior LAAO device who underwent PFA alone or during a concomitant leak closure procedure for symptomatic AF. The primary endpoints were procedural success define as successful PFA delivery, and safety defined as the absence of device dislodgment, new peri-device leaks (PDLs), and device-related thrombus (DRT).
RESULTS: 73 consecutive patients were included in our analysis. PFA was performed using the Farapulse and Affera system in 45 (61.6%) and 28 (38.4%) respectively. Concomitant peridevice leak closure was performed in 18 patients (24.6%). The combined procedural endpoint was achieved in 70 (95.9%) of patients. At 2-months transoesophageal echocardiography follow-up, no new PDLs, DRT or dislodgment were detected in patients undergoing PFA alone, while two patients (11.1%) in the combined procedure group had residual leaks. Use of radiofrequency was necessary in 3 patients with an Amulet device to isolate the LAA.
CONCLUSION: Our findings suggest that PFA in patients with an implanted LAAO device is feasible. The combined approach of PFA and leak closure demonstrated high procedural efficacy.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation; however, recurrences often originate from non-pulmonary vein (non-PV) foci. The Complex Signal Identification (CSI) algorithm in CARTO 3 assigns electrogram-fractionation scores (0-10). This study evaluated the feasibility of CSI-assisted mapping for identifying non-PV triggers.
METHODS: We retrospectively analyzed 23 consecutive patients undergoing first-time AF ablation between January and June 2024. After PVI, non-PV triggers were induced using isoproterenol and adenosine triphosphate (ATP). When ectopy was absent, rapid pacing during isoproterenol infusion followed by defibrillation was performed, and ATP testing was repeated. High-density CSI mapping was conducted during sinus rhythm or high right atrial pacing using system default settings, targeting atrial components after ventricular blanking.
RESULTS: A total of 33 non-PV foci were localized (20 left atrium [LA], 13 right atrium [RA]). The mean CSI scores of LA and RA foci were 9.0 ± 2.3 and 8.8 ± 2.7, respectively. ROC analysis showed an AUC of 0.917 for discriminating non-PV foci, with an optimal cutoff of 8.5 (sensitivity 87.9%, specificity 88.3%). At 12 months, arrhythmia-free survival was 82.4% under symptom-driven follow-up. Ablation was selectively performed at the earliest activation and adjacent high-CSI points, avoiding indiscriminate lesion delivery.
CONCLUSIONS: CSI-assisted mapping provided practical, adjunctive guidance to provocation and activation mapping for non-PV focus localization. While apparent discrimination was promising, the 8.5 threshold remains exploratory. Larger multicenter studies with standardized CSI settings and systematic post-ablation assessment are warranted to validate these preliminary findings.

BACKGROUND: Posterior wall isolation (PWI) is often added to pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) and at redo ablation. Still, procedural performance with the Affera pulsed field ablation (PFA) platform is not well described.
METHODS: We retrospectively analyzed consecutive patients who underwent PWI with the Affera Sphere-9 lattice-tip catheter from April to August 2025. Baseline characteristics and procedural data, including PWI time, number of lesions, and acute success, were analyzed. The primary procedural endpoint was acute PWI success. Secondary measures included time to PWI, number of applications, posterior wall area isolated, and complications.
RESULTS: Forty patients underwent PWI (paroxysmal AF 13 [32.5%], persistent AF 27 [67.5%]). First pass PWI was achieved in 97.5%; overall acute PWI success was 100%. Median time to complete PWI was 7.0 min (IQR 5.1-11.0). Mean lesions for PWI were 19.6 ± 6.6, and the mean posterior wall area isolated was 12.9 ± 4.5 cm². Two minor vascular complications occurred (5.0%): one acute and one delayed femoral hematoma, both managed conservatively. After a median follow-up of 76 [58.5-121] days, 38/40 (95%) patients remained free from atrial arrhythmia.
CONCLUSIONS: PWI with the Affera Sphere-9 system achieved 97.5% first-pass isolation with rapid, consistent procedural times. Further study of lesion durability and clinical outcomes is warranted.

Catheter ablation therapy for persistent atrial fibrillation (PeAF) is both difficult and has limited outcomes. The mechanisms underlying the development and persistence of atrial fibrillation (AF) are not fully understood; therefore, ablation strategies are diverse. A 45-year-old man was referred to our hospital for persistent atrial fibrillation to undergo radiofrequency catheter insertion (RFCA). In the first session we conducted pulmonary vein isolation and additional linear ablation, including that of the roof line and posterior inferior line (posterior box lesion) as the stepwise ablation. However, AF was recurred in six months, therefore he was readmitted for second session ablation preoperative 3D computed tomography (CT) scan for drug-refractory PeAF was performed. The additional isolation of the left superior pulmonary vein and potential drivers of AF by mapping wavefront propagation using multipolar catheters by CARTOFINDER (Biosense Webster, Inc, Diamond Bar, CA, USA) was conducted. However, AF did not terminate. Tomography revealed that the left atrial (LA) diverticulum (LAD) was found uniquely. Electrophysiological findings showed focal firing of the myocardial sleeve and LA diverticulum by an approach for defragmented potentials by re-visiting in interval confidence level (ICL) mode included in the electroanatomical mapping system (CARTO 3, Biosense Webster, Inc, Diamond Bar, CA, USA) and the ablation by encircling this site finally made AF terminate. The AF has not recurred for more than 12 months without the use of antiarrhythmic drugs. This case report suggests that additional ablation around substrates in LAD may be effective for treating refractory AF.

BACKGROUND: Scar-related atrial flutter (AFL) comprises complex reentrant atrial arrhythmias arising from areas of slow conduction typically in the setting of prior ablation, cardiac surgery, or atrial cardiomyopathy. Three-dimensional electroanatomic mapping is essential to define these complex circuits.
OBJECTIVE: This study evaluated the feasibility of mapping and ablation of AFL using the Affera mapping and ablation system.
METHODS: This single-center retrospective study included consecutive patients who underwent high-density mapping and catheter ablation of scar-related AFL using Sphere-9 catheter and Prism-1 software. The primary efficacy outcome was defined as termination of the AFL at the initial ablation site or within the surrounding area. Secondary efficacy outcomes were termination of AFL with ablation at any site and AFL recurrence on/off antiarrhythmic drugs during follow-up.
RESULTS: A total of 65 patients were included. Most patients had undergone ≥1 previous atrial fibrillation ablation procedure (87.7%). Median mapping time was 8 (6-10) minutes, with a median number of points acquired on activation maps of 835 (510-1175) for the right atrium and 1859 (1418-2531) for the left atrium. Termination of the clinical AFL at the initial ablation size or surrounding area was achieved in 79.4% of patients. Termination of AFL with ablation at any site was achieved in all patients. During a median follow-up of 69 (49-116) days, AFL recurrence occurred in 15% of patients.
CONCLUSIONS: The study results demonstrate the feasibility of Affera 3D-EAM System to successfully map and ablate scar-related AFLs.

The learning curve for the novel RHYTHMIA HDx™ 3-dimensional electroanatomic system is unknown. Retrospective data collection was carried out at 3 U.K. centers from the introduction of RHYTHMIA HDx™ (Boston Scientific, Marlborough, MA, USA) and associated mapping and ablation catheters. Patients were matched with controls using the CARTO® 3 mapping system (Biosense Webster Inc., Diamond Bar, CA, USA). Fluoroscopy, radiofrequency ablation, and procedure times; acute and long-term success; and complications were assessed. A total of 253 study patients along with 253 controls were included. Significant correlations existed between procedural efficiency metrics and center experience for de novo atrial fibrillation (AF) ablation (procedure time, Spearman's ρ = -0.624; ablation time, ρ = -0.795; both P < .0005) and de novo atrial flutter (AFL) ablation (ablation time, ρ = -0.566; fluoroscopy time, ρ = -0.520; both P = .001). No correlations existed for other assessed atrial arrhythmias. For de novo AF and AFL, metrics significantly improved after 10 procedures in each center (procedure time [AF only, P = .001], ablation time [AF, P < .0005; AFL, P < .0005], and fluoroscopy time [AFL only, P = .0022]) and became comparable to those of controls. Acute success and long-term success did not experience significant improvements with experience, but they were comparable to the control group throughout. Complications with RHYTHMIA HDx™ were comparable to those associated with CARTO® 3. In conclusion, a short learning curve exists with the use of RHYTHMIA HDx™ for standardized procedures (de novo AF/AFL). Procedural performance improved and became comparable to that seen with CARTO® 3 following 10 cases at each center. Clinical outcomes at 6 and 12 months and complications were no different from those observed in controls.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

BACKGROUND: Cardioneuroablation (CNA) is recognized as a promising therapeutic option for adults with severe symptomatic bradycardia caused by excessive vagal tone. However, no pediatric cases have been reported to date. Therefore, the aim of this study is to evaluate the feasibility and efficacy of CNA in children.
METHODS: A 12-year-old male patient was hospitalized with symptoms of fatigue, palpitations, and syncope for more than 2 months, and was definitively diagnosed with functional sinoatrial node dysfunction by using a 12-lead electrocardiogram, 24-h Holter monitoring, loading dose of atropine test (0.04 mg/kg), and treadmill exercise test. Simultaneously, whole-exome sequencing was performed on the child and his core family members. After completing the preoperative examination and signing the informed consent form, the child underwent CNA therapy.
RESULTS: First, the electroanatomic structures of both atria were mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. Then, the local fractionated intracardiac electrograms of each cardiac ganglionated plexus (GP), including the GP between the aortic root and the medial wall of the superior vena cava, the GP between the posterior wall of the coronary sinus ostium and the left atrium, the GP between the anterior antrum of the right superior pulmonary vein and the superior vena cava, the GP in the superolateral area around the root of the left superior pulmonary vein, the GP around the root of the right inferior pulmonary vein, and the GP around the root of the left inferior pulmonary vein, were used as targets for ablation at a power of 30 W with an ablation index of 350-400. At a 6-month follow-up, the child's heart rhythm saw a complete restoration to sinus rhythm and clinical symptoms disappeared.
CONCLUSION: The first application of CNA in a child with symptomatic sinus bradycardia was achieved with better clinical outcomes. CNA can be carried out cautiously in children under suitable indications.

AIMS: Catheter ablation is an effective treatment method for recurrent ventricular tachycardias (VTs). However, at least in part, procedural and clinical outcomes are limited by challenges in generating an adequate lesion size in the ventricular myocardium. We investigated procedural and clinical outcomes of VT ablation using a novel 'large-footprint' catheter that allows the creation of larger lesions either by radiofrequency (RF) or by pulsed field (PF) energy.
METHODS AND RESULTS: In prospectively collected case series, we describe our initial experience with VT ablation using a lattice-tip, dual-energy catheter (Sphere-9, Medtronic), and a compatible proprietary electroanatomical mapping system (Affera, Medtronic). The study population consisted of 18 patients (aged 55 ± 15 years, one woman, structural heart disease: 94%, ischaemic heart disease: 56%, left ventricular ejection fraction: 34 ± 10%, electrical storm: 22%) with recurrent sustained VTs and ≥1 previously failed endocardial RF ablation with conventional irrigated-tip catheter in 66% of patients. On average, 12 ± 7 RF and 8 ± 9 PF applications were delivered per patient. In three-fourths of patients undergoing percutaneous epicardial ablation, spasms in coronary angiography were observed after PF applications. All resolved after intracoronary administration of nitrates. No acute phrenic nerve palsy was noted. One patient suffered from a stroke that resolved without sequelae. Post-ablation non-inducibility of VT was achieved in 89% of patients. Ventricular-arrhythmia-free survival at three months was 78%.
CONCLUSION: VT ablation using a dual-energy lattice-tip catheter and a novel electroanatomical mapping system is feasible. It allows rapid mapping and effective substrate modification with good outcomes during short-term follow-up.

BACKGROUND: Pulsed field ablation (PFA) has emerged as a non-thermal, tissue-selective modality for pulmonary vein isolation (PVI) in atrial fibrillation (AF) treatment, potentially minimizing collateral damage to adjacent structures. The VARIPULSE™ PFA system, integrated with the CARTO™ 3 electroanatomical mapping system, facilitates real-time catheter visualization, enabling procedures with minimal or no fluoroscopy. The objective is to evaluate the feasibility and acute safety of performing zero-fluoroscopy AF catheter ablation using the VARIPULSE™ PFA system in a cohort of consecutive patients with paroxysmal or persistent AF for 1 year.
METHODS: A prospective, single-center study was conducted involving consecutive patients undergoing AF ablation (PVI ± linear ablations) with the VARIPULSE™ system. Procedures were guided exclusively by the CARTO™ 3 system, without the use of fluoroscopy as well as intracardiac echocardiography (ICE). Data on procedural parameters, acute success rates, and complications were collected and analyzed.
RESULTS: A total of 121 consecutive patients were included in the study during 1 year with 60% of paroxysmal AF. Additional extra-pulmonary vein ablation (CTI or posterior wall isolation or both) was performed in 93 patients (76.9%). The mean time procedure was 44.5 ± 15.2 min and the success rate of zero-fluoroscopy was 98.4%. Two patients had an acute complication (1 TIA and 1 cardiogenic shock).
CONCLUSION: This study demonstrates the feasibility, safety, and time-efficiency of a fully standardized fluoroscopy-free workflow, including posterior wall and CTI ablation. The use of TEE instead of ICE enhances cost-efficiency, potentially facilitating broader adoption of the protocol. However, the single-center nature of the study and the lack of a comparative fluoroscopy group represent important limitations.

BACKGROUND: Ablation of persistent atrial fibrillation and atypical atrial flutter (AAFL) is limited by the durability of pulmonary vein isolation, progression of underlying atrial myopathy, and incomplete formation of linear and focal lesions from radiofrequency energy. Tissue characteristics and proximity to vulnerable tissue such as the esophagus and phrenic nerve play a role. Herein, we demonstrate that a focal form factor with dual-energy capability using predominantly pulsed field ablation (PFA) and integrated high-density mapping can yield improved results for complex AAFL circuits. METHODS: We analyzed data from consecutive patients at Minneapolis Heart Institute who underwent de novo or repeat ablations for AAFL or persistent atrial fibrillation between January and June 2025. Ablation was performed in all patients using the Affera (Medtronic) ablation system with the Sphere 9 dual-energy lattice tip focal form factor. Patients were followed for up to 6 months. RESULTS: Our cohort included 209 patients treated with Affera, of whom 74 patients (median age 72 [62,78], 55% male, and 99% Caucasian) underwent ablation for persistent atrial fibrillation or atypical atrial flutter. The mean procedural time was 94 min, with a median fluoroscopy time of 2.5 (0.0, 5.5) minutes and a median fluoroscopy dose of 3 (0,13) mGy. Acute procedural success was achieved in 99% of patients. No major cardiovascular and cerebrovascular events were reported within 30 days after the procedure. More than 80% of patients remained in sinus rhythm during a 6-month follow-up period. CONCLUSIONS: A significant percentage of patients presenting for ablation with the Affera system who had persistent atrial fibrillation or underwent repeat ablation demonstrated AAFL circuits. Sphere 9 is the first FDA-approved focal catheter with PFA capability for persistent atrial fibrillation, and our analysis of the Sphere 9 catheter with Affera in complex atrial flutter cases demonstrates safety, efficacy, and efficiency that may improve long-term outcomes in patients with complex atrial arrhythmias.

AIMS: Electrical reconnections between pulmonary veins (PVs) and the left atrium (LA) are frequently responsible for atrial fibrillation (AF) recurrences after pulmonary vein isolation (PVI). Multidetector computed tomography (MDCT)-derived images can be post-processed to detect intramyocardial fat (inFAT) by signal radiodensity thresholding. The role of inFAT on PV-LA reconnections remains unknown. The aim of this study was to analyse the relationship between inFAT localization at pre-procedural MDCT-derived inFAT maps from first AF ablation and PV-LA reconnections in patients with AF recurrence undergoing redo ablation.
METHODS AND RESULTS: We included 45 consecutive patients who underwent AF redo ablation presenting at least one PV-LA reconnection. First AF ablation pre-procedural MDCT-derived data were post-processed with ADAS 3D™ to create 3D LA inFAT maps, which were loaded into CARTO3 navigation system and merged with the electroanatomical map for reconnection site analysis. In 103 out of 156 (66.0%), PV-LA reconnection points inFAT was identified in the 6 mm diameter tag point depicted in the navigation system. When dividing the PVI line into standardized segments, those identified as containing PV-LA reconnection points (i.e. reconnection segments) exhibited significantly higher total inFAT volumes compared with non-reconnection segments (8.05 ± 6.56 vs. 5.40 ± 5.18 μL, P < 0.001). Additionally, reconnection segments showed greater volumes of inFAT components, specifically dense inFAT (0.06 ± 0.06 vs. 0.03 ± 0.04 μL, P < 0.001) and fat-myocardial admixture (7.98 ± 6.52 vs. 5.37 ± 5.16 μL, P < 0.001).
CONCLUSION: Intramyocardial fat is co-localized with two-thirds of PV-LA reconnection points in patients undergoing AF redo ablation. Reconnection segments exhibit significantly higher inFAT volumes compared to non-reconnection segments. This proof-of-concept study suggests that inFAT may play a role in PV-LA electrical reconnections following PVI.

BACKGROUND: Pulsed-field ablation (PFA) is a nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation (RFA). We compared the effects of PFA and RFA on heterogeneous ventricular scar in a swine model of healed infarction.
METHODS: In 9 swine, myocardial infarction was created by balloon occlusion of the left anterior descending artery. After a survival period of 8 to 10 weeks, ablation with PFA or RFA was performed at infarct border zones identified by abnormal electrograms. In the PFA group (4 swine), ablation was performed with a lattice catheter (Sphere-9, Affera, Inc). In the RFA group (5 swine), ablation was performed using a 3.5-mm tip catheter (Thermocool ST-SF; Biosense Webster). To further investigate the effect of RFA on temperature development in scar tissue, intramyocardial temperature was measured in healthy and infarcted myocardium using an ex vivo bath model.
RESULTS: A total of 11 PFA and 15 RFA lesions were created at infarct border zones with heterogeneous scar. PFA produced uniform and well-demarcated lesions exhibiting irreversible injury characterized by cardiomyocyte death, contraction bands, and lymphocytic infiltration. This effect of PFA extended from the subendocardium through collagen and fat to the epicardial layers. In contrast, the effect of RFA is less uniform and largely limited to the subendocardium with minimal effect on viable myocardium deeper to separating layers of collagen and fat. PFA produced deeper and more transmural lesions (6.4 [interquartile range, 5.5-7.5) versus 5.4 [interquartile range, 4.8-5.9]), 72% versus 30%, respectively; P≤0.02 for each comparison). The limited effect of RFA on viable myocardium at deeper infarct layers was related to a lower intramyocardial maximal temperature compared with healthy myocardium (P=0.01).
CONCLUSIONS: PFA may be advantageous for ablation in ventricular scar, producing lesions that unlike RFA are not limited to the subendocardium, but also eliminate viable myocardium separated from the catheter by collagen and fat.

BACKGROUND: Frequent premature atrial complexes (PACs) can increase the risk of atrial fibrillation or atrial tachycardia, and pharmacological therapy can be challenging.
OBJECTIVE: To report the use of three-dimensional electro-anatomical mapping of PAC originating from the right atrial free wall and treatment by radiofrequency ablation in three horses.
STUDY DESIGN: Retrospective case report.
CASE DESCRIPTION: Frequent premature atrial complexes (PACs) were diagnosed in three horses. Twelve-lead ECG and vectorcardiography suggested an origin in the right lateral free wall in two horses and the caudal right atrium in one horse. Three-dimensional electro-anatomical mapping (3D EAM) and radiofrequency ablation using the CARTO™ 3 system were performed. Isoprenaline or dobutamine administration allowed activating the focus of PACs during general anaesthesia. Activation mapping using Pattern Matching Filtering identified the origin of PACs at the mid portion of the right atrial free wall in all horses. In the first horse, ablation was not performed due to pacing-induced phrenic nerve stimulation at the site of earliest activation. In the second horse, PACs disappeared after the 18th energy application and were no longer inducible by dobutamine. In the last horse, ablation was not successful in eliminating PACs.
MAIN LIMITATION: Small number of cases.
CONCLUSION: The 3D EAM identified the focus of PACs at the right atrial free wall in three horses, revealing it as a possible arrhythmogenic area. Although still challenging, radiofrequency ablation has promise as a treatment to provide a permanent solution for frequent PACs.

AIMS: Single-shot pulmonary vein isolation can improve procedural efficiency. To assess the capability of a novel, expandable lattice-shaped catheter to rapidly isolate thoracic veins using pulsed field ablation (PFA) in healthy swine.
METHODS AND RESULTS: The study catheter (SpherePVI; Affera Inc) was used to isolate thoracic veins in two cohorts of swine survived for 1 and 5 weeks. In Experiment 1, an initial dose (PULSE2) was used to isolate the superior vena cava (SVC) and the right superior pulmonary vein (RSPV) in six swine and the SVC only in two swine. In Experiment 2, a final dose (PULSE3) was used for SVC, RSPV, and left superior pulmonary vein (LSPV) in five swine. Baseline and follow-up maps, ostial diameters, and phrenic nerve were assessed. Pulsed field ablation was delivered atop the oesophagus in three swine. All tissues were submitted for pathology. In Experiment 1, all 14/14 veins were isolated acutely with durable isolation demonstrated in 6/6 RSPVs and 6/8 SVC. Both reconnections occurred when only one application/vein was used. Fifty-two and 32 sections from the RSPVs and SVC revealed transmural lesions in 100% with a mean depth of 4.0 ± 2.0 mm. In Experiment 2, 15/15 veins were isolated acutely with 14/15 veins (5/5 SVC, 5/5 RSPV, and 4/5 LSPV) durably isolated. Right superior pulmonary vein (31) and SVC (34) sections had 100% transmural, circumferential ablation with minimal inflammation. Viable vessels and nerves were noted without evidence of venous stenosis, phrenic palsy, or oesophageal injury.
CONCLUSION: This novel expandable lattice PFA catheter can achieve durable isolation with transmurality and safety.

BACKGROUND: Pulmonary vein isolation (PVI) has become the cornerstone of atrial fibrillation (AF) treatment. Nevertheless, the efficacy of radiofrequency ablation remains limited by a substantial rate of recurrence. The selection of anesthesia, the surgeon's operative experience and medical expertise, as well as the ablation surgery strategy, all have an impact on the recurrence after atrial fibrillation surgery. Our research aims to explore a novel method for predicting atrial fibrillation (AF) recurrence.
METHODS: This study enrolled 148 patients with atrial fibrillation (AF) undergoing first-time radiofrequency ablation. Based on the data from the AIFV system (an artificial intelligence-based ablation quality analysis system that generates structured Vistag scores from CARTO3 mapping data), patients were divided into two groups: the high-score group(Vistag analysis scores ≥ V5) and the low-score group(scores < V5). Baseline characteristics, intraoperative parameters, and AIFV system-related data were collected. Multivariate logistic regression analysis was performed to identify factors associated with atrial fibrillation (AF) recurrence.
RESULTS: Among the 148 enrolled patients, 84 were categorized into the high-score group and 64 into the low-score group. Patients in the low-score group had significantly higher Left Ventricular End-Diastolic Volume (LVEDV), Left Ventricular Ejection Fraction (LVEF), and Left Ventricular End-Systolic Volume (LVESV), as well as a higher prevalence of diabetes (29.5% vs. 9.5%, p = 0.002). During a minimum follow-up of 365 days, 11 patients (13.1%) in the high-score group experienced recurrence of atrial arrhythmia, compared to 19 patients (29.7%) in the low-score group. Kaplan-Meier analysis revealed a significantly higher atrial arrhythmia-free survival rate in the high-score group (log-rank test, P = 0.012). Multivariate logistic regression analysis revealed that being in the high-score group was an independent protective factor against AF recurrence (OR = 0.383, 95% CI 0.160-0.912, P = 0.030).
CONCLUSIONS: The AIFV system was used to evaluate six procedural parameters in each atrial fibrillation procedure, which could play a crucial role in predicting the recurrence of atrial fibrillation.

BACKGROUND: A novel ultra-high-resolution mapping system (Clarysense, Biosense Webster, Inc) has been developed that consists of a 100-electrode deflectable bidirectional basket-shaped high-density mapping catheter that incorporates a central TRUEref electrode and is integrated with the CARTO 3 system.
OBJECTIVE: This study aimed to assess the clinical safety and performance of the novel system for mapping in complex atrial and ventricular arrhythmias.
METHODS: This prospective, single-arm, multicenter study included patients undergoing catheter mapping and ablation of atrial and ventricular arrhythmias. Mapping was performed with the study catheter, and participants were ablated per the investigator's standard of care. The primary effectiveness endpoint was completion of preablation electroanatomic mapping without resorting to a nonstudy catheter. The primary safety endpoint was the incidence of device-related serious adverse events within 7 days. Physician feedback on catheter performance was collected using a 7-point Likert scale.
RESULTS: 40 participants (mean age 58.0 ± 15.73 years; 62.5% male; 30 with atrial arrhythmias, 10 with ventricular arrhythmias) underwent mapping with the study catheter. The primary effectiveness endpoint was achieved in all participants; ≥1 area of interest for mappable rhythms was identified in 23 of 30 participants with atrial arrhythmia. One serious adverse event of transient complete atrioventricular block was reported in a participant with persistent atrial fibrillation during preablation mapping, with full recovery. Physician feedback indicated that the device met or exceeded expectations for signal quality; most responders rated highly on bipolar signal quality in atria and noise encountered.
CONCLUSION: In this first-in-human study, the novel mapping system improved high-density mapping in complex arrhythmias with high-quality signals and map resolution. The catheter exceeded operators' expectations in signal fidelity.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is widely used to treat arrhythmias. However, for atrial fibrillation, the recurrence rate after RFCA is still high. The development of an animal model that mimics the recurrence of electrical conduction after ablation is essential before we can explore the mechanisms involved or develop new therapeutic strategies.
METHODS: Eighteen beagles aged 12 to 24 months were randomly assigned to this study. RFCA ablation of the right atrial free wall was performed. Then, electrical block and conduction recovery in the ablation area were evaluated using voltage mapping and pacing tests assisted by CARTO3 system. Finally, liposome doxorubicin (DOX-L) was intravenously injected after ablation to investigate the effect of DOX-L on this animal model.
RESULTS: The conduction block (CB) rates at 5 min after ablation were 16.7%, 83.3%, and 100%, corresponding to 30w, 35w, and 40w power, respectively. However, after 20 min, the rate of CB was 0%, 33.3%, and 75%; thus, the combined success rate of CB and conduction recurrence was 16.7%, 50%, and 25%, respectively. The optimal ablation parameter is 35 W for 20 s, based on the CB rate, REC rate. After 10 days of ablation, the residual conduction recurrence rate was as high as 83.3% in the RFCA alone group, whereas there was no recurrence with RFCA combined with DOX-L treatment.
CONCLUSIONS: The novel model accurately simulated the electrical conduction recurrence after cardiac radiofrequency ablation. RFCA combined with DOX-L treatment dramatically reduces the recurrence rate of electrical conduction after ablation.

Catheter ablation in longstanding persistent atrial fibrillation (AF) presents unique challenges, particularly in patients with large left atria and prior atrioventricular nodal dysfunction. While novel pulsed-field ablation (PFA) has been shown to be safer, no data yet show that a large focal lattice-tip catheter may be more effective. We present a 66-year-old man with symptomatic, longstanding, persistent AF and underlying sick sinus syndrome who underwent catheter ablation using Affera 3D mapping (Medtronic, Minneapolis, MN) and the Sphere 9 catheter (Medtronic, Inc, Mounds View, MN) to provide a combined pulsed field and radiofrequency approach. High-resolution electroanatomic mapping guided pulmonary vein isolation, which was extended to include posterior wall isolation, mitral isthmus ablation, and cavotricuspid isthmus ablation due to multiple arrhythmia foci. During delivery of PFA to complete posterior wall isolation, there was termination of AF to a normal sinus rhythm. This case highlights the utility of comprehensive lesion sets and advanced mapping technologies in achieving rhythm control in complex persistent AF.

BACKGROUND: Dextrocardia is a rare congenital condition, affecting approximately 1 in 10,000-12,000 individuals. When combined with atrial fibrillation (AF), it becomes even rarer. "One-stop" surgery, including combined radiofrequency ablation (RFA) and left atrial appendage occlusion (LAAO), has become a common clinical treatment for patients with AF who develop cerebral infarction despite regular oral anticoagulants. To date, no cases have been reported of patients with AF and dextrocardia undergoing the "one-stop" procedure, making this surgery particularly challenging.
CASE PRESENTATION: An 85-year-old dextrocardia male with total visceral inversion and persistent AF developed cerebral infarction despite regular oral anticoagulation therapy. He was referred to our hospital for RFA of AF and LAAO. The procedure was successfully performed using a three-dimensional electroanatomical mapping system (Carto3, Biosense Webster, Diamond Bar, CA, USA), intracardiac echocardiography (ICE), and x-ray, with no complications.
CONCLUSION: This is the first reported case of a "one-stop" surgery for dextrocardia with AF. This procedure is safe and feasible with the assistance of advanced technologies such as ICE and the VIZIGO bidirectional adjustable bent sheath.

AIMS: Catheter ablation is an effective treatment method for recurrent ventricular tachycardias (VTs). However, at least in part, procedural and clinical outcomes are limited by challenges in generating an adequate lesion size in the ventricular myocardium. We investigated procedural and clinical outcomes of VT ablation using a novel 'large-footprint' catheter that allows the creation of larger lesions either by radiofrequency (RF) or by pulsed field (PF) energy.
METHODS AND RESULTS: In prospectively collected case series, we describe our initial experience with VT ablation using a lattice-tip, dual-energy catheter (Sphere-9, Medtronic), and a compatible proprietary electroanatomical mapping system (Affera, Medtronic). The study population consisted of 18 patients (aged 55 ± 15 years, one woman, structural heart disease: 94%, ischaemic heart disease: 56%, left ventricular ejection fraction: 34 ± 10%, electrical storm: 22%) with recurrent sustained VTs and ≥1 previously failed endocardial RF ablation with conventional irrigated-tip catheter in 66% of patients. On average, 12 ± 7 RF and 8 ± 9 PF applications were delivered per patient. In three-fourths of patients undergoing percutaneous epicardial ablation, spasms in coronary angiography were observed after PF applications. All resolved after intracoronary administration of nitrates. No acute phrenic nerve palsy was noted. One patient suffered from a stroke that resolved without sequelae. Post-ablation non-inducibility of VT was achieved in 89% of patients. Ventricular-arrhythmia-free survival at three months was 78%.
CONCLUSION: VT ablation using a dual-energy lattice-tip catheter and a novel electroanatomical mapping system is feasible. It allows rapid mapping and effective substrate modification with good outcomes during short-term follow-up.

A patient with tricuspid valve atresia and pulmonary artery valve stenosis underwent a total cavo-pulmonary circulation with an unfenestrated intracardiac conduit. He experienced poorly tolerated atrial tachycardia and was referred for radiofrequency catheter ablation (RFCA). No interatrial shunt was evident. Before the procedure, a computed tomography (CT) scan with 3D rendering was performed. At the time of the procedure, the 3D rendering was merged with an electroanatomical map (EAM) performed by CARTO3 in sinus rhythm (SR). The merge guided the identification of the exact target point for a safe transeptal puncture, without using intracardiac and/or transesophageal echocardiography. The EAM during the tachycardia showed a reentrant circuit with a critical isthmus in the lateral portion of the Fontan conduit, and RFCA was performed restoring SR.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

OBJECTIVES: To compare the safety and efficacy of completely zero-fluoroscopy radiofrequency ablation (RFA) with that of conventional RFA guided by three-dimensional mapping in Chinese children with paroxysmal supraventricular tachycardia (PSVT).
METHODS: The study had a single-center observational design and included 46 children aged 6-14 years who underwent RFA for PSVT at the Second Hospital of Hebei Medical University between March 2019 and September 2021. The children were divided according to whether they underwent zero-fluoroscopy RFA (zero-fluoroscopy group, n = 26) or routine RFA under X-ray guidance (conventional group, n = 20). Three-dimensional mapping was used in both groups. Baseline characteristics, total procedure time, RFA time, volume and duration of X-ray exposure, target mapping time, the immediate RFA success rate, incidence of complications, and recurrence rate were compared between the two groups.
RESULTS: The children had a median age of 12 years (interquartile range 10, 13), 47.8% (22/46) were boys, and 52.2% (24/46) were girls. The mean body weight was 48.75 ± 15.26 kg. There was no significant between-group difference in the baseline data (P > 0.05). All children were followed up as outpatients at 1, 3, and 6 months postoperatively. The target mapping time was significantly longer in the zero-fluoroscopy group than in the conventional group (12.96 ± 2.24 min vs. 6.65 ± 2.56 min, P < 0.05); however, there was no significant between-group difference in the immediate success rate (100% vs. 100%), success rate at 6 months postoperatively (92.30% vs. 95.00%), complication rate (0% vs. 0.05%), recurrence rate (7.70% vs. 5.00%), RFA time (212.50 s vs. 214.00 s), or total procedure time (78.50 min vs. 74.00 min) (P > 0.05).
CONCLUSION: Zero-fluoroscopy catheter ablation can completely avoid fluoroscopy exposure in children without affecting the safety and efficacy of RFA.

The Affera system features a versatile and large footprint catheter with a lattice-tip design that is capable of delivering both pulsed field and radiofrequency energy. It provides precise mapping and ablation capabilities, demonstrating high acute success rates and durable lesion formation, with excellent safety profile in both radiofrequency and pulsed field ablation modes. Preclinical and clinical studies have shown high lesion durability, reduced procedural time, and promising outcomes in pulmonary vein isolation with minimal complications.

BACKGROUND: A novel 3D mapping system (KODEX-EPD, EPD Solutions) enables catheter localization and real-time 3D cardiac mapping.
OBJECTIVE: To evaluate left atrium (LA) anatomical mapping accuracy created by the KODEX-EPD system during pulmonary vein isolation (PVI) compared with gold standard computed tomography (CT) images acquired from the same patients before the procedure.
METHODS: In 15 consecutive patients who underwent PVI, 3D mapping of the LA was created on the KODEX-EPD system using the Achieve catheter. Pulmonary vein (PV), posterior wall, and appendage anatomy and diameters, were compared to the CT 3D reconstruction measured on the CARTO 3 system. Measurements were done independently by two physicians in each method. Linear correlation and agreement between CT and EPD measurements were assessed by Spearman correlation and Bland-Altman plot.
RESULTS: Mean LA mapping time was 7.7 ± 3.6 min. Very high interobserver correlation was found for both EPD and CT measurements (Spearman r = .9). High correlation (r = .75) was found between CT and EPD measurements. Bland-Altman plot method revealed that measurements assessed by EPD were slightly higher than those assessed by CT. Mean difference was 3.5 mm, p < .01. In 2 (13.5%) patients each, disagreement regarding the presence of a left common PV and a right middle accessory vein anatomy was seen.
CONCLUSION: The new KODEX-EPD mapping system allows quick and accurate mapping of the LA with high correlation to CT imaging. Some differences in left common and accessory right middle vein anatomy were seen.

AIMS: Single-shot pulmonary vein isolation can improve procedural efficiency. To assess the capability of a novel, expandable lattice-shaped catheter to rapidly isolate thoracic veins using pulsed field ablation (PFA) in healthy swine.
METHODS AND RESULTS: The study catheter (SpherePVI; Affera Inc) was used to isolate thoracic veins in two cohorts of swine survived for 1 and 5 weeks. In Experiment 1, an initial dose (PULSE2) was used to isolate the superior vena cava (SVC) and the right superior pulmonary vein (RSPV) in six swine and the SVC only in two swine. In Experiment 2, a final dose (PULSE3) was used for SVC, RSPV, and left superior pulmonary vein (LSPV) in five swine. Baseline and follow-up maps, ostial diameters, and phrenic nerve were assessed. Pulsed field ablation was delivered atop the oesophagus in three swine. All tissues were submitted for pathology. In Experiment 1, all 14/14 veins were isolated acutely with durable isolation demonstrated in 6/6 RSPVs and 6/8 SVC. Both reconnections occurred when only one application/vein was used. Fifty-two and 32 sections from the RSPVs and SVC revealed transmural lesions in 100% with a mean depth of 4.0 ± 2.0 mm. In Experiment 2, 15/15 veins were isolated acutely with 14/15 veins (5/5 SVC, 5/5 RSPV, and 4/5 LSPV) durably isolated. Right superior pulmonary vein (31) and SVC (34) sections had 100% transmural, circumferential ablation with minimal inflammation. Viable vessels and nerves were noted without evidence of venous stenosis, phrenic palsy, or oesophageal injury.
CONCLUSION: This novel expandable lattice PFA catheter can achieve durable isolation with transmurality and safety.

AIMS: To assess potential benefits of a local activation time (LAT) automatic acquisition protocol using wavefront annotation plus an ECG pattern matching algorithm [automatic (AUT)-arm] during premature ventricular complex (PVC) ablation procedures.
METHODS AND RESULTS: Prospective, randomized, controlled, and international multicentre study (NCT03340922). One hundred consecutive patients with indication for PVC ablation were enrolled and randomized to AUT (n = 50) or manual (MAN, n = 50) annotation protocols using the CARTO3 navigation system. The primary endpoint was mapping success. Clinical success was defined as a PVC-burden reduction of ≥80% in the 24-h Holter within 6 months after the procedure. Mean age was 56 ± 14 years, 54% men. The mean baseline PVC burden was 25 ± 13%, and mean left ventricular ejection fraction (LVEF) 55 ± 11%. Baseline characteristics were similar between the groups. The most frequent PVC-site of origin were right ventricular outflow tract (41%), LV (25%), and left ventricular outflow tract (17%), without differences between groups. Radiofrequency (RF) time and number of RF applications were similar for both groups. Mapping and procedure times were significantly shorter in the AUT-arm (25.5 ± 14.3 vs. 32.8 ± 12.6 min, P = 0.009; and 54.8 ± 24.8 vs. 67.4 ± 25.2, P = 0.014, respectively), while more mapping points were acquired [136 (94-222) AUT vs. 79 (52-111) MAN; P < 0.001]. Mapping and clinical success were similar in both groups. There were no procedure-related complications.
CONCLUSION: The use of a complete automatic protocol for LAT annotation during PVC ablation procedures allows to achieve similar clinical endpoints with higher procedural efficiency when compared with conventional, manual annotation carried out by expert operators.

BACKGROUND: Posterior wall isolation (PWI) is often added to pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) and at redo ablation. Still, procedural performance with the Affera pulsed field ablation (PFA) platform is not well described.
METHODS: We retrospectively analyzed consecutive patients who underwent PWI with the Affera Sphere-9 lattice-tip catheter from April to August 2025. Baseline characteristics and procedural data, including PWI time, number of lesions, and acute success, were analyzed. The primary procedural endpoint was acute PWI success. Secondary measures included time to PWI, number of applications, posterior wall area isolated, and complications.
RESULTS: Forty patients underwent PWI (paroxysmal AF 13 [32.5%], persistent AF 27 [67.5%]). First pass PWI was achieved in 97.5%; overall acute PWI success was 100%. Median time to complete PWI was 7.0 min (IQR 5.1-11.0). Mean lesions for PWI were 19.6 ± 6.6, and the mean posterior wall area isolated was 12.9 ± 4.5 cm². Two minor vascular complications occurred (5.0%): one acute and one delayed femoral hematoma, both managed conservatively. After a median follow-up of 76 [58.5-121] days, 38/40 (95%) patients remained free from atrial arrhythmia.
CONCLUSIONS: PWI with the Affera Sphere-9 system achieved 97.5% first-pass isolation with rapid, consistent procedural times. Further study of lesion durability and clinical outcomes is warranted.

BACKGROUND: An RFA lesion quality indicator, Surpoint Tag Index® (TI) incorporates key factors: power, time, and contact force, impacting lesion quality. TI accurately estimates lesion depth in animal studies. However, the relationship between TI and in-vivo atrial wall thickness in patients exhibiting bidirectional block remains unknown.
OBJECTIVE: To describe the relationship between atrial wall thickness and TI in CTI exhibiting bidirectional block.
METHODS: Data from 492 RFA lesions from 25 patients undergoing PVI and CTI ablations in SR with point-by-point RF lesions (<45 W) utilizing a Thermocool Smarttouch® SF ablation catheter and CARTO-3 mapping were retrospectively analyzed. Operators were blinded to TI data and CTI thickness. CTI thickness was obtained using ICE images on Cartosound pre-ablation. Durable lesions were defined as part of a lesion set exhibiting bidirectional block of >30 min.
RESULTS: In lesions exhibiting bidirectional block, the thinnest (1-2 mm; 5% lesions) and thickest (8-10 mm; 6% lesions) portions of the CTI correlated with the lowest (429 ± 75) and highest (516 ± 64) TI. The bulk of thickness (2-6 mm; 80%) correlated with a TI of 455 ± 72 (p = 0.001). There was a weak but positive correlation between TI and CTI thickness (r = 0.2; p ≤ 0.01). Examined in sectors, the anterior 1/3rd CTI was the thickest (4.8 ± 1.9 mm) but correlated with a similar TI value (479 ± 75 vs. 471 ± 70; p = 0.34) as the thinner middle 1/3rd (3.8 ± 1.7 mm; p ≤ 0.0001).
CONCLUSION: A mean TI value of 455 correlates with bidirectional block across the bulk of CTI with lower and higher values needed for the thinner and thicker portions, respectively. Tissue composition, aside from wall thickness, influences TI values for the creation of the bidirectional block.

Background and Objectives: Atrial fibrillation (AF) is the most common cardiac arrhythmia, present in up to 14-20% of patients undergoing cardiac surgery, with the number of patients expected to double within the next decade. Despite a Class I recommendation for concomitant surgical ablation and a Class I-B recommendation for left atrial appendage (LAA) occlusion in patients with AF undergoing cardiac surgery (Class IIa for endoscopic or hybrid AF ablation), both procedures remain substantially underutilized in clinical practice. The design of the Mapping atrial fibrillation after Epicardial Surgical Ablation plus AtriClip to Guide Endocardial ablation (MESAGE) prospective study is presented. Materials and Methods: A narrative literature review was conducted using PubMed through March 2025. Randomized controlled trials, multicenter registries, meta-analyses and current clinical guidelines were prioritized. The MESAGE study protocol is presented in accordance with the SPIRIT recommendations. Results: Randomized evidence demonstrates that hybrid ablation achieves 32-48% greater arrhythmia freedom than catheter ablation (CA) alone in persistent and long-standing persistent AF, with comparable safety and significantly fewer interventions at two-year follow-up. Epicardial LAA occlusion with the AtriClip device achieves complete occlusion in all patients with an 87.5% relative reduction in ischemic stroke risk in anticoagulation-free follow-up. Continuous implantable loop recorder (ILR)-based monitoring reveals AF recurrence in substantially more patients than conventional monitoring, with AF burden emerging as a more meaningful endpoint than arrhythmia freedom. The MESAGE study enrolls 40 patients undergoing cardiac surgery who have pre-existing AF, pre-randomized 1:1 to pulmonary vein isolation (PVI) alone versus PVI-BOX, with mandatory pre-operative ILR implantation, intra-operative AtriClip LAA exclusion, and systematic Day-60 endocardial mapping and supplementary ablation using the Affera dual-energy system. Conclusions: Hybrid epicardial-endocardial ablation combined with LAA exclusion and continuous ILR monitoring represents a comprehensive, mechanistically rational and evidence-informed approach to AF management in patients undergoing cardiac surgery, although current evidence remains heterogeneous, and the benefits depend on the AF phenotype and monitoring strategy. The MESAGE pilot study will generate hypothesis-generating prospective comparative data on epicardial PVI versus PVI-BOX in the concomitant surgical setting, assessed through systematic post-surgical endocardial mapping and continuous rhythm monitoring.

BACKGROUND: No evidence exists regarding whether tissue proximity indication (TPI), an impedance-based contact indicator, can improve in vivo lesion formation and durability during pulsed field ablation (PFA).
OBJECTIVE: This in vivo study investigated the relationship between catheter-tissue contact and lesion formation.
METHODS: In 5 porcine subjects, PFA applications were delivered at 35 atrial target sites using the VARIPULSE variable-loop circular catheter with the CARTO 3 mapping system. We compared acute ablative low-voltage zones (LVZs; <0.5 mV), chronic LVZs, and pathologic lesions between no/minimum contact (TPI-negative/flickering TPI-positive status) and consistent tissue contact (consistent TPI-positive status) for typical clinical scenarios and tissue tenting (TPI-positive status with electrodes extensively away from the 3-dimensional mapping surface) for safety margin. Ultrasound imaging also confirmed contact category assessments.
RESULTS: Acute and chronic LVZs were significantly larger with consistent contact compared with no/minimum contact, including pathologic lesion length (36.0 ± 12.5 mm vs 17.4 ± 15.2 mm; P = .002) and maximum width (10.3 ± 2.7 mm vs 5.7 ± 5.1 mm; P = .035); results with tenting (length: 34.6 ± 11.7 mm; width: 11.3 ± 1.9 mm) were comparable to consistent contact. Lesion transmurality was achieved in all lesions with consistent contact or tissue tenting but only in 54.5% with no/minimum contact (P = .001 for each). The TPI-based electrode contact distance, measured as the cumulative length of the multielectrode catheter tip positive for TPI, significantly correlated with lesion length, maximum width, and transmurality.
CONCLUSION: Consistent TPI-based contact during PFA was strongly associated with distinct chronic transmural lesions, emphasizing the importance of tissue contact in optimizing circumferential lesion formation with circular PFA catheters.

OBJECTIVE: This report describes the first use of the Affera Sphere-9 dual-energy catheter for slow pathway modification in atrioventricular nodal re-entrant tachycardia (AVNRT) during atrial fibrillation (AF) ablation in a patient with a dual-chamber pacemaker, illustrating a streamlined single-catheter approach.
CASE PRESENTATION: A 74-year-old man with prior cryoablation for AF, mitral valve repair, and a recently implanted dual-chamber pacemaker was referred for repeat AF ablation due to symptomatic, recurrent AF (30% burden). Left atrial mapping with the Sphere-9 catheter revealed reconnection at the right superior pulmonary vein, right carina, and across prior roof and floor lines. Using pulsed field (4-s lesions, 8 mm spacing) and supplemental radiofrequency (RF) energy, the left atrial posterior wall was re-isolated. Cavo-tricuspid isthmus ablation was performed with RF and pulsed field applications, achieving bidirectional block. During subsequent testing, typical AVNRT was induced. To maximize efficiency, slow pathway modification was performed with the same Sphere-9 catheter, using shortened RF applications (3 s), a lower target temperature (60°C), and an 80% current limit, at an inferior-posterior site 1.3-2.5 cm from the His signal. Junctional acceleration was observed without atrioventricular block, indicating successful slow pathway modification. The procedure was completed without fluoroscopy or complications, and follow-up device interrogation showed no recurrence of AF or AVNRT.
CONCLUSION: This case demonstrates the feasibility and acute safety of using a single dual-energy lattice-tip catheter for combined AF and AVNRT ablation, potentially reducing procedure time, catheter exchanges, and cost; larger studies are needed to assess long-term outcomes.

Aim: Pulsed field ablation (PFA) is a minimally thermal alternative to traditional thermal catheter ablation for atrial fibrillation (AF), with comparable efficacy and minimal risk of collateral tissue injury. Three-dimensional (3D) electroanatomical mapping systems have been adopted with nonintegrated PFA catheters to improve precision and procedural efficiency. This study compared arrhythmia-related hospital readmissions and procedure-related complications among patients with AF treated with PFA, using either the CARTO™ 3 or EnSite™ electroanatomical mapping system. Materials & methods: Patients who underwent PFA for AF using nonintegrated pulsed field catheters with either CARTO 3 or EnSite were identified from the 2023-2024 Premier Healthcare Database (PHD). The primary outcome was 30-day inpatient readmission and emergency room (ER) visit for AF/atrial flutter (AFL)/atrial tachycardia following the index PFA procedure. Secondary outcomes included 30-day cardiovascular-related readmissions and procedure-related complications. Cohorts were balanced using inverse probability of treatment weighting. Descriptive analyses and a weighted Generalized Estimating Equation (GEE) model were used to assess differences in outcomes between groups. Results: A total of 2894 patients were treated using CARTO 3 and 2015 using EnSite. After weighting, patient and hospital characteristics were well balanced across cohorts. The CARTO 3 group was significantly less likely to experience AF/AFL/atrial tachycardia-related readmissions (0.3% vs 0.9%, chi-square p = 0.023; odds ratio [OR], 0.39; 95% CI, 0.17-0.90, GEE p = 0.028) and a composite outcome of AF/AFL/atrial tachycardia-related inpatient readmission or ER visits (0.5% vs 1.1%, chi-square p = 0.020; OR: 0.44, 95% CI: 0.21-0.89, GEE p = 0.023) within 30 days of PFA procedure than the EnSite group. No differences were observed in cardiovascular-related readmission or complications. Conclusion: In this retrospective, real-world study, patients with AF who underwent PFA using CARTO 3 had lower 30-day AF/AFL/atrial tachycardia-related readmissions rates than those treated with EnSite suggesting that choice of mapping system may influence early AF outcomes and could translate into reduced downstream hospitalizations and resource use.
What is this article about? Atrial fibrillation (AF) is a common heart rhythm disorder that can be treated with a procedure called pulsed field ablation (PFA), which uses electrical pulses to target and destroy heart muscle cells responsible for the abnormal rhythm. During the procedure, electroanatomical mapping systems help guide the treatment by creating a detailed map of the heart. This study compared hospital readmission rates and complications after PFA procedures performed using two different electroanatomical mapping systems: CARTO™ 3 and EnSite™. What were the results? This study analyzed the data of 4909 patients with AF treated with PFA in 2023–2024. Patients treated using the CARTO 3 system were 56% less likely to be readmitted to the hospital or emergency room within 30 days for AF, atrial flutter, or atrial tachycardia compared with those treated using the EnSite system. Both groups had similar rates of cardiovascular-related hospital readmissions and procedure-related complications. What do the results mean? These findings suggest that the choice of mapping system used to guide PFA may influence early heart rhythm-related hospital readmissions. The CARTO 3 system may offer an advantage in preventing recurrence of arrhythmia after the procedure.

BACKGROUND: Because of its safety, "single-shot" pulsed field ablation (PFA) catheters have been developed for pulmonary vein isolation (PVI). However, most atrial fibrillation (AF) ablation procedures are performed with focal catheters to permit flexibility of lesion sets beyond PVI.
OBJECTIVES: This study sought to determine the safety and efficacy of a focal ablation catheter able to toggle between radiofrequency ablation (RFA) or PFA to treat paroxysmal or persistent AF.
METHODS: In a first-in-human study, a focal 9-mm lattice tip catheter was used for PFA posteriorly and either irrigated RFA (RF/PF) or PFA (PF/PF) anteriorly. Protocol-driven remapping was at ∼3 months postablation. The remapping data prompted PFA waveform evolution: PULSE1 (n = 76), PULSE2 (n = 47), and the optimized PULSE3 (n = 55).
RESULTS: The study included 178 patients (paroxysmal/persistent AF = 70/108). Linear lesions, either PFA or RFA, included 78 mitral, 121 cavotricuspid isthmus, and 130 left atrial roof lines. All lesion sets (100%) were acutely successful. Invasive remapping of 122 patients revealed improvement of PVI durability with waveform evolution: PULSE1: 51%; PULSE2: 87%; and PULSE3: 97%. After 348 ± 652 days of follow-up, the 1-year Kaplan-Meier estimates for freedom from atrial arrhythmias were 78.3% ± 5.0% and 77.9% ± 4.1% for paroxysmal and persistent AF, respectively, and 84.8% ± 4.9% for the subset of persistent AF patients receiving the PULSE3 waveform. There was 1 primary adverse event-inflammatory pericardial effusion not requiring intervention.
CONCLUSIONS: AF ablation with a focal RF/PF catheter allows efficient procedures, chronic lesion durability, and good freedom from atrial arrhythmias-for both paroxysmal and persistent AF. (Safety and Performance Assessment of the Sphere-9 Catheter and the Affera Mapping and RF/PF Ablation System to Treat Atrial Fibrillation; NCT04141007 and NCT04194307).

Cardioneuroablation (CNA) is currently considered as a promising treatment option for patients with symptomatic bradycardia caused by vagotonia. This study aims to further investigate its safety and efficacy in patients suffering from vagal bradycardia. A total of 60 patients with vagal bradycardia who underwent CNA in the First Affiliated Hospital of Xinjiang Medical University from November 2019 to June 2022. Preoperative atropine tests revealed abnormal vagal tone elevation in all patients. First, the electroanatomic structures of the left atrium was mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. The upper limit of ablation power of superior left ganglion (SLGP) and right anterior ganglion (RAGP) was not more than 45W with an ablation index of 450.Postoperative transesophageal cardiac electrophysiological examination was performed 1 to 3 months after surgery. The atropine test was conducted when appropriate. Twelve-lead electrocardiogram, Holter electrocardiogram, and skin sympathetic nerve activity were reviewed at 1, 3, 6 and 12 months after operation. Adverse events such as pacemaker implantation and other complications were also recorded to analyze the safety and efficacy of CNA in the treatment of vagus bradycardia. Sixty patients were enrolled in the study (38 males, mean age 36.67 ± 9.44, ranging from 18 to 50 years old). None of the patients had a vascular injury, thromboembolism, pericardial effusion, or other surgical complications. The mean heart rate, minimum heart rate, low frequency, low/high frequency, acceleration capacity of rate, and skin sympathetic nerve activity increased significantly after CNA. Conversely, SDNN, PNN50, rMSSD, high frequency, and deceleration capacity of rate values decreased after CNA (all P < 0.05). At 3 months after ablation, the average heart rate, maximum heart rate, and acceleration capacity of heart rate remained higher than those before ablation, and the deceleration capacity of heart rate remained lower than those before ablation and the above results continued to follow up for 12 months after ablation (all P < 0.05). There was no significant difference in other indicators compared with those before ablation (all P > 0.05). The remaining 81.67% (49/60) of the patients had good clinical results, with no episodes of arrhythmia during follow-up. CNA may be a safe and effective treatment for vagal-induced bradycardia, subject to confirmation by larger multicenter trials.

BACKGROUND: Concomitant atrial fibrillation ablation and left atrial appendage (LAA) occlusion are increasingly considered in patients with elevated thromboembolism and bleeding risk. Emerging data suggest a higher incidence of peridevice leak with pulsed field ablation (PFA).
CASE SUMMARY: Two patients underwent concomitant PFA with the Sphere-9 catheter (Affera/Medtronic) and Watchman FLX Pro (Boston Scientific); postablation LAA changes were managed with tailored upsizing in one case and standard sizing in the other. At 6 months, both maintained sinus rhythm on antiplatelet therapy with no thromboembolic or bleeding events, and cardiac computed tomography confirmed well-seated devices with peridevice leak ≤2 mm.
DISCUSSION: These are the first reported cases of concomitant LAA occlusion with Watchman FLX Pro and Sphere-9 PFA. Postablation LAA anatomical changes influenced device selection, and larger studies are needed to validate these findings.
TAKE-HOME MESSAGES: Focal PFA led to specific, observable changes in LAA anatomy, directly affecting device sizing decisions. Tailoring device sizing to account for postablation LAA remodeling-using standard sizing or upsizing-may optimize device seal and compression.

BACKGROUND: Ventricular lead implantation is relatively difficult for patients with bradyarrhythmia after tricuspid valve replacement. Right atrial (RA) abnormalities often occurred in patients with tricuspid valve disease; conventional coronary sinus (CS) lead implantation is not easy to operate. Therefore, it is necessary to develop a safe method for implanting LV endocardial leads in patients after tricuspid valve replacement.
CASE PRESENTATION: A 76-year-old Asian woman who had been implanted with a metal tricuspid valve replacement 4 years ago was admitted to the Department of Cardiology for pacemaker implantation due to transient blackout related to persistent atrial fibrillation with long pauses. The patient's family rejected the surgical placement of an epicardial LV lead. Therefore, we first intended to operate LV lead implantation through the CS; however, the orifice of the CS was virtually difficult to seek. Ultimately, we utilized total 3-dimensional (T3D) transseptal puncture (TSP) under the guidance of the CARTO 3 system; thus, we implanted the LV endocardial lead, which contributed to the accurate puncture of the central fossa ovalis and ensured the safety of TSP in the case of RA enlargement. Meanwhile, the CARTO 3 system contributed to the localization of the LV lead to the LV free wall during implantation. All the intraoperative and postoperative pacemaker parameters were favorable; no intraoperative or postoperative complications occurred.
CONCLUSIONS: This case report may provide a novel surgical approach for LV lead implantation in patients who underwent tricuspid valve replacement or patients who may benefit from cardiac resynchronization therapy but failed to implant CS lead.

BACKGROUND: Among patients with persistent atrial fibrillation, linear ablation lesions beyond pulmonary vein isolation (PVI) are often performed with variable efficacy and inconsistent added value. New catheter designs and energy sources have the potential to improve outcomes.
OBJECTIVE: This study aimed to examine (1) the performance of a novel dual-energy (pulsed field/radiofrequency) lattice-tip mapping and ablation system for linear ablation and (2) the impact of the ablation strategy on outcomes in the randomized SPHERE Per-AF trial.
METHODS: Linear lesion characteristics, safety, and effectiveness were assessed for a conventional radiofrequency ablation system in the control arm vs the dual-energy lattice-tip system in the investigational arm.
RESULTS: In the investigational arm, 203 patients (95.8%) received left atrial roof and/or posterior wall isolation, 117 (55.2%) cavotricuspid isthmus line, and 76 (35.8%) mitral line. In the control arm, 102 patients (68.9%) received left atrial roof and/or posterior wall isolation, 76 (51.4%) cavotricuspid isthmus line, and 19 (12.8%) mitral line. Transpired ablation and energy application times were shorter for each lesion type using the investigational than the control catheter (all P < .0001). Overall, there was a trend toward numerically higher 12-month effectiveness of a "PVI + all linear lesions combined" approach (n = 25) than a PVI-only ablation strategy (n = 56) (P = .07), and the effect was more pronounced in the investigational arm, but subgroups were small.
CONCLUSION: There was a trend toward numerically higher effectiveness with linear lesions than PVI alone. These findings are exploratory and hypothesis generating and should prompt future randomized controlled trials of additional lesion sets vs PVI with this new technology.
CLINICAL TRIAL REGISTRATION: NCT05120193 - Treatment of Persistent Atrial Fibrillation with Sphere-9 and Affera Mapping and Ablation System (SPHERE Per-AF).

BACKGROUND: Very-high-power-short-duration (vHPSD) ablation is increasingly adopted for pulmonary vein isolation (PVI) in atrial fibrillation (AF). While inadequate catheter-tissue contact is known to impair lesion formation under fixed 90 W/4-s setting, independent role of probe stability versus rapid oscillatory motion has not been quantitatively defined.
OBJECTIVE: To evaluate the independent and interactive effects of contact force (CF), positional stability (PS/PSV), and oscillation (OS/OSV) on lesion biophysics during vHPSD ablation in vivo.
METHODS: We retrospectively analyzed 80 consecutive AF patients undergoing PVI with a QDOT-MICRO catheter in vHPSD-mode (90 W/4-s, temperature-controlled). For each application (5198), CARTO3 trace data provided impedance, temperature, tip-to-tag distance, and CF (62.5Hz-sample). Stability parameters were defined as mean and variability of tip-to-tag distance (PS, PSV); oscillation parameters as mean and variability of tip velocity (OS, OSV). Primary endpoints were impedance drop (ID) and maximum temperature (Tmax). Mixed-effects regression models adjusted for baseline impedance, temperature, and CF; sensitivity analyses tested operator effect, and regional segments.
RESULTS: Minimum CF (p < 0.001) and oscillation parameters (OS p < 0.001, OSV p = 0.004) were the strongest predictors of ID and Tmax, whereas stability parameters had attenuated effects after adjustment. Interactions showed that increasing PSV and OSV reduced ID and Tmax, especially under higher CF. Regional analysis confirmed modestly lower signals in posterior/inferior segments, but oscillation remained the main determinant.
CONCLUSION: Oscillation, more than positional stability, is the primary motion determinant of lesion efficacy in vHPSD. Minimizing oscillation rather than increasing CF is key to optimizing energy delivery. Prospective studies should assess whether reducing oscillation improves long-term outcomes.

BACKGROUND: A novel focal lattice-tip catheter allowing the delivery of either pulsed field (PF) or radiofrequency (RF) energy has recently received regulatory approval. The technology features a proprietary 3-dimensional electroanatomic mapping system.
OBJECTIVE: We describe the first real-world and multicenter experience.
METHODS: Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the Affera system were prospectively enrolled at 3 different centers. PF was the only energy source allowed when ablating the posterior left atrium; anterior applications were performed with either RF (PF/RF strategy) or PF (PF/PF strategy) on the basis of the operator's preference. The primary efficacy end point included acute electrical isolation of pulmonary veins and posterior wall or bidirectional block in case of linear lesions.
RESULTS: The study included 130 patients (mean age, 67 ± 10 years; 63.8% [n = 83] male; 61.5% [n = 80] nonparoxysmal AF; 55.4% first-time AF ablation). First-time pulmonary vein isolation was performed in 72 patients: RF/PF in 13 (18.1%) patients and PF/PF in the remaining 59 (81.9%); first-pass isolation for pulmonary vein and posterior wall was achieved in 100% of cases. A total of 289 ablation lines were performed (roof line, 91 patients; inferior line, 83 patients; anterior mitral line, 32 patients; posterior mitral line, 45 patients; cavotricuspid isthmus line, 38 patients). First-pass isolation and primary efficacy end point were 96.2% (roof line, 100%; inferior line, 100%; anterior mitral line, 96.9%; posterior mitral line, 84.4%; cavotricuspid isthmus, 92.1%) and 100%, respectively. We had 2 (1.5%) major complications: 1 ST-segment elevation at the inferolateral leads requiring intracoronary administration of nitrate and 1 complete atrioventricular block.
CONCLUSION: Catheter ablation with a novel 9-mm lattice-tip catheter confirmed high efficacy and safety in a real-world scenario.

INTRODUCTION: Scar-related ventricular tachycardia (VT) usually results from an underlying reentrant circuit facilitated by anatomical and functional barriers. The later are sensitive to the direction of ventricular activation wavefronts. We aim to evaluate the impact of different ventricular activation wavefronts on the functional electrophysiological properties of myocardial tissue.
METHODS: Patients with ischemic heart disease referred for VT ablation underwent high-density mapping using Carto®3 (Biosense Webster). Maps were generated during sinus rhythm, right and left ventricular pacing, and analyzed using a new late potential map software, which allows to assess local conduction velocities and facilitates the delineation of intra-scar conduction corridors (ISCC); and for all stable VTs.
RESULTS: In 16 patients, 31 high-resolution substrate maps from different ventricular activation wavefronts and 7 VT activation maps were obtained. Local abnormal ventricular activities (LAVAs) were found in VT isthmus, but also in noncritical areas. The VT isthmus was localized in areas of LAVAs overlapping surface between the different activation wavefronts. The deceleration zone location differed depending on activation wavefronts. Sixty-six percent of ISCCs were similarly identified in all activating wavefronts, but the one acting as VT isthmus was simultaneously identified in all activation wavefronts in all cases.
CONCLUSION: Functional based substrate mapping may improve the specificity to localize the most arrhythmogenic regions within the scar, making the use of different activation wavefronts unnecessary in most cases.

BACKGROUND: Pulsed field ablation (PFA) has emerged as a novel nonthermal modality for atrial fibrillation (AF) ablation, offering tissue selectivity and procedural safety. However, emerging data have raised concerns about hemolysis-related biomarker shifts and potential renal failure after PFA.
OBJECTIVE: This study aimed to evaluate biomarker-defined hemolysis and the incidence of acute renal injury after PFA in patients undergoing AF.
METHODS: In this prospective observational study, 84 patients with paroxysmal or persistent AF undergoing PFA using either the Affera or PulseSelect system were enrolled. Paired venous blood samples were obtained before and 24 hours after the procedure. Biomarkers of hemolysis (lactate dehydrogenase [LDH], haptoglobin, hemoglobin, and bilirubin), renal function parameters (serum creatinine, urea, and electrolytes), and cardiac enzymes (high-sensitivity cardiac troponin, N-terminal pro-B-type natriuretic peptide) were systematically analyzed. Clinically significant hemolysis was defined as a postprocedural haptoglobin concentration of <0.04 g/L or a combination of indirect bilirubin of >1.5 times baseline and LDH more than twice baseline. Multivariable linear regression and mediation analyses were performed to identify procedural predictors of biomarker changes and explore the potential mediating role of myocardial injury.
RESULTS: Significant postprocedural changes were observed in biomarkers of hemolysis, including a reduction in haptoglobin (-0.17 ± 0.21 g/L; P < .001), an increase in LDH (+43.32 ± 79.98 U/L; P < .001), and bilirubin concentrations (P < .001). No patient met the predefined criteria for clinically significant hemolysis. Acute kidney injury stage 1, without oliguria, was observed in 3 patients (3.6%). Cardiac biomarker analysis revealed a substantial rise in high-sensitivity troponin (+1151.7 ± 750.8 ng/L; P < .001), whereas N-terminal pro-B-type natriuretic peptide decreased significantly after ablation (P < .001). The total number of PFA applications independently predicted changes in both LDH and haptoglobin.
CONCLUSION: In our study, PFA for AF was associated with an increase in hemolytic parameters, without significant short-term renal impact or occurrence of clinically significant hemolysis. Hemolysis seems to be influenced by both lesion burden and myocardial injury, highlighting the need for further investigation into the long-term clinical relevance of biomarker-defined hemolysis in PFA-treated patients.

OBJECTIVE: Radiofrequency catheter ablation (RFCA) has evolved into an effective and safe technique for the treatment of tachyarrhythmia in children. Concerns about children and involved medical staff being exposed to radiation during the procedure should not be ignored. "Fluoroscopy integrated 3D mapping", a new 3D non-fluoroscopic navigation system software (CARTO Univu Module) could reduce fluoroscopy during the procedure. However, there are few studies about the use of this new technology on children. In the present study, we analyzed the impact of the CARTO Univu on procedural safety and fluoroscopy in a wide spectrum of tachyarrhythmias as compared with CARTO3 alone.
METHODS: The data of children with tachyarrhythmias who underwent RFCA from June 2018 to December 2021 were collected. The CARTO Univu was used for mapping and ablation in 200 cases (C3U group) [boys/girls (105/95), mean age (6.8 ± 3.7 years), mean body weight (29.4 ± 7.9 kg)], and the CARTO3 was used in 200 cases as the control group (C3 group) [male/female (103/97), mean age (7.2 ± 3.9 years), mean body weight (32.3 ± 19.0 kg)]. The arrhythmias were atrioventricular reentrant tachycardia (AVRT, n = 78), atrioventricular node reentrant tachycardia (AVNRT, n = 35), typical atrial flutter (AFL, n = 12), atrial tachycardia (AT, n = 20) and ventricular arrhythmias [VAs, premature ventricular complexes or ventricular tachycardia, n = 55].
RESULTS: ① There was no significant difference in the acute success rate, recurrence rate, and complication rate between the C3 and C3U groups [(94.5% vs. 95.0%); (6.3% vs. 5.3%); and (2.0% vs. 1.5%); P > 0.05]. ② The CARTO Univu reduced radiation exposure: fluoroscopy time: AVRT C3: 8.5 ± 7.2 min vs. C3U: 4.5 ± 2.9 min, P < 0.05; AVNRT C3: 10.7 ± 3.2 min vs. C3U: 4.3 ± 2.6 min, P < 0.05; AT C3: 15.7 ± 8.2 min vs. C3U: 4.5 ± 1.7 min, P < 0.05; AFL C3: 8.7 ± 3.2 min vs. C3U: 3.7 ± 2.7 min, P < 0.05; VAs C3: 7.7 ± 4.2 min vs. C3U: 3.9 ± 2.3 min, P < 0.05. Corresponding to the fluoroscopy time, the fluoroscopy dose was also reduced significantly. ③ In the C3U group, the fluoroscopy during VAs ablation was lower than that of other arrhythmias (P < 0.05).
CONCLUSION: The usage of the "novel image integration technology" CARTO Univu might be safe and effective in RFCA for a wide spectrum of tachyarrhythmias in children, which could significantly reduce fluoroscopy and has a more prominent advantage for VAs ablation.

BACKGROUND: Ventricular arrhythmias arising from the left ventricular (LV) summit are technically challenging to ablate because of limited accessibility and proximity to the coronary arteries. Dual energy lattice-tip catheter (DLTC) could provide both very high-power temperature-controlled radiofrequency (RF) ablation and pulse field (PF) ablation.
OBJECTIVE: To describe the use of combined radiofrequency (RF) and pulsed field (PF) ablation using a dual-energy large lattice-tip catheter for treatment of ventricular tachycardia originating from the LV summit region.
METHODS: We report a 66-year-old man with atrial fibrillation, heart failure with reduced ejection fraction, and recurrent VT despite prior endocardial and epicardial radiofrequency ablation. Mapping localized the PVC/VT to a LV summit-adjacent region, with an endocardial target along the superior septum/LVOT consistent with an intramural or epicardial summit substrate. Given prior failed RF ablations compassionate-use ablation with the dual-energy lattice-tip catheter and Affera™ mapping system (Medtronic, Minneapolis, MN) was performed under intracardiac echocardiogram guidance. Interventional cardiology was directly involved, providing coronary angiography and intravascular imaging before and after ablation to ensure the absence of vasospasm or ischemia.
RESULTS: At 6 week follow up, following dual-energy ablation with DLTC, there was significant suppression of ventricular arrhythmia off antiarrhythmic amiodarone. There was no evidence of coronary injury post ablation confirmed by coronary angiogram and intravascular ultrasound. This case highlights the feasibility of high-power temperature controlled-RFA and focal PFA for VT in anatomically regions where success with conventional energy sources is limited.
CONCLUSION: Combined RF and PF ablation using the DLTC achieved safe and effective ablation of LV summit ventricular tachycardia without coronary injury.

BACKGROUND: Supraventricular tachycardia (SVT) can lead to cardiogenic shock, particularly in patients with severely impaired left ventricular function. Acute management typically includes electrical cardioversion combined with antiarrhythmic drugs to restore sinus rhythm. In cases of therapy-resistant SVT, atrioventricular nodal ablation may be considered, although this results in permanent pacemaker dependency. Definitive treatments, such as atrial fibrillation (AF) or atrial flutter (AFLUT) ablation, which could potentially avoid pacemaker implantation, are seldom pursued in such critical settings, despite advancements in therapeutic efficacy.
CASE SUMMARY: We present the case of a 79-year-old male with ischaemic cardiomyopathy and advanced heart failure, admitted with cardiogenic shock and regular narrow-complex tachycardia. Initial attempts at electrical cardioversion combined with pharmacological rhythm control provided only temporary success, followed by recurrent episodes of alternating AF and AFLUT. This prompted the decision to perform pulmonary vein isolation (PVI) and posterior wall isolation (PWI) using pulsed field ablation (PFA), supported by the Impella CP device for mechanical circulatory support. The procedure, guided by the CARTO 3 electroanatomic mapping system, successfully achieved PVI and PWI with restoration of sinus rhythm. Following the procedure, the patient's haemodynamics stabilized, and sinus rhythm was maintained, along with significant improvement in left ventricular function.
DISCUSSION: This case underscores the feasibility of PFA-assisted PVI and PWI with Impella CP in the management of acute AF/AFLUT-induced cardiogenic shock. It highlights the role of mechanical circulatory support in enabling successful SVT ablation in haemodynamically unstable patients, offering an alternative to atrioventricular node ablation in critical situations.

AIMS: The feasibility and safety of the lattice-tip catheter for ventricular arrhythmia (VA) ablation in humans remain largely unknown. This study aimed to assess feasibility, safety profile as well as patient outcomes after VA ablation with a lattice-tip catheter in a multicentre European registry.
METHODS AND RESULTS: All 18 European centres using the AFFERA system in September 2024 agreed to participate. Clinical, procedural, and follow-up data (minimum 3 months) were systematically collected and analysed. A total of 126 patients (18% female; mean age 59 ± 16 years) underwent VA ablation using the lattice-tip catheter during the inclusion period. Ablation indications included ventricular tachycardia (VT) in 99, premature ventricular complexes (PVCs) in 23, and ventricular fibrillation (VF) in 4 patients. Major and minor acute complications were observed in 7 (6%) and 18 (14%) procedures, respectively. They included thrombo-embolic event (n = 2), major bleeding (n = 2), ventricular fibrillation induction (n = 1), tamponade due to epicardial access (n = 1), and cardiogenic shock due to prolonged VT mapping (n = 1). Within the first month post-procedure, three patients died [from multi-organ failure (n = 2) and sepsis (n = 1)], two had worsening heart failure, one myocardial infarction, one sepsis, and one major gastro-intestinal bleeding. After a mean follow-up of 5.6 ± 3.7 months, absence of recurrence was 78% for PVC, 70% for VT, and 100% for VF.
CONCLUSION: In this complex population with refractory VA, ablation using the lattice-tip catheter appears feasible and relatively safe. In the absence of large, randomized trials, exhaustive registry is of key importance to ensure safety and efficacy of new catheter technologies.

BACKGROUND: Catheter ablation is a common means of treatment for atrial fibrillation (AFib). This approach involves electrical isolation of the pulmonary veins (PVs) from the left atrium (LA). However, in patients with persistent AFib, outcomes remain suboptimal. In addition to PV isolation (PVI), additional substrate ablation is likely required to improve outcomes. Aside from PVI, drivers for AFib and substrate necessary for AFib maintenance are incompletely understood and may involve certain regions of LA.
OBJECTIVE: This study aimed to use our previously developed approaches to visualize drivers of AFib and to identify their spatial correlation within the atrium. To accomplish this goal, we compared the spatial location of these AFib drivers from the LA before PVI (pre-PVI), as well as after PVI during AFib.
METHODS: Intracardiac electrograms were collected from swine (n = 7) using the CARTO 3 mapping system and PentaRay multielectrode mapping catheter. Bipolar and unipolar intracardiac electrograms were analyzed using our recently developed novel signal processing approaches, and similarity scores for every catheter position were calculated to identify AFib drivers within the atria. These AFib drivers were spatially correlated with 9 anatomic hallmarks of LA, and the presence of focal activity was quantified.
RESULTS: We demonstrated the ability to identify and track AFib drivers in a large-animal model using our similarity-score-based framework in both pre- and post-PVI AFib and successfully correlated these drivers with LA anatomic hallmarks while capturing their spatial and temporal changes.
CONCLUSION: Our findings indicate that pre-PVI drivers for AFib were identified both within and outside the PV regions. Post-PVI drivers were located in different parts of LA. We also noted a predominance of non-PV drivers to be from the appendage, septal wall, and posterior wall. These data highlight the need for further research on these regions and underscore the importance of non-PV sites in AFib maintenance.

AIMS: Catheter ablation is an effective treatment method for recurrent ventricular tachycardias (VTs). However, at least in part, procedural and clinical outcomes are limited by challenges in generating an adequate lesion size in the ventricular myocardium. We investigated procedural and clinical outcomes of VT ablation using a novel 'large-footprint' catheter that allows the creation of larger lesions either by radiofrequency (RF) or by pulsed field (PF) energy.
METHODS AND RESULTS: In prospectively collected case series, we describe our initial experience with VT ablation using a lattice-tip, dual-energy catheter (Sphere-9, Medtronic), and a compatible proprietary electroanatomical mapping system (Affera, Medtronic). The study population consisted of 18 patients (aged 55 ± 15 years, one woman, structural heart disease: 94%, ischaemic heart disease: 56%, left ventricular ejection fraction: 34 ± 10%, electrical storm: 22%) with recurrent sustained VTs and ≥1 previously failed endocardial RF ablation with conventional irrigated-tip catheter in 66% of patients. On average, 12 ± 7 RF and 8 ± 9 PF applications were delivered per patient. In three-fourths of patients undergoing percutaneous epicardial ablation, spasms in coronary angiography were observed after PF applications. All resolved after intracoronary administration of nitrates. No acute phrenic nerve palsy was noted. One patient suffered from a stroke that resolved without sequelae. Post-ablation non-inducibility of VT was achieved in 89% of patients. Ventricular-arrhythmia-free survival at three months was 78%.
CONCLUSION: VT ablation using a dual-energy lattice-tip catheter and a novel electroanatomical mapping system is feasible. It allows rapid mapping and effective substrate modification with good outcomes during short-term follow-up.

INTRODUCTION: Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple mapping (RM; CARTO-3© Biosense Webster Inc) displays each electrogram at its three-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the SP and assess its use in guiding ablation for AVNRT.
METHODS: Patients ≤18 years with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019 to 2021, whereas standard electro-anatomical mapping was used from 2017 to 2019. All ablations were performed using cryotherapy. Demographics, outcomes, and analysis of variance in number of test lesions until success was compared between groups.
RESULTS: A total of 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4 mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p = .01).
CONCLUSION: RM is a novel technique that can help identify SP location, allowing for successful ablation of AVNRT with decreased variability.

AIMS: Single-shot pulmonary vein isolation can improve procedural efficiency. To assess the capability of a novel, expandable lattice-shaped catheter to rapidly isolate thoracic veins using pulsed field ablation (PFA) in healthy swine.
METHODS AND RESULTS: The study catheter (SpherePVI; Affera Inc) was used to isolate thoracic veins in two cohorts of swine survived for 1 and 5 weeks. In Experiment 1, an initial dose (PULSE2) was used to isolate the superior vena cava (SVC) and the right superior pulmonary vein (RSPV) in six swine and the SVC only in two swine. In Experiment 2, a final dose (PULSE3) was used for SVC, RSPV, and left superior pulmonary vein (LSPV) in five swine. Baseline and follow-up maps, ostial diameters, and phrenic nerve were assessed. Pulsed field ablation was delivered atop the oesophagus in three swine. All tissues were submitted for pathology. In Experiment 1, all 14/14 veins were isolated acutely with durable isolation demonstrated in 6/6 RSPVs and 6/8 SVC. Both reconnections occurred when only one application/vein was used. Fifty-two and 32 sections from the RSPVs and SVC revealed transmural lesions in 100% with a mean depth of 4.0 ± 2.0 mm. In Experiment 2, 15/15 veins were isolated acutely with 14/15 veins (5/5 SVC, 5/5 RSPV, and 4/5 LSPV) durably isolated. Right superior pulmonary vein (31) and SVC (34) sections had 100% transmural, circumferential ablation with minimal inflammation. Viable vessels and nerves were noted without evidence of venous stenosis, phrenic palsy, or oesophageal injury.
CONCLUSION: This novel expandable lattice PFA catheter can achieve durable isolation with transmurality and safety.

INTRODUCTION: Pulmonary vein isolation (PVI) in atrial fibrillation (AF) is the current cornerstone for AF ablation. Besides thermal ablation techniques, nonthermal pulsed-field ablation (PFA) is rapidly transforming the way PVI is achieved. As every new technology has its own learning curve, we would like to report the lessons we learned by treating a 63-year-old woman admitted for paroxysmal AF ablation, with symptomatic palpitations.
METHODS AND RESULTS: We initially performed PVI with a pulsed-electrical field variable-loop circular catheter with the CARTO 3 mapping system. When the patient experienced recurrence of AF even after 3 months, the scheduled reablation procedure showed a reconnection of both posterior carinae. When revisiting the initial map, both recurrences occurred at the points where tissue proximity indication (TPI) during ablation was likely not sufficient, leading to reversible electroporation and subsequent reconnection of the veins. Those remaining areas were again ablated using PFA energy with a linear ablation catheter.
CONCLUSION: TPI-based contact filtering for transmural lesion success and durability seems to be a relevant tool to ensure irreversible electroporation and is likely of prognostic relevance.

BACKGROUND: Pulsed field ablation (PFA) has emerged as a promising non-thermal alternative to conventional atrial fibrillation (AF) ablation techniques. However, intravascular haemolysis has been increasingly recognised as a potential complication, with variable incidence and clinical significance.
OBJECTIVE: To systematically review the available clinical evidence on PFA-related haemolysis, focusing on biochemical markers, clinical manifestations and device-specific differences.
METHODS: PubMed, Embase and Cochrane databases were searched until 20 May 2025 for clinical studies evaluating primarily PFA-pulmonary vein isolation for AF that reported haemolysis, acute kidney injury (AKI) or relevant biomarker changes. The primary outcome was evaluation of incidence and biochemical evidence of PFA-related haemolysis. Secondary outcomes included incidence of AKI and its clinical consequences.
RESULTS: 12 studies (≈20 000 patients) were included. Biomarker evidence of haemolysis was consistent, with postablation lactate dehydrogenase elevations of 250-438 U/L and bilirubin 15-48 µmol/L, often accompanied by reduced haptoglobin and elevated free haemoglobin. Incidence of haemolysis varied widely (0-94.3%), reflecting heterogeneity in definitions and reporting. Clinical sequelae were uncommon: haemoglobinuria was observed in five studies, and AKI occurred in 83 patients (0.4%), 12 requiring transient dialysis. All returned to baseline renal function except one patient with severe chronic kidney disease. Procedural factors and catheter design may influence haemolysis burden. Observations of lower haemolytic biomarker changes with devices such as PulseSelect, Affera and Volt are preliminary and require confirmation, given the predominance of Farawave data.
CONCLUSIONS: Haemolysis is a reproducible biochemical outcome of PFA, but clinically significant events such as AKI are rare and usually reversible. Catheter design, energy delivery and patient baseline renal function are likely to modulate haemolysis risk. Standardised haemolysis definitions and prospective head-to-head comparisons across PFA platforms are needed to clarify clinical relevance and optimise safety.
PROSPERO REGISTRATION NUMBER: CRD420251069612.

INTRODUCTION: Transseptal puncture (TSP) is widely used in clinical practice but is negatively affected by a nonneglectable rate of complications and X-ray exposure. To address these problems, we investigated whether or not impedance mapping could correctly identify fossa ovalis (FO) and safely guide TSP.
METHODS AND RESULTS: Electroanatomic mapping was performed with CARTO 3 system version 7 and a ThermoCool® SmartTouch® mapping catheter was employed. In each patient, an impedance map and a bipolar voltage map of the whole interatrial septum were collected, acquiring at least 150 points with a contact force ≥2 g and using the pattern matching filter. Thirty-five patients were enrolled. A low impedance area was clearly identified in 34 of them. In 30 patients (88%), the FO was located in the low impedance area. The map was obtained in sinus rhythm in 17 cases (50%); in 15 of these (88%), the TSP site, the patent foramen ovale, or the FO tenting area fell inside the low impedance area. The same numbers were observed when mapping during atrial fibrillation.
CONCLUSION: To the best of our knowledge, this is the first study that provides the reliability and reproducibility of impedance mapping in identifying FO, an affordable and feasible tool that could be potentially introduced into clinical practice.

BACKGROUND: The SPHERE Per-AF trial demonstrated noninferiority for a primary composite effectiveness endpoint in patients with persistent atrial fibrillation (AF) treated with a 9-mm, lattice-tip, pulsed field (PF)/radiofrequency (RF) system (74%) vs conventional contact force-sensing RF (65%). Although operators were highly experienced with the control, the vast majority was new to the investigational system.
OBJECTIVE: The aim of this study was to assess the learning curve using this novel system.
METHODS: Patients were grouped based on the sequential procedures performed per operator. Operators who performed ≤2 investigational procedures were excluded. The composite effectiveness endpoint was freedom from acute procedural failure, repeat ablation at any time, recurrence of arrhythmia, drug initiation/escalation, or cardioversion each at 1 year excluding a 3-month blanking period. Efficiency endpoints included "skin-to-skin" procedure time.
RESULTS: The total cohort included 443 patients (235 investigational [31 roll-in], 208 control). Primary effectiveness in the investigational cohort improved significantly with increased procedural order. Efficacy was 65% (74 of 114) for the first 5 patients per operator, 75% (33 of 44) for patients 6 to 10, and 80% (60 of 75) for patients >10. Kaplan-Meier effectiveness estimates at 1-year follow-up were significantly higher in the investigational cohort after 10 procedures performed, compared with control (80% vs 65%, P < .05). With the investigational system, total procedure time was reduced by 25 minutes (100 vs 125) within the first 5 procedures performed (P < .001).
CONCLUSION: AF ablation with a novel dual-energy, lattice-tip ablation system resulted in greater clinical efficacy compared with conventional RF after a rapid operator learning curve, with superior procedural efficiency noted from the initial procedures onward.
CLINICAL TRIAL REGISTRATION: NCT05120193.

BACKGROUND: Catheter ablation is routinely used to treat scar-related atrial tachycardia (s-AT). Conventional ablation often involves creating anatomical "lines" that transect myocardial tissue supporting reentry. This can be extensive, creating iatrogenic scar as a nidus for future reentry, and may account for arrhythmia recurrence. High-density mapping may identify "narrower isthmuses" requiring less ablation, with ripple mapping proven to be an effective approach in identifying. This trial explores whether ablation of narrower isthmuses in s-AT, defined using ripple mapping, results in greater freedom from arrhythmia recurrence compared to conventional ablation.
METHODS: The Ripple-AT-Plus trial (registration ClinicalTrials.gov , NCT03915691) is a prospective, multicentre, single-blinded, randomised controlled trial with 12-month follow-up. Two hundred s-AT patients will be randomised in a 1:1 fashion to either "ripple mapping-guided isthmus ablation" vs conventional ablation on the CARTO3 ConfiDENSE system (Biosense Webster). The primary outcome will compare recurrence of any atrial arrhythmia. Multicentre data will be analysed over a secure web-based cloud-storage and analysis software (CARTONETTM).
CONCLUSION: This is the first trial that considers long-term patient outcomes post s-AT ablation, and whether targeting narrower isthmuses in the era of high density is optimal.

BACKGROUND: A compressible lattice-tip catheter designed for focal ablation using radiofrequency or pulsed-field energies has been recently described. The objective of this study is to describe a new lattice catheter designed for single-shot pulmonary vein isolation (PVI).
METHODS: This 8F catheter consists of a compressible lattice tip that is delivered over the wire and is expandable up to 34 mm (SpherePVI™, Affera Inc.). Pulsed field ablation (PFA) was applied from 6 elements using a biphasic waveform of microsecond scale (± 1.3-2.0 kV, 5 s per application). In 12 swine, the superior vena cava (SVC) and right superior pulmonary vein (RSPV) were targeted for isolation. Animals were survived for 12-24 h (n = 6) or 3 weeks (n = 6) for evaluation of short and long-term safety and efficacy parameters. PVI was evaluated immediately after ablation and at the terminal procedure. Ablation-related microbubbles were examined using intracardiac echocardiography and phrenic nerve function by pacing. The tissue was examined by histopathology.
RESULTS: In all 12 animals, PFA resulted in successful acute isolation of the SVC and RSPV using 2.8 ± 1.1 and 3.2 ± 1.2 applications per vein, respectively. After a survival period of 23 ± 5.9 days, all targeted veins remained isolated, and the level of isolation persisted without significant regression or expansion. In one animal, SVC isolation at the level of the right atrial appendage resulted in sinus node arrest. PFA did not affect phrenic nerve function, and it was associated with a few isolated bubbles formation.
CONCLUSIONS: In this pre-clinical study, a new expandable lattice catheter designed for single-shot PVI was able to achieve rapid and durable isolation.

BACKGROUND: Catheter ablation is the key element of rhythm control in atrial fibrillation (AF), yet its reliance on fluoroscopy exposes patients and operators to radiation. A fluoroscopy-free procedure is possible using intracardiac echocardiography (ICE), but due to high cost, the learning curve, and added procedural steps, ICE is rarely used in Europe. Similarly, non-fluoroscopic tracking systems (NCTS) like MediGuide for near-zero fluoroscopy ablation have fallen out of favor. The SHORT LOOK study evaluates the efficiency and safety of a streamlined near-zero fluoroscopy workflow for first-time pulmonary vein isolation (PVI) based solely on advanced 3D mapping and an ultra-low-dose fluoroscopy protocol. The aim was to determine whether near-zero fluoroscopy ablation can be achieved using conventional techniques, enabling broader adoption in modern electrophysiology labs.
METHODS: The SHORT LOOK registry is a single-center, investigator-initiated prospective standard-of-care study enrolling consecutive patients undergoing first-time PVI for AF. A total of 450 patients were included in the final analysis. The workflow used a 3D mapping system (CARTO3, J&J MedTec) with an ultra-low-dose fluoroscopy protocol, without adjunctive technologies. Baseline assessments included medical history, physical examination, labs, ECG, EQ-VAS, and echocardiography. The primary efficacy endpoint was median fluoroscopy time; the primary safety endpoint was a composite of procedure-related death or cardiovascular, neurological, or vascular events. Secondary endpoints included 1-year freedom from atrial arrhythmia > 30 s, skin-to-skin time, fluoroscopy dose, and proportion of procedures with fluoroscopy < 1 min. Patients were followed up for 1 year.
RESULTS: The SHORT LOOK cohort (n = 450) achieved a median procedural time of 57 min, with median fluoroscopy time of 26 s and dose of 9.1 µGy*m². The complication rate was < 1% and no major adverse events occurred. Follow-up revealed that for paroxysmal atrial fibrillation, 86.1% were AT/AF-free at 3 months, decreasing to 82.6% at 12 months, while for persistent atrial fibrillation, the rates were 77.3% and 71.7%, respectively, confirming sustained rhythm control. EQ-VAS analyses revealed a significant improvement in health-related quality of life from baseline (p < 0.05). Compared to a historical NCTS group, our workflow leads to similarly low fluoroscopy times and radiation doses.
CONCLUSION: The streamlined workflow for initial atrial fibrillation ablation, which nearly eliminates fluoroscopy, demonstrates a significant reduction in both fluoroscopy time and radiation dose. This approach is feasible in any electrophysiology laboratory and offers a practical method for performing rapid, safe, and effective AF ablations while maintaining minimal radiation exposure-all without the need for additional adjunctive technologies.

AIMS: The aim of this study was to assess the risk of haemolysis and the extent of myocardial and neural injury after monopolar, monophasic pulsed field ablation (PFA) using a lattice-tip catheter in comparison to single-shot PF ablation platforms employing bipolar, biphasic waveforms.
METHODS AND RESULTS: This prospective study included consecutive patients undergoing PFA for atrial fibrillation (AF) using the Affera™ mapping and ablation system (n = 40). Biomarkers for haemolysis (haptoglobin, lactate dehydrogenase, bilirubin), myocardial injury [high-sensitive troponin T, creatine kinase (CK), creatine kinase MB (CK-MB)], neurocardiac injury (S100), and renal function (creatinine) were assessed pre- and within 24 h post-ablation. A subgroup analysis of first-time pulmonary vein isolation-only procedures compared biomarker changes across Affera™, Farapulse™ (PFA-F), and PulseSelect™ (PFA-P). Post-procedural haemolysis occurred across all PFA platforms. The decrease in Δhaptoglobin was most pronounced in PFA-F [AfferaTM: (-) 13.8 ± 18.5 vs. PFA-P: (-) 36.8 ± 35.9 vs. PFA-F: (-) 60.7 ± 26.3 mg/dL, P = <0.001], without haemolysis-related complications. AfferaTM shows a trend towards a higher increase in myocardial injury markers (Δtroponin, 1537 [580] vs. 970 [1023] vs. 1051 [592] pg/mL, P = 0.180; ΔCK, 232 [168] vs. 153 [132] vs. 102 [144] U/L, P = 0.006; ΔCK-MB, 28.5 [15.3] vs. 14.6 [12.4] vs. 13.6 [10.5] U/L, P = 0.055, for Affera TM, PFA-P, and PFA-F, respectively). After ablation, S100 increased in PFA-P and PFA-F, but not in AfferaTM.
CONCLUSION: Post-procedural haemolysis after PFA for AF treatment is common and occurs across all PFA platforms. Pulsed field ablation using AfferaTM results in more myocardial injury than bipolar PFA systems with no indication of neural damage.

INTRODUCTION: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) catheter ablation. However, a PVI alone has been considered insufficient for persistent AF. This study aimed to evaluate the efficacy of persistent AF ablation targeting complex fractionated atrial electrogram (CFAE) areas within low voltage zones identified by high-resolution mapping in addition to the PVI.
METHODS: We randomized 50 patients (mean age 58.4 ± 9.5 years old, 86.0% males) with persistent AF to a PVI + CFAE group and PVI only group in a 1:1 ratio. CFAE and voltage mapping was performed simultaneously using a Pentaray Catheter with the CARTO3 CONFIDENSE module (Biosense Webster, CA, USA). The PVI + CFAE group, in addition to the PVI, underwent ablation targeting low voltage areas (<0.5 mV during AF) containing CFAEs.
RESULTS: The mean persistent AF duration was 24.0 ± 23.1 months and mean left atrial dimension 4.9 ± 0.5 cm. In the PVI + CFAE group, AF converted to atrial tachycardia (AT) or sinus rhythm in 15 patients (60%) during the procedure. The PVI + CFAE group had a higher 1-year AF free survival (84.0% PVI + CFAE vs 44.0 PVI only, P = .006) without antiarrhythmic drugs. However, there was no difference in the AF/AT free survival (60.0% PVI + CFAE vs 40.0% PVI only, P = .329).
CONCLUSION: Persistent AF ablation targeting CFAE areas within low voltage zones using high-density voltage mapping had a higher AF free survival than a PVI only. Although recurrence with AT was frequent in the PVI+CFAE group, the sinus rhythm maintenance rate after redo procedures was 76%.

Catheter ablation in longstanding persistent atrial fibrillation (AF) presents unique challenges, particularly in patients with large left atria and prior atrioventricular nodal dysfunction. While novel pulsed-field ablation (PFA) has been shown to be safer, no data yet show that a large focal lattice-tip catheter may be more effective. We present a 66-year-old man with symptomatic, longstanding, persistent AF and underlying sick sinus syndrome who underwent catheter ablation using Affera 3D mapping (Medtronic, Minneapolis, MN) and the Sphere 9 catheter (Medtronic, Inc, Mounds View, MN) to provide a combined pulsed field and radiofrequency approach. High-resolution electroanatomic mapping guided pulmonary vein isolation, which was extended to include posterior wall isolation, mitral isthmus ablation, and cavotricuspid isthmus ablation due to multiple arrhythmia foci. During delivery of PFA to complete posterior wall isolation, there was termination of AF to a normal sinus rhythm. This case highlights the utility of comprehensive lesion sets and advanced mapping technologies in achieving rhythm control in complex persistent AF.

BACKGROUND: Ventricular tachycardia (VT) originating in the right ventricular outflow tract (RVOT) is the most common form of idiopathic VT. Catheter ablation of right ventricular outflow tract tachycardia (RVOT-VT) is associated with high success rates. However, non-inducibility of VT on electrophysiological (EP) study can severely impact ablation outcome. We describe a novel catheter ablation strategy which proved feasible and safe in a case of highly symptomatic, non-inducible RVOT-VT.
CASE SUMMARY: A 51-year-old male with a history of non-sustained VT (NSVT) was referred to our hospital after two syncopal episodes resulting in collapse. Upon admission, a cluster of monomorphic NSVT (250-270 b.p.m.) resulted in haemodynamic instability and required transfer to the intensive care unit. On twelve-lead electrocardiogram, NSVT showed inferior axis and left bundle branch block, suggestive of RVOT-VT. Diagnostic workup including echocardiography, coronary angiography, and late enhancement computed tomography (CT) revealed no evidence of structural heart disease. On two EP studies, non-inducibility of clinical VT despite repeated ventricular pacing and isoproterenol infusion rendered precise mapping of triggered activity unfeasible. Therefore, a bailout ablation strategy was developed by performing a circumferential electrical RVOT isolation using a 3.5 mm irrigated-tip ablation catheter under the guidance of high-density electroanatomic mapping (CARTO® 3) and CT reconstruction of cardiac anatomy. No procedural complications occurred, and the patient remained arrhythmia-free during a 6-month follow-up period.
DISCUSSION: Catheter ablation is a first-line therapy for symptomatic and drug-refractory idiopathic RVOT-VT. Non-inducibility of RVOT-VT represents a relevant limitation for successful ablation which might be overcome by electrical RVOT isolation as a bailout ablation strategy.

BACKGROUND: Pulsed-field ablation (PFA) is a nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation (RFA). We compared the effects of PFA and RFA on heterogeneous ventricular scar in a swine model of healed infarction.
METHODS: In 9 swine, myocardial infarction was created by balloon occlusion of the left anterior descending artery. After a survival period of 8 to 10 weeks, ablation with PFA or RFA was performed at infarct border zones identified by abnormal electrograms. In the PFA group (4 swine), ablation was performed with a lattice catheter (Sphere-9, Affera, Inc). In the RFA group (5 swine), ablation was performed using a 3.5-mm tip catheter (Thermocool ST-SF; Biosense Webster). To further investigate the effect of RFA on temperature development in scar tissue, intramyocardial temperature was measured in healthy and infarcted myocardium using an ex vivo bath model.
RESULTS: A total of 11 PFA and 15 RFA lesions were created at infarct border zones with heterogeneous scar. PFA produced uniform and well-demarcated lesions exhibiting irreversible injury characterized by cardiomyocyte death, contraction bands, and lymphocytic infiltration. This effect of PFA extended from the subendocardium through collagen and fat to the epicardial layers. In contrast, the effect of RFA is less uniform and largely limited to the subendocardium with minimal effect on viable myocardium deeper to separating layers of collagen and fat. PFA produced deeper and more transmural lesions (6.4 [interquartile range, 5.5-7.5) versus 5.4 [interquartile range, 4.8-5.9]), 72% versus 30%, respectively; P≤0.02 for each comparison). The limited effect of RFA on viable myocardium at deeper infarct layers was related to a lower intramyocardial maximal temperature compared with healthy myocardium (P=0.01).
CONCLUSIONS: PFA may be advantageous for ablation in ventricular scar, producing lesions that unlike RFA are not limited to the subendocardium, but also eliminate viable myocardium separated from the catheter by collagen and fat.

BACKGROUND: Catheter mapping and ablation of premature ventricular contractions (PVCs) requires accurate annotation of earliest local activation time (LAT), but displacement in catheter position between sinus rhythm (SR) and the PVC complicates three-dimensional mapping localization. An automated algorithm to annotate LAT sites at the corresponding sinus rhythm sites would provide an alternative to manual annotation and improve procedural efficiency.
METHODS: A retrospective single center study assessed 64 patients undergoing catheter ablation of PVCs. We divided the study patients into two groups: the patients underwent RF ablation using the CARTO 3 version 7 with LAT-hybrid™ module (hybrid group) and the other patients using the CARTO 3 version 6 without LAT-hybrid™ module (conventional group).
RESULTS: The primary results of this study demonstrate that the mean hybrid distance is 4.03 ± 2.33 mm, and this automated algorithm can correct for the positional shift with accuracy comparable to manual correction. Moreover, this algorithm showed significantly shorter RF time and the shorter PVC offset compared to the conventional method.
CONCLUSION: PVC mapping with the LAT-hybrid™ module demonstrated that an automated algorithm can map in more detail with no compromise in accuracy. The LAT-hybrid™ module showed significantly shorter RF time and PVC offset from the earliest LAT in LVOT cases.

BACKGROUND: Recent advancements in a 3-dimensional mapping system allow for the assessment of detailed conduction properties during sinus rhythm and thus the establishment of a strategy targeting functionally abnormal regions in scar-related ventricular tachycardia (VT). We hypothesized that a rotational activation pattern (RAP) observed in maps during baseline rhythm was associated with the critical location of VT.
METHODS: We retrospectively examined the pattern of wavefront propagation during sinus rhythm in patients with scar-related VT. The prevalence and features of the RAP on critical VT circuits were analyzed. RAP was defined as >90° of inward curvature directly above or at the edge of the slow conductive areas.
RESULTS: Forty-five VTs in 37 patients (66±15 years old, 89% male, 27% ischemic heart disease) were evaluated. High-density substrate mapping during sinus rhythm (median, 2524 points) was performed using the CARTO3 system before VT induction. Critical sites for reentry were identified by direct termination by radiofrequency catheter ablation in 21 VTs or by pace mapping in 12 VTs. Among them, RAP was present in 70% of the 33 VTs. Four VTs had no RAP at the critical sites during sinus rhythm, but it became visible in the mappings with different wavefront directions. Six VTs, in which intramural or epicardial isthmus was suspected, were rendered noninducible by radiofrequency catheter ablation to the endocardial surface without RAP. RAP had a sensitivity and specificity of 70% and 89%, respectively, for predicting the elements in the critical zone for VT.
CONCLUSIONS: The critical zone of VT appears to correspond to an area characterized by the RAP with slow conduction during sinus rhythm, which facilitates targeting areas specific for reentry. However, this may not be applicable to intramural VT substrates and might be affected by the direction of wavefront propagation to the scar during mapping. Graphic Abstract: A graphic abstract is available for this article.

The Affera system features a versatile and large footprint catheter with a lattice-tip design that is capable of delivering both pulsed field and radiofrequency energy. It provides precise mapping and ablation capabilities, demonstrating high acute success rates and durable lesion formation, with excellent safety profile in both radiofrequency and pulsed field ablation modes. Preclinical and clinical studies have shown high lesion durability, reduced procedural time, and promising outcomes in pulmonary vein isolation with minimal complications.

BACKGROUND: Catheter ablations are increasingly performed with zero or minimal fluoroscopy, enabled by ultrasound imaging and electro-anatomical mapping. Pulsed field ablation (PFA) using Farawave has been dependent on fluoroscopic assessment of catheter conformation and contact. We aimed to demonstrate the feasibility of a PFA workflow for pulmonary vein isolation (PVI) and extrapulmonary ablation.
METHOD: Patients with paroxysmal or persistent atrial fibrillation who underwent fluoroless PVI between August 2023 to October 2024 were included in this study. After transoesophageal echocardiography-guided transeptal puncture, the PentaRay catheter was used to acquire left atrial and pulmonary branch anatomy. The Farawave catheter and Rosen wire, clipped using alligator clips, were visualised using the CARTO 3D Electroanatomical Mapping System (https://www.jnjmedtech.com/en-US/product/carto-3-system). Arrhythmia induction and mapping were routinely performed after PVI to guide further extrapulmonary ablation.
RESULTS: A total of 36 patients were included in this study, with a median age of 60 (52-67) years. All pulmonary veins (PVs) were antrally isolated (130/130 PVs) and 16 patients (44.4%) underwent further extrapulmonary ablations with 13 of 13 successful posterior wall isolations (100%), six of seven linear line ablations achieving bidirectional block (85.7%) and two of two successful superior vena cava isolations (100%). The median total procedure time was 77 (65-93) minutes, left atrial dwelling time of 54 (46-74) minutes, with ablation time of 24 (20-29) minutes.
CONCLUSIONS: A fluoroless PFA workflow is feasible and rapid in achieving successful PVI and extrapulmonary ablation to treat atrial fibrillation and induced organised atrial tachyarrhythmias.

PURPOSE: To provide a brief overview of some relevant technological advances in the field of three-dimensional electroanatomical mapping (3D-EAM) that have recently entered the clinical arena and their role in guiding catheter ablation (CA) of complex atrial and ventricular arrhythmias.
METHODS: In this technical report, we describe the general features of three novel algorithms featured in the updated CARTO PRIME™ mapping module for CARTO®3 version 7 3D-EAM system (Biosense Webster Inc., Diamond Bar, CA, USA): local activation time (LAT) hybrid, coherent mapping and map replay modules. We also report three challenging arrhythmia cases in which CA was successfully guided by these softwares.
RESULTS: The LAT hybrid module was used in a case of premature ventricular complex originating from the right coronary cusp. This algorithm facilitated safe positioning of the ablation catheter away from the right coronary ostium, avoiding potential harm to this vital structure. The coherent mapping module helped to identify the critical as well as a bystander isthmus of an atrial macro-re-entrant tachycardia in a grown-up patient with congenital heart disease. The map replay module allowed rapid retrospective activation mapping of two unstable ventricular tachycardias in a case of nonischemic cocaine-associated cardiomyopathy.
CONCLUSION: 3D-EAM systems offer significant advantages in the management of challenging arrhythmias, and the introduction of novel algorithms underpins improvements in patients' outcomes. Given the increasing sophistication of these systems, however, a close collaboration among cardiac electrophysiologists, engineers and technicians is highly needed in order to get the best from the available technology.

A two-year and four-month, male German Shepherd was referred for exercise intolerance and panting. Irregular heart auscultation (250 beats per minute (bpm)) and pulse deficits were noted on physical exam. Electrocardiogram (ECG) showed irregular, narrow-QRS tachycardia without P waves compatible with coarse atrial fibrillation (AF). A 24-h ECG showed sustained AF (mean ventricular response rate 92 bpm). Echocardiography showed no structural abnormalities. Given the young age and presence of AF-related symptoms, rhythm control was preferred. Transthoracic electrical cardioversion was successfully performed six weeks later but AF recurred within 24-h. Sotalol was started but discontinued due to poor tolerance and AF persisted. Seven months after AF diagnosis, radiofrequency catheter ablation (RFCA) aiming for pulmonary vein isolation was performed under general anaesthesia. After transseptal puncture, three-dimensional electroanatomical mapping of the left atrium was performed. Point-by-point pulmonary vein isolation was achieved by RFCA. Seventy-eight RFCA lesions were placed in the left atrium encircling the three pulmonary vein ostia followed by electrical cardioversion. No complications occurred and the dog was discharged with amiodarone. In the immediate post-operative phase, there was recurrence of persistent AF requiring electrical cardioversion. Furthermore, at one month after the ablation, the dog experienced a single and transient paroxysm of AF. Since then, stable sinus rhythm (SR) was retained on daily ECG monitoring at home and confirmed by 24-h ECG three months post-operatively. Amiodarone was stopped subsequently. At the time of writing (one year post-operative), the dog remains in SR with normal exercise tolerance.

[Figure: see text]

Cardiac dysfunction secondary to manifest ventricular pre-excitation via accessory pathways (AP) in the absence of tachyarrhythmias is rarely studied. To evaluate pathophysiology, AP location impact, diagnostic approach, and role of catheter ablation (CA) in pre-excitation-related cardiac dysfunction without tachyarrhythmias. Electronic databases were queried for WPW/pre-excitation and cardiac dysfunction-related studies without age restrictions. A total of 34 studies met inclusion criteria, including 27 case reports/series (42 patients, 62% female) and 7 observational studies (412 participants, 41% female). Pediatric patients age ranged from infancy to 21 years and adults from 20 to 59 years. Right septal and right free-wall APs were most commonly associated with cardiomyopathy. Heart failure predominated in pediatric presentations, whereas adults most often exhibited asymptomatic LV dysfunction. Intra-LV dyssynchrony, particularly when accompanied by septal dyskinesia, emerged as a consistent pathophysiologic feature. Two-dimensional strain echocardiography (2D-STE) reliably identified LV dysfunction, localized AP, and assessed response to CA. Although cardiac function mostly normalized after successful AP ablation, irreversible myocardial changes have been reported. Preexcitation-related cardiac dysfunction in the absence of tachyarrhythmias, appears to be mediated primarily by intra-LV dyssynchrony and is most commonly associated with right-sided and septal APs. 2D-strain imaging is a useful diagnostic tool. CA typically restores cardiac function, however, irreversible myocardial changes can occur. Therefore, close surveillance and consideration of early ablation in patients with evidence of dyssynchrony are warranted. Large prospective cohort studies can further validate these findings.

BACKGROUND: Catheter ablation for atrial fibrillation (AF) in patients with dextrocardia, complete situs inversus, and interrupted inferior vena cava is technically demanding because of mirror-image cardiac anatomy and the absence of femoral venous access. Pulsed field ablation (PFA), a nonthermal and tissue-selective modality, may offer advantages in such challenging conditions.
CASE SUMMARY: A 53-year-old man with dextrocardia, complete situs inversus, and interrupted inferior vena cava with azygos continuation had previously undergone catheter ablation via the internal jugular vein. Three years later, recurrent symptomatic persistent AF led to repeat ablation. Using a superior approach under general anaesthesia, transseptal puncture was guided by intracardiac echocardiography. Electroanatomical mapping identified conduction gaps in the right pulmonary veins. A variable-loop circular catheter was used to eliminate the gaps. Posterior left atrial wall isolation was additionally performed to address the substrate for persistent AF. The procedure was completed without fluoroscopy.
DISCUSSION: To the best of our knowledge, this is the first report of AF ablation using a multielectrode variable-loop circular catheter via a superior approach without fluoroscopy. This strategy demonstrated the feasibility of PFA in the presence of mirrored cardiac anatomy. Impedance-based catheter-to-tissue contact assessment and lesion-visualization tools supported precise and acute lesion formation without fluoroscopy. These features emphasize the usefulness of pulsed field ablation when femoral venous access is limited.

Inferior epigastric artery injury during femoral vein puncture is rare but typically occurs near its origin, requiring a careful and technically demanding approach. We report two cases of proximal right inferior epigastric artery injury following femoral vein puncture during catheter ablation. To minimize further damage, a steerable microcatheter was used to approach the distal inferior epigastric artery by adjusting its tip direction, and coil embolization was initiated distally. For proximal embolization, a balloon catheter was placed in the right external iliac artery for balloon-assisted, controlled coil packing at the origin. Complete hemostasis was achieved in both cases without complications. Balloon-assisted coil embolization using a steerable microcatheter appears to be an effective technique for managing proximal inferior epigastric artery injuries associated with femoral vein puncture.

OBJECTIVE: To evaluate the performance of the left atrial time-to-peak (TTP) derived from time-resolved magnetic resonance angiography (TR-MRA) as a noninvasive indicator of left atrial pressure (LAP) in patients with atrial fibrillation (AF).
MATERIALS AND METHODS: This retrospective study included 92 patients who underwent cardiac TR-MRA and catheter-based LAP measurements prior to catheter ablation for AF between January 2021 and December 2022. TR-MRA-derived TTP was measured in the left atrium using contrast-enhanced time-signal intensity curves. Catheter-based LAP measured during sinus rhythm served as the reference standard, with high LAP defined as ≥15 mmHg. Univariable and multivariable linear regression analyses were performed, with LAP as the dependent variable and echocardiographic parameters as covariates. The diagnostic performance of TTP for high LAP was evaluated using receiver operating characteristic (ROC) curve analysis.
RESULTS: Among the 92 patients (mean age ± standard deviation, 60 ± 10 years; 70 male), 70 (76.0%) had low LAP, and 22 (23.9%) had high LAP. Mean TTP was significantly longer in patients with high LAP than in those with low LAP (25.1 ± 6.9 s vs. 16.9 ± 5.7 s, P < 0.001). In multivariable linear regression analysis, TTP remained independently associated with LAP (β = 0.46, P < 0.001). ROC analysis demonstrated good discriminative performance of TTP for identifying high LAP, with an area under the curve of 0.834 (95% confidence interval, 0.742-0.904). Using a TTP cutoff of >19.6 seconds, the sensitivity and specificity for identifying elevated LAP levels were 81.8% (18/22) and 75.7% (53/70), respectively.
CONCLUSION: TR-MRA-derived TTP showed a significant independent association with invasively measured LAP. It may serve as a reliable noninvasive imaging marker for identifying high LAP in patients with AF undergoing catheter ablation.

BACKGROUND: The role of dominant frequency (DF)-guided ablation after pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF) remains uncertain. We evaluated the clinical and mechanistic impact of DF mapping in a multicenter randomized study.
METHODS AND RESULTS: In this multicenter, prospective study, 103 patients were enrolled. Patients with high-DF sites (≥ 7 Hz) were randomized 1:1 to PVI plus DF ablation (DF group, n = 32) or PVI alone (PVI group, n = 32). Patients without high-DF sites (< 7 Hz, n = 39) underwent PVI only (non-DF group; exploratory cohort). The primary endpoint was freedom from documented AF recurrence without antiarrhythmic drugs (AADs) at 12 months. AF-free survival off AADs was 81.3% in the DF group versus 68.9% in the PVI group (p = 0.228) at 12 months. Arrhythmia-free survival with or without AADs was 78.1% versus 65.6% (p = 0.263). The non-DF group showed the most favorable outcomes (83.3%, p = 0.065 vs PVI group). No adverse events were associated with DF mapping or ablation. Multivariate analysis identified right atrial (RA) low-voltage area extent (HR 1.031, 95% CI 1.005-1.058, p = 0.018) and LA diameter (HR 0.899, 95% CI 0.816-0.991, p = 0.032) as independent predictors of recurrence.
CONCLUSIONS: In this multicenter randomized trial, adjunctive DF-guided ablation following PVI did not result in a statistically significant improvement in arrhythmia-free survival compared with PVI alone. However, the absence of high-DF sites was associated with favorable outcomes, and RA low-voltage burden emerged as an independent predictor of recurrence, supporting the potential mechanistic value of DF mapping and highlighting the prognostic importance of right atrial structural remodeling.
TRIAL REGISTRATION: UMIN000042543.