harada masahide

BACKGROUND: Pulsed field ablation (PFA) is a novel therapy for atrial fibrillation (AF) with myocardial selectivity and safety. The VARIPULSE catheter (variable-loop circular catheter [VLCC]; Biosense Webster, Inc.) was recently introduced in Japan, but multicenter real-world data remain scarce. OBJECTIVE: This study aimed to evaluate procedural features, acute safety, and early outcomes of tissue proximity indication (TPI)-guided PFA under structured training and standardized protocols. METHODS: We retrospectively analyzed 387 consecutive patients with AF (66.4 ± 10.9 years, 69% male, 87.1% paroxysmal) undergoing initial pulmonary vein isolation (PVI) with the VLCC at 10 Japanese centers (April 2024-May 2025). TPI-guided first-pass PVI targeted ≥12 applications per vein in 4 sets (proximal/distal), with additional ablation at TPI-negative sites. Operators received training and followed a harmonized workflow emphasizing TPI guidance and sheath management. RESULTS: First-pass PVI was achieved in 360 patients (93.0%). After limited touch-up (6.9 ± 3.6 applications), complete PVI was obtained in all. Mean PVI time was 32.1 minutes, procedure duration 89.7 minutes, and median fluoroscopy time 3.0 minutes. Three patients (0.8%) had vascular complications; no tamponade, stroke, transient ischemic attack, or renal injury occurred. Predictors of first-pass failure were higher body mass index and lack of pre-mapping, mainly in early cases, declining from 11.4% to 3.0% (P < .001). At median follow-up of 182 days, arrhythmia-free survival was 94.1% at 3 months and 88.5% at 6 months. CONCLUSION: In this first multicenter real-world study, TPI-guided PFA with the VLCC demonstrated high acute efficacy, no clinical strokes or TIAs, low complication rates, and favorable mid-term outcomes with structured training and standardized protocols.

ABSTRACT Background High‐power short‐duration (HPSD) ablation is an established therapy for pulmonary vein (PV) isolation (PVI) in atrial fibrillation (AF), aiming to form efficient transmural lesions. Very HPSD (vHPSD) can further shorten ablation time but may increase the risk of acute PVI failure compared with HPSD. A combined HPSD and vHPSD strategy (90 W/50 W combination workflow) potentially balances efficiency and durability, though its clinical feasibility remains unknown. Therefore, this multicenter registry evaluated the acute and long‐term efficacy of a 90 W/50 W combination workflow for PVI in patients with paroxysmal AF. Methods In this prospective study, a total of 101 consecutive patients with paroxysmal AF underwent PVI using radiofrequency ablation with a 90 W/50 W combination workflow. We evaluated acute outcomes, including first‐pass isolation and acute PV reconnection, and monitored atrial tachyarrhythmia recurrences over 12 months. Results Median PVI procedure time was 35 min, with total procedure time at 105 min. First‐pass PVI was achieved in 58.4% of patients, including 74.3% in the right PV and 72.3% in the left PV. Acute PV reconnection occurred in 31.7% (32/101). In multivariate analysis, carina sites independently predicted acute PVI failure in both HPSD and vHPSD groups, while contact force also predicted failure in the HPSD group. After 1 year, 89.9% of patients remained free from documented atrial tachyarrhythmias. Conclusion The 90 W/50 W combination workflow did not notably shorten procedure time or enhance first‐pass success. More standardized strategies, particularly in carina segments with higher contact force and ablation index under HPSD, may be required to ensure optimal lesion durability and favorable outcomes.