Pulsed filed ablation: comparison of procedural data and re-do data for the 31mm and 35mm device

Abstract Background Pulsed field ablation (PFA) with the pentaspline catheter is a non-thermal technology for atrial fibrillation (AF) ablation. Our initial experience from repeat procedures suggested more pulmonary vein (PV) reconnections and more organized atrial tachycardias (ATs) with the larger 35mm device involving a small slow-conduction corridor at the posterior wall between the lesions. This study compares procedural data and long-term outcomes to investigate if the 35mm device leads to more PV reconnections and whether larger lesions from the 35mm device lead to more organized ATs due to a critical isthmus between lesions at the posterior wall. Methods Consecutive patients who underwent PFA-PVI with our conventional approach of 8 applications per PV between 2021-2024 were included. Ablation beyond PVI was excluded. Success was defined as no recurrence of atrial tachyarrhythmia after a 3-month blanking period. Data were compared between the 31mm and 35mm groups. Results A total of 652 patients (62.7% male, median age 69 (IQR [61-76] years) were included, with 202 (31%) treated with the 35mm device. LA size was larger in the 35mm group (35mm: 42 [38-47]mm vs. 31mm: 41 [37-45]mm; p=0.01). All 2578 targeted PVs were isolated using solely PFA. Procedure time was slightly longer with the 35mm device (33 [28-40] min vs. 30 [26-28] min; p=0.009) while complication rate was 1.8% without difference between groups (35mm: 5 (2,5%) vs. 31mm: 7 (1,6%); p=0.419). Most complications resulted from access site (8/12). No significant difference was found in recurrence rates during blanking period (35mm: 22.3% vs. 31mm: 16.0%; p=0,053) or in the type of recurrence (organized AT: 35mm: 28.9% vs. 31mm: 29.2%; p=0.974) was found. Median follow up time was 379 [204-546] days. At one year, there was no difference in arrhythmia free survival (35mm: 71.8% vs. 31mm: 74.5%; p=0.277) or the rate of organized AT (35mm: 34.2% vs. 31mm: 34.2%; p=1.0). A total of 98 repeat procedures were performed, with no significant difference in durable PVI between groups (35mm: 120/157 (76.4%) vs. 31mm: 182/232 (78.5%); p=0.219). The highest PVI durability was observed for the LIPV and LSPV (both 81.9%) and the lowest for the RIPV (73.5%). Conclusion Both PFA devices demonstrated strong safety profiles, short procedure times, and favorable long-term outcomes with high rates of durable PVI. The larger atria in the 35mm group are likely due to the more frequent use of the 35mm device in these cases. Surprisingly, no difference was observed in 1-year follow-up or PVI durability between the groups. The lager lesions created by the 35mm device were likely offset by the larger atria in this group, resulting in a similar risk of developing a small slow-conduction corridor at the posterior wall between lesions. This may explain the same rate of organized atrial tachycardia observed during follow-up and underlines the importance of considering anatomy when choosing the device.