Anterior mitral isthmus line using pulsed-field ablation with the pentaspline catheter or radiofrequency ablation: procedural characteristics, safety, and mid-term outcomes

AIMS: Pulsed-field ablation (PFA) is a non-thermal energy source for pulmonary vein isolation (PVI), offering advantages in safety and procedural efficiency. However, data comparing anterior mitral isthmus line (MIL) ablation using PFA vs. conventional radiofrequency ablation (RFA) are scarce. This study aimed to compare procedural characteristics, safety, and arrhythmia recurrence following PVI with additional anterior MIL ablation using PFA vs. RFA. METHODS AND RESULTS: In this prospective, single-centre analysis from the SWISS-AF-PVI registry, 129 patients (median age 70 years, 40% female) undergoing PVI with anterior MIL ablation were included. Patients received either PFA with a pentaspline catheter (n = 61) or RFA using a 3.5 mm irrigated tip catheter (n = 68). Procedural parameters, complications, and arrhythmia recurrence were assessed over a median follow-up of 327 days. PFA significantly reduced total procedure time (71 vs. 108 min, P < 0.001), LA dwell time (53 vs. 80 min, P < 0.001), and ablation time (27 vs. 50 min, P < 0.001) compared to RFA. MIL ablation with PFA required fewer applications (14; 35 s vs. 473 s RFA, P < 0.001). Arrhythmia-free survival was similar between groups (PFA 48.8% vs. RFA 61.8%, P = 0.34). Among 34 patients undergoing redo procedures, incomplete MIL was found in 53%, with no significant difference between groups. Three major complications occurred. CONCLUSION: Anterior MIL ablation using PFA is feasible, safe, and more time-efficient than RFA, with comparable mid-term arrhythmia outcomes. However, high rates of MIL reconnection and arrhythmia recurrence highlights the need to improve lesion durability.