Durability of a Posterior Mitral Line after Pulsed-Field Ablation with a Pentaspline Catheter: Insight from Redo Procedures

Background Durability of a posterior mitral line (PML) via a pentaspline pulsed field ablation (PFA) catheter is uncertain. Objective To assess mitral isthmus (MI) block durability and recurrence mechanisms after fluoroscopy-guided PML ablation using a pentaspline PFA catheter. Methods In a multicenter registry, we included consecutive patients undergoing redo procedure for recurrent atrial arrhythmia after an index procedure that included fluoroscopy-guided PML ablation with a pentaspline PFA catheter. The primary endpoint was durable MI block at redo procedure. Results The study included 54 patients (age 68.8 ± 8.5 years, 29.6% female) from three European tertiary centers. Acute MI block at index procedure had been achieved in 49/54 (90.7%) after a median of 28 applications [19–48]. Redo procedures were performed after a median time of 287 days [161-489]. Durable MI block was present in only 11 patients (20.4% of the whole cohort; 22.4% of those with documented acute block). Perimitral flutter was the dominant presenting rhythm (38.9%). Reconnection involved predominantly the ventricular portion of the MI (33/43; 76.7%); epicardial breakthrough was identified in 5/43 (11.6%). Neither catheter size nor left atrial volume was independently associated with durability. Conclusion Despite a high acute success rate, durable MI block after PML ablation with a pentaspline PFA catheter was the exception in patients undergoing redo procedures for recurrent atrial arrhythmia, with the ventricular portion of the MI as the principal site of reconnection.