Characteristics of Recurrent Atrial Arrhythmias and Lesion Assessment Late After Pulsed Field Ablation of Atrial Fibrillation

BACKGROUND: Pulsed field ablation (PFA) is a novel and rapidly expanding energy for the ablation of atrial fibrillation (AF). The relationships between the characteristics of pulmonary vein (PV) and extra-PV PFA applications, and the type of arrhythmia recurrence or durable lesion observed during redo procedures remain unclear. METHODS: In this substudy of the FRANCE PFA national exhaustive multicentric registry, we collected detailed data on PFA applications delivered during the initial AF ablation procedure. Among patients with arrhythmia recurrence undergoing redo procedures with 3-dimensional mapping (n=145), we analyzed the type of recurrence, rates of durable PV isolation (PVI), and the presence of complete block over the ablation lines. RESULTS: Recurrent arrhythmias comprised AF in 58%, atrial tachycardia in 28%, and typical atrial flutter in 8%. AF was less frequently observed when initial ablation targeted extra-PV areas (45 versus 71%; P =0.01) and when a 35-mm diameter catheter was used for PVI only (50 versus 77%; P =0.01). Complete durable PVI was observed in 42% of patients (69% to 76% for each separate PV), and durable roof/PW and mitral isthmus blocks were observed in 62% and 31% of cases, respectively. The rate of durable PVI increased with the number of PFA applications ( P <0.05), reaching 84% with >12 applications. Similarly, roof/PW block rates increased to 88% with >16 applications ( P <0.01). Mitral isthmus block rate remained low (31%) and was not significantly associated with application number. CONCLUSIONS: In patients undergoing redo procedures after an initial AF ablation using the pentaspline PFA catheter, AF was less frequently observed when ablation lesions were performed beyond PVs. A high rate of durable PVI or block was achieved with >12 PFA applications per PV and >16 for the roof/PW. Long-term durability of mitral isthmus block was poor using the Pentaspline PFA catheter.