Impact of Initial Extensive Ablation on Left Atrial Gaps During Redo Procedures and Subsequent Outcomes in Persistent Atrial Fibrillation.

Background: The efficacy of extensive linear ablation strategies, in addition to pulmonary vein (PV) isolation, remains controversial in persistent atrial fibrillation (AF) ablation. Gaps in previously ablated lesions can induce arrhythmias and potentially decrease the effectiveness of extensive ablation. This study evaluated the incidence of conduction gaps, gap-related reentry, and subsequent recurrence following redo AF ablation in the EARNEST-PVI trial (Efficacy of Pulmonary Vein Isolation Alone in Patients With Persistent Atrial Fibrillation; REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03514693).

Methods: The EARNEST-PVI trial is a randomized controlled study evaluating index ablation strategies for persistent AF. Of the 512 trial participants, 115 who underwent redo AF ablation (pulmonary vein isolation [PVI]-alone redo [n=69] and PVI-plus linear redo [n=46]) were included in the present study. Left atrial conduction gaps, the occurrence of left atrial tachycardias during redo procedures, and subsequent recurrences were compared between the PVI-alone redo group and the PVI-plus linear ablation redo group.

Results: In the PVI-alone redo group, electrical PV gaps were observed in 38 (57%) patients. In the PVI-plus redo group, 19 (41%) had PV gaps, 10 (22%) had gaps in left atrial linear lines, and 11 (24%) had gaps in both. During the redo session, 19 left atrial tachycardias were observed or induced in 15 patients. Atrial tachycardias were more frequently observed in the PVI-plus group than in the PVI-alone group (23.9% versus 5.8%; =0.005). The occurrence of left atrial tachycardias was associated with gaps in linear lesions, whereas PV gaps alone were associated with subsequent recurrence after redo (hazard ratio, 0.54 [95% CI, 0.31-0.95]; =0.033).

Conclusions: In the redo AF ablation of the EARNEST-PVI trial, left atrial conduction gaps were more frequent in patients who underwent extensive linear ablation during the index procedure. While all gaps during redo were potentially arrhythmogenic, PV gaps alone were associated with recurrence after redo AF ablation.

Registration: URL: https://www.umin.ac.jp/ctr/index-j.htm; Unique identifier: UMIN000019449.