Very Late Recurrence After Atrial Fibrillation Ablation: Clinical Characteristics and Pulmonary Vein Reconnection...

Delayed recurrence of atrial fibrillation (AF) after index ablation is increasingly recognised, but its clinical and procedural phenotypes remain poorly described.

To characterise patients undergoing very late redo (VLR) AF ablation (>5 years after prior ablation) and compare pulmonary vein (PV) findings across redo interval groups.

Consecutive patients undergoing redo AF ablation at Alfred Health and Cabrini Health (2007-2025) were included and grouped by redo interval (<1 year, 1-5 years, >5 years).

Of 596 patients undergoing redo AF ablation, 71 (12%) patients underwent VLR AF ablation (median redo interval 7.1 years [IQR 5.9-8.2]). VLR patients had a mean age of 62.1 years; 72% were male, and median CHA₂DS₂-VASc was 2 (IQR 1-3) with 57.7% having paroxysmal AF at redo procedure. PV reconnection (any) was less likely with increasing time from index PVI: At <1 year 80.1% (189/236), 1-5 years 65.1% (188/289), >5 years 49.3% (35/71); p<0.001. Each additional year from index to redo ablation was associated with an 8.6% lower expected number of reconnected PVs (RR 0.91, 95% CI 0.88-0.95; p<0.001). In total 32/71 (45%) of patients undergoing VLR AF ablation developed recurrent AF at a median follow-up of 243 days (IQR 103-1097) from repeat procedure.

The likelihood of PV reconnection declines significantly with increasing time to redo AF ablation, with the majority of patients > 5 years having enduring PV isolation. This suggests a greater contribution from non-PV triggers and/or AF substrate in this cohort.