Very late recurrence after atrial fibrillation ablation: Clinical characteristics and pulmonary vein reconnection patterns

BACKGROUND: Delayed recurrence of atrial fibrillation (AF) after index ablation is increasingly recognized, but its clinical and procedural phenotypes remain poorly described. OBJECTIVE: This study aimed to characterize patients undergoing very late redo (VLR) AF ablation (>5 years after prior ablation) and compare pulmonary vein (PV) findings across redo interval groups. METHODS: 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). RESULTS: Of the 596 patients undergoing redo AF ablation, 71 (12%) underwent VLR AF ablation (median redo interval, 7.1 years [interquartile range [IQR], 5.9-8.2]). These patients had a mean age of 62.1 years; 72% were male, and the median congestive heart failure, hypertension, age, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism, vascular disease, age, sex category score was 2 (IQR, 1-3), with 57.7% having paroxysmal AF at the redo procedure. PV reconnection (any) was less likely with increasing time from index PV isolation: at <1 year, 80.1% (189/236); 1-5 years, 65.1% (188/289); >5 years, 49.3% (35/71); P < .001. Each additional year from index to redo ablation was associated with an 8.6% lower expected number of reconnected PVs (rate ratio, 0.91, 95% CI, 0.88-0.95; P < .001). In total, 32/71 (45%) of the patients undergoing VLR AF ablation developed recurrent AF at a median follow-up of 243 days (IQR, 103-1097) from the repeat procedure. CONCLUSION: The likelihood of PV reconnection declines significantly with increasing time to redo AF ablation; the majority of patients >5 years have enduring PV isolation. This suggests a greater contribution from non-PV triggers and/or AF substrate in this cohort.