OUTCOMES OF A COMPREHENSIVE STRATEGY DURING REPEAT ATRIAL FIBRILLATION ABLATION

BACKGROUND Recurrence of atrial fibrillation (AF) post-ablation occurs in 30-50% of patients. The approach to a repeat ablation, beyond isolation of reconnected pulmonary veins (PVs), is not well established. We sought to prospectively assess outcomes and determine predictors of recurrence among consecutive patients who underwent repeat AF ablation with a standardized approach. METHODS AND RESULTS This was a single-center prospective study of consecutive patients who underwent repeat AF ablation. Our ablation protocol consisted of six steps: PV re-isolation, ablation of left atrial low-voltage areas (LVAs), ablation of isoprenaline induced non-PV triggers, electrophysiology study (EPS), and ablation of all clinical and induced atrial flutters. Between February 2017 and January 2020, 725 AF ablations were performed at our center. Of these, 74 were repeat AF ablation using the new protocol. The average age was 62.5 ± 9.2 years; 18% were female; 51% had paroxysmal AF at time of initial ablation. The indication for repeat ablation was paroxysmal AF in 39 (53%) patients, persistent AF in 24 (32%) patients. Among the study cohort of 74 patients undergoing repeat AF ablation, 53 (72%) had PV reconnection; 30 (41%) had LVA; 7 (10%) had non-PV triggers; five (7%) had AVNRT, and five (7%) had typical atrial flutter. Arrhythmia-free survival was 65% at one year. The absence of PV reconnection was the only factor independently associated with recurrence (overall rate 71%, adjusted OR 7.91, 95% CI 2.31-27.16, p=0.001). The arrhythmia-free survival was 29% in those without PV reconnection; meanwhile it was 88% in those with all PVs reconnected. Those with absence of reconnection had more LVA (67% vs 30%, p=0.004) and hypertension (67% vs 30%, p=0.004), suggesting more atrial myopathy. CONCLUSION We describe a comprehensive approach to repeat AF ablation using a standardized protocol that included isolation of reconnected PVs, targeting all areas of low-voltage, ablating all non-PV triggers, inducible SVT, and atrial flutters. Finding reconnected PVs at repeat procedure was a strong predictor of arrhythmia-free survival. Recurrence rates were high among those with absence of PV reconnection, potentially suggesting advanced atrial substrate as the underlying etiology. Our findings demonstrate that PV re-isolation remains the most important treatable cause of atrial arrhythmia recurrence after AF ablation; however further research is needed to investigate therapies beyond PV re-isolation.