Electrogram morphology recurrence guided catheter ablation for repeat ablation of persistent atrial fibrillation

Background: There are no standard mapping approaches for patients with persistent atrial fibrillation (PeAF), particularly after failed prior catheter ablation (CA). In this study, we assess the feasibility of using Electrogram Morphology Recurrence (EMR) to guide ablation. Methods: Ten patients with recurrent PeAF after prior CA underwent detailed mapping of both atria during PeAF using the PentaRay (4 mm interelectrode spacing) and 3D mapping with CARTO. At each site, 15 s recordings were made. Custom software identified each electrogram and cross-correlation was used to identify the most recurrent electrogram morphology from which the % recurrence and cycle length of the most repeatable morphology (CL_R) was calculated. Sites of shortest CL_R and sites within 5 ms of shortest CL_R with recurrence ≥ 80% were used to inform CA strategy. Results: A mean of 342.9 ± 131.9 LA and 328.6 ± 91.5 RA sites were recorded per patient. Nine had PV reconnection. Shortest CL_R sites guided ablation in 6/10 patients while 1 patient failed to fulfill shortest CL_R criteria, and another 3 did not undergo CA guided by shortest CL_R due to operator preference. On 12-month follow-up, all 4 patients without shortest CL_R guided CA had recurrent PeAF. Of the 6 patients with shortest CL_R guided CA, 5 patients did not have recurrent PeAF (p = 0.048), although 1 had paroxysmal AF and 2 had atypical atrial flutter. Conclusion: EMR is a feasible, novel technique to guide CA in patients with PeAF. Further evaluation is needed to provide an electrogram-based method for mapping guided targeted ablation of key areas.