Characteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial Tachycardia

Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non‐PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non‐PV ectopy initiating AF/AT. Methods: Twenty‐three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non‐PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real‐time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8‐second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non‐PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non‐PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non‐PV ectopy in all patients (100%). During a follow‐up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non‐PV ectopy during the follow‐up. Conclusion: The sites of the origin of the non‐PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non‐PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated.