Mechanisms of Recurrent Arrhythmia in Patients With Prior Surgical Ablation of Atrial Fibrillation Who Undergo Catheter Ablation.

BACKGROUND: Atrial tachyarrhythmias frequently recur after surgical ablation and often require catheter ablation (CA). METHODS: We conducted a retrospective cohort study of patients who underwent CA for symptomatic atrial fibrillation or flutter (AF hereafter) following surgical ablation. Clinical data, including patient and surgical characteristics and results of electrophysiology testing and mapping, were recorded. Recurrence was defined as 30 s of AF, atrial flutter, or atrial tachycardia following a 3-month blanking period. RESULTS: Thirty-seven patients were included in the study (mean age 67.0 ± 9.8 years, 43% female) who underwent isolated surgical ablation (n = 5), concomitant mitral valve surgery (n = 21), aortic valve (n = 5), tricuspid valve surgery (n = 6), and/or coronary artery bypass grafting (n = 6). The mean time from surgical ablation to CA was 5.9 ± 5.1 years. Among the 37 patients, 19 (51%) experienced one or more pulmonary vein reconnections (mean 3.0 ± 1.3 veins per patient), and 15 (41%) developed mitral annular flutter. Following ablation, 12 (32%) patients developed recurrent arrhythmia by 1-year post-ablation. Age, sex, body mass index, time from surgical ablation to CA left ventricular ejection fraction < 50%, prior CA, left atrial diameter, and mitral annular flutter were not associated with recurrence. The number of pulmonary vein reconnections at the time of repeat CA was predictive of arrhythmia recurrence in subsequent follow-up (OR 2.148 [95% CI: 1.059-4.357]; p = 0.034). CONCLUSIONS: Pulmonary vein reconnection and mitral annular flutter are common recurrence mechanisms in patients with symptomatic arrhythmia recurrence following surgical ablation. The number of pulmonary vein reconnections predicts recurrent arrhythmia.