Atrial Tachycardias After Surgical Atrial Fibrillation Ablation: Clinical Characteristics, Electrophysiological Mechanisms, and Ablation Outcomes From a Large, Multicenter Study

Objectives: The clinical characteristics, electrophysiological mechanisms, and ablation outcomes of post-surgical atrial fibrillation ablation (SAFA) atrial tachycardias (ATs) have not been studied in a large, multicenter cohort. Background: ATs are often seen following SAFA. Methods: Analysis was performed on 137 patients (age, 62 ± 10 years; 74% male) who underwent catheter ablation for symptomatic post-SAFA AT from 2004 to 2013 at 3 high-volume institutions in the United States. Results: A total of 137 patients had 149 ATs that were mapped; 103 (69%) had a left atrial (LA) origin and 46 (31%) had a right atrial origin. Of the 149, a total of 44 (30%) had a focal mechanism, with 29 (66%) having an LA origin, with 53% localized to LA posterior wall. Of the 105 re-entrant ATs, 74 (71%) were of LA origin. The predominant circuits were cavotricuspid isthmus (n = 25), perimitral (n = 19), LA roof (n = 17), left pulmonary veins (n = 13), right pulmonary vein/LA septum (n = 12), and LA appendage (n = 7). A total of 93% of patients had ≥1 pulmonary vein reconnection requiring reisolation. Catheter ablation resulted in termination and noninducibility of 97% of right atrial and 93% of LA ATs. Over a 12-month follow-up, 80% of patients were free of any AT or AF. Conclusions: In this large multicenter cohort of post-SAFA ATs, most were of LA origin, with macro–re-entry being the most common arrhythmia mechanism. Wide variability in location of AT circuits was seen in both right atrial and LA and likely reflects underlying arrhythmogenic substrate and differences in modified SAFA techniques. Catheter ablation was highly successful in eliminating the culprit AT with favorable long-term outcomes.