Relation of early termination of persistent atrial fibrillation by cardioversion or drugs to ablation outcomes.

Current ablation consensus documents define persistent atrial fibrillation (AF) as AF lasting >1 week to 1 year or AF requiring cardioversion or pharmacologic conversion in <1 week. These 2 persistent AF subgroups may have different clinical characteristics and ablation outcomes. We compared 179 patients whose persistent AF was always terminated in <1 week by cardioversion/drugs to 244 whose AF actually lasted >1 week to 1 year. Patients with AF termination in <1 week by cardioversion/drugs had smaller left atrial (LA) size (4.1 ± 0.6 vs 4.5 ± 0.7 cm, p <0.0001), a longer AF history (7.5 ± 7.5 vs 6.0 ± 7.2 years, p = 0.035), more failed drugs (1.6 ± 1.0 vs 1.3 ± 1.0, p = 0.004), lower body mass index (28.5 ± 5.5 vs 30.3 ± 5.5, p = 0.0008), and fewer cardiomyopathies (3.9% vs 11.1%, p = 0.01). Cox multivariate analysis showed that LA size (p = 0.02), female gender (p = 0.001), and coronary artery disease (p = 0.03) predict ablation failure. There was a linear relation between duration of longest AF episode and LA size (p = 0.0001). Longest AF episode duration was the only factor predicting LA size (p = 0.001). Kaplan-Meier analysis showed more patients with AF termination in <1 week by cardioversion/drugs were free of AF after ablation (p = 0.042) than those whose AF actually lasted >1 week to 1 year. Once AF lasted >1 week, duration up to 1 year did not affect ablation success. In conclusion, patients whose persistent AF is always terminated by drugs/cardioversion in <1 week have different clinical characteristics and better ablation outcomes than patients whose AF persists beyond 1 week. This suggests that maintaining sinus rhythm before ablation is beneficial and that the definition of AF2 may need revision.