Very late recurrences of atrial fibrillation after pulmonary vein isolation
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, accounting for approximately one-third of all hospitalizations from cardiac rhythm disturbances. Over the past decade, catheter ablation (predominantly in the form of pulmonary vein isolation [PVI]) has become an important therapy in the treatment of patients with symptomatic, drug-refractory AF. Despite the improvements in technology, operator experience, and advances in methodology that have led to higher success rates and a reduction in complications, the recurrence rate of AF after PVI is still relatively high. Published studies suggest that approximately 33% to 86% of patients undergoing catheter ablation of AF have freedom from recurrent AF, with 30% to 40% requiring a second procedure. Although most studies looking at the efficacy of PVI are limited by relatively short follow-up, recent data suggest that patients with an initially favorable procedural response may have very late recurrences of AF, even years after PVI. It is likely that the mechanism behind very late recurrences of AF is multifactorial, involving both recurrent pulmonary vein triggers and progressive remodeling of left atrial substrate over time, making it more vulnerable to triggering. These recurrences have important clinical implications in the care of patients, specifically with regard to the increased risk of stroke associated with AF.