Post-shock sinus node recovery time is an independent predictor of recurrence after catheter ablation of longstanding persistent atrial fibrillation

Background Electro-anatomical remodeling of the atria has been reported to be associated with sinus node dysfunction in patients with atrial fibrillation (AF). We hypothesized that post-shock sinus node recovery time (PS-SNRT: the time from cardioversion to the earliest sinus node activation) is related to the degree of left atrial (LA) remodeling and the clinical outcome of radiofrequency catheter ablation (RFCA) in patients with longstanding persistent AF (L-PeAF). Methods and results We included 117 patients with L-PeAF (82.0% males, 55.4 ± 10.7 years old) who underwent RFCA. PS-SNRTs were measured after internal cardioversion (serial shocks 2, 3, 5, 7, 10, and 15 J) before RFCA. All patients underwent the same ablation design, and we compared regional LA volume (3D-CT imaging) and LA voltage (NavX). Results: 1. During the 13.5 ± 5.8-month follow-up period, it was noted that the patients with recurrent AF 3 months after RFCA (n = 31) had longer PS-SNRTs (1622.90 ± 1196.92 ms vs. 1112.53 ± 690.68 ms, p = 0.005) and greater anterior LA volume (p = 0.032) than those who remained in sinus rhythm. 2. The patients with PS-SNRT ≥ 1100 ms showed lower AF-free rates (58.3%) compared to those with PS-SNRT < 1100 ms (89.5%, p < 0.001). However, shock energy, number of cardioversion, and LA volume were not different between two groups. 3. Multivariate Cox regression analysis demonstrated PS-SNRT ≥ 1100 ms was a significant predictor of clinical recurrence of AF (HR 5.426, 95% CI 2.099-14.028, p < 0.001). Conclusion In patients with L-PeAF, prolonged PS-SNRT is an independent predictor of clinical recurrence of AF after RFCA, but not closely associated with electro-anatomical remodeling of LA.