Impact of the sinus node recovery time after termination of atrial fibrillation during catheter ablation on clinical outcomes in patients with persistent atrial fibrillation

BACKGROUND: Although long sinus arrest is occasionally observed during atrial fibrillation (AF) catheter ablation when the fibrillation was terminated, its meaning and prognosis have not yet been clearly elucidated. We hypothesized that sinus node recovery time (SNRT) after termination of AF (time from termination of AF to the earliest sinus node activation) could reflect the extent of atrial remodeling, influencing the formation of non-pulmonary vein (non-PV) triggers and post-ablation outcomes. METHOD: The participants were 157 consecutive patients with persistent AF (male: 77.1%, age: 63.3±11.2 years) who underwent catheter ablation. We recorded SNRT after terminating AF by radiofrequency delivery or electrical cardioversion during the first ablation and evaluated the relationships between SNRT and atrial tachyarrhythmia recurrence and between SNRT and non-PV triggers after repeat ablation. RESULTS: Forty-five patients (28.7%) experienced recurrence of atrial tachyarrhythmias. Patients with recurrence had longer SNRTs (1738 ms vs. 1394 ms, p = 0.012). In the multivariate logistic regression analysis, only SNRT ≥2128ms was a significant independent predictor of clinical AF recurrence (hazard ratio 7.48; 95% confidence interval 2.94–19.00; P<0.001). Kaplan–Meier estimator showed that the recurrence-free rate was significantly lower if ≥ 2128ms (log-rank, p<0.001). Thirty-five patients (77.8%) underwent a second ablation. Although there was no difference in the rate of pulmonary vein reconnections (78.6% vs. 71.4%, p = 0.712), non-PV triggers were observed more frequently in the longer SNRT group (57.1% vs. 14.3%, p = 0.012). CONCLUSIONS: Patients with a prolonged SNRT had a higher prevalence of AF recurrence after the first ablation and higher inducibility of non-PV triggers. Measuring SNRT might be used for the stratification of patients with persistent AF.