Influence of pulmonary vein ablation sequences on vagal reflex during cryoballoon ablation of paroxysmal atrial fibrillation

Objective To evaluate the influence of changing pulmonary vein (PV) ablation sequences from left PV to right PV on vagal reflex during cryoballoon ablation of paroxysmal atrial fibrillation (AF) . Methods A total of 90 patients with paroxysmal AF underwent the second generation cryoballoon ablation were enrolled in General Hospital of Northern Theater Command from January 2017 to May 2017. The first 56 patients were Group A, in which left superior PV (LSPV) was ablated first, followed by right PV ablation. The other 34 patients were Group B, in which right superior PV (RSPV) was initially ablated, followed by left PV ablation. Vagal reflex occurred was monitored and recorded in all patients in two groups.Baseline data, preoperative baseline heart rate, intraoperative parameters (ablation time and times) and intraoperative vagal reflex (sinus bradycardia, sinus arrest, atrioventricular block) were compared between the two groups. Results There was no significant difference between the two groups in the aspects of hypertension, diabetes, cerebral infarction, left atrium diameter, heart function, operation time, X-ray exposure time, exposure amount, baseline heart rate and postoperative heart rate. During operation, vagal reflex occurred after rewarming in LSPV in 15 of the 56 (26.8%) cases in Group A. In contrast, vagal reflex occurred in only 1 of the 34 (2.9%) patients in Group B after rewarming in LSPV (P=0.004) . Conclusion In the process of cryoballoon ablation for paroxysmal atrial fibrillation, LSPV ablation first often lead to vagal reflex. Initial RSPV ablation could significantly reduce the incidence of vagal reflex. Key words: Atrial fibrillation; Catheter ablation; Cryoballoon; Pulmonary vein isolation; Vagal reflex