Changes in Heart Rate after Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation and Sinus Bradycardia

This study aimed to evaluate the effect of circumferential pulmonary vein isolation (CPVI) on autonomic nervous function and prognosis in patients with paroxysmal atrial fibrillation (AF) with or without sinus brady-cardia.A total of 66 patients with paroxysmal AF accompanied by sinus bradycardia and who underwent CPVI were recruited as the sinus bradycardia group. A total of 91 patients with paroxysmal AF but without sinus bradycardia and who underwent catheter ablation were selected as the control group. After surgical contraindi-cations were eliminated, CPVI was performed by three-dimensional mapping system. 24-hour dynamic electro-cardiogram was used to observe the changes of heart rate before and 2 days after surgery.A total of 45 (68%) and 51 (56%) patients in the sinus bradycardia and control groups, respectively, main-tained sinus rhythm. There was an increase in heart rate after CPVI in both groups. The standard deviation of normal-to-normal (NN) intervals (SDNN), standard deviation of the average NN intervals (SDANN), low fre-quency (LF), and LF/high frequency (HF) in the sinus bradycardia and control groups decreased after CPVI (P < 0.01). Moreover, SDANN was higher in patients with sinus bradycardia treated by successful ablation than in those with recurrence (P < 0.01), while SDNN, a standard statistical measure of heart rate variability (rMSSD), LF, and HF were significantly lower in patients with sinus bradycardia (P < 0.05).CPVI was able to produce a significant reduction effect on vagal nerve and sympathetic activity regardless of whether patients with paroxysmal AF had sinus bradycardia. Moreover, CPVI exerted a certain influence on the success rate of AF catheter ablation.