Comparison of the results of irrigated monopolar and bipolar radiofrequency ablation in the surgical treatment of atrial fibrillation

Abstract

Chronic atrial fibrillation (AF) is a frequent arrhythmia in patients undergoing open-heart surgery. In this study, we compared the results of irrigated monopolar and bipolar radiofrequency (RF) ablation in the surgical treatment of AF. Sixty-three patients with chronic AF, who underwent open cardiac surgery and concomitant irrigated RF ablation between October 2004 and January 2006, were retrospectively studied in two groups. Group 1 included 31 patients (22 female, 9 male), who underwent monopolar RF ablation, and Group 2 included 32 patients (18 female, 14 male), who underwent bipolar RF ablation. All patients received amiodarone during the first 6 months after surgery. Rhythm status of patients after RF ablation was followed-up postoperatively in the intensive care unit, on the day of discharge, and at their follow-ups with electrocardiography. In patients with a documented sinus rhythm (SR) at follow-up, the presence of atrial transport function was assessed with transthoracic echocardiography. Statistical analyses were performed by using t-test for independent samples, Chi-square test and McNemar's test. Complication-free survival during follow-up was evaluated using Kaplan-Meier analysis. There was no hospital mortality in both groups. One patient from Group 1 had non-cardiac mortality (colon carcinoma). While in monopolar ablation group SR was documented in 83.3% of patients at a mean follow-up period of 11.5 ± 4.0 months (between 4-18 months), 68.8% of patients from bipolar ablation group was in SR at a mean follow-up period of 9.3 ± 3.0 months (between 4-15 months). In patients with documented SR during follow-up visits, atrial transport function was 76.6% in cases undergoing monopolar ablation, whereas it was 72.7% in cases undergoing bipolar ablation (p=0.797). Pacemaker implantation was performed in one (3.4%) patient from Group 1 after hospital discharge and in one (3.1%) patient from Group 2 during hospital stay. Irrigated monopolar and bipolar RF ablation are both safe and effective in terms of restoring SR and atrial transport function in patients with chronic AF, who underwent open cardiac surgery.