Early results of monopolar versus bipolar radiofrequency ablation for atrial fibrillation during open heart surgery

BACKROUND: In patients with atrial fibrillation (AF) for whom open heart surgery is scheduled, it is suggested to treat AF by ablation. OBJECTIVE: To compare the efficacy of monopolar and bipolar surgical radiofrequency ablation systems in patients undergoing concomitant open heart surgery and reveal the factors affecting the conversion to sinus rhythm. METHODS: Forty-three patients (19 male and 24 female) who underwent irrigated monopolar or bipolar radiofrequency ablation for persistent AF at concomitant cardiac surgery between 2007 and 2012 were included in the study. RESULTS: Monopolar ablation was performed in 24 and bipolar ablation was performed in 19 patients. Twenty of the 24 patients who underwent monopolar radiofrequency ablation and 15 of the 19 patients in the bipolar ablation group were in sinus rhythm at the three-month follow-up. There was no statistically significant difference between the two ablation procedures on the conversion of AF to sinus rhythm. When the effect of left atrial diameter on conversion to sinus rhythm was compared, left atrial diameter >60 mm was found to have pronounced negative influence on procedural success, while left atrial diameter <60 mm had no effect. CONCLUSION: A concomitant monopolar or bipolar modified Cox maze procedure during open heart surgery is equally effective technique for AF ablation at three months of follow up. Left atrial diameters >60 mm significantly reduced the rate of conversion to sinus rhythm.