Surgical ablation in patients undergoing mitral valve surgery: impact of lesion set and surgical techniques on long-term success

To assess the results and impact of lesion set and surgical technique on long-term success of surgical ablation during mitral surgery. The patient population consisted of 685 subjects with persistent and long-standing persistent atrial fibrillation (AF) undergoing cardiac surgery for mitral valve disease as the primary indication and concomitant ablation between January 2003 and January 2012 at three institutions. One hundred and sixty-six underwent unipolar (24.2%), 371 (54.2%) bipolar, and 148 (21.6%) had combined ablation. Median follow-up was 58.4 months (interquartile range 43.3-67.9). To appropriately account for death, a competing risk model was employed to identify predictors of cumulative incidence of recurrent AF among lesion set and surgical techniques. Eight-year freedom from recurrent arrhythmia without antiarrhythmic drugs was 0.60 +/- 0.02. Success rate was higher using bipolar radiofrequency (RF) (P <0.001), after performing mitral isthmus line (P = 0.003) and following the biatrial technique (P <0.001). Competing risk regression revealed that use of unipolar RF [sub-hazard ratio (SHR) 2.41 (1.52-3.43), P <0.001], combined unipolar/bipolar ablation [SHR 1.93 (0.89-2.57), P = 0.003] and the absence of right atrial ablation [SHR 2.79 (1.27-3.48), P <0.001] were predictors of cumulative incidence of long-term recurrence. Our experience suggests that the use of bipolar clamp improves long-term results in surgical treatment of AF and that right-sided ablation should be routinely added. Randomized studies are necessary to confirm our findings.