Microwave and radiofrequency ablation yield similar success rates for treatment of chronic atrial fibrillation

Objective: To evaluate the influence of two different ablation devices (microwave AFx® and radiofrequency Medtronic®), designed to create linear lesion lines, with respect to efficacy and restoration of sinus rhythm (SR). Methods: Between February 2001 and December 2002, 42 patients with chronic, persistent atrial fibrillation (AF) >6 months were submitted to different combinations of valve surgery (mitral±tricuspid, n=30; mitral and aortic±tricuspid reconstruction, n=6; aortic±tricuspid, n=8) and concomitant Maze procedure. The biatrial Maze followed the concept of the Cox III procedure, using either microwave energy (AFx Lynx) (group I: age 65.8±11.9 years, mean duration of AF 61.9±28.9 months, n=23) or radiofrequency (Medtronic Cardioblate) (group II: age 64.1±11.1 years, mean duration of AF 53.5±49 months, n=19). Results: There was one death with group I (4%), due to liver failure. Both groups were comparable with regard to Euro Score, ejection fraction, cross clamp time, cardiopulmonary bypass time, ICU (median 1 day in both groups) and hospital stay, and type of indication. The preoperative diameter of the left atrium was 69.7±10.8 and 74.0±14.3 mm in groups I and II, respectively (P=0.359). The Maze procedure resulted in 23±2 and 17±1 min additional cross clamp time in groups I and II, respectively (P=0.013). At the 12-month follow up, freedom from AF was 81 and 80% in groups I and II, respectively. Twenty percent in group I and 21% in group II needed a pacemaker (PM), due to sick sinus syndrome (2 versus 2 cases), AV bloc (2 versus 1 case) and preoperative bradycardia (0 versus 1 case), respectively. Conclusions: The combination of complex valve surgery and Maze procedure was safe and reproducible. Following the Cox Maze III line concept, microwave and radiofrequency ablation gave similar results even in patients with more complex double or triple valve procedures.