Permanent chronic atrial fibrillation: is pulmonary vein isolation alone enough?

BACKGROUND: The efficacy of mere pulmonary vein isolation epicardially for the treatment of permanent chronic atrial fibrillation, in comparison with the left atrial endocardial maze procedure was evaluated. METHODS: Retrospective data collection and analysis toward the outcome of 72 consecutive patients who underwent left atrial maze procedures between January 2003 and December 2005 was performed. Surgical ablation was performed concomitantly with valve and (or) coronary procedures. Group I (n = 29) received an endocardial left atrial ablation using unipolar saline irrigated radiofrequency (Medtronic Cardioblate surgical ablation pen; Medtronic Inc, Minneapolis, MN). Group II (n = 43) received epicardial isolation of the pulmonary veins using bipolar saline irrigated radiofrequency (Medtronic Cardioblate). Follow-up included 24h electrocardiogram and echocardiography 6 and 12 months postoperatively. RESULTS: Mean follow-up was 19.5 +/- 1.0 months (17.7 +/- 19.5 months group I vs 20.6 +/- 1.1 months group II). Both groups were comparable with regard to duration of preoperative atrial fibrillation, European system for cardiac operative risk evaluation, left ventricular ejection fraction, aortic cross-clamp time, bypass time, intensive care unit and hospital stay (p > 0.05). No maze procedure-related mortality was observed. In group I, three patients required postoperative pacemaker implantation due to atrioventricular (AV) bloc, bradycardia, and sick sinus syndrome, respectively. In group II, five patients required postoperative pacemaker implantation (three AV bloc and two bradycardia). Freedom from atrial fibrillation at last follow-up was 85.7% and 58.5% in groups I and II, respectively (p = 0.016). CONCLUSIONS: Pulmonary vein isolation alone seems to be insufficient in treating permanent chronic atrial fibrillation. In case of chronic permanent atrial fibrillation, left atrial endocardial maze, providing the connection lines to the mitral annulus and (or) between the pulmonary veins, seems to be mandatory.

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.