Left atrial reduction in modified maze procedure with concomitant mitral surgery.

Background: An association between mitral valve disease and atrial fibrillation is common. Modifications of energy sources have simplified surgical ablation. Left atrial size reduction should improve outcomes of the maze operation.

Methods: Between 2004 and 2011, 236 patients with permanent atrial fibrillation and mitral valve disease underwent mitral valve surgery and modified biatrial radiofrequency ablation. The study evaluated cardiac rhythm, atrial size, atrial contractility, and survival.

Results: The mitral valve was repaired in 88 (37.3%) patients and replaced in 148 (62.7%). The left atrium was reduced in 192 (81.4%) patients: 31 (13.1%) had posterior wall reduction and 161 (68.2%) had right lateral and posterior wall resection. The 30-day mortality was 4.2% (10/236). The median follow-up was 41 months. Actuarial freedom from atrial fibrillation at 1 year and last follow-up was 87.7% and 84.9%, respectively. Predictors of recurrence were preoperative left atrial diameter >60 mm (p = 0.002), postoperative diameter >50 mm (p < 0.001), atrial fibrillation on day 7 (p < 0.001), and technique of reduction (posterolateral/posterior) in patients with atrial size >60 mm (p = 0.017). Atrial fibrillation during follow-up (p = 0.002) and age >60 years (p = 0.003) were significant predictors of poorer survival. During 5-year follow-up, non-atrial fibrillation patients survived significantly longer than atrial fibrillation patients (p = 0.002).

Conclusions: Radiofrequency ablation is an effective option for treatment of permanent atrial fibrillation concomitant with mitral valve surgery. Atrial reduction to <50 mm improves success. Elimination of atrial fibrillation significantly prolongs patient survival.