Aims This study is the first prospective randomized trial evaluating the efficacy of an antiarrhythmic surgical procedure in patients with chronic atrial fibrillation undergoing mitral valve replacement.
Methods and Results Thirty consecutive patients with chronic atrial fibrillation undergoing mitral valve replacement were randomized for an additional modified MAZE-operation using intra-operatively cooled-tip radiofrequency ablation (group A) or mitral valve replacement alone (group B). Biatrial contraction was studied and functional capacity was evaluated in spiro-ergometry 6 months after surgery. Thirty-day mortality was 0% in both groups. After 12 months, sinus rhythm was reinstituted significantly more often in patients of group A (cumulative rate of sinus rhythm 0·800) compared to patients in group B (0·267) (P<0·01). 66·7% of patients in sinus rhythm of group A had documented biatrial contraction. Electrocardioversion showed long-term success in only 17% of patients in group A and 0% in group B. Maximal aerobic uptake at the 6-month spiro-ergometry revealed no significant difference (9·3 vs 8·5ml.min−1 kg−1, P=0·530).
Conclusions A modified MAZE operation using cooled-tip radiofrequency ablation can be safely combined with mitral valve surgery and is highly effective in restoring sinus rhythm. Biatrial contraction is found in 66·7% of patients with sinus rhythm undergoing mitral valve replacement plus the MAZE operation.