Surgical treatment of permanent atrial fibrillation using microwave energy ablation: a prospective randomized clinical trial☆

OBJECTIVE: Radiofrequency or the use of microwave energy in combination with atrial size reduction during open heart surgery have been reported to be effective in up to 75% in the treatment of permanent atrial fibrillation. However, no data from prospective randomized trials using microwave energy are available. METHODS: Forty-three patients with permanent atrial fibrillation undergoing open-heart surgery were randomly stratified into treatment group receiving microwave ablation and atrial size reduction (n=24) or control group (n=19). Patients in either group were treated with amiodarone or sotalol for 3 months if sinus rhythm or any atrioventricular rhythm was successfully restored. Follow-up time points were at 3, 6 and 12 month after surgery. RESULTS: In the treatment group 22 out of 24 patients (91,7%) were successfully converted to sinus rhythm by using intraoperative microwave ablation therapy whereas only six out of 19 (31.5%) patients converted to sinus rhythm directly after surgery. At 12-month follow-up there were still a significantly higher percentage of patients in the treatment group free from atrial fibrillation when compared to control (80 vs. 33.3%, P=0.036). CONCLUSION: The preliminary data from this first prospectively randomized trial indicate that microwave ablation combined with atrial size reduction is a safe and highly efficient treatment in permanent atrial fibrillation.