Cryoablation for surgical treatment of chronic atrial fibrillation combined with mitral valve surgery: a clinical observation

OBJECTIVE: Although the classical Cox-Maze III is the gold standard surgical therapy with a proven efficacy in the treatment of atrial fibrillation (AF), complexity of this procedure has resulted in a search for a simpler, less invasive and more cost-effective method. In this study we evaluated the results of cryosurgical ablation in the treatment of chronic AF in patients undergoing concomitant mitral valve surgery. METHODS: Ninety patients (mean age: 50.9+/-12 years) with chronic AF who were having mitral valve surgery as the main procedure underwent cryoablation with a newly designed N(2)O-based cryotherapy device. Pulmonary vein isolation with or without left atrial appendage closure (group A) was carried out in 65 cases and cryoablative bi-atrial Cox-Maze III (group B) in 25 patients. This additional procedure took only an extra 10 min for group A and about 20 min for group B. Half of the patients received a beta-blocker following the procedure. RESULTS: The overall success rate of cryoablation was 65.5%. Normal sinus rhythm was achieved in 26.7% in the operating room, 10% in ICU and the remaining cases reverted to sinus rhythm during the follow-up period. There were no major ablation-related complications such as bleeding, thromboembolic events or A-V block. The only predictor for failure of ablative procedure was left atrial size of greater than 6 cm. CONCLUSION: Although in this study the efficacy rate of cryoablative surgery was not the same as classical Cox-Maze III, it seems that this procedure is safe, simple, cost-effective and at the same time does not increase the operative time significantly. Using cryoablation may enhance the cure rate of chronic AF during mitral valve surgery.