OBJECTIVETo apply the off-pump epicardial microwave ablation (MW) to treat the permanent atrial fibrillation (PAF) and evaluate the clinical effect.

METHODSFrom April 2003 to April 2005, a total of 46 patients with PAF underwent off-pump epicardial MW, including the patients with mitral valve disease (28 cases), mitral and aortic valve disease (5 cases), coronary artery disease (8 cases) and lone PAF (5 cases). FLEX 10 probe was placed around four pulmonary orifices and the access orifice of the inferior vena cava to tricuspid annulus. The microwave application was set 65 W, 90 s and a continuous ablation line was finished encircling the pulmonary veins. Subsequently, patients underwent either off-pump coronary artery bypass graft or valve surgery on-pump. Mean left atrial diameter was (52.5 +/- 15.3) mm, LVEF 42% - 70% before operation. All patients were followed up in the discharge, 3, 6, 12 months after surgery by standard 12-lead ECG, 24 h Holter, UCG and clinical examination.

RESULTSAll procedures were completed successful on the off-pump cardiac surgery and 46 patients were converted sinus rhythm when the operations were performed. Mean ablation time was (37.7 +/- 7.8) min, without any related complications. At discharge, 3, 6 and 12 months follow-up, 63.0%, 66.7%, 72.7% and 80.6% of the patients kept sinus rhythm and left atrial diameter of < 50 mm.

CONCLUSIONSUsing MW, electrical isolation of the pulmonary veins can be achieved epicardially without cardiopulmonary bypass support. Off-pump epicardial microwave ablation is an efficient option with an excellent benefit/risk ratio for the treatment of PAF with or without other cardio-surgical disease.