RESUMO
BACKGROUND: Current surgical treatments for atrial fibrillation (AF) lack intraoperative metrics that predict long-term outcomes. The extracardiac maze (Ex-Maze) procedure is a beating-heart maze procedure that causes spontaneous conversion to sinus rhythm (SR) during lesion creation. Spontaneous conversion and confirmation of pulmonary vein exit block are 2 important predictors of long-term freedom from AF. METHODS: A beating-heart Ex-Maze procedure was performed in 54 AF patients (paroxysmal, n = 2; persistent, n = 11; longstanding persistent, n = 41) undergoing concomitant cardiac surgery (mitral valve replacement [MVR] = 23, aortic VR [AVR] = 7, coronary artery bypass graft [CABG] = 17, CABG +/- AVR = 3, CABG +/- MVR = 2, atrial-septal defect = 2). The Ex-Maze lesion set is a comprehensive, biatrial ablation pattern created epicardially with unipolar, radiofrequency energy applied by a vacuum-integrated device. Electrocardiogram data were collected during the procedure and at 1, 3, 6, and 12 months postoperatively; 24-hour Holter monitors data were also obtained 12 month postprocedure. RESULTS: Mean left atrial size was 5.4 cm. Average procedure time was 39 minutes. There were no device- or procedure-related complications. At the time of surgery 48 patients were in AF; 32 (67%) patients spontaneously converted to SR during lesion creation. At a mean follow-up of 262 days, 42 of 48 patients (88%) were free from AF, 39 of 48 (81%) were in SR; and 35 of 47 (74%) were free from AF and had discontinued class I and III antiarrhythmic drugs. In 32 of 33 patients (97%), exit block at 15 mA was confirmed, in which pulmonary vein isolation was tested. Follow-up was completed for 30 of the exit-block patients; freedom from AF was observed in 29 of 30 (97%), SR in 26 of 30 (87%), and freedom from AF and class I/III antiarrhythmic drugs in 25 of 29 (86%). CONCLUSIONS: Recent advances in techniques and technologies permit the creation of a comprehensive biatrial lesion pattern on the epicardium of a beating heart. Observation of spontaneous conversion and confirmation of pulmonary vein exit block are important metrics that predict improved long-term outcomes.