Intraoperative map guided operation for atrial fibrillation due to mitral valve disease

Background. This study was designed to determine if intraoperative atrial activation mapping facilitates operations for chronic atrial fibrillation associated with mitral valve disease. Methods. Surgical treatment guided by intraoperative electrophysiologic mapping was performed in 12 patients with chronic atrial fibrillation associated with isolated mitral valve disease. In 10 of 12 patients, regular and repetitive activation (cycle length ranged from 118 to 210 msec) originated in the left atrial appendage and/or orifice of the left pulmonary vein. In the remaining 2 patients, dominant repetitive activation and sporadic complex activation were alternately observed in the left atrium. However, the activation sequence of the right atrium was extremely complex and chaotic. Results. On the basis of intraoperative mapping, surgical procedures, including resection of the left atrial appendage and/or cryoablation of the orifice of the left pulmonary vein, were applied on the breakthrough site of the repetitive activation. No surgical procedure was performed on the right atrium in 11 patients. Ten of 12 patients (83%) have maintained sinus rhythm for 6 to 40 months (average 24.8 months) after operation. Conclusions. In the majority of the patients with isolated mitral valve disease, the left atrium acts as an electrical driving chamber for chronic atrial fibrillation. Computerized intraoperative mapping should guide surgeons in determining the appropriate surgical procedure for chronic atrial fibrillation.