Operative risks of the maze procedure associated with mitral valve surgery.

Twelve patients were operated on for mitral valve disease with concomitant chronic atrial fibrillation. Valve repair was performed in five patients and replacement in seven. Maze I and maze III procedures were applied in eight and four patients, respectively, and are compared. There was a regular rhythm in all maze I patients with a constant junctional rhythm in three and an alternating sinus and junctional rhythm in the remainder. In one case, part of the left atrium was in atrial fibrillation with the remaining atria in sinus rhythm. In the maze III group, one patient was always on a regular rhythm, two had episodes of atrial fibrillation and one was in atrial fibrillation with controlled ventricular rate. Echocardiography showed atrial contraction in two maze I patients, but systolic atrial flow across both atrioventricular valves could only be demonstrated in two patients in the maze III group.