Maze and mini-maze procedures

The MAZE procedure is offered to patients at high risk for stroke who have unsuccessful attempts at pharmacologic treatment. It is an “open-heart” cardiac surgery procedure intended to eliminate atrial fibrillation (AF). The name refers to the series of incisions arranged in a mazelike pattern in the atria. The Cox MAZE III procedure is now considered to be the “gold standard” for effective surgical cure of AF. It may be performed concomitant with mitral valve repair or replacement for patients who also have mitral valve disease. MAZE is performed using pulmonary vein isolation and a number of incisions in the right and left atria. These incisions or cryoablations ultimately form scar tissue, thereby mechanically interrupting transmission of triggering impulses of AF. For open MAZE, it is necessary for the patient to have a sternotomy and cardiopulmonary bypass (CPB). All of the monitoring and medication necessary for CPB is required for the MAZE procedure. In addition to the lesions made in the atria, the left atrial appendage is often removed because it is thought to be a culprit in the stasis of blood flow, thereby increasing the possibility of thrombus formation and stroke. The term mini-MAZE is still sometimes used to describe an open-heart procedure requiring CPB, but it more commonly refers to minimally invasive epicardial procedures not requiring CPB.

The mini-MAZE procedure is performed using thoracoscopy on a beating heart. “Keyhole” incisions are used for the mini-MAZE, and the patient is placed in the lateral position. Routine monitoring with the addition of an arterial line and one-lung ventilation are adjuncts of this procedure.