The closed heart MAZE: A nonbypass surgical technique

Background. The MAZE-III is the surgical treatment of choice for medically refractory atrial fibrillation. Although a number of nonsurgical techniques are evolving to duplicate the transmural atrial lesions of the MAZE-III, t he surgical atriotomy remains the gold standard for conduction block. It wa s the objective of this study to surgically create the atrial incisions of the MAZE-III without the use of cardiopulmonary bypass. Methods. A technique was developed to create and intersect the linear incis ions of the MAZE-III on 10 beating canine hearts without the use of cardiop ulmonary bypass using a "tunnel" of atrial tissue. The effectiveness of the procedure was tested by atrial burst pacing. Results. This technique was successfully performed on 10 mongrel dogs witho ut operative mortality. Preoperatively, sustained atrial fibrillation (>30 seconds) was induced in all animals. Postoperatively, all the animals remai ned in sinus rhythm even after burst pacing. Conclusions. In an experimental canine model, the MAZE-III can be performed on beating hearts without the assistance of cardiopulmonary bypass using a "tunnel" technique. This technique allows for the immediate assessment of electrophysiologic and mechanical function after the MAZE-III, or any other type of procedure using the "maze principle" and may find future applicati on in the clinical arena. (C) 1999 by The Society of Thoracic Surgeons.