The Standard Maze-III Procedure

Abstract

The original Maze procedure (Maze-I) was introduced clinically in September 1987. Although this technique was extremely effective in controlling atrial fibrillation, it resulted in two unforseen problems: 1. Chronotropic inadequacy of the sinoatrial (SA) node. Many patients were unable to develop a sinus tachycardia rate commensurate with the level of their physical activity postoperatively because one of the incisions was positioned in the ‘‘sinus-tachycardia region’’ of the SA node, immediately anterior to the orifice of the superior vena cava (SVC). 2. Prolonged intra-atrial conduction delay. This resulted in the sinus node impulse arriving in the left atrium at the same time it arrived in the left ventricle. This, in turn, resulted in apparent absence of left atrial contraction postoperatively because it was contracting at the same time as the left ventricle. Because of these problems in the first 32 patients, the Maze-I procedure was modified to the Maze-II procedure in the next 15 patients. This technique was equally effective in controlling atrial fibrillation but proved to be extremely difficult to perform technically because of the frequent necessity for transection of the SVC. As a result, the Maze-II was further modified to the Maze-III procedure, which is depicted in the following figures. This technique has been in continuous use since April 1992 and, therefore, has been used in the vast majority of patients in our series. Both of the problems mentioned above were abolished by this last modification in technique.