Ann Thorac Surg 1998;65:1569-1570
© 1998 The Society of Thoracic Surgeons
Original articles: cardiovascular
Invited commentary
James L. Cox, MDa
a Division of Cardiovascular and Thoracic Surgery Georgetown University Medical Center 3800 Reservoir Rd, NW-4PHC Washington, DC 20007-2197, USA
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Invited commentary
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 Invited commentary
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In this article, Dr Fukada and associates question whether the maze procedure should be used to treat atrial fibrillation in patients with rheumatic valve disease because their results with the maze procedure in such patients do not match those in nonrheumatic patients. Fukada and associates’ study consisted of 29 patients with atrial fibrillation, 22 with rheumatic valve disease and 7 with nonrheumatic valve disease.
Unfortunately, the question they posed cannot be answered by this study because the surgical procedure used for the treatment of atrial fibrillation in these patients was not the maze procedure. Fukada and associates describe a "modified maze procedure" in which a lateral right atrial incision was carried from the base of the excised right atrial appendage toward the inferior vena cava "which is cryoablated (-60°C for 1 minute) after institution of cardiac arrest." There is no incision in any of the iterations of the maze procedure that corresponds to such an incision. In addition, the extensive body of experimental and clinical experience with cardiac cryosurgery dating back over 25 years is replete with the admonition that permanent cardiac tissue ablation requires at least 2 minutes of cryothermia application rather than the 1 minute reported in this article. Therefore, it is not safe to assume that any of the cryolesions as performed in this study functioned as permanent barriers to electrical conduction.
Evidence of a failure of at least some of these cryolesions is that only 59% of patients in the series (17 of 29) were cured of atrial fibrillation. This figure is in marked contrast to the results of the maze procedure when performed as described, in which 96% of patients are cured of atrial fibrillation without the need for postoperative antiarrhythmic drugs and the other 4% are cured with a combination of the maze procedure and postoperative drugs. These results include patients with and without mitral valve disease regardless of whether it is rheumatic or nonrheumatic in origin. Thus, it would seem that the failure of this "modified maze procedure" to cure atrial fibrillation is less related to the cause of the associated mitral valve disease than to the modifications of the surgical technique. A frequently overlooked aspect of the maze procedure is that its effectiveness can be negated by improper placement of the atriotomies or by the persistence of even a small conducting fiber across any of the various atriotomies. The placement of the right atriotomies in the present study and the extensive use of cryosurgery for periods that are less than the accepted standards virtually assures an unacceptably high failure rate. I do not believe that it is accurate to attribute that failure either to the true maze procedure or to the rheumatic valve disease that was present in some of the patients.
