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Current Status of the Maze Procedure for the Treatment of Atrial Fibrillation

Since the first patient underwent the Maze procedure on September 25, 1987, 346 patients have undergone this operation for the treatment of atrial fibrillation. The procedure was designed as an open-heart operation performed through a median sternotomy. It underwent 2 major modifications relatively early in the series, evolving into the so-called Maze-III procedure, which has been used exclusively since April 16, 1992. Since that time, the Maze-III procedure has been adapted to allow it to be done by minimally invasive techniques. In addition, we recently performed the entire procedure in 2 patients without the use of cardiopulmonary bypass. The operative mortality rate has remained at 2% to 3%. This includes patients undergoing concomitant high-risk cardiac surgical procedures and all re-do cases. The overall success rate in curing atrial fibrillation has been 99%. The procedure itself has been shown to cause no permanent damage to the sinus node. The left atrium has been documented to function long-term postoperatively in 93% of patients and the right atrium functions in 99% of patients. The Maze-III procedure remains the surgical procedure of choice for the treatment of medically refractory atrial fibrillation.

New Surgical and Catheter-Based Modifications of the Maze Procedure

There is currently an intense interest in applying the principles of the Maze procedure in a less invasive manner so that a wider group of patients with atrial fibrillation can be treated safely and effectively. These efforts have centered around surgical attempts to curtail the number of lesions placed in the atria at the time of valve surgery and catheter-based attempts to re-create a part or all of the Maze procedure with radiofrequency ablation. Thus far, these techniques remain highly experimental and largely without merit. Many of the problems that we encountered several years ago in developing the surgical Maze procedure are now being repeated in patients undergoing these highly experimental and inadequately evaluated procedures. Nevertheless, there are occasional flashes of promise with some of these approaches. Moreover, it is clear that only a miniscule percentage of the patients with atrial fibrillation will ever become candidates for the open-heart Maze procedure as it is now performed. Therefore, the continuing struggle to relieve the invasive downside of the Maze procedure is warranted but with the caveat, especially to our cardiologist colleagues, to proceed with caution.

The importance of cryoablation of the coronary sinus during the Maze procedure.

Although the Maze procedure has proven to be very effective in the treatment of atrial fibrillation, some authors have chosen to delete some of the important steps of the technique. Both our experimental and clinical experiences with the Maze procedure indicate that 1 of the most important principles is to interrupt conduction across the posterior-inferior portion of the left atrium. This is accomplished by creating a transmural lesion in the myocardium and then creating a circumferential lesion at the same site in the coronary sinus. We have used surgical incisions in the atrium and a cryolesion in the coronary sinus to block conduction in this area. If either fails, there is a high rate of arrhythmia recurrence.

Stroke Prevention as an Indication for the Maze Procedure in the Treatment of Atrial Fibrillation

The Maze procedure has proven to be extremely effective in curing medically refractory atrial fibrillation. This analysis of our surgical results with the Maze procedure indicates that the Maze procedure, with or without associated cardiac surgery, has the lowest perioperative stroke rate of any major cardiac surgical procedure. This is surprising in view of the fact that all of the patients who undergo the Maze procedure have an elevated risk of stroke because of the presence of atrial fibrillation. In addition, many of the patients have already had strokes, further increasing the likelihood of perioperative stroke. Only 1 patient has had a stroke in the 12-year follow-up period following the Maze procedure. This is comparable to the risk of stroke in the general population and indicates that the Maze procedure essentially abolishes the risk of stroke associated with atrial fibrillation.

The Maze-III Procedure Combined With Valve Surgery

Previous studies have suggested that the Maze procedure is not as effective in controlling atrial fibrillation when the arrhythmia is associated with significant valvular heart disease. In this study, we evaluate our own results in 83 patients who underwent 96 valve procedures in combination with the Maze-III procedure. Our results indicate that the Maze-III procedure is just as safe and effective in controlling atrial fibrillation associated with valvular heart disease as it is in controlling atrial fibrillation not associated with valvular heart disease.

The effect of the maze procedure on the secretion of arginine-vasopressin and aldosterone

BACKGROUNDnExcessive fluid retention is a serious complication after the maze procedure that cannot be totally explained by changes in levels of atrial natriuretic peptide. We therefore measured circulating levels of arginine vasopressin and aldosterone in patients undergoing the maze procedure to study their possible role in this postoperative complication.nnnMETHODSnSerial arginine vasopressin and aldosterone levels were monitored for 72 hours in 11 patients after coronary artery bypass grafting and in 13 patients after the maze procedure. Hemodynamic data, urine output, fluid balance, and complications were recorded prospectively during the same period of time.nnnRESULTSnPlasma levels of arginine vasopressin and aldosterone were significantly higher in patients after the maze procedure when compared with patients after coronary artery bypass grafting.nnnCONCLUSIONSnThis study documents that the maze procedure results in increased plasma arginine vasopressin and aldosterone levels and indicates that they, rather than atrial natriuretic peptide alone, participate in the excessive postoperative fluid retention that follows the maze procedure. We believe that these hormone elevations are most likely secondary to a temporary lack of response of the atrial baroreceptors. These results may explain the effectiveness of spironolactone therapy after the maze procedure.

Observations on the Perioperative Management of Patients Undergoing the Maze Procedure

In addition to the usual measures that constitute optimal perioperative care after cardiac surgery, the Maze procedure demands several other measures because of certain complications that are unique to this particular operation. These complications include preoperative conditions such as amiodarone therapy, thromboembolism, diastolic dysfunction of the left ventricle, and associated valvular heart disease, as well as intraoperative differences that include multiple atriotomies and excision of both atrial appendages. The most common postoperative complications are atrial arrhythmias, excessive fluid retention, and pulmonary complications. In this article, we outline our own approach to the perioperative care of patients undergoing the Maze procedure.