Affecting more than 2 million Americans, atrial fibrillation is the most common heart rhythm abnormality. Washington University cardiac surgeons offer a minimally invasive approach to curing atrial fibrillation, and research at the medical school has shown that this approach takes half the time of the traditional surgical procedure but is equally effective.*

Normally, electric signals trigger the synchronized contraction of muscles in the heart’s two upper chambers, the atria. During atrial fibrillation, a chaotic web of electric impulses spreads throughout the atria, causing the chambers to quiver rather than contract in unison. The result is a host of painful symptoms and significantly increased risk of heart attack or stroke.

Medications can alleviate symptoms in some patients, but they cannot cure the problem. So, in 1987, researchers at Washington University School of Medicine developed a surgical cure called the Cox Maze procedure to control these erratic impulses. In this procedure, surgeons make small, strategically placed incisions in the atria. The slits generate scar tissue that serves as barriers, trapping abnormal electric signals in a “maze” of barricades. Only one path remains intact, guiding impulses to their correct destination.

The Cox Maze procedure has a success rate of more than 90 percent; however, it is technically difficult and therefore is not performed frequently. Surgeons also must temporarily stop the heart and use a heart-lung machine to take over the heart’s role of circulating blood in order to make the incisions. Thus, not all patients are healthy enough to endure the operation.

Ralph J. Damiano, M.D., chief of cardiac surgery at Washington University School of Medicine, and his colleagues developed an alternative using two electrodes that pass a current through a section of heart tissue, heating and killing a thin band of tissue. This bipolar radiofrequency variation of the Cox Maze procedure creates scar tissues that similarly block abnormal impulses responsible for atrial fibrillation.

The team replaced most of the Cox Maze incisions with lesions created using the new, less invasive approach in 40 consecutive patients treated for atrial fibrillation at Barnes-Jewish Hospital from January 2002 to October 2003.

Overall, the success of the procedure was equivalent to the team’s success using the traditional Cox Maze approach between January 1988 and January 2002. All patients survived the operation, and about 15 percent needed a pacemaker after surgery to help maintain a normal heart rhythm. A little over 90 percent of patients followed for six months still had healthy heart rhythms.

The length of the operation was the only notable difference between the patients in the study and those who had undergone the traditional surgery. Traditional Cox Maze procedures took, on average, 93 minutes to perform, while procedures that incorporated the new approach took only 54 minutes.

For more information on the Cox Maze procedure, contact Marci Bailey, RN, MSN, atrial fibrillation research nurse coordinator:

Phone: (314) 747-1930

E-mail: baileym@wudosis.wustl.edu

FOR AN APPOINTMENT, PHYSICIANS MAY CALL (314)362-7260 or (888)800-9484 (toll free).

More about Cox maze procedure.

* Gaynor SL, Diodato MD, Prasad SM, Ishii Y, Schuessler RB, Bailey MS, Damiano NR, Bloch JB, Moon MR, Damiano RJ. A prospective, single-center clinical trial of a modified Cox maze procedure with bipolar radiofrequency ablation. The Journal of Thoracic and Cardiovascular Surgery, Vol. 128(4), pp. 535-542, October 2004.

Funding from Atricure, Inc. supported this research.

Washington University physicians are the medical staff of
Barnes-Jewish Hospital and St. Louis Children's Hospital