Cox Maze Procedure for Atrial Fibrillation

In a person with a normal heart rhythm, 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.

In 1987, researchers at Washington University School of Medicine led by James Cox, M.D., 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.

Specialists who perform the Cox Maze procedure or treat atrial fibrillation:

• Ralph Damiano, Jr., M.D., cardiac surgeon
• Mitchell Faddis, M.D., cardiologist/electrophysiologist
• Marye Gleva, M.D., cardiologist/electrophysiologist
• Bruce B. Lindsay, M.D., cardiologist/electrophysiologist
  

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).

What causes atrial fibrillation?
A variety of conditions can lead to atrial fibrillation. The most common cause of atrial fibrillation is simply aging. The risk of atrial fibrillation increases as we grow older and areas of scarring or fibrosis develop in our atrial tissue as a result of simple wear and tear. Abnormalities of the valves in the heart, most often the mitral valve, also can cause wear and tear and lead to atrial fibrillation. Some specific conditions that can lead to atrial fibrillation, such as thyroid disease, may be treatable with medications alone. Other conditions may be treatable by Washington University cardiologists in the cardiac catheterization laboratory. In a small number of cases, atrial fibrillation appears to be inherited, while the cause is unknown in many cases.

Why is atrial fibrillation a problem?
Atrial fibrillation results in: 1) an irregular heartbeat that may be too slow at times, and racing at others, 2) loss of the atrial contraction that normally contributes to filling of the ventricle (the main pumping chamber of the heart) and improves pump performance, and 3) an abnormal flow of blood through the atrium with areas of stagnation (eddies), which increase the risk of stroke.

Who is a candidate for the Cox Maze procedure?
The Cox Maze procedure is not necessary in most patients with atrial fibrillation. Most patients are not bothered by the rhythm or the medications required for its control. In some patients, our cardiology electrophysiologists are able to disrupt the circuits that cause atrial fibrillation with catheters using radiofrequency. Other patients, however, are so troubled by the way they feel when they are in atrial fibrillation or by the medications they must take that a surgical option is appropriate. The Cox Maze procedure also may be indicated for individuals with atrial fibrillation who have experienced a stroke because they are at significant risk for another stroke.

Is it an open-heart procedure?
Yes, the Cox Maze is an open-heart procedure. The surgeon makes an incision about 10-12 inches in length and divides the sternum (breastbone) to gain access to the heart. The patient is transferred to a heart-lung machine during the procedure. After surgery, the sternum is wired together and the skin sutured. If other procedures such as valve replacement or coronary bypass are to be performed concurrently with the Cox Maze procedure, then the standard open-chest approach is likely to be used.

What are the risks associated with the Cox Maze procedure?
Because the Cox Maze procedure is usually open-heart, there is operative risk. Although the risk is low in general terms, it is affected by the individual's specific health conditions (heart, lung, kidney and other organ function). Like any open-heart procedure, there also is a risk of stroke, kidney failure, other organ failure and death.

Although the procedure is directed toward curing abnormal heart rhythm, there is some risk that the procedure may fail and that atrial fibrillation will persist. In the early postoperative period, up to one third of patients may have temporary atrial fibrillation. This is easily controlled with medicines, however, and it resolves within 6 to 12 weeks. In addition, some patients may require a permanent pacemaker postoperatively. This is probably because many patients with atrial fibrillation also have underlying disease of the SA node.

What is the success rate for the Cox Maze procedure?
The Cox Maze procedure is highly effective in restoring sinus rhythm. Success rates vary by center, but generally are reported in the range of 80 to 100 percent. The majority (about 90 percent) of patients will be restored to sinus rhythm without the need for any medications. The majority of the remaining patients will have control of their rhythm with a single medication, even if that medication did not control their rhythm preoperatively.

What can I expect after surgery?
Most patients are hospitalized an average of 10 to 12 days. Much of that time is spent waiting for the atrial tissue swelling to decrease and the sinus node function to return. Patients usually are in the intensive care unit for two days, and the remainder of the time is spent on the step-down unit. Typically, at this point, patients can walk around a bit wearing a portable telemetry monitor while they wait for the heart's rhythm to stabilize.

In general, the recovery is complete about six to eight weeks after surgery. Depending on the type of work that a patient performs and the surgical approach that was used (minimally invasive versus open chest), the decision to return to a full schedule is somewhat individualized. For those patients with physically demanding work, the recovery may be extended to three months for open-chest procedures.