Maze Procedure In Detail

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What Is a Maze Procedure?

Heart Valves and Chambers
Human Heart, Chambers of the Heart and Heart Valves Image. Image: © ADAM

What Is a Maze Procedure?

A maze procedure is a surgery used to control atrial fibrillation -- or "a-fib," a heart condition where the heart rhythm is irregular. If it can't be controlled by medication or other treatments, a maze procedure may be an appropriate treatment. It gets this name from the linear scars left on the heart's chambers post-surgery, like a maze.

Uncontrolled atrial fibrillation can increase the risk for strokes. It can also make a person feel weak and distressed, since the heart is pumping less efficiently.

To understand the procedure, it is important to know that the heart has its own electrical system, which directs the different activities of the heart muscle. In a normal heart, the electrical system first triggers the left and right atrium (upper heart chambers) to contract, then the ventricles (lower heart chambers).

During atrial fibrillation, the signal is splintered as though it is taking multiple routes through a maze, causing different areas of the atrium to contract at different times as each route takes a different length of time to for the signal to travel. This fluttering effect, with different parts of the atrium contracting at different times, is called fibrillation.

The maze procedure stops the electrical impulse from taking multiple paths, and forces the signal into a single path, which allows the entire atrium to contract at the same time.

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Are You a Candidate for the Maze Procedure?

Heart Valves and Chambers
Human Heart, Chambers of the Heart and Heart Valves Image. Image: © ADAM

Who Is a Candidate For a Maze Procedure?

A maze procedure is not necessary for the vast majority of atrial fibrillation patients. Medication works well for most people. For patients not helped by medication alone, cardioversion may be the next step. Cardioversion is a procedure where an electrical impulse is sent to the heart, and may return the patient to a normal rhythm for a long period of time.

In other cases, patients choose to live with mild symptoms, but consider surgery when the symptoms increase or become too irritating or concerning to ignore. Over time, patients may find that a regimen that worked in the past may no longer control the symptoms of atrial fibrillation. If adjustments to the therapy are not successful, a maze procedure may be an option.

If you've looked into this option in the past, keep in mind that there are now newer and less invasive catheter ablation technique that do not require the large chest incision and placement on the cardiopulmonary bypass machine, although this technology is still new and not offered at all hospitals.

In some cases, a maze procedure may be combined with an additional procedure, such as heart bypass surgery (CABG).

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Maze Procedure: How It Works

Heart Valves and Chambers
Human Heart, Chambers of the Heart and Heart Valves Image. Image: © ADAM

How the Maze Procedure Works

The procedure can be done via open heart surgery, or via a minimally invasive procedure that uses a catheter threaded through the large blood vessels of the groin. The minimally invasive technique is currently being performed in a few specialized hospitals and is relatively new.

In both procedures, the goal is to correct the splintering effect that causes different parts of atrium to contract at different times. This is done by surgically forcing the electrical impulse into a single path, which causes the atrium to fire efficiently. Instead of taking multiple paths through a “maze” to the muscle of the atrium, the electrical signal is forced to take one path, ending the splintering effect.

This is done by cutting or scarring the alternative paths. The electrical impulse can’t cross severed or scarred pathways, so the surgeon uses either a scalpel, radio-frequency ablation (a type of heat) or cryonics (cold) to stop the unwanted pathways.

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4
During a Maze Procedure

Heart Valves and Chambers
Human Heart, Chambers of the Heart and Heart Valves Image. Image: © ADAM

During a Maze Surgical Procedure

The surgery begins with general anesthesia. Once the anesthesia takes effect and the patient is intubated (breathing with the assistance of a machine), the surgeon can begin by making a sternal incision, an incision over the sternum (breastbone). The sternum is cut into two parts using a special saw, splitting the bone vertically.

The surgeon can use several tools at this point to scar the unwanted pathways that conduct the electrical impulses of the heart, such as a scalpel, or a very hot or a very cold instrument.

Once the surgeon determines that all of the pathways have been scarred, the sternum, or breastbone, is closed and using sterile surgical wire, braced together so that it can heal properly. In some cases, small incisions may be made under the breast area, and chest tubes are inserted to remove any blood that may accumulate around the heart. The tubes are connected to a sterile collection device so that blood output can be measured, or in some cases, the blood can be given back to the patient after the surgery.

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5
After a Maze Procedure

Heart Valves and Chambers
Human Heart, Chambers of the Heart and Heart Valves Image. Image: © ADAM

Recovery After a Maze Procedure

After a Maze procedure, you can expect to spend several days in an ICU being closely monitored. Unlike most surgeries, no medication is given to wake the patient from anesthesia. Instead, the anesthesia is allowed to wear off over several hours.

During the recovery in the ICU, the heart’s electrical activity will be closely monitored to determine if the procedure was successful. Once the anesthesia wears off, the breathing tube will be removed, and typically within 12 hours of surgery the patient will be helped to a chair. While it may seem strange to be up and moving so quickly after surgery, this is an important part of the recovery and helps prevent complications like blood clots and pneumonia.

There may be temporary pacemaker wires that come out of the incision, so that an external pacemaker can be used in case of emergency. In the vast majority of cases this is not necessary -- the wires are a precautionary measure in case a pacemaker is needed during recovery.

In very rare cases, a permanent pacemaker may required, typically if the electrical path that has been left intact isn’t conducting the impulse properly to the atrium. The pacemaker sends the electrical impulse that is normally initiated by the heart and is programmed to send a signal to one atrium or both, depending on the location and nature of the problem.

Patients who have the minimally invasive procedure are typically in the ICU for several days for monitoring, but can return to normal activity and work faster than patients with the open heart maze procedure. During this time, and the weeks following, incision care is very important to prevent infection.

A typical recovery from open heart surgery is 8 weeks or longer, while the minimally invasive procedure is significantly shorter. About 90% of the patients who have the procedure have relief from the symptoms of atrial fibrillation after recovering from the surgery.

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Sources

Sources:

Atrial Fibrillation Ablation. The Mayo Clinic. Accessed April, 2009 http://www.mayoclinic.org/atrial-fibrillation-ablation/

What Is The Cox-Maze Procedure. The Cleveland Clinic. Accessed April, 2009 http://my.clevelandclinic.org/heart/disorders/electric/surgtx.aspx

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