The MAZE Procedure is performed by cardiothoracic surgeons on the left and right atrium for the treatment of atrial fibrillation. Atrial fibrillation is an abnormality of the electrical system of the heart. Normally, the heartbeat is triggered by an electrical impulse which starts in the Sinoatrial (SA) node. This structure resides in the right atrium and is the normal "pacemaker" of the heart. The electrical signal to contract starts in the SA node and normally moves evenly across the atrium, triggering it to contract all at once. The impulse then travels across the atrioventricular (AV) node and triggers the ventricles (the main pumping chambers of the heart) to contract. This is called sinus rhythm. Atrial fibrillation occurs when this electrical impulse no longer travels from SA node to the AV node in the normal manner. Instead of the impulse traveling evenly across the atrium straight from the SA node to the AV node, the impulse is "side-tracked" such that the atrium is no longer triggered evenly and in synchrony, but is triggered one small region at a time. The atrium no longer contracts in a coordinated manner, but instead it fibrillates irregularly. The electrical signal to ventricle through the AV node is therefore irregular and hence the heartbeat is irregular.

Atrial fibrillation causes
A variety of conditions can lead to atrial fibrillation. The most common cause of atrial fibrillation is simply aging. Our 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, can also cause "wear and tear" and lead to atrial fibrillation. Some specific conditions, such as thyroid disease, may be treatable with medications alone. Other conditions may be treatable by our colleagues the cardiologists in the cardiac catheterization laboratory. In a small number of cases, atrial fibrillation appears to be inherited - which is to say that it runs in some families - while in many cases its cause is unknown.

Surgical Procedure

The surgical procedure consists of creating a number of incisions in the atrium that disrupt the re-entrant circuits. Once the incisions are made, they are sewn together again. We can now perform this with radio frequency energy, without making the incisions in the heart. The atrium can then hold blood on its way to the ventricle and can squeeze or contract to push the blood in to the ventricle, but the electrical impulse cannot cross the incisions. The result is what looks like a children's maze in which there is only one path that the electrical impulse can take from the SA node to the AV node. The atrium can no longer fibrillate, and sinus rhythm (the normal rhythm of the heart) is restored.

The MAZE procedure is not necessary in most patients with atrial fibrillation. Many patients are not bothered by the rhythm or the medications required to control it. In some cases, cardiologists are able to disrupt the circuits with catheters. Some 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.

What to expect
The night before surgery you will be allowed to eat dinner. Nothing to eat or drink after midnight except for small sips of water with medication. No aspirin products. Sleeping pills will be provided if needed. Fleets enema will be prescribed. Antibacterial soap should be used for last shower. You will be called by the ambulatory surgery unit and told what time to come to the hospital the next morning. The operating room has been specially prepared for your surgery. The anesthesiologist will give you medication shortly before your surgery begins which will make you drowsy. After you are asleep a breathing tube will be inserted and your breathing will be taken over by a ventilator (breathing machine.) After surgery you will go to the Intensive Care unit for 24 hours. The breathing tube will be discontinued when you are fully awake. From the Intensive Care Unit you will be transferred to a private room on the cardiothoracic Surgery Unit. You will be in the hospital for 4 - 5 days.

In addition to the cardiothoracic surgeon the following personnel will help care for you: nurse practitioners, specially trained cardiac surgery nurses, pharmacists, music therapist, physical therapist, respiratory therapist, dietician, discharge planning nurses and cardiac rehabilitation nurses.

If you would like additional information or would like to make an appointment, call 847.570.2868.

Cardiothoracic Surgery

2650 Ridge Avenue
Evanston, IL 60201

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