HEART AND LUNG SURGERY << BACK Minimally Invasive Atrial Fibrillation Surgery (MAZE Surgery) An abnormal heart rhythm, or arrhythmia, is caused by a disruption of the normal electrical conduction that occurs in the heart. Some types of arrhythmias may be life-threatening if not promptly and adequately treated. Fibrillation is the most serious form of arrhythmia, characterized by fast, uncoordinated heartbeats that don't pump blood. Surgeons often treat atrial fibrillation with what is called the MAZE procedure. This surgery creates a "maze" of new electrical routes so electrical impulses can easily move through the heart. The procedure takes two to three hours under general anesthesia. During surgery, a breathing tube is inserted through the mouth into the lungs, and the right lung is deflated. A ventilator allows the patient to breath using the left lung while the surgeon performs the surgery. The surgery requires three small incisions on the left side and three small incisions on the right side of the chest. Using a small video camera and instruments inserted through the first three incisions, the surgeon opens the sac around the heart (the pericardium) and inserts catheters around the heart. He then re-inflates the right lung and makes three incisions on the left side of the chest. After deflating the left lung, he inserts the camera and instruments and opens the pericardium from the left side. The surgeon pulls the catheters around the heart and connects them at the left side, forming a loop around the heart. The surgeon then uses the catheter loop as a guide and places a microwave probe around the left atrium, at the base of the left and right pulmonary veins. When the probe is used to generate heat, creating a lesion around the atrium called an ablation. Later, as the heart muscle heals, scar tissue effectively blocks the old electrical pathways. After surgery, a patient generally stays in the ICU for six to eight hours where heart rhythm and other vital signs are monitored. Then the patient may be moved to a regular hospital room for the night. Most patients are able to go home three days after surgery, and can return to work in two to three weeks.