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The success of radifrequency catheter ablation for the termination of atrial fibrillation has been documented by many studies. In patients with paroxysmal atrial fibrillation, success rates of 60% to 85% have been reported following pulmonary vein isolation and ablation. In patients with persistent atrial fibrillation, radifrequency catheter ablation of the left atrium has been reported to cure atrial fibrillation is 85% to 95% of patients.

Although radifrequency catheter ablation is generally considered to be an effective and safe procedure for the treatment of atrial fibrillation, it is not completely without risk. The most frequent complication of pulmonary vein isolation and ablation is a condition known as pulmonary vein stenosis - the narrowing of the orifice of the pulmonary veins at the entrance into the left atrium. The incidence of pulmonary vein stenosis has been reported to range from 1% to 10%.

The most serious potential complication associated with radiofrequency catheter ablation of the left atrium is the formation of an atrioesophageal fistula. This is a potentially life-threatening condition whereby, as a consequence of the ablation procedure, a hole forms between the esophagus ("foodpipe") and the heart's atrial chamber. Although this complication is rare, occurring in less than 1% of patients, it is associated with a high mortality rate exceeding 50%.

Other potential complications of radifrequency catheter abalation for atrial fibrillation may include:

• Cardiac tamponade - The pooling a large amount of blood in the pericardial sac - the thin membrane that surrounds and protects the heart. The resulting compression and constriction of the heart can lead to a drop in blood pressure and may result in shock and death. Cardiac tamponade has been reported to occur in about 2% of cases.

• Injury to the phrenic nerve which can cause a serious condition known as diaphragmatic paralysis that may result in temporary or permanent impairment of breathing. Injury to the phrenic nerve has been reported to occur in about 0.5% of cases.

• Stroke - The risk of stroke following radifrequency catheter ablation is about 1% with most strokes occuring within the first 30 days after the procedure. To reduce the risk of stroke, most experts recommend that anticoagulation therapy be continued for at least 30 days after the procedure. Extending anticoagulation therapy beyond 30 days after radiofrequency catheter ablation for atrial fibrillation is still controversial and is an issue that still remains to be resolved.

• Pericarditis - Inflammation of the pericardial sac - the thin membrane that surrounds and protects the heart.

Surgical Maze Procedure

The Maze procedure is a novel and highly successful surgical technique for the treatment of atrial fibrillation that was originally developed in 1987 by Dr. James L. Cox. Since that time, the surgical technique has been revised and improved several times and has culminated in the development of the Maze III procedure which is still considered as the "gold standard" for the surgical treatment of atrial fibrillation.

The goal of the Maze procedure is to interrupt or block the conduction of the multiple re-entrant electrical circuits that are necessary for the propogation of atrial fibrillation. In the earlier versions of the Maze procedure (Maze I and II), this goal was accomplished by creating a series of linear "cut and sew" incisions throughout both the right and left atria to produce linear scars that separate the atria into small strips. The scars between the strips act as barriers that block the conduction of the multiple re-entrant electrical circuits and also enable the electrical impulses generated by the sinoatrial (SA) node to be transmitted directly to the atrioventricular (AV) node.