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Get in Rhythm. Stay in Rhythm.® Atrial Fibrillation Patient Conference August 6-8, 2021, in Dallas, TX
Get in Rhythm. Stay in Rhythm.® Atrial Fibrillation Patient Conference August 6-8, 2021, in Dallas, TX

Cox Maze III Procedure

In 1987, Dr. James Cox pioneered an open-heart surgical procedure to cure atrial fibrillation. Called the Cox Maze procedure, it involved a complicated set of incisions made in a maze-like pattern on the left and right atria (the upper chambers of the heart) to permanently interrupt the abnormal electrical signals that cause irregular heartbeats. When these incisions healed, the resulting scar tissue blocked the erratic electrical impulses that caused atrial fibrillation, which could no longer be conducted throughout the heart.

Over time it evolved into the Cox Maze III procedure, which is also called the "cut-and-sew-Maze". A study at Washington University in St. Louis of the results from their Cox Maze III procedures showed greater than a 96% cure rate 10 years after the surgery.1 Freedom from stroke has generally been reported as exceeding 99% for Cox Maze procedures.

According to the HRS Consensus Statement,

The Cox-Maze procedure for the surgical treatment of AF was designed to interrupt all macro-reentrant circuits that might potentially develop in the atria by creating a myriad of incisions across both the right and left atria placed so that the SA node could ''direct'' the propagation of the sinus impulse throughout both atria. In contrast to previous unsuccessful procedures, the Cox-Maze procedure successfully restored both atrioventricular synchrony and a regular heartbeat, and decreased the incidence of late stroke. Over the last decade, the Cox-Maze procedure has become the gold standard for the surgical treatment of AF. 2

Cox Maze III is extremely complex, and thus few surgeons do it. Complications are common, as shown in a Mayo Clinic study of Cox Maze procedures from 1993 to 1999 that found an early mortality rate of 1.4% and the need for pacemakers in 3.2% of patients.3

The newest iteration is a maze procedure using surgical ablation rather than incisions. It uses one of several energy sources to scar the tissue and create a conduction block that stops errant electrical signals from progressing into the atria and throughout the heart. This version is sometimes called Cox Maze IV. There is now also a minimally-invasive version of surgical ablation, called the mini maze procedure.

To learn more about these two variations of surgical ablation, see:

1 Damiano, Ralph J., Jr, MD, "Alternative energy sources for atrial ablation: judging the new technology" <>, The Annals of Thoracic Surgery, 2003;75:329-330

2 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Personnel, Policy, Procedures and Follow-Up <>, Heart Rhythm Society [Internet], Copyright, 2007.

3 Schaff H, et al, "Cox-Maze procedure for atrial fibrillation: Mayo Clinic experience" <>, Seminars in Thoracic and Cardiovascular Surgery, 2000;12:30-37.

Last Modified 5/7/2009

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