Radiofrequency Ablation Simplifies Heart Surgery

A new study recommends that radiofrequency (RF) ablation technology be used for the surgical treatment of atrial fibrillation (AF), modifying the Cox-Maze procedure, the current gold standard of AF care.

Researchers from the Washington University School of Medicine and Barnes-Jewish Hospital (St. Louis, MO, USA) conducted a retrospective review of patients with AF who underwent a Cox-Maze procedure, utilizing bipolar radiofrequency ablation, a limited Cox-Maze procedure, or pulmonary vein isolation alone. Follow-up was available on 129 of 130 patients.

The RF device used for the ablation delivered high-energy radiofrequency waves to heart tissue, forming precisely placed scars, or ablations. The ablations disrupt the atria's abnormal electrical activity, placing roadblocks in the way of these misplaced electrical impulses, redirecting them down their normal route so that they stimulate regular heartbeats. The research team found that surgeons needed to apply the devices for only a few seconds at a time to get effective ablation of the atrial wall, and the devices caused no injury to surrounding tissue. The time needed for the procedure was reduced from more than 90 minutes to about 30 minutes.

At the last follow-up, freedom from AF was 90% in the Cox-Maze procedure group, 86% in the limited Cox-Maze procedure group, and 59% in pulmonary-vein isolation-alone group. About three-quarters of the treated patients no longer need drugs to prevent abnormal heart rhythms or excessive blood clotting. The researchers concluded that the use of bipolar RF ablation to replace Cox-Maze incisions was safe and effective at controlling AF. The researchers also found that pulmonary-vein isolation alone was much less effective, and recommended that it be used cautiously in this population. The results were published in the October 2006 edition of Annals of Surgery.

"Because of the devices, the Cox-Maze procedure has gone from an operation that hardly anyone was doing to one that 80- 90% of U.S. heart surgeons are now performing,” said lead author Ralph J. Damiano Jr., M.D., chief of cardiac surgery at the Washington University School of Medicine and a cardiac surgeon at Barnes-Jewish Hospital.

The Cox-Maze procedure is named after James Cox, M.D., former director of Washington University's division of cardiothoracic surgery, who led the research group that developed the procedure in 1987. The original Cox-Maze procedure calls for 10 precisely placed incisions in the upper chambers of the heart that are then sewn up and eventually form scars in the atrial tissue. Using RF ablation replaced all but two of the complex incisions required by the original procedure.



Related Links:
Washington University School of Medicine and Barnes-Jewish Hospital