UAB' s Approaches to Surgical and Catheter Ablation

Atrial fibrillation (AF) affects more than 2 million Americans and is increasing in frequency. AF causes hemodynamic compromise, heart failure, a two-to-seven times increased risk of ischemic stroke, and higher overall mortality.

Antiarrhythmic drugs and anticoagulation remain front-line therapy for patients with highly symptomatic AF, but these approaches carry potentially serious adverse effects and failure rates of approximately 50% at 1 year and 84% at 2 years. Class I drugs block sodium and/or potassium channels and class III drugs primarily block potassium channels thereby prolonging ventricular repolarization. For people with symptomatic AF refractory to or intolerant of at least one class I or III antiarrhythmic drug, nonpharmacologic therapies increasingly are viable options.

“Current recommendations now place ablation of AF earlier in the treatment course,” says cardiac electrophysiologist G. Neal Kay, MD. The UAB Section of Cardiac Electrophysiology and the Division of Cardiac and Thoracic Surgery offer percutaneous and surgical ablation procedures.

“The Cox-Maze III operation is the gold standard, with a success rate of approximately 95%. The procedure is not widely used because it is technically challenging, time-consuming, and requires cardiopulmonary bypass,” Kay says. It involves an extensive cut-and-sew incision pattern to create a linear conduction barrier in the atrial wall and to isolate the pulmonary veins, pulmonary antrum, or both, the most common origins of electrical triggers that cause AF.

“We have modified the Cox-Maze III by simplifying the pattern of atrial lesions and combining cut-and-sew techniques with radiofrequency ablation and cryoablation,” says UAB cardiac surgeon David C. McGiffin, MD. “We decrease stroke risk by oversewing the left atrial appendage, which is where clots tend to form. We achieve a success rate equal to that of the traditional Maze III but have minimized the risk of the operation and shortened recovery time,” he says.

Candidates for surgical ablation are those with indications for concomitant cardiac surgery, such as mitral valve replacement, repair of coronary bypass, or repair of congenital heart defects.

The vast majority of patients with AF do not require cardiac surgery but may be candidates for catheter ablation. “We perform about 500 catheter ablations for atrial fibrillation a year,” Kay says. “The technique has an 80% long-term success rate, although approximately 25% of patients require a repeat procedure.” Using catheters that irrigate radiofrequency delivery with a saline-cooling system and electroanatomic mapping systems that sync with imaging to supply a three-dimensional picture of the catheter’s location and the ablation site have improved success and lowered risk for adverse events.

Kay and McGiffin are involved in several clinical trials for patients with AF, including a study of catheter cryoablation using a cryoballoon and a trial comparing catheter ablation with drug therapy. “This 125-center study proposes that catheter ablation is superior to antiarrhythmic drugs for reducing total mortality and incidence of stroke and other adverse events. It will be a landmark trial that shapes therapy and policy in years to come,” Kay says.

For more information:
Dr. Neal Kay
Dr. David McGiffin
1.800.UAB.MIST
mist@uabmc.edu