The U.S. Food and Drug Administration has approved the first ablation catheters for the treatment of atrial fibrillation (uncoordinated contractions of the upper heart chambers), one of the most common types of arrhythmias-or abnormal heart rhythms--affecting more than two million Americans.
The devices approved today, the NaviStar ThermoCool saline irrigated radio-frequency ablation catheter and the EZ Steer ThermoCool Nav, can be used to create small, strategically placed scars in heart tissue to block irregular electrical waves that cause atrial fibrillation. The FDA previously approved other ablation catheters to treat arrhythmias such as atrial flutter and ventricular tachyarrhythmia, but not atrial fibrillation.
Atrial fibrillation is usually treated with drugs, and in certain severe cases, with open heart surgery. Catheter ablation should be used only after drug treatment has failed to adequately control the symptoms of the condition.
"This approval provides physicians with another option for treating this common and potentially debilitating condition," said Daniel G. Schultz, M.D., director of the FDA's Center for Devices and Radiological Health.
While atrial fibrillation is a major risk factor related to stroke, there is no conclusive evidence that links the treatment of symptoms by ablation to a reduction in stroke. Therefore, the FDA agrees with the American College of Cardiology, the American Heart Association and the European Society of Cardiology, which recommend that patients at risk for stroke continue to take blood-thinning medications after ablation procedures for atrial fibrillation.
The FDA based this approval on a clinical study of 167 patients at 19 medical centers in the United States, Brazil, Canada, the Czech Republic, and Italy. Data from the study showed the devices to be effective in eliminating symptomatic recurrence of atrial fibrillation episodes for one year in approximately 63 percent of treated patients versus 17 percent of the patients in the control group.
The catheters were the focus of an FDA Circulatory System Devices advisory panel on Nov. 20, 2008, when they received the panel's unanimous recommendation for approval.
As a condition of approval, manufacturer BioSense Webster must establish a physician training program and conduct postmarket studies to collect data on these devices' long-term safety and effectiveness (including incidence of stroke, mortality, cardiac arrest, major bleeding, and pulmonary vein stenosis), and the effect of physicians' experience in operating the device on procedural safety.
Both catheters are manufactured by BioSense Webster of Diamond Bar, Calif.