BOSTON--In patients with paroxysmal atrial fibrillation (AF) unresponsive to prior antiarrhythmic drug, catheter ablation substantially reduced the risk of recurrent atrial arrhythmias, according to Thermocool AF trial results presented May 14 at the 30 th annual meeting of the Heart Rhythm Society (HRS) late-breaking clinical trials.
The study included 167 patients at 19 centers including 15 centers in the U.S. Lead researcher David Wilber, MD, director of the Cardiovascular Institute at Loyola University Stritch School of Medicine in Maywood, Ill., presented the results at HRS.
One year after undergoing catheter ablation, 63 percent of patients with AF were free of any recurrent atrial arrhythmias or symptoms. By comparison, only 17 percent of those treated with drugs were arrhythmia-free. Results were so convincing the trial was halted early.
In the study, 106 patients with frequent episodes of AF were randomly assigned to undergo ablation and 61 similar patients were randomly assigned to receive drug therapy. He reported that all patients had experienced at least three episodes of AF during the previous six months and had failed at least one attempt to control the rhythm with drugs.
The ablation group also scored significantly higher on a quality-of-life scale, according to Wilber.
Typically, drugs such as beta blockers and calcium channel blockers can slow the heart rate during an AF episode, Wilber noted. Other drugs such as flecainide and propafenone can help maintain a normal rhythm. When drugs don't work or produce unacceptable side effects, alternative treatments include a pacemaker, surgery and catheter ablation.
The study was the largest to date to compare ablation to drug therapy for AF, Wilber said, and earlier studies involved single centers and smaller sample sizes. An additional study called CABANA is designed to determine whether ablation patients live longer than patients receiving medication. Researchers will follow about 3,000 patients for three years.
Biosense Webster, which makes the ThermoCool catheter used in the trial, funded the study. Wilber disclosed that he is a consultant to Biosense.