The use of catheter ablation resulted in significantly better outcomes in patients with paroxysmal atrial fibrillation (AF) who had not responded previously to antiarrhythmic drug therapy, according to a randomized study in the Jan. 27 issue of Journal of the American Medical Association.

Although antiarrhythmic drugs are generally used as first-line therapy to treat patients with AF, they are associated with cumulative adverse effects over time and their effectiveness remains inconsistent, according to the authors. As a result, catheter ablation has become an alternative therapy for AF.

David J. Wilber, MD, of Loyola University Medical Center in Maywood, Ill., and colleagues conducted a study to compare catheter ablation with antiarrhythmic drug therapy in patients with symptomatic paroxysmal AF, who previously did not respond to at least one antiarrhythmic drug.

From 19 hospitals, the researchers included 167 patients who had experienced at least three AF episodes within six months before randomization. Enrollment occurred between Octocber 2004 and October 2007, with the last follow-up on Jan. 19, 2009.

Researchers randomized patients to catheter ablation (106 patients with Navistar ThermoCool Catheter, Biosense Webster) or antiarrhythmic drug therapy in (61 patients), with assessment for effectiveness in a nine-month follow-up period.

The primary outcome was time to protocol-defined failure, which included documented symptomatic paroxysmal AF during the evaluation period.

Wilber and colleagues found that at the end of the nine-month effectiveness evaluation period, 66 percent of patients in the catheter ablation group remained free from protocol-defined treatment failure versus 16 percent of patients treated with antiarrhythmic drug therapy.

“Similarly, 70 percent of patients treated by catheter ablation remained free of symptomatic recurrent atrial arrhythmia versus 19 percent of patients treated with antiarrhythmic drug therapy,” the authors wrote. “In addition, 63 percent of patients treated by catheter ablation were free of any recurrent atrial arrhythmia versus 17 percent of patients treated with antiarrhythmic drug therapy.”

Patients in the catheter ablation group also reported significantly better average symptom frequency and severity scores at three months on measures of quality of life.

According to the researchers, major 30-day treatment-related adverse events occurred in 8.8 percent of patients in the drug therapy arm compared with 4.9 percent in the catheter ablation group.

“Our multicenter randomized trial demonstrates the superiority of catheter ablation over antiarrhythmic drug therapy in the treatment of patients with paroxysmal AF who did not respond to one or more drugs,” Wilber and colleagues concluded “Catheter ablation provided significantly better rhythm control and improved quality of life with a favorable safety profile. These findings argue for early use of catheter ablation therapy in patients with paroxysmal AF unresponsive to initial attempts with pharmacologic control.”