Use of catheter ablation, in which radiofrequency energy is emitted from a catheter to eliminate the source of an irregular heartbeat, resulted in significantly better outcomes in patients with paroxysmal atrial fibrillation (intermittent cardiac rhythm disturbance) who had not responded previously to antiarrhythmic drug therapy, according to a study in the January 27 issue of JAMA.
Atrial fibrillation (AF) represents an important public health problem, with patients having an increased long-term risk of stroke, heart failure and all-cause death. 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 background information in the article. Catheter ablation has become an alternative therapy for AF.
David J. Wilber, M.D., of Loyola University Medical Center, Maywood, Ill., and colleagues conducted a study to compare catheter ablation with antiarrhythmic drug therapy (ADT) in patients with symptomatic paroxysmal AF who previously did not respond to at least one antiarrhythmic drug. The randomized study was conducted at 19 hospitals and included 167 patients who had experienced at least three AF episodes within six months before randomization. Enrollment occurred between Oct. 2004 and Oct. 2007, with the last follow-up on January 19, 2009. Patients were randomized to catheter ablation (n = 106) or ADT (n = 61), with assessment for effectiveness in a 9-month follow-up period.
The primary outcome the researchers focused on was time to protocol-defined failure, which included documented symptomatic paroxysmal AF during the evaluation period.
The researchers found that at the end of the 9-month effectiveness evaluation period, 66 percent of patients in the catheter ablation group remained free from protocol-defined treatment failure vs. 16 percent of patients treated with ADT. "Similarly, 70 percent of patients treated by catheter ablation remained free of symptomatic recurrent atrial arrhythmia vs. 19 percent of patients treated with ADT. In addition, 63 percent of patients treated by catheter ablation were free of any recurrent atrial arrhythmia vs. 17 percent of patients treated with ADT," they write. 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.
Major 30-day treatment-related adverse events occurred in 5 of 57 patients (8.8 percent) treated with ADT and 5 of 103 patients (4.9 percent) treated with catheter ablation.
"Our multicenter randomized trial demonstrates the superiority of catheter ablation over ADT in the treatment of patients with paroxysmal AF who did not respond to 1 or more drugs. 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," the authors conclude.
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