DENVER – After a failed first ablation procedure for paroxysmal atrial fibrillation, redo ablation proved more effective than did antiarrhythmic drug therapy in a randomized trial, Dr. Jonathan Steinberg reported at the annual meeting of the Heart Rhythm Society.
The success rate of a first ablation procedure in patients with symptomatic paroxysmal AF is typically about 60%. What to do for the 40% who are nonresponders has been unclear, with no prior randomized clinical trial evidence available to guide decisions, noted Dr. Steinberg of Columbia University, New York.
The study comprised 154 patients with recurrent symptomatic paroxysmal AF 3 months after an initial ablation procedure involving only pulmonary vein isolation. All participants received an implantable loop recorder to track atrial arrhythmic events.
They were then randomized to redo-ablation limited to reisolation of the pulmonary vein, which was successfully accomplished in all instances, or to guideline-based antiarrhythmic drug therapy. The choice of drug was left to individual investigator discretion. The three options were propafenone at 450-900 mg/day, sotalol at 160-320 mg/day, or flecainide at 200-400 mg/day. Propafenone was selected in the majority of cases, at an average dose of 579 mg/day.
The average AF burden as measured by implantable loop recorder at randomization was 15%. The primary study endpoint was AF burden at 36 months of follow-up, which was 5.6% in the redo-ablation group compared with 18.8% in the antiarrhythmic drug group.
Secondary endpoints uniformly favored redo-ablation as well.
Data from the implantable loop recorders was evaluated every 3 months during 3 years of follow-up. As early as 3 months into the study, the group given antiarrhythmic drugs had an AF burden of 3.3%, significantly higher than the 1.9% rate seen in the redo-ablation group. Thereafter, the drug therapy group experienced a gradual increase in AF burden throughout the first 12-15 months, followed by a much more substantial increase during the remainder of the study.
"The redo-ablation group had a different pattern" of AF burden, Dr. Steinberg observed. "It was low throughout the first 12-15 months, with just a slight increase, and it then rose only gradually over time until the 36-month end of the study."
Freedom from any atrial tachyarrhythmia at 1 year was 30% in the antiarrhythmic drug therapy group and 75% in the redo-ablation group. By 3 years, 12% of those in the drug therapy group were free of atrial tachyarrhythmias as were 58% in the redo-ablation group.
Complications in the redo-ablation group consisted of two cases of cardiac tamponade. In contrast, 49 patients, or 64%, in the antiarrhythmic drug therapy group discontinued medication due to intolerance or ineffectiveness.
Session cochair Dr. Gordon Tomaselli of Johns Hopkins University, Baltimore, said that in light of the potential proarrhythmic effects of virtually all antiarrhythmic drugs, it would have been useful to include a no-antiarrhythmic drug control group in the study.
Dr. Steinberg reported having no conflicts of interest.