The study results published in the Journal of the American Medical Association suggest that patients with paroxysmal atrial fibrillation (AF) who are refractory to antiarrhythmic drug therapy (ADT) may benefit from the addition of catheter ablation. Catheter ablation utilizes radiofrequency to eliminate the source of the irregular heartbeat and has been proposed as an alternative therapy for AF. However, there is a paucity of clinical data to support its use for this purpose.

This was a prospective, randomized, multisite study of 167 patients with symptomatic paroxysmal AF who had at least three episodes of AF within 6 months of randomization and who had not responded to at least one prior ADT. The patients were randomized to receive either catheter ablation (n=106) or a previously unused ADT (n=61) and were followed for 9 months. The mean age of the patients was 55.7, and 66% were male. The average length of symptomatic AF was 5.7 years, and the patients had tried and discontinued an average of 1.3 ADTs before enrolling in the trial.

The primary outcome measure was time to treatment failure, defined as any incidence of paroxysmal AF during the evaluation period. The secondary outcome measure was the emergence of major adverse events within 30 days of either treatment. The patients underwent scheduled and emergency monitoring and electrocardiogram recordings throughout the 9 months of follow-up.

At 9 months, 66% of patients who underwent catheter ablation had not met the criteria for treatment failure versus 16% of the patients on ADT (hazard ratio [HR], 0.30 (95% confidence interval [CI], 0.19 to 0.47; P<0.001). In addition, 70% of patients in the catheter ablation group had no recurrence of symptomatic atrial arrhythmia compared with 19% of those on ADT (P<0.001); over the same 9 months, 63% of patients in the ablation group were free of any arrhythmia—symptomatic or not—versus 17% of those on ADT (P<0.001). Major treatment adverse events within the first 30 days occurred in 8.8% of patients treated with ADT and 4.9% of patients treated with catheter ablation.

The major limitations of the study include that most of the researchers had considerable experience with catheter ablation, which might not be the case in smaller facilities. The patients in this study were younger and had less cardiac dysfunction than most patients with paroxysmal AF. The study also did not address longer-term outcomes such as mortality, stroke risk, heart failure, or whether AF progressed to a more persistent arrhythmia. Another study now underway, known as Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation (CABANA), will try to determine whether patients who undergo ablation live longer than patients receiving medication and will follow approximately 3000 subjects for 3 years.

The study was sponsored by BioSense Webster Inc., the catheter-design division of Johnson & Johnson, who manufactured the ablation cathether used in the study.

1. Wilber DJ, Pappone C, Neuzil P, et al. Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial. JAMA. 2010;303(4):333-340. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/20103757?itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum&ordinalpos=2. Accessed February 2, 2010.

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This entry was posted on Tuesday, February 2nd, 2010 at 12:00 pm.