MAYWOOD, ILLINOIS. Antiarrhythmic drug therapy (ADT) is usually the first approach to dealing with atrial fibrillation. However, the long-term efficacy of antiarrhythmics is not great with 60 to 80% of patients on sotalol, propafenone or flecainide experiencing recurrence within one year when first exposed to these drugs. Having failed one antiarrhythmic increases the risk of failing another one with recurrence rates now approaching 80 to 90% within one year. Amiodarone is the exception to this with a one-year recurrence rate of 30 to 40%. However, amiodarone has the potential for very serious adverse effects.
A large group of electrophysiologists from 15 centers in the USA, 2 in Europe, and 1 each in Canada and Latin America now attempts to answer the question – Having failed one antiarrhythmic drug, is it worth trying another, or is catheter ablation a better option?
Their study involved 167 paroxysmal afibbers who had all failed therapy with at least one antiarrhythmic and who experienced at least 3 afib episodes in the 6 months prior to being randomized to undergo catheter ablation (106 patients) or try a different antiarrhythmic (61 patients). Both groups consisted mainly of lone paroxysmal afibbers (90% in ablation group and 85% in ADT group). The average age of patients was 56 years and about 65% were male. Fifty percent had been treated (ineffectively) with propafenone prior to joining the study, while 35% had taken sotalol, and 28% flecainide.
The 61 patients in the ADT group were assigned to a not previously administered antiarrhythmic (dofetilide, flecainide, propafenone, sotalol, or quinidine) and followed for 9 months. The study protocol did not allow the use of amiodarone. Patients in the ADT group were allowed to opt for an ablation after 90 days of ineffectual ADT – 36 patients (54%) chose to do so within 3 to 5 months of being assigned to ADT.
The patients assigned to ablation underwent a circumferential pulmonary vein isolation procedure (Pappone protocol) with additional lesion lines placed at the discretion of the EP. A repeat procedure was performed in 13 patients (12.6%) within 80 days of the initial ablation.
At the end of the 9-month effectiveness evaluation period, 66% of the participants in the ablation group remained afib-free as compared to 16% in the ADT group. Major adverse events occurred in 4.9% of the ablation group and in 8.8% in the ADT group. Quality of life scores, while being similar in the two groups prior to randomization, improved substantially within 3 months following ablation, but remained unchanged in the ADT group. The researchers conclude that, "Among patients with paroxysmal AF who had not responded to at least 1 antiarrhythmic drug, the use of catheter ablation compared with ADT resulted in a longer time to treatment failure during the 9-month follow-up period."
Wilber, DJ, et al. Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation. JAMA, Vol. 303, No. 4, January 27, 2010, pp. 333-40
Editor's comment: This study certainly provides convincing evidence that, if a first antiarrhythmic drug fails to control paroxysmal AF episodes, a catheter ablation is a better second step than trying another antiarrhythmic. However, this may not apply to everyone. For example, if a vagal afibber has had no success with sotalol or propafenone, which both have beta-blocking properties, it is not inconceivable that flecainide might be effective in a "second try". It is also possible that long-term therapy with amiodarone might approach the efficacy of ablation, but the risk of adverse effects would be substantially higher and quality of life would no doubt be lower.