Radiofrequency ablation of atrial flutter due to administration of class IC antiarrhythmic drugs for atrial fibrillation

In selected patients, atrial fibrillation (AF) converts to atrial flutter ( AFI) due to treatment with class IC antiarrhythmic drugs. In this study, we prospectively investigated the effects of AFI ablation and continuation of drug therapy in patients with AF who developed AFI due to long-term admini stration of class IC antiarrhythmic drugs. The study population consisted o f 187 patients from an AF registry with paroxysmal AF who were orally treat ed with flecainide (n = 96) or propafenone (n = 91). Twenty-four patients ( 12.8%) developed AFI during the course of treatment. In 20 of these patient s (10.7%), electrophysiologic study revealed typical AFI. These patients un derwent radiofrequency ablation of AFI. Ablation failed in 1 patient. All p atients continued preexisting drug treatment. Recurrence of AF was assessed by ambulatory Halter monitoring and serial questionnaires. During a mean f ollow-up of 11 +/- 4 months, the incidence of AF episodes was significantly lower in patients with a combined therapy (2.7 +/- 3.6 per year) than in c ontrol subjects with a sole drug treatment (7.8 +/- 9.2 per year, p <0.05) and than before therapy (10.2 +/- 5.4 per year, p <0.001). Subgroup analysi s revealed that 7 patients (36.8%) remained symptom free with no evidence o f atrial tachyarrhythmia. Eight additional patients (42.1%) had ongoing par oxysmal AF, however, with a significantly lower incidence of AF episodes th an before therapy (2.3 +/- 1.6 per year vs 11.5 +/- 5.0 per year, p <0.001) . In the remaining 4 patients (14.7%), no beneficial effect of AFI ablation was found. It is concluded that in patients with AF who develop typical AF I due to administration of class IC antiarrhythmic agents, a combined thera py with catheter ablation of AFI and continuation of drug treatment is high ly effective in reducing occurrence and duration of atrial tachyarrhythmias . (C)1999 by Excerpta Medica, Inc.