Oral Propafenone Therapy for Patients with Paroxysmal Supraventricular Tachyarrhythmia

Abstract

P ropafenone, a class IC antiarrhythmic drug with sodium-channel blocking properties along with weak calcium-channel and �3-blocking activity, has been shown to be effective for a variety of supraventricular and ventricular arrhythmias. ‘‘#{176} To assess its effect on paroxysmal supraventricular tachyarrhythmia, we evaluated 16 patients with paroxysmal atrial fibrillation (eight), atrioventncular (AV) nodal reentry (five), or intra-atrial tachycardia (three). There were seven men and nine women, aged 30 to 82 (mean 59) years, who had paroxysms of tachyarrhythmia for a mean of 8. 6 years and had not improved with a mean of 3.4 prior antiarrhythmic drugs. Propafenone was initiated at a dose of 150 mg every 8 h and therapy titrated upward at intervals of at least 48 h to efficacy, intolerable side effects, or a maximum of 1,050 mg/day. Four patients continued to receive �3blockers for hypertension, and two received digoxin therapy to control the ventricular response during the study. Baseline arrhythmia frequency was assessed by patient interview. The efficacy of propafenone was assessed by follow-up interview and 24-h ambulatory ECG monitoring. Successful oral therapy was defined as complete absence or a marked reduction of symptomatic arrhythmia compared with baseline measurements. Long-term oral therapy with propafenone was successful in treating five of eight (63 percent) patients with atrial fibrillation and four of eight (50 percent) patients with either AV nodal reentry or intra-atrial tachycardia as judged by history and follow-up 24-h