Electrophysiologic effects of intravenous propafenone at rest, during isoproterenol infusion and during exercise in the Wolff-Parkinson-White syndrome

Propafenone, a class Ic antiarrhythmic agent, 1 has been shown to be effective in restoring sinus rhythm in patients with symptomatic orthodromic tachycardia associated with Wolff-Parkinson-White syndrome (WPW). 2,3 The high rate of conversion to sinus rhythm (>60%) is attributed to the relatively high dose administered (2 mg/kg). In addition, recurrence of tachycardia can be prevented in most cases. The effectiveness of the antiarrhythmic agent is usually tested at rest. Information concerning the pharmacologic effects of drugs during exercise in patients with supraventricular arrhythmias is scarce. In this study, the electrophysiologic effects of propafenone were examined in 10 patients with WPW at rest, during isoproterenol infusion and during exercise to evaluate its antiarrhythmic properties under these conditions.