Effect of intra venous propafenone on termination of paroxysmal supraventricular tachycardia

To assess the effects of intravenous propafenone on termination of supraventricular tachycardia, eighteen patients with sustained paroxysmal supraventricular tachycardia (PSVT) received 25 to 140 mg propafenone, administered as a slow intervenous infusion. Termination of supraventricular tachycardia occurred in 14 of the 18 (77.8%) patients. Among the 14, ten with atrioventricular reentrant tachycardia (AVRT) were hospitalized for electrophysiological study. We found propafenone prolonged refractoriness and slowed conduction of the atrioventricular node and accessory atrioventricular bypass tracts. These effects provided antiorrhythmic action to terminate tachycardia. Nine patients whose AVRT responded to propafenone showed that the blockage of the reentry circle occurred at retrograde Kent bundle. No adverse effects were observed except one patient showed proarrhythmic VT. We conclude that intravenous propafenone is safe and effective in the acute treatment of PSVT.