Paroxysmal Supraventricular Tachycardia: Experience with Propafenone

Abstract

The authors studied the efficacy of intravenous (IV) (1.5-2 mg/kg) and oral propafenone (450 to 900 mg/day) in 16 patients with paroxysmal, sus tained, recurrent supraventricular tachycardia (SVT). In 5 patients IV propafenone was not given, because of intolerant SVT. Nine patients had Wolff-Parkinson-White syndrome.

IV propafenone immediately stopped and prevented reinduction of SVT in 9/11 patients. Oral propa fenone prevented SVT induction in 3 of 5 patients. In the 9 patients re sponsive to IV propafenone, oral pro pafenone was effective: in particular, in 6 patients SVT tachycardia was not induced by serial transesophageal pacings, and in the remaining 3 pa tients the arrhythmia was still in duced but was slower and of brief duration (3-5 seconds). In 11/12 pa tients responsive to oral propafenone the minimum effective dosage in pre venting the induction of the arrhyth mia was 600 mg/day. In only 1 patient was the dose of 450 mg/day equally effective.

Propafenone administration was not associated with major side ef fects. In conclusion, propafenone is very effective in the control of parox ysmal supraventricular tachycardia; intravenous propafenone can predict the efficacy of oral therapy.