Use of Propafenone in Patients With Supraventricular Tachycardia

Propafenone prolongs refractoriness and slows conduction of the atrium, atrioventricular node, and accessory atrioventricular pathway. By interfering with conduction in locations necessary to support supraventricular tachycardia, propafenone effectively treats several mechanisms of rhythm disturbance. Early experience shows that propafenone, when administered in the electrophysiology laboratory, effectively terminates or prevents reinduction of paroxysmal supraventricular reentrant tachycardia in 50% to 75% of patients. The most effective dose associated with the fewest side effects has been 2 mg/kg infused over 10 minutes. Long‐term success with propafenone has been demonstrated in patients with paroxysmal atrial fibrillation, paroxysmal atrial flutter, atrioventricular node reentrant tachycardia, atrioventricular reentrant tachycardia using a concealed accessory pathway, and tachycardias associated with the Wolff‐Parkinson‐White syndrome, including paroxysmal atrial fibrillation and atrioventricular reentrant tachycardia. In 67% (range, 27% to 89%) of patients receiving long‐term therapy with propafenone, episodes of supraventricular tachycardia have been either eliminated or significantly reduced in frequency and treatment has not had to be stopped because of side effects. The effective daily dose for longterm therapy has been 550 to 750 mg administered in three or four divided doses. Although the number of patients reported in the literature at this time is small, propafenone appears to be an effective agent for treating supraventricular tachycardia due to one of several mechanisms.