Efficacy and safety of intravenous and oral propafenone in pediatric cardiac dysrhythmias.

Propafenone was administered to 58 patients with a mean age of 3.2 years (range 0.1 to 16). Mean intravenous dose was 1.2 mg/kg body weight (range 0.3 to 1.5 mg). The final mean oral maintenance dose was 308 mg/m2 body surface area (range 200 to 600 mg/m2, 16.8 mg/kg body weight). After intravenous application, propafenone was effective in 21 of 36 patients; atrial flutter was converted in 1 of 5 patients, and reentry supraventricular tachycardia was controlled in 15 of 25 patients. Propafenone was partially or completely effective in 3 of 4 patients with chaotic atrial tachycardia. Junctional ectopic tachycardia was suppressed in 2 infants. Thirty-seven patients had oral treatment with a mean follow-up of 2.2 years. Propafenone was effective in 33 of 37 patients (89%); atrial flutter was controlled in 2 patients, ventricular ectopy was suppressed in 1 of 2 patients. In reentry supraventricular tachycardia, propafenone was effective in 25 of 28 patients. Chaotic atrial tachycardia (n = 3) and junctional ectopic tachycardia (n = 2) were controlled after successful intravenous therapy. Systemic side effects were rare. Two patients developed a proarrhythmic effect, and 1 patient with ventricular ectopy after repair of tetralogy of Fallot died suddenly during propafenone maintenance therapy.