Oral propafenone therapy for children with arrhythmias: efficacy and adverse effects in midterm follow-up.

The use of oral propafenone was assessed in 57 children. Mean age was 4.8 +/- 5.2 years (range 1 day to 17 years). Twenty-three patients were less than 1 year of age (40%) and 10 were less than 1 month of age (18%). Arrhythmias included supraventricular tachycardia in 32 patients (57%), atrial flutter in six (10%), and ventricular tachycardia in 19 (33%). Cardiac diagnoses included: an otherwise normal heart in 30 (53%); unoperated congenital heart defect in 11 (19%); cardiomyopathy in nine (16%); and an operated congenital heart defect in seven (12%). Mean dose of propafenone was 13.1 mg/kg/day (range 8 to 15). Success (assessed by relief of symptoms and serial 24-hour ECGs) was achieved in 16 of 32 patients with supraventricular tachycardia (50%), three of six with atrial flutter (50%), and 8 of 19 with ventricular tachycardia (42%). Drug efficacy in patients with and without organic heart disease was 30% (8 of 27) and 63% (19 of 30), respectively (p less than 0.05). Mean duration of therapy in patients in whom the drug was effective was 22.9 +/- 13.2 months (range 6 to 60). Growth was unimpaired in all patients. A neonate with nonsustained monomorphic ventricular tachycardia had sustained ventricular tachycardia during the second day of propafenone therapy at a dose of 13 mg/kg/day. Sustained ventricular tachycardia disappeared when the drug was discontinued. Another patient had an asymptomatic and transient increase in the glutamic pyruvic transaminase level. No adverse hemodynamic effects were observed. In conclusion, propafenone is an effective antiarrhythmic drug in children with normal hearts; it is less effective in patients with heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)