Efficacy and proarrhythmi of oral sotalol in pediatric patients

Objectives. This study sought to assess the efficacy of oral sotalol for various arrhythmias in pediatric patients and to evaluate the incidence of proarrhythmi and systemic side effects. Background. Sotalol is beta-adrenergic blocking agent with additional class III antiarrhythmic properties. Experience in pediatric patients is limited. Dat concerning the incidence of proarrhythmi in children are lacking. Methods. Seventy-one pediatric patients (mean age 7.3 years) with various supraventricular and ventricular tachyarrhythmias were treated with oral sotalol. All the patients were admitted to the hospital for initiation of sotalol therapy. Antiarrhythmic and proarrhythmic effects of sotalol were assessed by daily surface electrocardiograms (ECGs) during the in-hospital phase and by serial Holter monitoring. Results. Sotalol was either completely (27 [66%] of 41 patients) or partially effective (11 [27%] of 41) in 38 (93%) of 41 patients with supraventricular reentrant tachycardias. In patients with atrial flutter predominantly after operation for congenital heart disease, sotalol was effective in 84% of patients (completely in 9 of 19 and partially in 7 of 19). Ventricular tachycardi was completely (3 of 11) or partially (4 of 11) controlled in 64% of children. Proarrhythmi occurred in seven patients (10%) and consisted of symptomatic bradycardi from sinoatrial block and high grade atrioventricular (AV) block, respectively, in two children; asymptomatic high grade AV block in one; torsade de pointes in one; and relevant increased ventricular ectopic activity in three. Proarrhythmi required drug discontinuation in four patients. Mean duration of treatment for all patients was 18 months (range 1 to 40). Conclusions. Sotalol was an effective antiarrhythmic drug for wide range of pediatric tachyarrhythmias. The considerable number of patients with proarrhythmic effects indicates the need for initiation of treatment on an inpatient basis and close monitoring by serial Holter electrocardiography.