To report our experience with high-dose propranolol monotherapy for prophylaxis and treatment of infant supraventricular arrhythmias (SAs).

Patients <1 year of age initiated on enteral propranolol as inpatients for management of SA were identified during a 10-year time period from the Texas Children's Hospital pharmacy database. Patients were included if they received propranolol monotherapy for SA. Propranolol therapy was considered successful when patients were initiated and discharged on monotherapy, without documented recurrence of arrhythmia or requiring additional antiarrhythmic medication. Patients discharged on propranolol were followed as outpatients until therapy was discontinued or a year from initiation, whichever came first.

A total of 287 patients met study criteria (59.2% male). Propranolol therapy was initiated at a median of 17 days of age (IQR 6-33 days) at a total daily dose of 3.6 ± 1.0 mg/kg/day. Propranolol was successful in controlling SA throughout the inpatient stay in 67.3% of patients. Only one patient experienced a clinically significant adverse event that required propranolol discontinuation. A multivariable logistic regression analysis identified the presence of congenital heart disease (OR 0.42, 95% CI 0.19-0.94, P = .04) and Wolff-Parkinson-White (OR 0.42, 95% CI 0.21-0.87, P = .01) as factors for nonsuccessful inpatient propranolol monotherapy. Of 190 patients discharged on propranolol monotherapy, 87.7% were recurrence free during follow-up.

High-dose propranolol is safe and reasonably successful in the treatment of infant SA. Inpatient control may be a predictor of continued outpatient efficacy.