Background:Propranolol has emerged as front-line therapy for infantile hemangiomas (IHs). However, a well-defined protocol for administering and predicting response to propranolol is unavailable.Methods:In this open-label trial, 31 children with IH (median age=5 mo; range,1 mo to 9 y) were administered propranolol (2 mg/kg/d) for a median duration of 28 weeks (12 to 50 wk). They were compared with 14 historical controls with IH who did not receive any treatment. An image-based scoring system was used to assess involution.Results:Propranolol (28/31, 90.3%) produced better and faster response compared with control treatment (4/14, 28.6%). With propranolol, 65% to 80% involution was obtained in the first 8 weeks, with an additional 2% to 10% involution until 20 weeks. After 20 weeks, the changes in IH were insignificant. Response was more pronounced among infants 6 months of age who attained a peak involution score of 1.86, suggesting >80% involution of IH. The similar score in the cohort aged 6 to 36 months was 3.31. The heart rate (HR) decline after propranolol treatment was significantly higher among patients whose hemangioma responded to propranolol than in those who did not respond (P=0.0006). Decline in HR by >20%, 2 weeks after propranolol administration, was predictive of IH involution (relative risk=0.11; 95% confidence interval, 0.02-0.51; P=0.036).Conclusions:Propranolol is efficacious in patients with IH. The most pronounced response is seen in the first 8 weeks and in infants aged 6 months or younger. A decline in HR >20% is an early marker of response to propranolol.