Study of Propranolol to Promote Heart Muscle Growth in Infants with Tetralogy of Fallot or Double Outlet Right Ventricle

What this Trial Is About

Tetralogy of Fallot and double outlet right ventricle are congenital heart conditions that can lead to heart failure. Researchers are studying whether the medicine Propranolol can help increase the growth of new heart muscle cells in infants with these conditions. This study is a phase 1 randomized trial aiming to understand if Propranolol can reactivate heart muscle cell division and support normal heart growth in infants up to about 4 months old undergoing surgical repair. Participants will be randomly assigned to receive either Propranolol or a placebo starting at 1 month of age until 4 months or just before surgery. Propranolol will be given by parents in four daily doses based on the infants weight. Additionally, patients will receive labeled N-thymidine by mouth for five days to help measure heart muscle cell growth. The study includes heart imaging using echocardiogram and cardiac MRI before and at surgery, as well as tissue and blood sample collection during surgery for detailed analysis. During the study, infants will have regular physical exams including vital signs and feeding and diaper diaries to monitor medication processing. Researchers will analyze heart tissue removed during surgery to measure new heart muscle cell growth using isotope mass spectrometry. The main outcome is cardiomyocyte division at surgery. Secondary outcomes include heart muscle size changes assessed by imaging and microscopy. Participants will be monitored from 1 month of age until surgery, with close follow-up and safety assessments during this time.

Beta-blocker Administration for Cardiomyocyte Division