1. From the Department of Pediatrics, Division of Pediatric Cardiology and Radiology (O.H.T.-S.), Department of Pediatrics, Division of Hematology-Oncology (E.G.), and Department of Research (G.S.B., J.F.), Connecticut Children’s Medical Center, Hartford, CT; The Heart Center at Nationwide Children’s Hospital and Ohio State University, Columbus, OH (K.N.H.); Hartford Hospital, Hartford, CT (M.T.O.); Applied Science Laboratory, GE Healthcare, Toronto, ON, Canada (J.S.); Pat and Jim Calhoun Cardiology...