1. From the Duke Pediatric and Congenital Heart Center (K.D.H., J.W.T., J.S.L.) and the Duke Clinical Research Institute (K.D.H., S.M.O., J.L.K., D.S.G., J.S.L.) — both in Durham, NC; Vanderbilt University Medical Center, Nashville (P.J.K., H.S.B., D.P.B.); the University of Florida Congenital Heart Center, Gainesville (J.P.J., M.B.); Johns Hopkins University School of Medicine, Baltimore (M.L.J., B.M.); the Medical University of South Carolina, Charleston (E.M.G.); the UPMC Children’s Hospital of...