1. From the Division of Cardiology (T.E.D., K.K.W., Y.D., M.J.G., M.A.H., M.A.F., J.J.R., A.C.G.) and Department of Radiology (K.K.W., M.A.H., M.A.F.), The Children’s Hospital of Philadelphia, PA; and Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.C.G).