1. From the Seattle Adult Congenital Heart Service, University of Washington Medical Center (E.V.K., K.K.S.); Seattle Children’s Hospital, Washington (E.V.K., K.K.S.); Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle (E.V.K., K.K.S.); and Labatt Family Heart Centre, Department of Pediatrics, and Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, ON, Canada (L.G.-W.).