1. MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (N.M., F.H.S.).
2. Georgetown University, Washington, DC (N.M., F.H.S.).
3. Johns Hopkins University Department of Medicine, Division of Cardiology, Baltimore, MD (M.M., K.C.W., H.C., C.A.J., N.A.G., H.T., A.G.H.).
4. Johns Hopkins University Department of Radiology, Baltimore, MD (S.L.Z.).
5. Johns Hopkins University Department of Pediatrics, Division of Pediatric Cardiology, Baltimore, MD (J.Z., S.K.).