1. From the University of Colorado at Denver and Health Sciences Center, Denver, Colo (M.R.G.T., D.S., L.K., E.C., K.H., D.F., S.L.G., X.Z., C.C.S., C.S.L., M.R.B., L.M.); Department of Cardiology, University Hospital, Trieste, Italy (A.D.L., G.S.); Division of Cardiology, The Children’s Hospital, Denver, Colo (M.M.B., J.C.); and Stanford University and the Cooperative Studies Program, Department of Veterans Affairs, Stanford, Calif (P.L.).