1. From the Department of Medicine/Cardiology (A.D.d.H., B.Y.T., M.N.Z., L.I.L., R.J., A.D., C.T., C.J., N.A.-A., T.A., S.D.R., H.C., D.D., D.P.J.), Johns Hopkins University School of Medicine, Baltimore, Md; Department of Cardiology, Division of Heart and Lungs (A.D.d.H.), University Medical Center Utrecht, Utrecht, The Netherlands; and National Institutes of Health, Radiology and Imaging Sciences (D.A.B.), Bethesda, Md.