1. From the Department of Medicine, Division of Cardiology (R.T.G., A.A.-Z., J.M.M., K.K., H.-J.C., D.A.B., L.B., O.Y., J.T., A.C.L., J.A.C.L.), Department of Biomedical Engineering (A.C.L.), and Department of Radiology (D.A.B., J.A.C.L.), Johns Hopkins University School of Medicine, Baltimore, Md.