1. From the Departments of Medicine (Cardiovascular Division: M.T.J., A.S.P., A.V., F.A., B.S., J.D.), Surgery (R.S.), and Pathology (I.N., G.H., W.C.Q.), Beth Israel Deaconess Medical Center and Harvard Medical School, and the Department of Biophysics and Physiology (J.H.), Boston University School of Medicine, Boston, Mass.