1. From Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston (J.H.W., E.A.S., R.W.Y.); Division of Cardiology, George Washington University School of Medicine and Health Sciences, Washington, DC (W.B.B.); Harvard Clinical Research Institute, Boston, MA (E.A.S., R.W.Y.); and Division of Cardiology, University of Washington Medical Center, Seattle (J.M.M.).