1. From the Department of Medicine (F.G.P.W., C.R.), Cardiac Catheterization Laboratory and Coronary Care Unit, Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass; the Harvard-MIT Division of Health Sciences and Technology (F.G.P.W., C.R.), Massachusetts Institute of Technology, Cambridge, Mass; and the West Roxbury Veteran’s Affairs Medical Center (F.G.P.W.), West Roxbury, Mass.