1. From the Division of Cardiology (G.C.F.), University of California, Los Angeles, Calif; the Department of Clinical Neurosciences (E.E.S.), University of Calgary, Calgary, Alberta, Canada; the Department of Epidemiology (M.J.R.), Michigan State University, East Lansing, Mich; Duke Clinical Research Center (W.P., D.O., A.F.H., E.D.P.), Durham, NC; and the Division of Neurology (L.H.S.), Massachusetts General Hospital, Boston, Mass.