1. From the Cardiovascular Research Center (S.A.L., P.T.E.) and Cardiac Arrhythmia Service (C.O., P.T.E.), Massachusetts General Hospital, Boston, Mass; the Division of Preventive Medicine, Brigham and Women's Hospital, Boston, Mass (S.A.L.); the Department of Medicine I, University Hospital Grosshadern, Ludwig-Maximilians-University, Munich, Germany (S.K.); Boston University and the NHLBI Framingham Heart Study (E.J.B.), Framingham, Mass; the Departments of Medicine (E.J.B.) and Preventive Medicine (E...