1. From the Divison of Cardiology (H.L., M.M., S.T., A.V.), Department of Medicine Emory University School of Medicine and the Atlanta Veteran Administration Hospital, Atlanta, GA; Department of Medicine (T.J.G), Jagiellonian University School of Medicine, Krakow, Poland; Department of Medicine (C.W.), Stanford University School of Medicine, Palo Alto, CA; Divisions of Clinical Pharmacology and Cardiology (D.G.H.), Department of Medicine, Vanderbilt University, Nashville, TN.