From the Division of Cardiovascular Diseases (P.B.B., D.R.H.), Mayo Clinic, Rochester, Minn; Division of Cardiology (A.L.S., R.M.C.), Duke Clinical Research Institute, Durham, NC; Division of Cardiology (E.R.B.), University of Michigan (Ann Arbor); and Department of Cardiology (E.J.T.), Cleveland Clinic, Cleveland, Ohio. (At 1997-07)