1. Department of Medicine and Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina (K.L.T., S.M.A.)
2. Duke Clinical Research Institute, Durham, North Carolina (A.S.K.)
3. Department of Psychology, East Carolina University, Greenville, North Carolina (S.F.S.)
4. Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina (N.M.A.L.)
5. Department of Medicine, Duke University School of Medicine, Duke Clinical Research Institute, Durham, North Carolina (L.R.J.)
6. Division of Geriatric Medicine, University of Colorado School of Medicine, Aurora, Colorado (D.D.M.)
7. Georgia Arrhythmia Associates, Macon, Georgia (D.H.)
8. Jackson Heart Clinic, Jackson, Mississippi (B.J.C.)
9. Department of Medicine, Emory University, Atlanta, Georgia (D.S.H.)
10. Department of Medicine, University of Texas Southwestern, Dallas, Texas (E.D.P.).