1. Cardiology Section, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina;
2. Gerontology Section, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina;
3. Divison of Cardiovascular Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina; and
4. Division of Public Health Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina;
5. Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada