1. Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
2. National Heart, Lung, and Blood Institute/National Institutes of Health, Bethesda, MD
3. Department of Health Sciences Research, Mayo Clinic, Rochester, MN
4. Brigham and Women's Hospital, Harvard Medical School, Boston, MA
5. Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN
6. Department of Medicine, University of Mississippi Medical Center, Jackson, MS