1. Department of Medicine, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
2. Department of Medicine, Forrest General Hospital, 6051 US 49, Hattiesburg, MS 39401, USA
3. Department of Medicine, University of Mississippi, 2500 N. State Street, Jackson, MS 39216, USA
4. Division of Cardiology, Department of Medicine, University Texas Southwestern, and Parkland Health and Hospital System, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
5. Division of Cardiology, Johns Hopkins University School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
6. Division of Cardiology, Department of Medicine, Duke University, 2301 Erwin Road, Durham, NC 27710, USA
7. Duke Clinical Research Institute, 300 W Morgan St, Durham, NC 27701, USA