[1] Florida Atlantic Univ, Dept Internal Med, Boca Raton, FL USA
[2] Univ Kentucky, Div Cardiovasc Med, Lexington, KY USA
[3] Univ Calif Berkeley, Dept Internal Med, Berkeley, CA USA
[4] Univ Texas San Antonio, Dept Internal Med, San Antonio, TX USA
[5] MedStar Washington Hosp Ctr, Dept Internal Med, Washington, DC USA
[6] Univ Texas Southwestern Med Ctr Dallas, Div Cardiol, Dallas, TX 75390 USA
[7] VA North Texas Healthcare Syst, Dallas, TX USA
[8] Keele Univ, Keele Cardiovasc Res Grp, Keele, England