1. Department of Medicine, Division of CardiologyThe University of Texas Health Science Center at San Antonio San Antonio Texas
2. Department of Epidemiology and BiostatisticsThe University of Texas Health Science Center at San Antonio San Antonio Texas
3. Division of Cardiovascular DiseasesThe University of Kansas Medical Center Kansas City Kansas
4. Department of Medicine, Division of Cardiology, The Dallas VA Medical Center and the University of Texas Southwestern Medical Center Dallas Texas