1. Department of Medicine, Division of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
2. Division of Pulmonary and Critical Care, Mayo Clinic, Rochester, MN, USA
3. Department of Internal Medicine, Wayne State University / Detroit Medical Center, Detroit, MI, USA
4. Department of Internal Medicine, Division of Cardiology, Wayne State University / Detroit Medical Center, Detroit, MI, USA
5. Department of Cardiology, MedStar Washington Hospital Center, Washington, DC, USA
6. Division of Cardiovascular Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
7. Office of Biostatistics Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA