1. Department of Medicine, Section of Cardiology and Division of Pulmonary, Allergy, Sleep, and Critical Care Medicine Veterans Affairs Boston Healthcare System Boston Massachusetts USA
2. Division of Cardiovascular Medicine Brigham and Women's Hospital and Harvard Medical School Boston Massachusetts USA
3. Department of Medicine Providence Veterans Affairs Medical Center Providence Rhode Island USA
4. Department of Medicine Alpert Medical School of Brown University Providence Rhode Island USA
5. Research and Development Service Veterans Affairs Boston Healthcare System Boston Massachusetts USA
6. Department of Medicine, Research and Development Service, Pulmonary, Allergy, Sleep, and Critical Care Medicine Section Veterans Affairs Boston Healthcare System Boston Massachusetts USA
7. Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School Boston Massachusetts USA
8. Cardiology Section Rocky Mountain Regional Veterans Affairs Medical Center Aurora Colorado USA
9. Pulmonary Sciences and Critical Care Medicine Section University of Colorado Anschutz Medical Campus Aurora Colorado USA
10. Department of Medicine Atlanta Veterans Affairs Medical Center Decatur Georgia USA
11. Department of Cardiology, Cardiology Section Greater Los Angeles VA Healthcare System Los Angeles California USA
12. Division of Pulmonary Critical Care David Geffen School of Medicine at UCLA Los Angeles California USA
13. Department of Medicine Boston University School of Medicine Boston Massachusetts USA