1 1Lifespan Cardiovascular Institute, Division of Cardiovascular Medicine, Dept. of Medicine, Brown University Alpert Medical School, Providence, RI USA.
2 2Dept. of Medicine (Cardiovascular Division) and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA USA.
3 3Dept. of Medicine, Cardiology Service, Walter Reed National Military Medical Center, Bethesda, MD USA.
4 4Dept. of Medicine, Cardiology Service, Fort Belvoir Community Hospital, Ft. Belvoir, Fairfax County, VA USA.