1. Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
2. Department of Cardiovascular Medicine, Lahey Clinic, Burlington, MA
3. Tufts University School of Medicine, Boston, MA
4. Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
5. Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA
6. Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
7. North Shore Medical Center, Salem, MA