1. Heart and Vascular Center; Brigham and Women's Hospital and Harvard Medical School; Boston Massachusetts
2. UCLA Division of Cardiology; Ahmanson-UCLA Cardiomyopathy Center; Los Angeles California
3. Duke Clinical Research Institute; Duke University Medical Center; Durham North Carolina
4. Department of Emergency Medicine; Baylor College of Medicine; Houston Texas
5. Division of Cardiology; University of New Mexico; Albuquerque New Mexico
6. Department of Neurology; Massachusetts General Hospital; Boston Massachusetts