1. Cardiovascular Engineering, Inc.; 327 Fiske Street Holliston MA 01746 USA
2. London Health Sciences Centre; London ON Canada
3. Louis Stokes VA Medical Center; Cleveland OH USA
4. Ralph H. Johnson V. A. Medical Center; Charleston SC USA
5. Duke University Medical Center; Durham NC USA
6. University of Pennsylvania Medical Center; Philadelphia PA USA
7. Brigham and Women's Hospital; Boston MA USA