1. UCLA Medical Center; Los Angeles California
2. The Cardiac and Vascular Institute; Gainesville Florida
3. St. Francis Hospital-The Heart Center; Roslyn New York
4. Cardiovascular Systems, Inc; Saint Paul Minnesota
5. Detroit Medical Center - Heart Hospital Detroit; Michigan
6. New York-Presbyterian Hospital and Columbia University Medical & Cardiovascular Research Foundation; New York New York
7. Metropolitan Heart and Vascular Institute, Mercy Hospital; Minneapolis Minnesota