1. Heart Research Follow-up Program, University of Rochester Medical Center, 265 Crittenden Blvd. CU 420653, Rochester, NY 14642, USA
2. Department of Cardiology, Gentofte University Hospital, Hellerup, Denmark
3. Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA
4. Cardiology Division, Duke University Medical Center, Durham, NC, USA
5. Greenville University Health System, Greenville, SC, USA
6. Division of Cardiovascular Medicine, Stanford University, Stanford, CA, USA