1. Division of Cardiology; University of Utah Health Sciences Centre; 30 N 1900 E, Room 4A100 Salt Lake City UT 84132-2401 USA
2. Division of Epidemiology; University of Utah; Salt Lake City UT USA
3. Department of Emergency Medicine; University of Cincinnati; Cincinnati OH USA
4. Department of Emergency Medicine; Cleveland Clinic Foundation; Cleveland OH USA
5. Division of Cardiology; San Diego VA Medical Centre; San Diego CA USA
6. Research Service; San Diego VA Medical Centre; San Diego CA USA