1. Division of Cardiology; Children's National Health System; Washington DC
2. Division of Pediatric Cardiology; University of Iowa, Stead Family Children's Hospital; Iowa City Iowa
3. Division of Cardiology; University of Michigan; Ann Arbor Michigan
4. Division of Cardiology; Vanderbilt University; Nashville Tennessee
5. Division of Cardiology; Advocate Children's Hospital; Oak Lawn Illinois
6. Division of Pediatric Cardiology; Stanford University; Palo Alto California
7. Division of Cardiology; University California; San Francisco California
8. Division of Cardiology; Sibley Heart Center; Atlanta Georgia
9. Division of Cardiology; Medical University of South Carolina; Charleston South Carolina
10. Division of Cardiology; University of Louisville; Louisville Kentucky
11. Division of Biostatistics and Study Methodology; Children's National Health System; Washington DC