1. Children’s National Medical Center, The George Washington University School of Medicine, Washington, District of Columbia;
2. Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio;
3. American College of Cardiology, Washington, District of Columbia;
4. New Jersey Department of Health, Trenton, New Jersey;
5. Department of Pediatrics, Duke University Medical Center, Durham, North Carolina;
6. Arkansas Children's Hospital, University of Arkansas for Medical Science College of Medicine, Little Rock, Arkansas;
7. National Heart, Lung, and Blood Institute/National Institutes of Health, Bethesda, Maryland; and
8. Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia