1. Department of Cardiology, Boston Children’s Hospital, MA (B.P.Q., P.C., A.G., L.B.).
2. The Heart Center, Nationwide Children’s Hospital, Columbus, OH (A.A.).
3. Division of Pediatric Cardiology, St. Louis Children’s Hospital, St. Louis, MO (D.B., S.S.).
4. Division of Cardiology, Rady Children’s Hospital, San Diego, CA (H.E.-s).
5. Division of Cardiology, Children’s Hospital of Wisconsin, Milwaukee (S.F.).
6. Division of Cardiology, Children’s Hospital of Philadelphia and Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania (A.C.G.).
7. The Heart Institute, Cincinnati Children’s Hospital and Department of Pediatrics, University of Cincinnati College of Medicine, OH (B.G.).
8. Division of Pediatric Cardiology, University of Virginia Children’s Hospital, University of Virginia, Charlottesville (M.H.).
9. Division of Pediatric Cardiology, Monroe Carell Jr. Children’s Hospital at Vanderbilt University Medical Center, Nashville, TN (D.J.).
10. Division of Cardiology, Children’s Hospital of Pittsburgh of UPMC, PA (J.K., S.T.). The Heart Institute, Joe DiMaggio Children’s Hospital and Memorial Healthcare System, Hollywood, FL.
11. The Heart Institute, Children’s Hospital of Colorado, Denver (R.L.).
12. Division of Pediatric Cardiology, Children’s Healthcare of Atlanta Sibley Heart Center, Atlanta, GA (C.P.).
13. Division of Pediatric Cardiology, University of Michigan Medical School, Ann Arbor (W.W., J.D.Z.).