1. Division of Cardiology, University of Texas Southwestern Medical Center, Dallas (R.K., M.S.L.).
2. Mid-America Heart Institute, Kansas City, MO (Y.T., P.S.C.).
3. Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City (S.G.).
4. Children’s Hospital of Philadelphia, PA (V.M.N., R.A.B.).
5. Department of Anesthesiology and Critical Care Medicine and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia (V.M.N., R.A.B.).
6. Division of Pediatric Cardiac Critical Care, Department of Pediatrics, Medical City Children’s Hospital, Dallas, TX (T.T.R.).
7. The Hospital for Sick Children, University of Toronto, ON, Canada (A.-M.G.).
8. Division of Cardiology, Department of Internal Medicine, University of Missouri-Kansas City (P.S.C.).