1. Department of Pediatrics, Division of Cardiology; Lucile Packard Children's Hospital at Stanford University; Palo Alto; Calif; USA
2. Department of Pediatrics, Lillie Frank Abercrombie Section of Pediatric Cardiology; Baylor College of Medicine; Houston; Tex; USA
3. Michael E. DeBakey Department of Surgery, Baylor College of Medicine; Texas Children's Hospital; Houston; Tex; USA
4. Department of Pediatrics, Division of Cardiology; University of Mississippi Medical Center/Batson Children's Hospital; Jackson; Miss; USA