1. Department of Thoracic and Cardiovascular Surgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Thoracic and Cardiovascular Surgery, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
3. Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Bucheon, Korea.
4. Division of Cardiology, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea.