1. Department of Pediatrics; Faculty of Medicine and Graduate School of Medicine; Hokkaido University; Hokkaido Japan
2. Department of Pediatric Cardiology; Chiba Children's Hospital; Chiba Japan
3. Department of Cardiovascular Surgery, Faculty of Medicine and Graduate School of Medicine; Hokkaido University; Hokkaido Japan
4. Department of Cardiovascular Surgery; Chiba Children's Hospital; Chiba Japan