1. Department of Cardiology, Dokkyo Medical University, Saitama Medical Center, Japan
2. Department of Pediatrics, Dokkyo Medical University, Saitama Medical Center, Japan
3. Ultrasound Diagnostic Center, Dokkyo Medical University, Saitama Medical Center, Japan
4. Department of Cardiovascular medicine, Dokkyo Medical University Hospital, Japan
5. Department of Cardiology, Mitsui Memorial Hospital, Japan