1. Department of Cardiovascular Medicine, Dokkyo Medical University, Japan
2. Department of Cardiology, Sano Kosei Hospital, Japan
3. Department of Cardiology, Shimotsuga General Hospital, Japan
4. Department of Cardiology, Haga Red Cross Hospital, Japan
5. Department of Cardiology, Ashikaga Red Cross Hospital, Japan
6. Department of Cardiology, Nikko Medical Center, Dokkyo Medical University, Japan