1. Department of Cardiology Toyohashi Heart Center 21‐1 Gobudori, Oyamachyo Toyohashi Aichi 441‐8530 Japan
2. Department of Cardiology Nagoya Heart Center Nagoya Japan
3. Department of Hygiene and Public Health Nippon Medical School Tokyo Japan
4. Center for Clinical Research Nippon Medical School Hospital Tokyo Japan
5. Department of Cardiology Saiseikai Utsunomiya Hospital Utsunomiya Tochigi Japan
6. Department of Cardiology Keio University School of Medicine Tokyo Japan
7. Department of Cardiology Sendai Kosei Hospital Sendai Japan
8. Department of Cardiology New Tokyo Hospital Matsudo Chiba Japan
9. Department of Cardiology Saiseikai Yokohama City Eastern Hospital Yokohama Japan
10. Department of Cardiology Shonan Kamakura General Hospital Kamakura Kanagawa Japan
11. Department of Cardiology Kokura Memorial Hospital Kokura Japan
12. Department of Cardiology Osaka City University Graduate School of Medicine Osaka Japan
13. Department of Cardiovascular Surgery Tokyo Bay Urayasu Ichikawa Medical Center Urayasu Chiba Japan
14. Department of Cardiology Toyama University Hospital Toyama Japan
15. Department of Cardiology Ogaki Municipal Hospital Ogaki Gifu Japan
16. Department of Cardiology Teikyo University School of Medicine Tokyo Japan