1. Department of Cardiology Keio University School of Medicine Tokyo Japan
2. Department of Cardiovascular Surgery Keio University School of Medicine Tokyo Japan
3. New Tokyo Hospital Matsudo Japan
4. Department of Cardiology Osaka City General Hospital Osaka Japan
5. Saiseikai Yokohama‐City Eastern Hospital Tsurumi Japan
6. Sendai Kousei Hospital Sendai Japan
7. Shonan Kamakura General Hospital Kamakura Japan
8. Kokura Memorial Hospital Kokura Japan
9. Department of Cardiovascular Surgery Tokyo Bay Urayasu‐Ichikawa Medical Center Chiba Japan
10. Toyama University Hospital Toyama Japan
11. Ogaki Municipal Hospital Gifu Japan
12. Teikyo University School of Medicine Tokyo Japan
13. Toyohashi Heart Center Toyohashi Japan
14. Nagoya Heart Center Nagoya Japan