1. Department of Cardiovascular Medicine Kyorin University Hospital 6‐20‐2 Shinkawa Mitaka 181‐8611 Japan
2. Department of Cardiology Keio University School of Medicine Tokyo Japan
3. Department of Medicine, Division of Cardiovascular Medicine Stanford University Stanford CA USA
4. Department of Cardiology Sakakibara Heart Institute Tokyo Japan
5. Department of Cardiology National Defense Medical College Saitama Japan
6. Department of Cardiology St. Lukes International Hospital Tokyo Japan
7. Department of Cardiology Tokyo Saiseikai Central Hospital Tokyo Japan
8. Department of Cardiology Saitama Medical University, International Medical Center Saitama Japan