1. Department of Cardiology Kasugai Municipal Hospital 1‐1‐1 Takaki‐cho Kasugai Aichi 486‐8510 Japan
2. Department of Cardiovascular Medicine Gunma University Graduate School of Medicine Gunma Japan
3. Department of Cardiology Nagoya University Graduate School of Medicine Nagoya Japan
4. Sumi Clinic and Ichinomiya Municipal Hospital Ichinomiya Japan
5. Division of Medical Statistics Fujita Health University Toyoake Japan