1. Department of Cardiology and Geriatrics, Kochi Medical School Kochi University Oko‐cho Nankoku Kochi 783‐8505 Japan
2. Department of Cardiology Chikamori Hospital Kochi Japan
3. Department of Cardiology Kochi Prefectural Hatakenmin Hospital Sukumo Japan
4. Department of Cardiology Kochi Prefectural Aki General Hospital Aki Japan
5. Department of Cardiology Susaki Kuroshio Hospital Susaki Japan