1. Department of Cardiology, Dokkyo Medical University Nikkyo Medical Center, Nikko 321-1298, Tochigi, Japan
2. Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Mibu 321-0293, Tochigi, Japan
3. Department of Cardiology, Sanin Rosai Hospital, Yonago 683-8605, Tottori, Japan
4. Department of Pharmacology, Chiba University Graduate School of Medicine, Chiba 260-8670, Chiba, Japan
5. Yonago Medical Center, National Hospital Organization, Yonago 683-0006, Tottori, Japan