1. Division of Cardiovascular Medicine, Department of Internal Medicine, Hyogo Prefectural Harima-Himeji General Medical Center , 3-264 Kamiya-cho , Himeji 670-8560, Japan
2. Department of Exploratory and Advanced Research in Cardiology, Kobe University Graduate School of Medicine , 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 6500017 , Japan