Division of Cardiology, Department of Internal Medicine, Memorial Heart Center, Iwate Medical University, Morioka-city, Iwate, Japan. Division of Cardiology, Department of Internal Medicine, Memorial Heart Center, Iwate Medical University, Morioka-city, Iwate, Japan. Electronic address: tomoitoh@iwate-med.ac.jp. Department of Cardiology, Edogawa Hospital, Edogawa-ku, Tokyo, Japan. Division of Cardiovascular Medicine, Department of Internal Medicine, Kitaharima Medical Center, Ono-city, Hyogo, Japan. Division of Cardiology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo-ku, Kobe-city, Japan. Division of Cardiovascular Medicine, Showa University School of Medicine, Sinagawa-ku, Kobe, Japan.