Department of Cardiovascular Medicine, Tokushima University Hospital, 2-50-1 Kuramoto, Tokushima, Japan. kusunosek@tokushima-u.ac.jp. Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka, Japan. Department of Cardiovascular Medicine, Saga University, Saga, Japan. Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Japan. Department of Cardiology, Tokyo Medical University, Tokyo, Japan. Devision of Cardiology, Osaka General Medical Center, Osaka, Japan. Department of Pharmacology, St. Marianna University School of Medicine, Kawasaki, Japan. Department of General Internal Medicine, Saitama Red Cross Hospital, Saitama, Japan. Department of Cardiovascular Medicine, JR Hiroshima Hospital, Hiroshima, Japan. Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan. Department of Cardiovascular Medicine, Nagoya City University East Medical Center, Nagoya, Japan. Department of Community Medicine for Cardiology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan. Department of Cardiovascular Medicine, Tokushima University Hospital, 2-50-1 Kuramoto, Tokushima, Japan.