Naoko Sawada1, Nobuhiko Ito2, Osamu Harada3. 1. Department of Cardiology, Kanto Central Hospital of the Mutual Aid Association of Public School Teachers, 6-25-1 Kamiyoga, Setagaya-Ku, Tokyo, 58-8531, Japan. always_bj_ns@yahoo.co.jp. 2. Department of Cardiology, Kanto Central Hospital of the Mutual Aid Association of Public School Teachers, 6-25-1 Kamiyoga, Setagaya-Ku, Tokyo, 58-8531, Japan. 3. Department of Clinical Laboratory, Kanto Central Hospital of the Mutual Aid Association of Public School Teachers, 6-25-1 Kamiyoga, Setagaya-Ku, Tokyo, 58-8531, Japan.