Rintaro Hojo1, Seiji Fukamizu2, Harumizu Sakurada3. 1. Department of Cardiology, Tokyo Metropolitan Hiroo Hospital, 2-34-10, Ebisu, Shibuya-ku, Tokyo 150-0013, Japan rinrintaro1979@hotmail.co.jp. 2. Department of Cardiology, Tokyo Metropolitan Hiroo Hospital, 2-34-10, Ebisu, Shibuya-ku, Tokyo 150-0013, Japan. 3. Tokyo Metropolitan Health and Medical Treatment Corporation, Ohkubo Hospital, Tokyo 160-8488, Japan.