1. Department of Cardiology, Sakakibara Heart Institute , 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003 , Japan
2. Department of Cardiovascular Medicine, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 , Japan
3. Department of Cardiovascular Medicine, Toho University Faculty of Medicine , 6-11-1 Omori-Nishi, Ota-ku, Tokyo 143-8541 , Japan
4. Sakakibara Heart Institute , 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003 , Japan