1. Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Tokyo, Japan
2. Institute for Adult Diseases, Asahi Life Foundation, Tokyo, Japan
3. Department of Cardiology, Sakakibara Heart Institute, Tokyo, Japan
4. Department of Cardiology, Saiseikai Kumamoto Hospital, Kumamoto, Japan
5. The Heart Institute of Japan, Tokyo Women's Medical College, Tokyo, Japan
6. Department of Cardiology, Mitsui Memorial Hospital, Tokyo, Japan