1. Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, Japan
2. Department of Internal Medicine, Cardiovascular Division, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan
3. Division of Cardiology, St. Luke's International Hospital, Tokyo, Japan
4. Department of Internal Medicine, Senri Central Hospital, Suita, Japan
5. Tokyo Medical and Dental University, Tokyo, Japan