1. Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
2. Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California
3. Medical Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
4. Department of Cardiology, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan
5. Department of Cardiology, National Hospital Organization Saitama Hospital, Wako, Saitama, Japan
6. Department of Cardiology, Japanese Red Cross Ashikaga Hospital, Ashikaga, Tochigi, Japan