1. Tachikawa Medical Center, Niigata University, Kandacho, 3-2-1, Nagaoka, Niigata, Japan
2. Cardiology, Tachikawa General Hospital, 3-2-11 Kandacho, Nagaoka, Japan
3. Internal Medicine, Keio University, School of Medicine, 35 Shinanomachi, Shinjuku-kum, Tokyo, Japan