1. Department of Cardiology, Urasoe General Hospital , 1-56-1/Maeda Urasoe City, Okinawa 9012102 , Japan
2. Department of Clinical Research Education and Management, University of Ryukyus Graduate School of Medicine , 207 Uebaru Nishihara town, Okinawa 9030215 , Japan
3. Department of Cardiology, Tenyoukai Central Hospital , Kagoshima , Japan
4. Department of Cardiology, Yuai Medical Center Hospital , Okinawa , Japan
5. Department of Cardiology, Naha City Hospital , Okinawa , Japan
6. Department of Cardiology, Hosogi hospital , Kochi , Japan