1. Division of Cardiovascular Surgery, Oita Prefectural Hospital, Oita City, Oita, Japan
2. Division of Cardiovascular Surgery, Nagasaki University Hospital, Nagasaki City, Nagasaki, Japan
3. Division of Cardiology, Aso Iizuka Hospital, Iizuka City, Fukuoka, Japan
4. Division of Cardiology, Oita Prefectural Hospital, Oita City, Oita, Japan