Y-T Zhao1, Y S Huang2, Z Yi3. 1. From the Department of Cardiology, Aerospace Center Hospital, 15 Yuquan Road, Beijing 100049, People's Republic of China. 2. Peking University Aerospace School of Clinical Medicine, Peking University Health Science Center, Beijing 100191, People's Republic of China. 3. From the Department of Cardiology, Aerospace Center Hospital, 15 Yuquan Road, Beijing 100049, People's Republic of China raas@hsc.pku.edu.cn.