1. Department of Cardiology, The Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524000, P.R. China
2. First Operating Room, The First Affiliated Hospital of Jilin University, Changchun, Jilin 130000, P.R. China
3. Department of Obstetrics and Gynecology, The Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524000, P.R. China