1. Department of Cardiology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
2. Department of Cardiology, Hengshui People’s Hospital, Hengshui, China
3. Department of Cardiology, Chengde Central Hospital, Chengde, China
4. Department of Cardiology, First Central Hospital of Baoding, Baoding, China
5. Department of Cardiology, Huabei Petroleum Administration Bureau General Hospital, Cangzhou, China
6. Department of Cardiology, First Hospital of Zhangjiakou, Zhangjiakou, China
7. Department of Cardiology, Affiliated Hospital of Chengde Medical University, Chengde, China
8. Department of Cardiology, First Hospital of Qinhuangdao, Qinhuangdao, China
9. Department of Cardiology, Cangzhou Central Hospital, Cangzhou, China
10. Department of Cardiology, Handan Central Hospital, Handan, China
11. Department of Cardiology, Xingtai People’s Hospital, Xingtai, China
12. Department of Cardiology, Shijiazhuang People’s Hospital, Shijiazhuang, China
13. Department of Cardiology, The 252nd Hospital of People’s Liberation Army, Baoding, China