1. Department of General Practice, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan 570102, P.R. China
2. Hainan Medical University, Haikou, Hainan 570000, P.R. China
3. Key Laboratory of Tropical Cardiovascular Diseases Research of Hainan Province, Key Laboratory of Emergency and Trauma of Ministry of Education, Research Unit of Island Emergency Medicine of Chinese Academy of Medical Sciences, Hainan Medical University, Haikou, Hainan 571199, P.R. China
4. Department of Cardiology, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan 570102, P.R. China