1. Department of Cardiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
2. Department of Cardiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
3. Department of Cardiology, Daoxian People's Hospital, Yongzhou, Hunan 425300, P.R. China