1. No. 6 Ward of Cardiology, Daqing Oilfield General Hospital, Daqing 163001, PR China
2. No. 5 Ward of Cardiology, Daqing Oilfield General Hospital, Daqing 163001, PR China
3. Coronary Care Unit, The Second Affiliated Hospital of Dalian Medical University, Dalian 116027, PR China
4. No. 4 Ward of Cardiology, The Second Affiliated Hospital of Dalian Medical University, Dalian 116027, PR China