1. Department of Heart Intensive Care Unit, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116001, P.R. China
2. Department of Cardiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning 116001, P.R. China
3. Department of Cardiology, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
4. Department of Cardiology, Jiche Hospital of Dalian, Dalian, Liaoning 116021, P.R. China