1. Department of Cardiology, Beijing Tian Tan Hospital, Capital Medical University, Beijing 100070, P.R. China
2. Department of Physiology and Pathophysiology, Capital Medical University, Beijing 100069, P.R. China
3. Department of Cardiology, Institute of Cardiovascular Disease, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China