1. Department of Geriatric Medicine; Xiangya Hospital, Central South University; Changsha; Hunan, P.R.; China
2. Department of Cardiology; the Second Xiangya Hospital, Central South University; Changsha; Hunan, P.R.; China
3. Department of Emergency; the Second Xiangya Hospital, Central South University; Changsha; Hunan, P.R.; China