Correspondence to: Jian-Cheng ZHANG MD, Provincial Clinical Medicine College of Fujian Medical University, Fuzhou 350001, Fujian, China. Emails: fjzhang:jiancheng@yahoo.com.cn (ZHANG JC) Correspondence to: Yang LI, MD, Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, China; Emails: liyangbsh@163.com (LI Y)