Study Selection
All abstracts were reviewed by Nanjun Zhang, Linlin Zhang, Liting Tang, Shuran Shao, Qinhui Wang, Li Zhao, Xiaoliang Liu and checked by Chuan Wang. Disagreement was resolved between the two reviewers. Full texts of eligible articles were retrieved for review. If there are studies that report ultrasound methods for assessing LV chamber stiffness or myocardial stiffness, they should be included.