| Abstract:Objective：To explore the effects of heart rate on two-dimensional speckle tracking imaging (2D-STI) parameters in evaluating left ventricular longitudinal, circumferential and radial systolic myocardial deformation in hypertensive rabbit models. Methods：24 New Zealand rabbits were randomly divided into 2 groups: the abdominal aortic constriction (AAC) group (n=12), and the sham operation group (n=12). The ACC group underwent the abdominal aortic constriction surgery while in the sham operation group, only the silk thread was placed below the abdominal aorta, and the abdominal aorta was not ligated. The longitudinal, circumferential and radial strains were analyzed by 2D-STI technique after 8 weeks of surgery.Results：Compared with the sham operation group, hypertensive rabbits had an increased left atrial internal dimension and increased left ventricular internal dimension (P＜0.05), a thickened interventricular septum and left ventricular wall (P＜0.05). In terms of strain, the longitudinal systolic strain of the left ventricle decreased (P< 0.05), the radial strain decreased (P<0.05), and the circumferential strain remained unchanged in the rabbit models of abdominal aortic constriction.Conclusions：In hypertensive rabbit models, the left ventricular longitudinal and radial strains were easily affected, which illustrated that heart rate had little effect on the systolic function parameters measured by 2D-STI. |