Evaluation Of Strain Rate In Different Layers Of Left Ventricular Myocardium In Hypertensive Individuals Using Velocity Vector Imaging

Objects: To evaluate strain rate (SR) in different layers (endocardium and epicardium) of left ventricular myocardium of normal people and essential hypertensive patients using velocity vector imaging (VVI). The objective is to explore its clinical value in the non-invasive evaluation of patients with essential hypertension of early changes in cardiac function.Methods: SR data were obtained from the left mid ventricular short-axis view in 22 healthy people and 39 patients with essential hypertension using VVI. Hypertensive patients were divided into two groups according to left ventricular mass index (LVMI): 18 patients with left ventricular hypertrophy (LVH); 21 patients who had no left ventricular hypertrophy (NLVH). LVH group: LVMI≥134 g/ m2 (M), LVMI≥110 g/ m2 (F). Using Acuson Sequoia C512 ultrasonograph, conventional measurements were measured by the echocardiography. To start VVI model, dynamic two- dimensional gray- scale images of three consecutive cardiac cycle were memoried from the different left ventricular walls at the mid ventricular short-axis view. The segmental circumferential systolic peak SR (SRs) in the endocardial (SRendo), epicardial (SRepi) layers were analyzed by offline software.Results: The circumferential SRs of six segments decreased significantly from the endocardium to the epicardium in the hypertension group and in the control group (P<0.01). SRendo of interventricular septum in LVH group was lower than in NLVH group, Normal group and the remaining segments of LVH group (P<0.05). SRendo appeared no significant difference in NLVH group and Normal group. SRepi appeared no significant difference in three groups and six segments of every group (P>0.05).Conclusions: VVI is useful in evaluating regional myocardial function of systole. Strain rate is different between endocardial and epicardial layer of the left ventricular myocardium in the mid short-axis view. SR is useful in evaluating the left ventricular myocardium function of systole in hypertensive patients with left ventricular hypertrophy.