ABSTRACT
Objective To analyze the strains of patients with hypertrophic cardiomyopathy (HCM) by vector velocity imaging(VVI),and to identify abnormal early systolic function.Methods Forty patients with HCM (HCM group) and 25 healthy subjects (control group) were enrolled.Standard two-dimensional echocardiography was performed.Left ventricular ejection fraction (LVEF),diameters and wall thickness were measured.Peak systolic strains in all directions and their time to peak were analyzed off-line.Results ①All but the endocardial circumferential strain were apparently smaller in HCM group than those in the control group(P ＜0.000 1).The difference was greater in long axis than that in short axis.②The HCM group maintained the characteristics of strain gradient as the control group,including the endocardiumepicardium gradient with endocardial strains was significantly greater than epicardial ones and the base-apex gradient,among which epicardial longitudinal strain decreased from the base to the apex and endocardial circumferential strain increased toward the apex.③The HCM group suffered significant dyssynchrony in terms of strain and rotation,with greater changes in longitudinal than in short axis,in epicardium than in endocardium.Conclusions VVI offers an overall assessment of regional and global left ventricular systolic function,including longitudinal and circumferential strain.Moreover,it can be used to evaluate subclinical systolic dysfunction and dyssynchrony in patients with HCM.
ABSTRACT
Objective To evaluate the left ventricular(LV) torsion and rotation in normal subjects using vector velocity imaging.Methods LV basal and apical short-axis images were captured in 10 healthy individuals to estimate LV torsion and rotation using routine 2-dimensional echocardiography and vector velocity imaging. Results As viewed from LV apex,the systolic basal rotation was clockwise (negative value),and apical rotation was counterclockwise (positive Value). The apical peak systolic rotational velocity was significantly higher than the basal [endo:(150±62)°/s vs (114±65)°/s;epi:(81±40)°/s vs (55±28)°s,respectively,P＜0.01]. The peak systolic endocardial rotational velocity and rotation was significantly higher than epicardial rotational velocity and rotation[basal:(-114±65)°/s vs (-55±28)°/s,(-12±6)°vs (-4±1)°;apical:(150±62)°s vs (81±40)°s,(10±4)°vs(6±2)°,respectivelv,P＜0.05]. There were no significant differences in the time to peak systolic rotational velocity/rotation between basal endocardium/epicardium and apical endocardium/epicardium. Conclusions Vector velocity imaging can assess LV torsion and rotation non-invasively,and normal LV has a kind of characteristic motion of torsion.