Evaluation of circumferential systolic function of left ventricle using speckle tracking imaging in healthy subjects

Objective To evaluate the left ventricular circumferential systolic function by speckle tracking imaging(STI)in healthy subjects.Methods Study population consisted of 35 healthy subjects(male 20,female 15)with mean age of(38.4±15.4)years.High frame rate two-dimensional(2D)images of three consecutive cardiac cycles were recorded from the left ventricular short-axis views at the levels of mitral annulus,papillary muscle and apex.2D images were transferred to Qlab 6.0 workstation for offline strain analysis.The peak systolic circumferential strain(CS)were measured in the left ventricu- lar short-axis views from 18 standard segments in the inner and outer layers of myocardium using two-dimensional strain software.Results The CS values of the inner layers showed higher than those of the outer layers at 18 segments(P0.05),especially in anteroseptal and posterior(P0.01).In the same level,the CS values of anteroseptal and inferior wall segment showed higher than those of the other segments.Conclusion Speckle tracking imaging technique is independent of insonation angle for assessing myocardial strain,illustrates a difference in CS between the inner and outer layers,has the po- tential to be used clinically in evaluation of LV regional myocardial systolic function.