Analysis of left ventricular circumferential strain in patients with left bundle branch block by layer-specific speckle tracking imaging / 中华超声影像学杂志

ABSTRACT

Objective To evaluate the left ventricular systolic circumferential strain by layer specific speckle tracking imaging in healthy volunteers and patients with left bundle branch block (LBBB).Methods Forty patients with LBBB were divided into two groups,LBBB1 group [left ventricular ejection fraction (LVEF≥50％] and LBBB2 group (LVEF＜50％),and 25 healthy subjects were selected as the control group.High frame rate two dimensional images were recorded from the left ventricular short-axis views at the levels of the mitral annulus,papillary muscle and apex respectively.The peak systolic circumferential strain of the endocardium,myocardium and epicardium were measured using layer-specific strain software.Results The circumferential strain of the epicardium and myocardium at the level of the apex showed a statistically significant difference between the LBBB1 group and the control group (P =0.004),while there was no statistically significant difference demonstrated at the levels of the mitral annulus and papillary muscle(P ＞0.01).The circumferential strain of the endocardium at the levels of the papillary muscle and apex showed a statistically significant difference between the LBBB1 group and the control group (P =0.000),while there was no statistically significant difference demonstrated at the level of the mitral annulus (P ＞0.01).The circumferential strain of the endocardium,myocardium and epicardium at the three short axis view levels showed statistically significant differences between the LBBB2 group and the control or LBBB1 groups respectively(P =0.000).Conclusions The circumferential strain of the endocardium at the level of the apex can provide more information about disease prognosis,especially in LBBB patients with a LVEF of ≥50％.