2D speckle tracking imaging to assess sepsis induced early systolic myocardial dysfunction and its underlying mechanisms

OBJECTIVE : The aim of this study was to apply speckle tracking imaging (STI) to evaluate rabbit sepsis induced myocar - dial injury. MATERIALS AND METHODS: Rabbits were injected with the endotoxin lipopolysaccharide (LPS). before and 2h, 4h, 6h, 8h, 12h after the in - jection of LPS, conventional echocardiography and STI were performed to measure left ventric - ular end diastolic diameter (LVDd), end-systolic diameter (LVDs), cardiac output (CO), left ven - tricular ejection fraction (EF), fractional shorten - ing (FS), left ventricular global longitudinal strain (GLS)/GLS rate (GLSr), global circumfer - ential strain/strain rate (GCS/GCSr), and the global radial strain/strain rate (GRS/GRSr). We also observed the injury with optical mi - croscopy. Serum troponin cTnT and TUNEL as - says determining myocardial apoptosis were al - so carried out to determine the induced injury levels. RESULTS: None of the indicators measured are statistically different in the two groups be - fore the LPS treatment ( p > 0.05). 2h after LPS in - jection, in LPS treated group, only GLS/GLSr, GCS/GCSr significantly reduced compared to the control group ( p < 0.05). 6h, 8h, 12h after LPS injection, EF and FS were lower ( p < 0.05), LVDd and LVDs were higher ( p < 0.05), and GLS/GLSr, GCS/GCSr, GRS/GRSr were significantly lower ( p < 0.05). LPS significantly elevated serum cTnT level in the experimental group ( p < 0.05). In the LPS treated group, we found pathological changes of the myocardium. CONCLUSIONS: STI is more sensitive than the conventional echocardiography for the early de - tection of abnormal myocardial contractility. It is a noninvasive, accurate and timely detection of myocardial dysfunction in sepsis .