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 myocardial injury. MATERIALS AND METHODS Rabbits were injected with the endotoxin lipopolysaccharide (LPS). before and 2h, 4h, 6h, 8h, 12h after the injection of LPS, conventional echocardiography and STI were performed to measure left ventricular end diastolic diameter (LVDd), end-systolic diameter (LVDs), cardiac output (CO), left ventricular ejection fraction (EF), fractional shortening (FS), left ventricular global longitudinal strain (GLS)/GLS rate (GLSr), global circumferential strain/strain rate (GCS/GCSr), and the global radial strain/strain rate (GRS/GRSr). We also observed the injury with optical microscopy. Serum troponin cTnT and TUNEL assays determining myocardial apoptosis were also carried out to determine the induced injury levels. RESULTS None of the indicators measured are statistically different in the two groups before the LPS treatment (p > 0.05). 2h after LPS injection, 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 detection of abnormal myocardial contractility. It is a noninvasive, accurate and timely detection of myocardial dysfunction in sepsis.