Single-segment velocity vector imaging for assessing sepsis-induced cardiac dysfunction: an exploratory feasibility study

Sepsis-induced cardiac dysfunction is associated with poor clinical outcomes, but conventional echocardiographic parameters may be insufficiently sensitive for detecting early or subtle myocardial impairment. Velocity vector imaging (VVI), a speckle-tracking-based technique, can quantify myocardial deformation. This exploratory feasibility study investigated whether single-segment VVI of the left ventricular posterior wall could help assess sepsis-induced cardiac dysfunction in mice and patients. A mouse model of sepsis was established by cecal ligation and puncture (CLP). Temporal and segmental ultrastructural changes in myocardial tissue were evaluated by transmission electron microscopy. Based on the absence of obvious segmental differences in myocardial injury, the left ventricular posterior wall was selected for single-segment VVI analysis. Conventional echocardiography and VVI were performed in septic mice and in a prospective exploratory clinical cohort of patients with sepsis and matched healthy controls. In septic mice, myocardial electron microscopy and semiquantitative analysis showed aggravation of myocardial damage with time, with no significant difference among myocardial segments ( P > 0.05). VVI-derived strain parameters showed significant changes at 6 h ( P < 0.001) and 24 h ( P < 0.0001) after CLP. In septic patients, the strains of the VVI in systole and diastole were significantly lower than those in the control group ( P < 0.0001), whereas FS and EF showed non-significant decreasing trends. Among the VVI parameters, longitudinal strain in diastole (L-Sd) showed the most pronounced reduction. L-Sd showed moderate preliminary prognostic value for mortality in this small exploratory cohort, and the combination of L-Sd and L-Ss yielded a modestly higher AUC. Sepsis-induced myocardial injury in mice showed global microstructural involvement without obvious segmental differences. Single-segment VVI of the left ventricular posterior wall may provide a feasible and potentially sensitive approach for detecting myocardial deformation abnormalities in sepsis. The preliminary prognostic value of L-Sd requires further validation in larger, multicenter studies with comprehensive global strain analysis and multivariable adjustment.