Two-dimensional speckle tracking imaging detects impaired myocardial performance in children with septic shock, not recognized by conventional echocardiography*

Abstract

Sepsis is common in children and often results in cardiac dysfunction. Assessment of patients with sepsis-associated myocardial depression using ejection fraction and fractional shortening with conventional echocardiography is load dependent and often reveals cardiac dysfunction only after clinical deterioration has occurred. Speckle tracking imaging is a novel technology that can assess deformation and strain by tracking displacement of acoustic markers in the myocardium. We hypothesize that speckle tracking imaging will detect cardiac impairments during sepsis that are not appreciated by conventional echocardiography. Retrospective, observational study. A large, tertiary-care pediatric intensive care unit. Fifteen pediatric patients with septic shock, and 30 age- and gender-matched healthy controls. Transthoracic echocardiograms from subjects with septic shock (by American College of Chest Physicians/Society of Critical Care Medicine consensus criteria) and controls were evaluated. Speckle tracking imaging was used to obtain tissue displacement, velocity, strain, and strain rate in radial, longitudinal, and circumferential planes. Ejection fraction and fractional shortening were determined by conventional methods. Comparisons between groups were made using a paired t test. Compared to control subjects, children with septic shock demonstrated impaired myocardial performance as quantified by speckle tracking imaging. Significant differences were seen in circumferential and longitudinal strain (p < .001), strain rate (p < .05), radial displacement (p < .001), and rotational velocity and displacement (p < .01). There was no significant difference in ejection fraction and fractional shortening between septic patients and controls. Speckle tracking imaging detected a number of significantly impaired measures of ventricular performance in children with sepsis, not appreciated by conventional echocardiography. This technology may improve our understanding and identification of myocardial depression in the critically ill septic child.