The strains of all segments could be analyzed in 136 of 180 children. There were no significant age-related changes in circumferential or radial strain in children, but regional heterogeneity in left ventricular strain. The circumferential and radial strains showed inverse distributions; the circumferential strain in the region with low radial strain was high, and that in the region with high radial strain was low. These observations indicated there are differences among the three-dimensional movements of the regions.

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The age-related changes suggest age-related alterations in left ventricular diastolic function. Right ventricular diastolic function is constant after birth.

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The purpose of this study was to assess cardiac function of newborns with mild asphyxia by a Doppler-derived index combining systolic and diastolic performance (Tei index). We studied 20 preterm infants with mild asphyxia. A control group consisted of 20 gestational age-matched preterm infants without asphyxia. Echocardiograms were performed during the fourth and seventh days after birth. Peak velocities of an early filling wave (E) and an atrial contraction wave (A) were measured from the mitral inflow velocity profile and the ratio of peak E to A was calculated. Ejection time was measured from the left ventricular outflow Doppler signal. The sum of isovolumetric times was obtained by subtracting the ejection time from the interval between cessation and onset of mitral inflow. The index was the sum of isovolumetric times divided by ejection time. Ejection fraction was also calculated. The ratio of peak E to A and ejection fraction were the same in both groups. The myocardial performance index in patients with asphyxia was higher than that in patients without asphyxia. We concluded that patients with mild asphyxia have a mild cardiac dysfunction and this change can be detected by a myocardial performance index.