Functional Geometry of the Left Ventricle in Term Newborns with Different Birth Weights

Resumo

Ontogenesis is associated with significant changes in the structure and function of the left ventricle (LV). The functional geometry of the LV concerns the dynamic changes in the ventricular shape during contraction and relaxation. The purpose of this study was to evaluate the LV functional geometry in term newborns with normal and low birth weights and to evaluate the heart maturation in newborns as compared with adults. A total of 24 healthy adults, 35 term singleton newborns and 40 term twin newborns were examined using 2D echocardiography. Systolic changes in the LV segmental areas were evaluated, and dynamic changes in the LV shape during the cardiac cycle were specified. The spatial heterogeneity in regional movements of the LV wall was higher and LV shape indexes were more complex than in adults. A negative correlation between the ejection fraction and spatial heterogeneity was found in all groups. No significant dependence was observed between the birth weight and the LV functional geometry characteristics in newborns with normal and low birth weights. The results suggest that regular temporal and spatial coordination of LV wall movements is not completely developed in newborns. No significant dependence was observed between the birth weight and the LV functional geometry characteristics in term newborns.