Distinctive features of the functional geometry of the left ventricle in newborn infants

Significant structural and functional development of the heart occurs during the ontogenesis. Age-related features of the left ventricular (LV) functional geometry (FG), i.e. changes in the LV shape during the cardiac contractile cycle, are insufficiently studied. We assessed the differences in quantitative characteristics of LVFG between healthy adults and newborn infants of the first five days of life. We used classical 2D apical four-chamber position in ultrasound video loop to evaluate the following quantitative characteristics of the LVFG: spatial and temporal distributions of the two-dimensional estimate of the regional ejection fractions (REF) and respective indexes of heterogeneity of LV wall regional movements; dynamics of shape indexes (sphericity, conicity, shape-power index). We conclude that LVFG develops during the ontogenesis: LVFG mainly determines by heterogeneous developmenst of longitudinal and circular fibers of the myocardium.