PATHOPHYSIOLOGY AND NATURAL HISTORY ECHOCARDIOGRAPHY

ABSTRACT Qualitative and quantitative changes in left ventricular shapes were analyzed in 14 normal fetuses, 29 normal newborns, and 12 normal infants. Qualitative observations demonstrated that most fetuses and newboms with dominant right ventricles had flattened or even indented interven-tricular septae, which changed left ventricular shape into an ellipse. In contrast, left ventricular shapes in infants were round, similar to shapes described in older children and adults. When changes in shape or septal distortions were gross, interobserver agreement was 100%; when changes were less altered from a circular shape, interobserver agreement was 78%. To avoid subjective misinterpretations, quantitative analyses were performed, including M mode echocardiographic comparisons of right ventricular/left ventricular dimensions and left ventricular cavity anterior-posterior/lateral diameters, as well as Fourier analysis of digitized tracings of the entire left ventricular shape. The right ventricular/ left ventricular ratio, determined by M mode echocardiography, showed significant differences be-tween fetuses (1.07 + 0.07) and newborns (0.62 + 0.12) (p <.001). Infants had a significantly lower right ventricular/left ventricular ratio (0.45 + 0.01) when compared with newborns (p <.01). Ratios of left ventricular anterior-posterior/lateral diastolic diameters were significantly lower (p <.001) in newborns (0.66 + 0.08) when compared with those of infants (0.82 + 0. 10). All diameters tended t