Changes in ventricular and muscle volumes of neonates

Background: To examine the changes in cardiac ventricular and muscle volumes in neonates, echocardiography was performed in 25 normal neonates at 3-5 and 30-35 days after birth. Methods: A standard apical four chamber view and a parasternal short axis view were used for the analysis of the left ventricle. For the analysis of the right ventricle, only an apical four- chamber view was used. A formula based on the area length method was used to calculate the left ventricular and muscle volumes and the single plane Simpson's role was used for the right ventricular and muscle volumes. Results: The left ventricular and muscle volumes per body surface did not change during the month following birth. The ratio of the muscle to ventricular volume of the left ventricle was also unchanged. However, the ratios of the right muscle volume to body surface and to the ventricular volume decreased after one month. Conclusions: The authors suggest that the decreases in pulmonary hypertension and right ventricular stroke volume play a role in the changes of right muscle volume.