Left Ventricular Regional Wall Motion in the Early Neonatal Period.

Abstract

To investigate the changes in regional wall motion of the left ventricle in the early neonatal period, serial echocardiography was performed in normal neonates at 2 and 120 hr after birth. Quantitative analysis of the regional wall motion was performed by the centerline method. We measured right ventricular systolic time intervals, left ventricular stroke volume, flow velocity-time integral of the pulmonary artery, and size of the ductus arteriosus. The ductus arteriosus was 4.5±0.5 mm at 2 hr but was closed in all subjects by 120 hr. At 2 hr, there was hyperkinesis of the interventricular septum which disappeared by 120 hr. The right ventricular systolic time intervals at 2 hr showed a sign of pulmonary hypertension. At 2 hr, the left ventricular stroke volume was at the highest level and the flow velocity-time intervals of pulmonary artery was at the lowest level. Thus the hyperkinesis of the interventricular septum at 2 hr might reflect the circulatory changes that are characteristic of the early neonatal period. echocardiography; neonate; left ventricular wall motionThe transition from the fetal to the neonatal circulatory status is accompanied by marked alteration of loading conditions. Two of the more important changes are the decrease in pulmonary artery pressure and the functional closure of the ductus arteriosus. The right ventricular pressure is approximately equal to the left ventricular pressure at birth and rapidly falls to near normal levels within a few days (Emmanouilides et al. 1964) In normal full-term neonates, the ductus arteriosus closes within the first day of life (Moss et al. 1963;Arcilla et al. 1967;Mahoney et al. 1985). These alterations after birth are considered to influence both global and regional performances of the left ventricle. Our previous studies demonstrated the changes in left ventricular function during the early neonatal period (Harada et al. 1994a, b; Takahashi et al. 1994a, b ) Although the left ventricular regional wall motion in normal newborns have been