Left ventricular regional wall motion in the early neonatal period.

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.