Analysis of left ventricular regional wall motion in normal neonates.

OBJECTIVE To investigate neonatal circulatory change by quantitative analysis of left ventricular regional wall motion. DESIGN Random prospective study. SETTING Department of paediatrics in a teaching hospital. PARTICIPANTS 66 neonates born after a normal pregnancy, labour, and delivery. INTERVENTIONS Quantitative analysis of left ventricular regional wall motion was performed on cross sectional echocardiograms. M mode, cross sectional, and Doppler echocardiograms were obtained simultaneously. MAIN OUTCOME MEASURES Manually traced endocardial contours at end diastole and at end systole were realigned by superimposing the centre of the ventricular mass and the axis. The contours were divided into 24 segments with 24 radii of equal arc from the centre. Then the ratio of the change in area between the outline of the contour and the two hemiaxes was calculated automatically. RESULTS There was hyperkinesis of the interventricular septum in the first 24 hours after birth which continued until the end of the first week. Simultaneous echocardiographic examination showed evidence of pulmonary hypertension, as indicated by an increase in the ratio of the right pre-ejection period to the right ventricular ejection time (RPEP/RVET) and of the diameter ratio of the pulmonary artery to the aorta and a shortening of the acceleration time of pulmonary arterial blood flow. These features disappeared within a week. CONCLUSIONS Hyperkinesis of the interventricular septum may reflect circulatory changes that are characteristic of the early neonatal period.