Left ventricular systolic and diastolic function during early neonatal period using transthoracic echocardiography

To examine the effects of ductal closure on left ventricular (LV) systolic and diastolic function during the early neonatal periods, 45 normal term neonates delivered after uncomplicated pregnancies (mean 39 weeks) were studied using two-dimensional and Doppler echocardiography. We measured ductus arteriosus size, arterial blood pressures, ascending aortic size, LV dimensions, and transmitral flow velocity patterns and calculated LV output and rate-corrected fiber shortening fraction (mVcfc) at 2, 12, 24, and 120 hours after birth. The inner diameter of the ductus arteriosus was 4.3 +/- 0.7mm at 2 hours, 2.1 +/- 0.6 mm at 12 hours, and had closed in 42 of 45 neonates at 24 hours. LV output and LV end-diastolic dimension showed the highest level at 2 hours of age. However, the mVcfc did not change from 2 to 120 hours of age. The peak velocity during early diastole (peak E) was significantly greater at 2 hours than at 12 hours. The peak velocity during atrial contraction (peak A) remained unchanged during this period. The normalized peak filling rate at isovolumic relaxation time did not change over 120 hours. The present study demonstrated changes in LV systolic function and LV diastolic filling during the early neonatal period. LV systolic and diastolic function was preserved under the hemodynamic changes associated with the early neonatal period.