Myocardial Velocities, Dynamics of the Septum Primum, and Placental Dysfunction in Fetuses with Growth Restriction

Abstract

Diastolic dysfunction may occur in fetuses with intrauterine growth restriction (IUGR) and may be assessed by myocardial tissue Doppler (MTD). We previously have shown that excursion index of the septum primum (EISP) is reduced in IUGR fetuses over 30 weeks because of a higher left atrial pressure. The sample was made up of 14 fetuses with IUGR. MTD examination was carried out with the sample volume placed at the basal lateral wall of the left ventricle (LV), interventricular septum (IVS), and free wall of the right ventricle (RV) to determine E'/A' ratios. EISP was calculated as the ratio between the maximal excursion of the septum primum into the left atrium during diastole and the maximal diastolic diameter of the left atrium. Mitral and tricuspid flows were assessed by the conventional Doppler method. Pearson's correlation test was used to analyze the correlations between the parameters. A positive correlation was observed between UARI and E'/A' ratios for RV (r = 0.63, P = .02), IVS (r = 0.59, P = .03), and LV (r = 0.41, P = .15). There was a negative correlation between EISP and IVS E'/A' ratios (r = -0.58, P = .03), and a positive correlation for LV (r = 0.49, P = .08). At the RV position, a weak negative correlation was observed (r = -0.32, P = .26). A higher left atrial pressure in fetuses with IUGR, indicated by the lower mobility of the septum primum, is accompanied by higher ratios between early and late diastolic myocardial velocities. Placental dysfunction was correlated to septal E'/A' ratios. Fetal MTD can be a useful method to assess severity of placental dysfunction and fetal distress.