ABSTRACT
First trimester nuchal translucency (NT) and ductus venosus reverse blood flow (DVRBF) are used as ultrasound markers (UM) to determine the risk of fetal aneuploidy, heart defects and subsequent maternal preeclampsia. One pathophysiological explanation for these UM, encompassing both normal and pathological outcomes, is the development of transient heart failure due to increased vascular resistance (afterload). Left ventricular isovolumic relaxation time (LV IRT) was demonstrated as sensitive index of afterload increase in the second and third trimester fetus. The objective of study was to determine LV IRT in normally developing embryos and embryos with early UM of chromosomal and cardiac abnormalities and to test the hypothesis of embryonic hypertension as a cause of transient heart failure. An ultrasound study in 122 normally developing and 27 human embryos with increased NT (>3 mm) and DVRBF at gestational ages 11-14 weeks was perfomed. Mean LV IRT (41 +/- 3 ms) was 36.6 percent longer in embryos with UM as compared to the normal subset (30 +/- 2 ms) (p < 0.001).
