Fetal regional myocardial strain rate in the membranous ventricular septum: changes with gestational age and the left ventricular mass and predictive value for a complete membranous ventricular septum (without defect)

Abstract

To describe the fetal regional myocardial strain rate in the membranous ventricular septum across gestation and to determine their predictive value for a complete membranous ventricular septum (without defect) after delivery. In 1150 fetuses, the peak systolic strain rate (SRs), peak early diastolic strain rate (SRe) and peak late diastolic strain rate (SRa) in the membranous ventricular septum were measured at four time points across gestation (18-20, 24-26, 30-32 and 36-38 weeks). The integrity of the interventricular septum was examined at 12 weeks' postnatal age. The correlations between myocardial strain rates and gestational age as well as fetal left ventricular mass were analyzed, and the performance of myocardial strain rates in predicting a complete membranous ventricular septum was deducted. Strain rate absolute values in the membranous ventricular septum all increased across gestation. They all significantly correlated with gestational age and left ventricular mass. At 24 weeks during pregnancy, the areas under the receiver operating characteristics curve (AUC) for SRe and SRa were all > 0.72 (p < 0.05) in predicting a complete membranous ventricular septum, while the AUC for SRs was only 0.55. The sensitivity, specificity and accuracy of the cut off value (> 1.53 s) for SRe was 62.5, 85.7 and 73.3%, respectively, and the sensitivity, specificity and accuracy of the cut off value (> 1.51 s) for SRa was 75.2, 71.9 and 73.8%, respectively. The changes of myocardial strain rates in the membranous ventricular septum across gestation maybe can be used to predict a complete membranous ventricular septum after delivery.

Advanced imaging of fetal cardiac function

“…Atrioventricular valve flow patterns can help to evaluate diastolic function by characterizing the biphasic E and A waves, their ratio, deceleration time, isovolumetric relaxation time and change with gestation ( 6 , 14 ), with normal E/A ratios usually <1 in the developing fetus ( 18 ). In congenital heart disease (CHD), abnormal and non-biphasic patterns can reflect pathologies like aortic stenosis, while reduced ratios may be seen in FGR and hydrops, although a high fetal heart rate can lead to the fusion of E and A waves ( 18 , 81 ). Tricuspid inflow, hepatic vein flow, lateral tricuspid annulus TDI, and collapsibility of the inferior vena cava help to define diastolic function ( 71 ), while the ejection force in the outflow tracts reflects systolic performance ( 6 ).…”

“…This variation in findings raises the possibility that the results of fetal strain imaging are likely to be dependent on equipment and software, as well as the study population and approach, emphasizing the importance of establishing standardized techniques. In addition to healthy pregnancies, strain has been measured in fetuses that are small for gestational age, and with FGR and ventricular septal defect ( 81 , 140 ). Fetal echocardiographic strain imaging has also been reported as an approach to assessing disease progression and determining the optimal timing of intervention in fetuses with maternal diabetes and pregnancies complicated by TTTS and fetal growth restriction ( 111 ).…”

“…In common with most non-invasive methods for assessing myocardial function, standard echocardiographic parameters such as ejection fraction or ventricular fractional area change are representative of the load-dependent pumping function of the ventricle, rather than cardiomyocyte contractility or changing cavity pressure in the fetal heart (79,80). Evaluation of strain rate, on the other hand, mainly reflects maturational changes in the myocardium while being relatively independent of loading conditions (81). Scoring systems like the fetal cardiovascular profile score (CVPS), shown in Figure 1, which incorporates cardiac functional indices with other imaging and Doppler findings including extracardiac vessels, as well as more specific measures of cardiac cycle intervals such as the myocardial performance index and Tei index have been established in the fetus (3,6,18,(82)(83)(84)(85)(86)(87)(88)(89).…”