HFSCCD: A Hybrid Neural Network for Fetal Standard Cardiac Cycle Detection in Ultrasound Videos

In the fetal cardiac ultrasound examination, standard cardiac cycle (SCC) recognition is the essential foundation for diagnosing congenital heart disease. Previous studies have mostly focused on the detection of adult CCs, which may not be applicable to the fetus. In clinical practice, localization of SCCs needs to recognize end-systole (ES) and end-diastole (ED) frames accurately, ensuring that every frame in the cycle is a standard view. Most existing methods are not based on the detection of key anatomical structures, which may not recognize irrelevant views and background frames, results containing non-standard frames, or even it does not work in clinical practice. We propose an end-to-end hybrid neural network based on an object detector to detect SCCs from fetal ultrasound videos efficiently, which consists of 3 modules, namely Anatomical Structure Detection (ASD), Cardiac Cycle Localization (CCL), and Standard Plane Recognition (SPR). Specifically, ASD uses an object detector to identify 9 key anatomical structures, 3 cardiac motion phases, and the corresponding confidence scores from fetal ultrasound videos. On this basis, we propose a joint probability method in the CCL to learn the cardiac motion cycle based on the 3 cardiac motion phases. In SPR, to reduce the impact of structure detection errors on the accuracy of the standard plane recognition, we use XGBoost algorithm to learn the relation knowledge of the detected anatomical structures. We evaluate our method on the test fetal ultrasound video datasets and clinical examination cases and achieve remarkable results. This study may pave the way for clinical practices.

An intelligent quantification system for fetal heart rhythm assessment: A multicenter prospective study

BACKGROUND

The motion relationship and time intervals of the pulsed-wave Doppler (PWD) spectrum are essential for diagnosing fetal arrhythmia. However, few technologies currently are available to automatically calculate fetal cardiac time intervals (CTIs).

OBJECTIVE

The purpose of this study was to develop a fetal heart rhythm intelligent quantification system (HR-IQS) for the automatic extraction of CTIs and establish the normal reference range for fetal CTIs.

METHODS

A total of 6498 PWD spectrums of 2630 fetuses over the junction between the left ventricular inflow and outflow tracts were recorded across 14 centers. E, A, and V waves were manually labeled by 3 experienced fetal cardiologists, with 17 CTIs extracted. Five-fold cross-validation was performed for training and testing of the deep learning model. Agreement between the manual and HR-IQS-based values was evaluated using the intraclass correlation coefficient and Spearman's rank correlation coefficient. The Jarque-Bera test was applied to evaluate the normality of CTIs' distributions, and the normal reference range of 17 CTIs was established with quantile regression. Arrhythmia subset was compared with the non-arrhythmia subset using the Mann-Whitney U test.

RESULTS

Significant positive correlation (P <.001) and moderate-to-excellent consistency (P <.001) between the manual and HR-IQS automated measurements of CTIs was found. The distribution of CTIs was non-normal (P <.001). The normal range (2.5th to 97.5th percentiles) was successfully established for the 17 CTIs.

CONCLUSIONS

Using our HR-IQS is feasible for the automated calculation of CTIs in practice and thus could provide a promising tool for the assessment of fetal rhythm and function.

Fully Automatic Classification of Cardiotocographic Signals with 1D-CNN and Bi-directional GRU

Prenatal fetal monitoring, which can monitor the growth and health of the fetus, is vital for pregnant women before delivery. During pregnancy, it is essential to classify whether the fetus is abnormal, which helps physicians carry out early intervention to avoid fetal heart hypoxia and even death. Fetal heart rate and uterine contraction signals obtained by fetal heart monitoring equipment are essential to estimate fetal health status. In this paper, we pre-process the obtained data set and enhance them using Hermite interpolation on the abnormal classification in the samples. We use the 1D-CNN and GRU hybrid models to extract the abstract features of fetal heart rate and uterine contraction signals. Several evaluation metrics are used for evaluation, and the accuracy is 96 %, while the sensitivity is 95 %, and the specificity is 96 %. The experiments show the effectiveness of the proposed method, which can provide physicians and users with more stable, efficient, and convenient diagnosis and decision support.

Diagnostic quality of 3Tesla postmortem magnetic resonance imaging in fetuses with and without congenital heart disease

BACKGROUND

Postmortem confirmation of prenatally diagnosed congenital heart disease after termination of pregnancy and evaluation of potential cardiac defects after spontaneous fetal or neonatal death are essential. Conventional autopsy rates are decreasing, and 1.5Tesla magnetic resonance imaging has demonstrated limited diagnostic accuracy for postmortem cardiovascular assessment.

OBJECTIVE

This study aimed to evaluate the feasibility and image quality of cardiac 3Tesla postmortem magnetic resonance imaging and to assess its diagnostic accuracy in detecting fetal heart defects compared with conventional autopsy. Secondarily, the study aimed to explore whether clinical factors affect the quality of 3Tesla postmortem magnetic resonance imaging.

STUDY DESIGN

A total of 222 consecutive fetuses between 12 and 41 weeks' gestation, who underwent 3Tesla postmortem magnetic resonance imaging and conventional autopsy after spontaneous death or termination of pregnancy for fetal malformations, were included. First, 3Tesla postmortem magnetic resonance imaging of each fetus was rated as diagnostic or nondiagnostic for fetal cardiac assessment by 2 independent raters. The image quality of individual cardiac structures was then further evaluated by visual grading analysis. Finally, the presence or absence of a congenital heart defect was assessed by 2 radiologists and compared with autopsy results.

RESULTS

Overall, 87.8% of 3Tesla postmortem magnetic resonance imaging examinations were rated as diagnostic for the fetal heart. Diagnostic imaging rates of individual cardiac structures at 3Tesla postmortem magnetic resonance imaging ranged from 85.1% (atrioventricular valves) to 94.6% (pericardium), with an interrater agreement of 0.82 (0.78-0.86). Diagnostic imaging of the fetal aortic arch and the systemic veins at 3Tesla postmortem magnetic resonance imaging was possible from 12+5 weeks' gestation onward in 90.1% and 92.3% of cases, respectively. A total of 55 fetuses (24.8%) had at least 1 cardiac anomaly according to autopsy, 164 (73.9%) had a normal heart, and in 3 fetuses (1.4%), autopsy was nondiagnostic for the heart. Considering all examinations rated as diagnostic, 3Tesla postmortem magnetic resonance imaging provided high diagnostic accuracy for the detection of fetal congenital heart defects with a sensitivity of 87.8%, a specificity of 97.9%, and concordance with autopsy of 95.3%. 3Tesla postmortem magnetic resonance imaging was less accurate in young fetuses (<20 weeks compared with ≥20 weeks; P<.001), in fetuses with low birthweight (≤100 g compared with >100 g; P<.001), in cases after spontaneous fetal death (compared with other modes of death; P=.012), in cases with increasing latency between death and 3Tesla postmortem magnetic resonance imaging (P<.001), and in cases in which there was a high degree of maceration (maceration score of 3 compared with a score from 0 to 2; P=.004).

CONCLUSION

Diagnostic 3Tesla postmortem magnetic resonance imaging assessment of the fetal heart is feasible in most fetuses from 12 weeks' gestation onward. In diagnostic images, sensitivity and, particularly, specificity in the detection of congenital heart disease are high compared with conventional autopsy. Owing to its high diagnostic accuracy, we suggest that 3Tesla postmortem magnetic resonance imaging may serve as a suitable imaging modality with which to direct a targeted conventional autopsy when pathology resources are limited or to provide a virtual autopsy when full autopsy is declined by the parents.

Assessment of fetal cardiac diastolic function of gestational diabetes mellitus using dual-gate Doppler

Gestational Diabetes Mellitus (GDM), as a common complication of pregnancy, has an increasing trend globally. GDM leads to maternal complications and fetal complications. Fetal cardiac diastolic dysfunction is strongly associated with GDM. This study aims to assess the ventricular diastolic function of fetuses exposed to GDM by looking into the diagnostic parameters using both conventional method and Dual-gate Doppler method (DD). And to investigate the potential of DD method in early detection of fetal cardiac diastolic dysfunction.56 women diagnosed with GDM and 55 non-GDM pregnant women were enrolled in their 24 to 30 weeks of gestation. Conventional method and DD method were applied to measure mitral and tricuspid inflow velocities E-waves, A-waves on pulsed-wave Doppler, and mitral and tricuspid annular velocities e'-waves, a'-waves on Tissue Doppler imaging. E/A, e'/a' and E/e' ratio was calculated. The difference between GDM and control groups was statistically tested and analysed using one-sample Kolmogorov-Smirnov test, Student t test, Mann-Whitney U test and Kruskal-Wallis test and Bland-Altman plot analysis.Intraobserver intraclass correlation coefficients of E/A, e'/a', and E/e' value of both mitral and tricuspid valve are all greater than 0.80, while interobserver intraclass correlation coefficients are between 0.71 and 0.88. Right (6.35 vs 6.79; P = .001) ventricular function showed significantly lower E/e' ratios in the GDM group compared with control fetuses by conventional method. Both left (6.16 vs 6.59; P = .036) and right (6.28 vs 6.75; P = .01) ventricular function showed significantly lower E/e' ratios in the GDM group compared with control fetuses by DD method.Exposure to high level of maternal blood glucose leads to impaired diastolic function in the fetuses. Fetal right ventricular function is a potential key point to study to enable an early detection for fetal diastolic dysfunction since the alteration and damage are more likely to happen in right ventricular. Measurement of E/e' ratio using DD method is considered as a promising method in fetal cardiac diastolic function assessment. Well or poorly control of the GDM does not have significant influence on the fetal diastolic function thus an early detection of GDM and GDM induced fetal cardiac dysfunction is necessary.

Doppler ultrasound measurements of the blood flow velocity in the fetal heart and aorta in Bulgarian White milk goats

The aim of the present study was to determine the parameters characterising the blood flow velocity in the fetal heart and aorta in goats by Doppler ultrasonography. Twenty-four Bulgarian White milk goats, aged 4-6 years, weighing 45-51 kg were used in the study. Doppler ultrasound measurements of the blood flow velocity in fetal heart were done at the end of first, second and third trimesters of pregnancy, and in the fetal aorta - at the end of the second and third trimesters of pregnancy. Ultrasound investigations were carried out by transabdominal approach with linear and convex transducers, with frequency 8.0 MHz. Blood flow parameters that included maximum and minimum systolic velocity, end-diastolic velocity, pulsatility index, resistance index and systolic/diastolic ratio were measured by spectral Doppler ultrasonography. The results showed that the highest maximum systolic velocity in the fetal heart was observed at the end of the first pregnancy trimester. Statistically significantly (p < 0.05) lower values of this parameter were registered in the second and third pregnancy trimesters. A similar tendency was observed for minimum systolic velocity, end-diastolic velocity and systolic/diastolic ratio. The pulsatility index and resistance index had similar values for the three studied periods. Examination of the fetal aorta showed statistically significant differences (p < 0.05) of minimum systolic velocity, end-diastolic velocity, pulsatility and resistance index in the third, compared with the second trimester of pregnancy. The analysis of the results suggested that Doppler ultrasonography can be used to monitor fetal blood flow changes during the various stages of pregnancy.

Impact of pulsed-wave-Doppler velocity-envelope tracing techniques on classification of complete fetal cardiac cycles

Fetal echocardiography is an operator-dependent examination technique requiring a high level of expertise. Pulsed-wave Doppler (PWD) is often used as a reference for the mechanical activity of the heart, from which several quantitative parameters can be extracted. These aspects suggest the development of software tools that can reliably identify complete and clinically meaningful fetal cardiac cycles that can enable their automatic measurement. Several scientific works have addressed the tracing of the PWD velocity envelope. In this work, we assess the different steps involved in the signal processing chains that enable PWD envelope tracing. We apply a supervised classifier trained on envelopes traced by different signal processing chains for distinguishing complete and measurable PWD heartbeats from incomplete or malformed ones, which makes it possible to determine the impact of each of the different processing steps on the detection accuracy. In this study, we collected 43 images and labeled 174,319 PWD segments from 25 pregnant women volunteers. By considering seven envelope tracing techniques and the 23 different processing steps involved in their implementation, the results of our study reveal that, compared to the steps investigated in most other works, those that achieve binarisation and envelope extraction are significantly more important (p < 0.05). The best approaches among those studied enabled greater than 98% accuracy on our large manually annotated dataset.

A 24-segment fractional shortening of the fetal heart using FetalHQ

OBJECTIVES

To evaluate 24-segment fractional shortening (FS) of the fetal heart using FetalHQ by speckle-tracking regarding reproducibility and the change with advancing gestation.

METHODS

Eighty-one pregnant women at 18-21+6 and 28-31+6 weeks of gestation were studied using FetalHQ with the speckle-tracking technique to calculate 24-segment FS of left and right ventricles. Intra- and inter-class correlation coefficients and intra- and inter-observer agreements of measurements for FS were assessed in each segment.

RESULTS

With respect to intra-observer reproducibility, all FS values showed correlations between 0.575 and 0.862 for the left ventricle, with good intra-observer agreements except for left ventricular segments 14-24. Right ventricular FS values showed correlations between 0.334 and 0.685, with good intra-observer agreements. With respect to inter-observer reproducibility, all FS values showed correlations between 0.491 and 0.801 for the left ventricle, with good intra-observer agreements except for left ventricular segments 16-22. Right ventricular FS values showed correlations between 0.375 and 0.575, with good inter-observer agreements. There were significant differences in the mean FS values in the basal segment (segments 1-5) of the left ventricle between 18 and 21+6 and 28-31+6 weeks of gestation (p<0.05), whereas there were significant differences in all mean FS values in the right ventricle between both gestational ages (p<0.05).

CONCLUSIONS

These results suggest that the reproducibility of the 24-segment FS of the fetal heart using FetalHQ is fair. However, there may be significant differences in FS values with advancing gestational age, especially for the right ventricle.

Measurement of fetal automated fractional shortening using two-dimensional tracking in multiple centers

PURPOSE

To establish a normal reference range for automated fractional shortening (Auto FS) in normal singleton fetuses measured at multiple centers.

METHODS

This study was conducted from May 2017 to March 2019. It was undertaken on normal singleton fetuses. First, a four-chamber view of the fetal heart was recorded in the B-mode. Then, the region of interest was set on the edge of the ventricular septum and on the edge of the ventricular muscle at a point one-third away from the atrioventricular valve and toward the cardiac apex. Tracking was automatically performed. Values measured in the right ventricle were defined as R-Auto FS, and in the left ventricle as L-Auto FS. Furthermore, combined-Auto FS was defined as the measurement across both ventricles.

RESULTS

A total of 442 normal fetuses were assessed. R-Auto FS decreased significantly with gestational age, and L-Auto FS showed a similar tendency (Spearman's correlation analysis: r_s =  - 0.415 and r_s =  - 0.252, respectively). Combined-Auto FS showed a similar decline as the gestational age increased (r_s =  - 0.451).

CONCLUSION

In this study, we succeeded in defining a reference Auto FS value not only at one institution but also multiple centers. This study suggests that Auto FS can be used clinically and effectively.

Fetal whole heart blood flow imaging using 4D cine MRI

Prenatal detection of congenital heart disease facilitates the opportunity for potentially life-saving care immediately after the baby is born. Echocardiography is routinely used for screening of morphological malformations, but functional measurements of blood flow are scarcely used in fetal echocardiography due to technical assumptions and issues of reliability. Magnetic resonance imaging (MRI) is readily used for quantification of abnormal blood flow in adult hearts, however, existing in utero approaches are compromised by spontaneous fetal motion. Here, we present and validate a novel method of MRI velocity-encoding combined with a motion-robust reconstruction framework for four-dimensional visualization and quantification of blood flow in the human fetal heart and major vessels. We demonstrate simultaneous 4D visualization of the anatomy and circulation, which we use to quantify flow rates through various major vessels. The framework introduced here could enable new clinical opportunities for assessment of the fetal cardiovascular system in both health and disease.

N95 Filtering Facepiece Respirator Use during Pregnancy: A Systematic Review

OBJECTIVE

This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy.

STUDY DESIGN

A comprehensive search for primary literature using Medline, Embase, Scopus, Web of Science, and ClinicalTrials.gov was conducted from inception until April 2020 to find articles reporting outcomes of pregnant women using filtering facepiece respirator (FFR). Studies were selected if they included the use of FFR in pregnant women and reported an outcome of interest including physiologic changes (heart rate, respiratory rate, pulse oximetry, and fetal heart rate tracing) or subjective measures (thermal or exertional discomfort or fit). The Newcastle-Ottawa Quality Assessment scale was used to assess the risk of bias. The main outcome was to describe the physiologic changes in pregnant women compared with nonpregnant women. Due to the small number of studies and heterogeneity of reported outcomes a meta-analysis was not conducted. Results of the studies were synthesized into a summary of evidence table.

RESULTS

We identified four studies, three cohort studies and one crossover study, comprising 42 women using FFR during pregnancy. Risk of bias was judged to be low. Studies were consistent in showing no significant increase in maternal heart rate, respiratory rate, oxygen saturation, and fetal heart rate between pregnant and nonpregnant women using N95 FFRs for short durations. Repeat fit testing was not supported for women gaining the recommended amount of weight during pregnancy. No evidence was found to reach conclusions about prolonged N95 FFR use in pregnancy.

CONCLUSION

Limited duration N95 FFR use during pregnancy is unlikely to impart risk to the pregnant women or her fetus.

KEY POINTS

· Limited N95 use unlikely to impart risk to pregnant woman/fetus.. · Prolonged N95 use in pregnancy is unstudied.. · Repeat fit testing in pregnancy likely unnecessary..

Analysis of the fetal cardio-electrohysterographic coupling at the third trimester of gestation in healthy women by Bivariate Phase-Rectified Signal Averaging

INTRODUCTION

The fetal cardio-electrohysterographic coupling (FCEC) is defined as the influence of the uterine electrical activity on fetal heart rate. FCEC has been mainly evaluated by visual analysis of cardiotocographic data during labor; however, this physiological phenomenon is poorly explored during the antenatal period. Here we propose an approach known as Bivariate Phase-Rectified Signal Averaging analysis (BPRSA) to assess such FCEC in the late third trimester of low-risk pregnancies. We hypothesized that BPRSA is a more reliable measure of FCEC than visual analysis and conventional measures such as cross-correlation, coherence, and cross-sample entropy. Additionally, by using BPRSA it is possible to detect FCEC even from the third trimester of pregnancy.

MATERIAL AND METHODS

Healthy pregnant women in the last third trimester of pregnancy (36.6 ± 1.8 gestational weeks) without any clinical manifestation of labor were enrolled in the Maternal and Childhood Research Center (CIMIGen), Mexico City (n = 37). Ten minutes of maternal electrohysterogram (EHG) and fetal heart rate (FHR) data were collected by a transabdominal non-invasive device. The FCEC was quantified by the coefficient of coherence, the maximum normalized cross-correlation, and the cross-sample entropy obtained either from the EHG and FHR raw signals or from the corresponding BPRSA graphs.

RESULTS

We found that by using BPRSA, the FCEC was detected in 92% cases (34/37) compared to 48% cases (18/37) using the coefficient of coherence between the EHG and FHR raw signals. Also, BPRSA indicated FCEC in 82% cases (30/37) compared to 30% cases (11/37) using the maximum normalized cross-correlation. By comparing the analyses, the BPRSA evidenced higher FCEC in comparison to the coupling estimated from the raw EHG and FHR signals.

CONCLUSIONS

Our results support the consideration that in the third trimester of pregnancy, the fetal heart rate is also influenced by uterine activity despite the emerging manifestation of this activity before labor. To quantify FCEC, the BPRSA can be applied to FHR and EHG transabdominal signals acquired in the third trimester of pregnancy.

The standardized 12-lead fetal electrocardiogram of the healthy fetus in mid-pregnancy: A cross-sectional study

Introduction

The examination of the fetal heart in mid-pregnancy is by ultrasound examination. The quality of the examination is highly dependent on the skill of the sonographer, fetal position and maternal body mass index. An additional tool that is less dependent on human experience and interpretation is desirable. The fetal electrocardiogram (ECG) could fulfill this purpose. We aimed to show the feasibility of recording a standardized fetal ECG in mid-pregnancy and explored its possibility to detect congenital heart disease (CHD).

Materials and methods

Women older than 18 years of age with an uneventful pregnancy, carrying a healthy singleton fetus with a gestational age between 18 and 24 weeks were included. A fetal ECG was performed via electrodes on the maternal abdomen. After removal of interferences, a vectorcardiogram was constructed. Based on the ultrasound assessment of the fetal orientation, the vectorcardiogram was rotated to standardize for fetal orientation and converted into a 12-lead ECG. Median ECG waveforms for each lead were calculated.

Results

328 fetal ECGs were recorded. 281 were available for analysis. The calculated median ECG waveform showed the electrical heart axis oriented to the right and inferiorly i.e. a negative QRS deflection in lead I and a positive deflection in lead aVF. The two CHD cases show ECG abnormalities when compared to the mean ECG of the healthy cohort.

Discussion

We have presented a method for estimating a standardized 12-lead fetal ECG. In mid-pregnancy, the median electrical heart axis is right inferiorly oriented in healthy fetuses. Future research should focus on fetuses with congenital heart disease.

Labour admission assessment results of index pregnancy as predictors of intrapartum stillbirth in public health facilities of Addis Ababa: A case-control study

BACKGROUND

Approximately one-third of the global stillbirth burden occurs during intrapartum period. The ability to assess obstetric parameters including effacement, dilatation, uterine contraction, decent, rupture of the uterus, and moulding of the foetal head are among the essential competencies required by obstetric service providers admitting women for labour in health facilities. Misdiagnosis of these conditions could result in unnecessary obstetric interventions and unfavourable obstetric outcomes including intrapartum stillbirth. This study aimed to assess associations between missed diagnosis plus complication of labour on admission and intrapartum stillbirth.

METHODS

A case-control study using primary data from chart review of medical records of women who experienced intrapartum stillbirth in 20 public health centres and three public hospitals of Addis Ababa between 01 July 2010 and 30 June 2015 was conducted. Data were collected from charts of all cases meeting the inclusion criteria. Medical records of women with livebirths were randomly selected and reviewed from each public health facilities in two to one (2:1) control to case ratio. Accordingly, 728 cases of stillbirth out of 1,056 charts met the inclusion criteria whereas 1,551 controls out of 1,705 were also considered in the study.

RESULTS

Proportionally, more women in the stillbirth group (39.4%) than in the livebirth group (30.2%) experienced ruptured membrane on admission, with the difference being statistically significant (OR 1.7, 95% CI 1.37-2.03). Significantly higher proportion of women in the intrapartum stillbirth group experienced FRH lower than 110/min, a result suggestive of foetal distress on admission. Proportionally, more women in the intrapartum stillbirth group (14.5%) than in the livebirth group (4.5%) had breech foetal presentation on admission for labour, the difference being statistically significant (aOR 3.26 95% CI 1.93-5.50). Intrapartum stillbirth was slightly higher among women with cervical dilatation 4cm or more on admission (OR 1.2, 95% CI 1.00-1.45). This could be owing to delay in seeking obstetric care or misdiagnosis of the condition, a situation that seeks more rigorous study to determine the underlying causal links. Diagnosis of foetal member was missed among more cases than controls where the difference was statistically significant (aOR 1.51, CI 1.03-2.19).

CONCLUSION

Low FHR, non-vertex foetal presentations and ruptured cervical membrane were predictors of intrapartum stillbirth. Health facilities could avert unnecessary foetal loss by undertaking timely actions to manage obstetric emergencies on admission to labour.

Z Score Reference Ranges of Fetal Cardiac Output From 12 to 40 Weeks of Pregnancy

OBJECTIVES

To develop the Z score reference ranges of fetal cardiac output (CO) in healthy fetuses from 12 to 40 weeks of pregnancy.

METHODS

A cross-sectional descriptive study was undertaken among low-risk singleton pregnancies with healthy fetuses between 12 and 40 weeks. The right ventricular cardiac output (RCO), left ventricular cardiac output (LCO), and combined cardiac output (CCO) were measured by 2-dimensional ultrasound with the Doppler velocity of the aorta and pulmonary arteries. The pregnancies were followed until delivery RESULTS: The RCO, LCO, and CCO were determined in 700 fetuses. The predictive models of the CO as a function of gestational age (GA) and biparietal diameter were identified, and the Z score reference ranges were constructed. The means and standard deviations of CO on both sides were increased with GA and biparietal diameter as power models. Nomograms for the LCO, RCO, and CCO were established (ie, RCO = 0.000148 × GA^4.283034 ; SD = 0.000131 × GA^4.026209 ; LCO = 0.000514 × GA^3.790944 ; SD = 0.000169 × GA^3.815546 ). The RCO was much more increased than the LCO with advancing GA.

CONCLUSIONS

The Z score reference ranges and percentile charts of fetal CO were constructed throughout gestation with a large sample size. This may be helpful in detection of cardiac disorders, especially cardiomyopathy, cardiac anomalies, fetal anemia, and fetal growth restriction.

Left ventricular torsional mechanics in term fetuses and neonates

OBJECTIVE

Left ventricular (LV) torsion is an important aspect of cardiac mechanics and is fundamental to normal ventricular function. The myocardial mechanics of the fetal heart and the changes that occur during the transition to the neonatal period have not been explored previously. The aim of this study was to evaluate perinatal changes in LV torsion and its relationship with myocardial function.

METHODS

This was a prospective study of 36 women with an uncomplicated term pregnancy. Fetal and neonatal conventional, spectral tissue Doppler and two-dimensional (2D) speckle tracking echocardiography were performed a few days before and within hours after delivery to measure cardiac indices including LV rotational parameters derived from short-axis views at the base and apex of the heart. Linear regression analysis was used to examine the relationship between LV rotational parameters and cardiac geometric and functional indices in term fetuses and neonates. Perinatal changes in LV rotational parameters were assessed.

RESULTS

There were three patterns of LV twist in term fetuses: those with reversed-apex-type LV twist had the lowest median values of LV torsion (0.1°/cm), with higher values (1.6°/cm) in those with infant-type LV twist and the highest values (4.4°/cm) in those with adult-type LV twist. LV torsion was associated significantly with cardiac geometric and functional indices. Perinatal evaluation revealed a significant increase in LV torsion following delivery in fetuses exhibiting reversed-apex-type LV twist (increase of 2.8°/cm, P = 0.009) and a significant decrease in those with adult-type LV twist (decrease of 3.2°/cm, P = 0.008).

CONCLUSIONS

This study demonstrates the feasibility of 2D speckle tracking imaging for accurate assessment of rotational cardiac parameters in term fetuses. There are unique perinatal patterns of LV twist that demonstrate different values of LV torsion, which was found to correlate with indices of ventricular geometry and myocardial function. Differences in patterns of LV twist may therefore reflect differences in compensatory myocardial adaptation to the physiological environment/loading conditions in late gestation in fetuses and postnatal cardiac adjustment to the acute loading changes that occur at delivery. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Fetal cardiac findings and hemodynamic changes associated with severe lower urinary tract obstruction in utero

OBJECTIVES

To describe fetal echocardiographic findings associated with lower urinary tract obstruction (LUTO) and to compare anatomic and hemodynamic measurements between fetuses with LUTO and gestational age (GA)-matched controls, with an emphasis on quantitative indices of diastolic function and cardiac output.

METHODS

This was a retrospective cohort study of fetuses diagnosed with severe LUTO with giant bladder, which underwent at least one fetal echocardiogram at our center between January 2005 and June 2018. Fetuses with major congenital heart disease were excluded. Control fetuses did not have any structural or functional abnormalities and were GA-matched to the LUTO fetuses based on the time of the first fetal echocardiogram. Cardiac anatomy and hemodynamic measurements were compared between fetuses with LUTO and controls. In infants with LUTO, serial fetal and postnatal echocardiographic data were assessed, when available, and clinical outcomes were reviewed.

RESULTS

Twenty-six fetuses with LUTO and at least one fetal echocardiogram available were identified, one of which was excluded due to hypoplastic left heart syndrome, leaving 25 LUTO fetuses in the final cohort. The mean GA at the first fetal echocardiogram was 25.4 ± 5.1 weeks in the LUTO group and 25.3 ± 5.0 weeks in the control group. Common findings in fetuses with LUTO included cardiomegaly (40%), pericardial effusion (44%), right ventricular (RV) hypertrophy (64%) and left ventricular (LV) hypertrophy (48%). Compared with GA-matched controls, LUTO fetuses had lower ascending aorta Z-score (-0.10 ± 0.94 vs -0.93 ± 1.03; P = 0.02) and aortic isthmus Z-score (-0.14 ± 0.86 vs -1.62 ± 1.11; P < 0.001), shorter mitral valve inflow time indexed to cardiac cycle length (0.46 ± 0.04 vs 0.41 ± 0.06; P = 0.002), and worse (increased) LV myocardial performance index (0.39 ± 0.03 vs 0.44 ± 0.04; P < 0.001). In addition, the ratio of RV to LV cardiac index was higher in LUTO fetuses compared with controls (1.62 ± 0.13 vs 1.33 ± 0.11; P < 0.001). Of the 25 LUTO pregnancies, two were lost to follow-up, three underwent elective termination of pregnancy and three ended in intrauterine fetal demise. Four (16%) patients had mildly hypoplastic left-heart structures, comprising two with aortic arch hypoplasia and two with mitral and aortic stenosis.

CONCLUSION

In addition to presenting with cardiomegaly, pericardial effusion and ventricular hypertrophy, fetuses with LUTO demonstrate LV diastolic dysfunction and appear to redistribute cardiac output as compared to control fetuses, which may contribute to the development of left-heart hypoplasia. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Evolution of strain and strain rate values throughout gestation in healthy fetuses

Myocardial deformation by speckle tracking echocardiography is a novel method for evaluating cardiac function. To test the hypothesis that right ventricular and left ventricular function have age-specific patterns of development, we tracked the evolution of ventricular strain mechanics by speckle tracking echocardiography in the fetus. We conducted a retrospective cross sectional echocardiography study in 154 healthy fetuses, and characterized cardiac function by measuring right and left ventricles global longitudinal strain and strain rate. Comparison of the data of both ventricles according to gestational age was carried out. The magnitudes of right and left ventricle global longitudinal strain show wide range values and decreased throughout gestation. Strain values are higher in left ventricle compared to the right one throughout pregnancy. Strain rate values were similar over gestation in each ventricle, but the magnitudes declined overtime in the right and left ventricle. The maturational patterns of left and right strain are gestational specific. With accepted physiological maturation patterns in healthy subjects, these myocardial deformation parameters can provide a valid basis that allows comparison between health and disease.

Assessing cardiovascular remodelling in fetuses and infants conceived by assisted reproductive technologies: a prospective observational cohort study protocol

INTRODUCTION

Assisted reproductive technologies (ART), namely in vitro fertilisation and intracytoplasmic sperm injection, have become widely used to treat infertility. Although the use of ART is generally considered favourable, there are ongoing concerns about the prenatal and perinatal risks as well as long-term risks for the child. Epidemiological studies have demonstrated an association between pathological events during fetal development and future cardiovascular risk, raising concerns about cardiovascular remodelling in fetuses conceived by ART. The authors hypothesise fetuses conceived by ART present signs of cardioventricular dysfunction, which can be detected by deformation analysis. To address these issues, we will assess comprehensive cardiovascular structure and function in ART offspring and explore the role of speckle-tracking in myocardial deformation.

METHODS AND ANALYSIS

This prospective observational cohort study will include 100 singleton pregnancies conceived by ART and 100 controls identified in fetal life and followed up to 6 months old. At inclusion, a baseline assessment of the mothers and ART characteristics will be recorded by interview and review of medical records. Between 28 and 32 weeks gestation, a detailed fetal echography will be performed, including an assessment of estimated fetal weight, fetoplacental Doppler, fetal echocardiography and fetal abdominal artery ultrasound. On delivery, maternal and neonatal characteristics will be assessed. Within 60 days of birth, the first postnatal cardiovascular assessment will be conducted which will include echocardiography and abdominal artery ultrasound. At 6 months of age, the second infants' follow-up evaluation will include the weight and length of the infant, echocardiography and abdominal artery ultrasound. Data will be presented as mean±SD, median or percentages where appropriate. A p<0.05 will be considered statistically significant.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Ethics Committee of Shengjing Hospital of China Medical University. Findings will be disseminated through scientific publications and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR1900021672.

Reference ranges for left, right and interventricular septum indices at 20 to 36+6 weeks of gestation derived using spectral myocardial tissue Doppler on Voluson ultrasound machines

AIM

To establish reference range values for peak myocardial tissue Doppler velocity (MTD) and myocardial performance index (MPI) of the left ventricle (LV), the right ventricle (RV), and the interventricular septum (IVS) at 20 to 36+6 weeks of gestation using spectral tissue Doppler.

MATERIAL AND METHODS

This cross-sectional study was conducted among 360 lowrisk singleton pregnancies. MTD during systole (S'), and early (E') and late diastole (A'), and MPI' were assessed by placing sample volume at the basal segment of the LV free wall, the RV free wall, and the IVS, respectively. Polynomial regression was used to obtain the best-fit curves for MTD and MPI' measurements as a function of gestational age (GA), and adjustments were made using the determination coefficient (R2). Intra- and inter-observer reproducibility was evaluated using the concordance correlation coefficient (CCC).

RESULTS

All MTD velocities (cm/s) progressively increased with advancing GA (p<0.0001). Mean LV MTD values were 4.19 to 6.86 for S', 3.52 to 7.22 for E', and 6.85 to 9.19 for A'; mean RV MTD were 4.85 to 7.97 for S', 4.49 to 8.66 for E', and 8.44 to 11.20 for A'; and mean IVS MTD values were 3.75 to 5.78 for S', 3.34 to 5.79 for E', and 5.88 to 7.98 for A'. LV MPI', RV MPI', and IVS MPI' did not significantly change with advancing GA. The CCC values for MTD were predominantly greater than 0.70, while those for MPI' were <0.70.

CONCLUSIONS

Reference values for the fetal MTD and MPI' of RV, LV and IVS using tissue Doppler between 20 and 36+6 weeks of gestation were described.

Patient participation and learning in medical consultations about congenital heart defects

In this article, patient activity in 8 audio recorded specialist consultations on fetal cardiology is investigated in order to explore how, why and when patients tend to participate in encounters in which the doctor dominates the interaction. The overall question is: How can the participation of patients in the consultations be connected to the development of higher levels of health literacy, i.e. to interactive literacy and to critical literacy? Patient participation is here understood as interactive action and is analyzed in terms of different interactive moves, which are related to different recurring topics. Despite the highly standardized format of the consultations, there is a large variation between the patients’ participation: between 0.7 and 2.8 moves per minute. The patients participate most during the topics ‘Prevalence’ and ‘Consultations’ and least during the topic ‘The normal heart’. Although most of the patients' moves are responses to what the doctor says, they remarkably often pose questions and use so called rejoinders. By posing questions, they take control of the information flow and sometimes even change the topics. By using rejoinders, they analyze the problems involved in the discussion e.g. by asking for clarifications or confirmation. Patients with a low over-all participation rate also use fewer moves that indicate higher literacy levels. The qualitative analysis problematizes the idea of a simple scale from basic literacy to critical literacy. Moves that indicate basic literacy skills are interactively important for the learning activity, led by the doctor. However, patients who mainly support the doctor’s initiatives don’t take the opportunity to influence the flow of information in ways that might favor their health literacy development.

Deep learning as a predictive tool for fetal heart pregnancy following time-lapse incubation and blastocyst transfer

STUDY QUESTION

Can a deep learning model predict the probability of pregnancy with fetal heart (FH) from time-lapse videos?

SUMMARY ANSWER

We created a deep learning model named IVY, which was an objective and fully automated system that predicts the probability of FH pregnancy directly from raw time-lapse videos without the need for any manual morphokinetic annotation or blastocyst morphology assessment.

WHAT IS KNOWN ALREADY

The contribution of time-lapse imaging in effective embryo selection is promising. Existing algorithms for the analysis of time-lapse imaging are based on morphology and morphokinetic parameters that require subjective human annotation and thus have intrinsic inter-reader and intra-reader variability. Deep learning offers promise for the automation and standardization of embryo selection.

STUDY DESIGN, SIZE, DURATION

A retrospective analysis of time-lapse videos and clinical outcomes of 10 638 embryos from eight different IVF clinics, across four different countries, between January 2014 and December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The deep learning model was trained using time-lapse videos with known FH pregnancy outcome to perform a binary classification task of predicting the probability of pregnancy with FH given time-lapse video sequence. The predictive power of the model was measured using the average area under the curve (AUC) of the receiver operating characteristic curve over 5-fold stratified cross-validation.

MAIN RESULTS AND THE ROLE OF CHANCE

The deep learning model was able to predict FH pregnancy from time-lapse videos with an AUC of 0.93 [95% CI 0.92-0.94] in 5-fold stratified cross-validation. A hold-out validation test across eight laboratories showed that the AUC was reproducible, ranging from 0.95 to 0.90 across different laboratories with different culture and laboratory processes.

LIMITATIONS, REASONS FOR CAUTION

This study is a retrospective analysis demonstrating that the deep learning model has a high level of predictability of the likelihood that an embryo will implant. The clinical impacts of these findings are still uncertain. Further studies, including prospective randomized controlled trials, are required to evaluate the clinical significance of this deep learning model. The time-lapse videos collected for training and validation are Day 5 embryos; hence, additional adjustment would need to be made for the model to be used in the context of Day 3 transfer.

WIDER IMPLICATIONS OF THE FINDINGS

The high predictive value for embryo implantation obtained by the deep learning model may improve the effectiveness of previous approaches used for time-lapse imaging in embryo selection. This may improve the prioritization of the most viable embryo for a single embryo transfer. The deep learning model may also prove to be useful in providing the optimal order for subsequent transfers of cryopreserved embryos.

STUDY FUNDING/COMPETING INTEREST(S)

D.T. is the co-owner of Harrison AI that has patented this methodology in association with Virtus Health. P.I. is a shareholder in Virtus Health. S.C., P.I. and D.G. are all either employees or contracted with Virtus Health. D.G. has received grant support from Vitrolife, the manufacturer of the Embryoscope time-lapse imaging used in this study. The equipment and time for this study have been jointly provided by Harrison AI and Virtus Health.

Does exercise during pregnancy impact on maternal weight gain and fetal cardiac function? A randomized controlled trial

OBJECTIVE

To evaluate the association between physical exercise during pregnancy and maternal gestational weight gain and fetal cardiac function.

METHODS

This was a randomized controlled trial of women with a singleton pregnancy managed from the first trimester at the Hospital de Torrejón, Madrid, between November 2014 and June 2015. Women were randomized to either follow a supervised physical conditioning program, consisting of a 60-min session 3 days per week for the duration of pregnancy, or not attend any exercise program (controls). The primary outcome was maternal weight gain during pregnancy. Secondary outcomes included fetal cardiac function parameters evaluated at 20, 28 and 36 weeks' gestation, Cesarean section, preterm delivery, induction of labor and birth weight. A sample size of 45 in each group was planned to detect differences in maternal weight gain of at least 1 kg, with a power of > 80% and α of 0.05.

RESULTS

During the study period, 120 women were randomized into the exercise (n = 75) and control (n = 45) groups. Following exclusions, the final cohort consisted of 42 women in the exercise group and 43 in the control group. Baseline characteristics (maternal age, prepregnancy body mass index, parity, conception by in-vitro fertilization, Caucasian ethnicity, physical exercise prior to pregnancy and smoker) were similar between the two groups. No differences were found between the groups in maternal weight at 20, 28, 36 and 38 weeks' gestation or in weight gain at 38 weeks. However, the proportion of women with weight loss ≥ 9 kg at 6 weeks postpartum was higher in the exercise compared with the control group (68.2% vs 42.8%; relative risk 1.593; P = 0.02). The ductus arteriosus pulsatility index (DA-PI) at 20 weeks (2.43 ± 0.40 vs 2.26 ± 0.33, P < 0.05) and the ejection fraction (EF) at 36 weeks (0.85 ± 0.13 vs 0.81 ± 0.11, P < 0.05) were higher in the exercise compared with the control group. All other evaluated fetal cardiac function parameters were similar between the two groups.

CONCLUSIONS

Performing exercise during pregnancy is not associated with a reduction in maternal weight gain but increases weight loss at 6 weeks postpartum. Physical exercise during pregnancy is associated with increased fetal DA-PI at 20 weeks and EF at 36 weeks, which could reflect adaptive mechanisms. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Speckle Tracking of the Basal Lateral and Septal Wall Annular Plane Systolic Excursion of the Right and Left Ventricles of the Fetal Heart

OBJECTIVE

Annular plane systolic excursion (APSE) has been evaluated for the right (RV) and left (LV) ventricles using M-mode echocardiography. This study examined APSE using 2-dimensional speckle tracking (2DST) of the lateral and septal annuli of the RV and LV in normal fetuses.

METHODS

Two hundred normal fetuses were prospectively examined between 20 and 40 weeks' gestation, in which the end-diastolic and end-systolic lengths were measured from the apex to the insertion of the annuli into the lateral and septal walls of the RV and LV using 2DST. Subtracting the end-systolic from the end-diastolic length resulted in the APSE measurement. The APSE values from the ventricular and septal locations were regressed against biometric and gestational age independent variables, and the mean and standard deviation computed using fractional polynomial analysis. Within-subject repeated measures of variance were used to compare results within and between the right ventricular and left ventricular basal APSE values.

RESULTS

When regressed against the independent variables the R² for the APSE of the right ventricular lateral wall ranged from 0.39 to 0.40, the left ventricular lateral wall 0.29 to 0.31, the right ventricular septal wall 0.22 to 0.40, and the left ventricular septal wall 0.05 to 0.07. There was a significant difference (P < .001) for APSE between the right ventricular and left ventricular lateral wall and their respective septal annuli, the left ventricular and right ventricular lateral wall annuli, and the left ventricular and right ventricular septal annuli.

CONCLUSIONS

The right ventricular and left ventricular lateral and septal wall APSE can be computed using 2DST and are associated with changing fetal biometric and age measurements.

Automated analysis of fetal cardiac function using color tissue Doppler imaging in second half of normal pregnancy

OBJECTIVES

Color tissue Doppler imaging (cTDI) is a promising tool for the assessment of fetal cardiac function. However, the analysis of myocardial velocity traces is cumbersome and time-consuming, limiting its application in clinical practice. The aim of this study was to evaluate fetal cardiac function during the second half of pregnancy and to develop reference ranges using an automated method to analyze cTDI recordings from a cardiac four-chamber view.

METHODS

This was a cross-sectional study including 201 normal singleton pregnancies between 18 and 42 weeks of gestation. During fetal echocardiography, a four-chamber view of the heart was visualized and cTDI was performed. Regions of interest were positioned at the level of the atrioventricular plane in the left ventricular (LV), right ventricular (RV) and septal walls of the fetal heart, to obtain myocardial velocity traces that were analyzed offline using the automated algorithm. Peak myocardial velocities during atrial contraction (Am), ventricular ejection (Sm) and rapid ventricular filling, i.e. early diastole (Em), as well as the Em/Am ratio, mechanical cardiac time intervals and myocardial performance index (cMPI) were evaluated, and gestational age-specific reference ranges were constructed.

RESULTS

At 18 weeks of gestation, the peak myocardial velocities, presented as fitted mean with 95% CI, were: LV Am, 3.39 (3.09-3.70) cm/s; LV Sm, 1.62 (1.46-1.79) cm/s; LV Em, 1.95 (1.75-2.15) cm/s; septal Am, 3.07 (2.80-3.36) cm/s; septal Sm, 1.93 (1.81-2.06) cm/s; septal Em, 2.57 (2.32-2.84) cm/s; RV Am, 4.89 (4.59-5.20) cm/s; RV Sm, 2.31 (2.16-2.46) cm/s; and RV Em, 2.94 (2.69-3.21) cm/s. At 42 weeks of gestation, the peak myocardial velocities had increased to: LV Am, 4.25 (3.87-4.65) cm/s; LV Sm, 3.53 (3.19-3.89) cm/s; LV Em, 4.55 (4.18-4.94) cm/s; septal Am, 4.49 (4.17-4.82) cm/s; septal Sm, 3.36 (3.17-3.55) cm/s; septal Em, 3.76 (3.51-4.03) cm/s; RV Am, 6.52 (6.09-6.96) cm/s; RV Sm, 4.95 (4.59-5.32) cm/s; and RV Em, 5.42 (4.99-5.88) cm/s. The mechanical cardiac time intervals generally remained more stable throughout the second half of pregnancy, although, with increased gestational age, there was an increase in duration of septal and RV atrial contraction, LV pre-ejection and septal and RV ventricular ejection, while there was a decrease in duration of septal postejection. Regression equations used for the construction of gestational age-specific reference ranges for peak myocardial velocities, Em/Am ratios, mechanical cardiac time intervals and cMPI are presented.

CONCLUSION

Peak myocardial velocities increase with gestational age, while the mechanical time intervals remain more stable throughout the second half of pregnancy. Using an automated method to analyze cTDI-derived myocardial velocity traces, it was possible to construct reference ranges, which could be used in distinguishing between normal and abnormal fetal cardiac function. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Differential Expression of Transforming Growth Factor-β1 Is Associated With Fetal Regeneration After Myocardial Infarction

BACKGROUND

Global extracellular matrix (ECM)-related gene expression is decreased after myocardial infarction (MI) in fetal sheep when compared with adult sheep. Transforming growth factor (TGF)-β1 is a key regulator of ECM; therefore we hypothesize that TGF-β1 is differentially expressed in adult and fetal infarcts after MI.

METHODS

Adult and fetal sheep underwent MI via ligation of the left anterior descending coronary artery. Expression of TGF-β1 and ECM-related genes was evaluated by ovine-specific microarray and quantitative polymerase chain reaction. Fibroblasts from the left ventricle of adult and fetal hearts were treated with TGF-β1 or a TGF-β1 receptor inhibitor (LY36497) to evaluate the effect of TGF-β1 on ECM-related genes.

RESULTS

Col1a1, col3a1, and MMP9 expression were increased in adult infarcts 3 and 30 days after MI but were upregulated in fetal infarcts only 3 days after MI. Three days after MI elastin expression was increased in adult infarcts. Despite upregulation in adult infarcts both 3 and 30 days after MI, TGF-β1 was not upregulated in fetal infarcts at any time point. Inhibition of the TGF-β1 receptor in adult cardiac fibroblasts decreased expression of col1a1, col3a1, MMP9, elastin, and TIMP1, whereas treatment of fetal cardiac fibroblasts with TGF-β1 increased expression of these genes.

CONCLUSIONS

TGF-β1 is increased in adult infarcts compared with regenerative, fetal infarcts after MI. Although treatment of fetal cardiac fibroblasts with TGF-β1 conveys an adult phenotype, inhibition of TGF-β1 conveys a fetal phenotype to adult cardiac fibroblasts. Decreasing TGF-β1 after MI may facilitate myocardial regeneration by "fetalizing" the otherwise fibrotic, adult response to MI.

Fetal hemodynamics and cardiac streaming assessed by 4D flow cardiovascular magnetic resonance in fetal sheep

BACKGROUND

To date it has not been possible to obtain a comprehensive 3D assessment of fetal hemodynamics because of the technical challenges inherent in imaging small cardiac structures, movement of the fetus during data acquisition, and the difficulty of fusing data from multiple cardiac cycles when a cardiac gating signal is absent. Here we propose the combination of volumetric velocity-sensitive cardiovascular magnetic resonance imaging ("4D flow" CMR) and a specialized animal preparation (catheters to monitor fetal heart rate, anesthesia to immobilize mother and fetus) to examine fetal sheep cardiac hemodynamics in utero.

METHODS

Ten pregnant Merino sheep underwent surgery to implant arterial catheters in the target fetuses. Anesthetized ewes underwent 4D flow CMR with acquisition at 3 T for fetal whole-heart coverage with 1.2-1.5 mm spatial resolution and 45-62 ms temporal resolution. Flow was measured in the heart and major vessels, and particle traces were used to visualize circulatory patterns in fetal cardiovascular shunts. Conservation of mass was used to test internal 4D flow consistency, and comparison to standard 2D phase contrast (PC) CMR was performed for validation.

RESULTS

Streaming of blood from the ductus venosus through the foramen ovale was visualized. Flow waveforms in the major thoracic vessels and shunts displayed normal arterial and venous patterns. Combined ventricular output (CVO) was 546 mL/min per kg, and the distribution of flows (%CVO) were comparable to values obtained using other methods. Internal 4D flow consistency across 23 measurement locations was established with differences of 14.2 ± 12.1%. Compared with 2D PC CMR, 4D flow showed a strong correlation (R2 = 0.85) but underestimated flow (bias = - 21.88 mL/min per kg, p < 0.05).

CONCLUSIONS

The combination of fetal surgical preparation and 4D flow CMR enables characterization and quantification of complex flow patterns in utero. Visualized streaming of blood through normal physiological shunts confirms the complex mechanism of substrate delivery to the fetal heart and brain. Besides offering insight into normal physiology, this technology has the potential to qualitatively characterize complex flow patterns in congenital heart disease phenotypes in a large animal model, which can support the development of new interventions to improve outcomes in this population.

Automated analysis of fetal cardiac function using color tissue Doppler imaging

OBJECTIVE

To evaluate the feasibility of automated analysis of fetal myocardial velocity recordings obtained by color tissue Doppler imaging (cTDI).

METHODS

This was a prospective cross-sectional observational study of 107 singleton pregnancies ≥ 41 weeks of gestation. Myocardial velocity recordings were obtained by cTDI in a long-axis four-chamber view of the fetal heart. Regions of interest were placed in the septum and the right (RV) and left (LV) ventricular walls at the level of the atrioventricular plane. Peak myocardial velocities and mechanical cardiac time intervals were measured both manually and by an automated algorithm and agreement between the two methods was evaluated.

RESULTS

In total, 321 myocardial velocity traces were analyzed using each method. It was possible to analyze all velocity traces obtained from the LV, RV and septal walls with the automated algorithm, and myocardial velocities and cardiac mechanical time intervals could be measured in 96% of all traces. The same results were obtained when the algorithm was run repeatedly. The myocardial velocities measured using the automated method correlated significantly with those measured manually. The agreement between methods was not consistent and some cTDI parameters had considerable bias and poor precision.

CONCLUSIONS

Automated analysis of myocardial velocity recordings obtained by cTDI was feasible, suggesting that this technique could simplify and facilitate the use of cTDI in the evaluation of fetal cardiac function, both in research and in clinical practice. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Assessment of diastolic function of normal fetal heart using dual-gate Doppler

OBJECTIVES

The ratio of mitral peak early diastolic filling to early diastolic mitral annular velocity (E/e') reflects diastolic cardiac function in adults. Dual-gate Doppler (DD) enables measurements of E/e' in the same heart beat. This study was designed to assess the utility of the DD method for measurement of fetal E/e' and determine reference ranges for normal fetuses.

METHODS

This prospective study comprised normal singleton pregnancies undergoing fetal echocardiography between 16 and 36 weeks of gestation. According to the DD method, E-wave velocity on pulsed-wave Doppler and e'-wave on tissue Doppler imaging were measured simultaneously on an apical or basal four-chamber view, and fetal E/e' was calculated. Spearman's correlation coefficient was used to assess the relationship between gestational age (GA) and E-wave and e'-wave velocities and E/e'.

RESULTS

A total of 133 pregnancies were included in this study and all E/e' measurements were successful. Significant correlation was observed between GA and both left ventricular (LV) E/e' (r _s  = -0.666, P < 0.001) and right ventricular (RV) E/e' (r _s  = -0.607, P < 0.001). The regression equations for bilateral E/e' were: LV-E/e' = 17.341 - 0.631GA + 0.008 × GA² (mean ± SD, R ²  = 0.440 ± 1.333); and RV-E/e' = 19.156 - 0.794GA + 0.012GA² (R ²  = 0.419 ± 1.329).

CONCLUSIONS

Bilateral E/e' of normal fetuses, measured using the DD method, decreased with GA, which is considered to be related to myocardial maturity. DD is a useful and convenient method for evaluating fetal E/e' in order to assess diastolic function in the prenatal period. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Relationship between fetal peak systolic velocity in Middle cerebral artery and umbilical blood gas values and hemoglobin levels in diabetic pregnant women

PURPOSE

To assess the relationship between peak systolic velocity in the middle cerebral artery (MCA-PSV) and fetal hypoxia in diabetic pregnant women requiring insulin therapy.

METHODS

The data of diabetic pregnant women using insulin who were followed in our departments were reviewed retrospectively. The relationships between MCA-PSV and umbilical cord pO2, pCO2, base deficit, hemoglobin, and birth weight were analyzed.

RESULTS

A total of 120 cases were included in the final analysis. The median (Q₁ - Q₃ ) gestational age at Doppler evaluation was 37 weeks 3 days (37-38 weeks and 2 days), and the mean ± SD gestational age at delivery was 38 weeks 4 days ± 3days. The mean ± SD hemoglobin A1c (HbA1c) level was 5.7% ± 1.0% and, median (Q₁ -Q₃ ) daily total insulin dose was 25 U (10U-48U). There was no statistically significant correlation between MCA-PSV and pH, PO2, PCO2, base deficit, Hb, and birth weight (Spearman correlation, r:-.001[P = .99], r:-.011[P = .90], r:-.052 [P = .51], r: .049[P = .59], r: .049 [P = .59], r: .030 [P = .75], respectively). Using binary logistic regression analysis, no independent factor for the prediction of fetal acidosis (venous pH < 7.23), and metabolic acidosis (base deficit >6.3 mmol/L) was detected.

CONCLUSION

MCA-PSV is not a good indicator of fetal polycythemia or chronic hypoxia in fetuses of diabetic pregnant women. Fetal well-being should be monitored with other tools in these circumstances.

Glucocorticoids, antenatal corticosteroid therapy and fetal heart maturation

Glucocorticoids are essential in mammals to mature fetal organs and tissues in order to survive after birth. Hence, antenatal glucocorticoid treatment (termed antenatal corticosteroid therapy) can be life-saving in preterm babies and is commonly used in women at risk of preterm birth. While the effects of glucocorticoids on lung maturation have been well described, the effects on the fetal heart remain less clear. Experiments in mice have shown that endogenous glucocorticoid action is required to mature the fetal heart. However, whether the potent synthetic glucocorticoids used in antenatal corticosteroid therapy have similar maturational effects on the fetal heart is less clear. Moreover, antenatal corticosteroid therapy may increase the risk of cardiovascular disease in adulthood. Here, we present a narrative review of the evidence relating to the effects of antenatal glucocorticoid action on the fetal heart and discuss the implications for antenatal corticosteroid therapy.

Fetal cardiac remodeling in twin pregnancy conceived by assisted reproductive technology

OBJECTIVE

Recent data suggest that singleton fetuses conceived by assisted reproductive technology (ART) present cardiovascular remodeling that may persist postnatally. Twin pregnancies are more frequent in the ART population and are associated with increased adverse perinatal outcomes, such as hypertensive disorders, gestational diabetes and preterm birth. However, it is unknown whether cardiac remodeling is also present in twin pregnancies conceived by ART. Our aim was to assess the presence of fetal cardiac remodeling and dysfunction in twin pregnancies conceived by ART as compared with those conceived spontaneously (SC).

METHODS

This was a prospective cohort study including 50 dichorionic twin fetuses conceived by ART and 50 SC twin fetuses. The study protocol included collection of baseline/perinatal data and a fetal ultrasound examination at 28-30 weeks' gestation, including assessment of estimated fetal weight, fetoplacental Doppler and fetal echocardiography. Measurements of atrial area, atrial/heart ratio, ventricular sphericity index, free wall thickness, mitral and tricuspid annular plane systolic excursions, and systolic and early diastolic peak velocities were assessed. Multilevel analyses were used to compare perinatal and ultrasonographic parameters. Comparisons of echocardiographic variables were adjusted for parental age, paternal body mass index and incidence of pre-eclampsia.

RESULTS

Compared with SC twins, ART twin fetuses showed significant cardiac changes, predominantly affecting the right heart, such as dilated atria (right atrial/heart area: 15.7 ± 3.1 vs 18.4 ± 3.2, P < 0.001), more globular ventricles (right ventricular sphericity index: 1.57 ± 0.25 vs 1.41 ± 0.23, P = 0.001) and thicker myocardial walls (septal wall thickness: 2.57 ± 0.45 mm vs 2.84 ± 0.41 mm, P = 0.034) together with reduced longitudinal motion (tricuspid annular plane systolic excursion: 6.36 ± 0.89 mm vs 5.18 ± 0.93 mm, P < 0.001).

CONCLUSIONS

ART twin fetuses present signs of cardiac remodeling and dysfunction. These changes are similar to those observed in ART singletons and reinforce the concept of fetal cardiac programing in ART. These results open opportunities for early detection and intervention in infants conceived by ART. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Adverse Intrauterine Environment and Cardiac miRNA Expression

Placental insufficiency, high altitude pregnancies, maternal obesity/diabetes, maternal undernutrition and stress can result in a poor setting for growth of the developing fetus. These adverse intrauterine environments result in physiological changes to the developing heart that impact how the heart will function in postnatal life. The intrauterine environment plays a key role in the complex interplay between genes and the epigenetic mechanisms that regulate their expression. In this review we describe how an adverse intrauterine environment can influence the expression of miRNAs (a sub-set of non-coding RNAs) and how these changes may impact heart development. Potential consequences of altered miRNA expression in the fetal heart include; Hypoxia inducible factor (HIF) activation, dysregulation of angiogenesis, mitochondrial abnormalities and altered glucose and fatty acid transport/metabolism. It is important to understand how miRNAs are altered in these adverse environments to identify key pathways that can be targeted using miRNA mimics or inhibitors to condition an improved developmental response.

Use of radiotelemetry to assess perinatal cardiac function in the ovine fetus and newborn

The late gestation fetal ECG (fECG) has traditionally been difficult to characterize due to the low fECG signal relative to high maternal noise. Although new technologies have improved the feasibility of its acquisition and separation, little is known about its development in late gestation, a period in which the fetal heart undergoes extensive maturational changes. Here, we describe a method for the chronic implantation of radiotelemetry devices into late gestation ovine fetuses to characterize parameters of the fECG following surgery, throughout late gestation, and in the perinatal period. We found no significant changes in mean aortic pressure (MAP), heart rate (HR), or ECG in the 5 days following implantation; however, HR decreased in the first 24 h following the end of surgery, with associated increases in RR, PR, and QRS intervals. Over the last 14 days of fetal life, fetal MAP significantly increased, and HR significantly decreased, as expected. MAP and HR increased as labor progressed. Although there were no significant changes over time in the ECG during late gestation, the duration of the PR interval initially decreased and then increased as birth approached. These results indicate that although critical maturational changes occur in the late gestation fetal myocardium, the mechanisms that control the cardiac conduction are relatively mature in late gestation. The study demonstrates that radiotelemetry can be successfully used to assess fetal cardiac function, in particular conduction, through the process of labor and delivery, and may therefore be a useful tool for study of peripartum cardiac events.

Common Findings in Late-Gestation Fetal Echocardiography

OBJECTIVES

Fetal echocardiography provides detailed information about cardiac structure and function in utero. Limited information is available regarding normal findings late in pregnancy. We therefore sought to identify and describe common cardiac findings in late gestation.

METHODS

Fetuses with structurally normal hearts were identified in mid gestation within a subset of pregnant women in a prospective study. The atrioventricular valves, right and left atria, aortic isthmus and ductus arteriosus dimensions and flow abnormalities, aneurysm of the septum primum, and presence and grade of tricuspid regurgitation were assessed throughout pregnancy. Linear and logistic regression analyses were used to characterize changes in quantitative and qualitative fetal echocardiographic parameters by gestational age (GA).

RESULTS

Forty fetuses between 24 and 38 weeks' GA were studied. Each had a fetal echocardiographic study completed before and after 34 weeks' gestation, which were compared. Tricuspid-to-mitral valve and right-to-left atrium ratios increased with GA (P < .001). More frequently noted after 34 weeks were tapering of the ductus arteriosus (2.5% versus 32%), prominent aortic isthmus diastolic flow (5% versus 67%), prominent ductus arteriosus diastolic flow (2.5% versus 25%), trivial or mild tricuspid regurgitation (35% versus 80%), and aneurysms of the septum primum (37.5% versus 80%). These findings all increased linearly with GA (P < .001).

CONCLUSIONS

Atrioventricular valve and right/left atrium disproportion, mild ductus arteriosus tapering, prominent aortic isthmus and ductus arteriosus diastolic flow, trivial or mild tricuspid regurgitation, and aneurysms of the septum primum are frequently identified after 34 weeks' GA. Their identification suggests that these fetal echocardiographic findings in isolation are likely normal and are results of the physiologic alterations that occur late in the third trimester.

Novel Technique for Measurement of Fetal Right Myocardial Performance Index Using Dual Gate Pulsed-Wave Doppler

OBJECTIVES

To evaluate the reproducibility of the fetal right myocardial performance index determined by simultaneous recording of inflow and outflow using a dual gate pulsed-wave Doppler (DD).

METHODS

This was a prospective study of 39 normal singleton fetuses. Two experienced operators each measured the right myocardial performance index in three ways, twice: (1) separate recording of the inflow and outflow using single-gate pulsed-wave Doppler (PD), (2) simultaneous recordings of the inflow and outflow using tissue Doppler (TD), and (3) simultaneous recordings of the inflow and outflow using DD. Intra- and interoperator reproducibility were assessed with intraclass correlation coefficients. The measurements from all three methods taken by the more experienced operator were compared using Bland-Altman plots and mean differences.

RESULTS

For both operators, intra-operator reproducibility was the highest when using DD, followed by PD, and TD. Interoperator agreement was the highest for PD measurements, followed by DD, and TD. The smallest mean difference was between the PD and DD measurements by the more experienced operator. There was a positive correlation between PD and DD values (r = 0.369, P < .001).

CONCLUSIONS

Dual gate pulsed-wave Doppler may be an effective alternative to the PD or TD methods, and can separately evaluate systolic and diastolic myocardial function.

Assessing the development of fetal myocardial function by a novel Doppler myocardial performance index

Doppler-derived myocardial performance index are used to assess aspects of systolic and diastolic function in adult as well as fetal heart. The Tei Index (TI) is a useful and non-invasive tool. The aim of this study was to determine normal values of fetal left ventricular (LV) TI in early (16-32 weeks) and late trimester (35-41 weeks) fetuses and to develop a new myocardial performance index (K-index; KI) which focuses on fetal diastolic interval when oxygenated blood from the placenta filled in the LV. Simultaneous recordings of Doppler Ultrasound Signal (DUS) of the LV outflow tracts and fetal electrocardiogram signals were obtained in 55 early- and late-trimester fetuses. The LV isovolumic contraction time (ICT), isovolumic relaxation time (IRT), ventricular ejection time (VET) and ventricular filling time (VFT) were measured from amplitudes and peaks of high frequency component of DUS signals by an automated model. The TI and the new index were calculated by using the formula (ICT + IRT)/VET and (ICT + IRT)/VFT respectively. The TI did not show any significant change from early-to late trimester fetuses (0.74± 0.057 vs 0.75±0.07; NS). On the other hand, KI showed significant decline in values (1.00±0.24 vs 0.87±0.23; p<;0.05) during this development period. The correlation of KI with gestational ages was found to be negative and significant (r=-0.35; p=0.007). No significant correlation of gestational ages with TI was found. Both TI and KI can be easily obtained in the fetus from DUS recording without the need for precise anatomic imaging. In conclusion, KI may be a useful tool to explore the healthy development of fetal myocardial function. More research is needed to check if KI could recognize the compromised fetuses from normal ones in future.

Longitudinal study of computerized cardiotocography in early fetal growth restriction

OBJECTIVES

To explore whether, in early fetal growth restriction (FGR), the longitudinal pattern of fetal heart rate (FHR) short-term variation (STV) can be used to identify imminent fetal distress and whether abnormalities of FHR recordings are associated with 2-year infant outcome.

METHODS

The original TRUFFLE study assessed whether, in early FGR, delivery based on ductus venosus (DV) Doppler pulsatility index (PI), in combination with safety-net criteria of very low STV on cardiotocography (CTG) and/or recurrent FHR decelerations, could improve 2-year infant survival without neurological impairment in comparison with delivery based on CTG monitoring only. This was a secondary analysis of women who delivered before 32 weeks and had consecutive STV data recorded > 3 days before delivery and known infant outcome at 2 years of age. Women who received corticosteroids within 3 days of delivery were excluded. Individual regression line algorithms of all STV values, except the last one before delivery, were calculated. Life tables and Cox regression analysis were used to calculate the daily risk for low STV or very low STV and/or FHR decelerations (below DV group safety-net criteria) and to assess which parameters were associated with this risk. Furthermore, it was assessed whether STV pattern, last STV value or recurrent FHR decelerations were associated with 2-year infant outcome.

RESULTS

One hundred and forty-nine women from the original TRUFFLE study met the inclusion criteria. Using the individual STV regression lines, prediction of a last STV below the cut-off used by the CTG monitoring group had sensitivity of 42% and specificity of 91%. For each day after study inclusion, the median risk for low STV (CTG group cut-off) was 4% (interquartile range (IQR), 2-7%) and for very low STV and/or recurrent FHR decelerations (below DV group safety-net criteria) was 5% (IQR, 4-7%). Measures of STV pattern, fetal Doppler (arterial or venous), birth-weight multiples of the median and gestational age did not usefully improve daily risk prediction. There was no association of STV regression coefficients, a low last STV and/or recurrent FHR decelerations with short- or long-term infant outcomes.

CONCLUSION

The TRUFFLE study showed that a strategy of DV monitoring with safety-net criteria of very low STV and/or recurrent FHR decelerations for delivery indication could increase 2-year infant survival without neurological impairment. This post-hoc analysis demonstrates that, in early FGR, the daily risk of abnormal CTG, as defined by the DV group safety-net criteria, is 5%, and that prediction is not possible. This supports the rationale for CTG monitoring more often than daily in these high-risk fetuses. Low STV and/or recurrent FHR decelerations were not associated with adverse infant outcome and it appears safe to delay intervention until such abnormalities occur, as long as DV-PI is within normal range. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound transducer positioning aid for fetal heart rate monitoring

Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily.

Developmental changes in the balance of glycolytic ATP production and oxidative phosphorylation in ventricular cells: A simulation study

The developmental program of the heart requires accurate regulation to ensure continuous circulation and simultaneous cardiac morphogenesis, because any functional abnormalities may progress to congenital heart malformation. Notably, energy metabolism in fetal ventricular cells is regulated in a manner that differs from adult ventricular cells: fetal cardiomyocytes generally have immature mitochondria and fetal ventricular cells show greater dependence on glycolytic ATP production. However, although various characteristics of energy metabolism in fetal ventricular cells have been reported, to our knowledge, a quantitative description of the contributions of these factors to fetal ventricular cell functions has not yet been established. Here, we constructed a mathematical model to integrate various characteristics of fetal ventricular cells and predicted the contribution of each characteristic to the maintenance of intracellular ATP concentration and sarcomere contraction under anoxic conditions. Our simulation results demonstrated that higher glycogen content, higher hexokinase activity, and lower creatine concentration helped prolong the time for which ventricular cell contraction was maintained under anoxic conditions. The integrated model also enabled us to quantitatively assess the contributions of factors related to energy metabolism in ventricular cells. Because fetal cardiomyocytes exhibit similar energy metabolic profiles to stem cell-derived cardiomyocytes and those in the failing heart, an improved understanding of these fetal ventricular cells will contribute to a better comprehension of the processes in stem cell-derived cardiomyocytes or under pathological conditions.

Assessment of fetal myocardial performance in severe early onset pre-eclampsia (EO-PET) with and without intrauterine growth restriction across deteriorating stages of placental vascular resistance and links to adverse outcomes

OBJECTIVE

To determine whether fetuses in severe early onset pre-eclampsia (EO-PET) with or without intrauterine growth restriction has cardiac dysfunction across deteriorating stages of placental vascular resistance and whether this dysfunction influences perinatal outcome.

STUDY DESIGN

This was a prospective cross-sectional study performed in a tertiary care university medical centre. Sixty pregnant patients with severe early-onset pre-eclampsia between 27 and 32 weeks were recruited and matched with 60 patients having normal pregnancies. An analysis of cardiac function using the myocardial performance index (MPI) and early ventricular filling (E) and late active atrial contraction (A) ratios (E/A ratios) in the study group was performed compared to controls and further analysis was performed based on worsening placental vascular resistance and presence of growth restriction.

RESULTS

MPI values were increased in the pre-eclamptic group, irrespective if growth restriction co-exists, compared to controls (0.61 vs 0.38, p<0.001). Its median value progressively increased with worsening placental vascular resistance. For adverse perinatal outcome cut-off MPI values have been suggested. The E/A ratios were significantly decreased in the pre-eclamptic group compared to controls (0.66 vs 0.79, p<0.0001). No adverse outcomes were noted in the control group.

CONCLUSION

Fetal cardiac function is significantly impaired in pregnancies complicated by severe early onset pre-eclampsia, irrespective if growth restriction co-exists and worsens with deteriorating grades of placental vascular resistance. The MPI can potentially be integrated into routine fetal surveillance techniques.

Fetal Ductus Venosus Pulsatility Index and Diameter during Second and Third Trimester of Gestation

INTRODUCTION

The ductus venosus is a small funnel shaped vessel found posterior to the fetal liver connecting the intra-abdominal umbilical vein and the inferior vena cava. It is one of the three physiological shunts in the fetus. The main objective of this study is to construct the reference table and normogram for fetal ductus venosus Pulsatility Index and diameter with gestational age.

METHODS

This was a prospective cross sectional study conducted during August 2011 to July 2012 taking 294 uncomplicated pregnancies using systemic random sampling method. Three measurements were made for ductus venosus diameter and Pulsatility Index in each fetus during period of fetal quiescence.

RESULTS

The ductus venosus diameter at <20weeks, 20-25 weeks, 25-30 weeks, >30 weeks were 1.16, 1.31, 1.62, 1.81 and Pulsatility Index at <20weeks, 20-25 weeks, 25-30 weeks, >30 weeks were 0.41, 0.44, 0.41 and 0.41 respectively.

CONCLUSIONS

The mean diameter of the ductus venosus was linear across gestational age. The Pulsatility Index shows a scattered distribution across the gestational age.

A multi-dimensional Hidden Markov Model approach to automated identification of fetal cardiac valve motion

Fetal cardiac assessment techniques are aimed to identify fetuses at risk of intrauterine compromise or death. Evaluation of the electromechanical coupling as a fundamental part of the fetal heart physiology, provides valuable information about the fetal wellbeing during pregnancy. It is based on the opening and closing time of the cardiac valves and the onset of the QRS complex of the fetal electrocardiogram (fECG). The focus of this paper is on the automated identification of the fetal cardiac valve opening and closing from Doppler Ultrasound signal and fECG as a reference. To this aim a novel combination of Emprical Mode Decomposition (EMD) and multi-dimensional Hidden Markov Models (MD-HMM) was employed which provided beat-to-beat estimation of cardiac valve event timings with improved precision (82.9%) compared to the one dimensional HMM (77.4%) and hybrid HMM-Support Vector Machine (SVM) (79.8%) approaches.

Maternal obesity affects fetal myocardial function as early as in the first trimester

OBJECTIVE

To investigate cardiac function from 14 weeks' gestation in fetuses of obese pregnant women (FOW). Animal studies have shown that maternal obesity induces fibrosis in fetal myocardium. We hypothesized that fetal cardiac function would be impaired among FOW.

METHODS

A case-control study with longitudinal follow-up was performed at Trondheim University Hospital, Norway. In total, 80 pregnant women were included and the final population comprised 52 obese and 24 of normal weight (mean body mass index before pregnancy, 34.8 ± 4.1 vs 21.0 ± 2.2 kg/m(2) ; P < 0.001). The main outcome measures were global strain rate (GSR) and strain by tissue Doppler imaging, tissue Doppler velocities (TDVs) and interventricular septal thickness assessed by fetal echocardiography at gestational ages of 14, 20 and 32 weeks.

RESULTS

In FOW, fetal left ventricle (LV) and right ventricle (RV) GSR and strain were significantly lower than in fetuses of normal-weight pregnant women: LV GSR was 33.3% lower at 14 weeks, 22.4% lower at 20 weeks and 22.8% lower at 32 weeks of gestation (P < 0.001) with no difference in fetal heart rate. Systolic and late diastolic TDVs for LV were significantly lower from 20 weeks' gestation and remained lower throughout pregnancy. Fetal interventricular septum was 26.6% (P < 0.001) thicker in late pregnancy in FOW compared with normal-weight pregnancies.

CONCLUSIONS

At 14 weeks of gestation, we detected fetal myocardial dysfunction with reduced LV and RV GSR and strain in FOW compared with fetuses of women with normal weight. Our finding is alarming considering the high prevalence of obesity and may partly explain the predisposition of offspring to cardiovascular disease later in life.

Utility of ductus venosus blood flow in the study of cardiac function in fetuses with intracardiac echogenic focus

PURPOSE

The purpose of this study was to investigate fetal ductus venosus (DV) wave velocities, DV velocity ratios, and DV diastolic time intervals to derive additional information on fetal cardiac function in the presence of an intracardiac echogenic focus (IEF).

METHODS

Seventy fetuses at 19-28 weeks of gestation with an IEF and 63 control fetuses were screened using two-dimensional and power Doppler echocardiography. DV wave velocities, DV velocity ratios, and diastolic time intervals were measured. The aortic peak velocity, pulmonary artery peak velocity, left ventricular shortening fraction, and right ventricular shortening fraction, atrioventricular early-diastolic filling velocity (E), atrial contraction velocity (A), and E/A ratio were also measured.

RESULTS

The study and control groups were similar in terms of maternal age, body mass index, and gestational age in weeks at the time of examination (p > 0.05). Significant between-group differences were found in DV v-descent (p = 0.03) and a-wave velocities (p = 0.04).

CONCLUSIONS

Although the presence of an IEF in the fetal heart does not influence conventional measurements (DV velocity ratios and DV diastolic time intervals), it is associated with changes in DV v-descent and a-wave velocities. These changes may be indirectly related to reduced end-systolic relaxation and augmented atrial contraction in the fetal heart. We therefore suggest examination of DV flow velocities in fetuses with IEF.

Cardiac axis shift within the cardiac cycle of normal fetuses and fetuses with congenital heart defect

OBJECTIVES

To investigate changes in the cardiac axis (CAx) within the cardiac cycle of normal fetuses and fetuses with congenital heart defects (CHD).

METHODS

This was a retrospective case-control study in which stored videoclips of four-chamber views from 527 prenatal ultrasound examinations performed at 18 + 0 to 36 + 6 weeks of gestation were reviewed. Among the ultrasound scans included, 287 were of normal fetuses (controls) and 240 were of fetuses with CHD. In each case, the CAx was measured at end systole (just before the atrioventricular (AV) valve opened) and at end diastole (just before the AV valve closed). CAx measurements of fetuses with CHD were compared to those of controls.

RESULTS

The mean CAx in the control group was 45.9 ± 8.5° at end systole and 38.3 ± 8.4° at end diastole (P < 0.001), resulting in an average difference of 7.6 ± 3.2°. The mean CAx in fetuses with CHD was 53.4 ± 17.8° at end systole and 47.5 ± 17.3° at end diastole (P < 0.001), resulting in an average difference of 5.9 ± 6.3°. However, in some forms of CHD, such as hypoplastic left heart syndrome and L-transposition of the great arteries, the CAx was greater at end diastole than at end systole, with a difference of more than 5°. In 21.3% of control fetuses, there was a CAx shift within the cardiac cycle of ≥ 10°. Abnormal CAx measured at end systole was strongly associated with CHD.

CONCLUSIONS

Measurement of the CAx at end systole provides values that differ from those when measured at end diastole, in both normal fetuses and those with CHD. We recommend that the CAx be measured at end systole as a greater proportion of fetuses with CHD and fewer normal fetuses have an abnormal CAx at this stage compared to at end diastole. The occurrence of an abnormal CAx and the CAx shift within the fetal cardiac cycle depend on the type of CHD.