Longitudinal survey of fetal ventricular ejection and shortening fraction throughout pregnancy

Comparisons of serum non-transferrin-bound iron levels and fetal cardiac function between fetuses affected with hemoglobin Bart's disease and normal fetuses

Objective

To compare the levels of Non-transferrin bound iron (NTBI) in fetuses with anemia, using Hb Bart's disease as a study model, and those in unaffected fetuses and to determine the association between fetal cardiac function and the levels of NTBI.

Patients and methods

A prospective study was conducted on pregnancies at risk of fetal Hb Bart's disease. All fetuses underwent standard ultrasound examination at 18-22 weeks of gestation for fetal biometry, anomaly screening and fetal cardiac function. After that, 2 ml of fetal blood was taken by cordocentesis to measure NTBI by Labile Plasma Iron (LPI), serum iron, hemoglobin and hematocrit. The NTBI levels of both groups were compared and the correlation between NTBI and fetal cardiac function was determined.

Results

A total of 50 fetuses, including 20 fetuses with Hb Bart's disease and 30 unaffected fetuses were recruited. There was a significant increase in the level of serum iron in the affected group (median: 22.7 vs. 9.7; p-value: 0.013) and also a significant increase in NTBI when compared with those of the unaffected fetuses (median 0.11 vs. 0.07; p-value: 0.046). In comparisons of fetal cardiac function, myocardial performance (Tei) index of both sides was significantly increased in the affected group (left Tei: p = 0.001, Right Tei: p = 0.008). Also, isovolumetric contraction time (ICT) was also significantly prolonged (left ICT: p = 0.00, right ICT: p = 0.000). Fetal LPI levels were significantly correlated inversely with fetal hemoglobin levels (p = 0.030) but not significantly correlated with the fetal serum iron levels (p = 0.138). Fetal LPI levels were also significantly correlated positively with myocardial performance index (Tei) of both sides (right Tei: R = 0.000, left Tei: R = 0.000) and right ICT (R = 0.013), but not significantly correlated with left ICT (R = 0.554).

Conclusion

Anemia caused by fetal Hb Bart's disease in pre-hydropic stage is significantly associated with fetal cardiac dysfunction and increased fetal serum NTBI levels which are significantly correlated with worsening cardiac dysfunction. Nevertheless, based on the limitations of the present study, further studies including long-term data are required to support a role of fetal anemia as well as increased fetal serum NTBI levels in development of subsequent heart failure or cardiac compromise among the survivors, possibly predisposing to cardiovascular disease in adult life.

Third Trimester Fetal Heart Rates in Antibody-Mediated Complete Heart Block Predict Need for Neonatal Pacemaker Placement

Congenital complete heart block (CCHB) affects 1 in 20,000 newborns. This study evaluates fetal and neonatal risk factors predictive of neonatal pacemaker placement in antibody-mediated complete heart block. The Children's Hospital Los Angeles institutional fetal, pacemaker, and medical record databases were queried for confirmed SSA/SSB cases of CCHB between January 2004 and July 2019. Cases excluded were those with a diagnosis beyond the neonatal period, diagnosis of a channelopathy, or if maternal antibody status was unknown. We recorded the gestational age (GA), birth weight (BW), fetal heart rates (FHRs) of the last echocardiogram before delivery, specific neonatal ECG and echocardiogram findings, age at pacemaker placement, and mortality. Of 43 neonates identified with CCHB, 27 had confirmed maternal antibody exposure. Variables associated with neonatal pacemaker implantation were FHRs < 50 bpm (p = 0.005), neonatal heart rates < 52 bpm (p = 0.015), and neonatal left ventricular fractional shortening (FS) percentages < 34% (p = 0.03). On multivariate analysis, FHR remained significant (p = 0.03) and demonstrated an increased risk of neonatal pacemaker placement by an odds ratio of 12.5 (95% CI 1.3-116, p = 0.05). The median GA at which the FHR was obtained was 34 weeks (IQR 26-35 weeks). Neonatal pacemaker placement was highly associated with a FHR < 50 bpm, neonatal HR < 52 bpm, and neonatal FS < 34%. FHRs at 34 weeks GA (IQR 26-35 weeks) correlated well with postnatal heart rates and were predictive of neonatal pacemaker placement.

The aorto-left ventricular tunnel from a fetal perspective: original case series and literature review

Introduction

Aorto‐left ventricular tunnel (ALVT) accounts for <0.1% of congenital heart defects. Evidence on the prognosis from a fetal perspective is limited. With this retrospective international case series, we provide information on the outcome of fetuses with ALVT.

Methods

All members of the Association for European Pediatric and Congenital Cardiology's (AEPC) fetal working group and fetal medicine units worldwide were invited for participation. We observed antenatal parameters, neonatal outcome and postnatal follow‐up. Additionally, a systematic search of the literature was performed.

Results

Twenty fetuses with ALVT were identified in 10 participating centers (2001–2019). Fetal echocardiographic characteristics of ALVT included an increased cardiac–thorax ratio (95%), left ventricular end‐diastolic diameter (90%) and a dysplastic aortic valve (90%). Extracardiac malformations were rare (5%). Eight fetuses died at a median gestational age (GA) of 21 + 6 weeks (range, 19–24): all showed signs of hydrops prior to 24 weeks or at autopsy. All others (60%, 12/2) were live–born (median GA 38 + 4, range 37–40), underwent surgery and were alive at last follow up (median 3.2 years, range 0.1–17). The literature reported 22 ALVT fetuses with similar outcome.

Conclusions

In the absence of fetal hydrops, ALVT carries a good prognosis. Fetuses who survive to 24 weeks without hydrops are likely to have a good outcome.

What's already known about this topic?

Aorto‐left ventricular tunnel (ALVT) is an extremely rare diagnosis that may cause congenital heart failure and fetal hydrops, leading to fetal or neonatal death.

A few case reports show that after corrective surgery in the neonatal period, cases with ALVT tend to have a good prognosis.

What does this study add?

This is the first study that evaluates prenatal characteristics, prognostic parameters and outcome following a prenatal diagnosis of ALVT in a cohort of cases worldwide, including a systematic review of the literature as well.

In the absence of fetal hydrops, ALVT carries a good prognosis. Fetuses who survive to 24 weeks without hydrops are likely to have a good outcome.

Prescriptive standards of echocardiographic morphometric and functional parameters in uncomplicated monochorionic diamniotic fetuses

OBJECTIVE

To create prescriptive standards of cardiac morphometric and functional parameters in a cohort of uncomplicated monochorionic diamniotic (MCDA) twins.

METHOD

Fetal echocardiography was performed in a cohort of uncomplicated monochorionic twin fetuses scanned longitudinally, including comprehensive morphometric and functional parameters, using 2-D imaging, M-mode and conventional Doppler. A multilevel polynomial hierarchical model adjusted by gestational age and estimated fetal weight was used to fit each cardiac parameter.

RESULTS

The global heart dimensions including the atrial and ventricular areas, the ventricles dimensions and myocardial wall thicknesses and most of the functional parameters, such as the longitudinal myocardial motion and the biventricular cardiac output showed a positive quadratic increment throughout pregnancy. On the other hand, the left ejection fraction, shortening fraction and right fractional area change decreased with gestational age. Scatterplots for the main structural and functional parameters and ratios by gestational age, with mean, 5th, 10th, 90th, and 95th percentiles are provided. Regression equations by estimated fetal weight are also created.

CONCLUSION

We provide specific comprehensive echocardiographic prescriptive standards for uncomplicated MCDA twin fetuses following current standardized methodology. The implementation of these charts will potentially help to better identify abnormal cardiovascular parameters associated to monochorionic complications.

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.

A transition point for the blood flow wall shear stress environment in the human fetal left ventricle during early gestation

Development of the fetal heart is a fascinating process that involves a tremendous amount of growth. Here, we performed image-based flow simulations of 3 human fetal left ventricles (LV), and investigated the hypothetical scenario where the sizes of the hearts are scaled down, leading to reduced Reynolds number, to emulate earlier fetal stages. The shape and motion of the LV were retained over the scaling to isolate and understand the effects of length scaling on its fluid dynamics. We observed an interesting cut-off point in Reynolds number (Re), across which the dependency of LV wall shear stress (WSS) on Re changed. This was in line with classical fluid mechanic theory where skin friction coefficient exhibited first a decreasing trend and then a plateauing trend with increasing Re. Below this cut-off point, viscous effects dominated, stifling the formation of LV diastolic vorticity structures, and WSS was roughly independent of Reynolds number. However, above this cut-off, inertial effects dominated to cause diastolic vortex ring formation and detachment, and to cause WSS to scale linearly with Reynolds number. Results suggested that this transition point is found at approximately 11 weeks of gestation. Since WSS is thought to be a biomechanical stimuli for growth, this may have implications on normal fetal heart growth and malformation diseases like Hypoplastic Left Heart Syndrome.

Uncomplicated Monochorionic Twins: Two Normal Hearts Sharing One Placenta

Cardiovascular dysfunction has been reported in complicated monochorionic diamniotic (MCDA) pregnancies; however, little is known whether hemodynamic changes occur in uncomplicated MCDA twins. A prospective observational study was conducted including 100 uncomplicated MCDA twins matched by gestational age to 200 low-risk singletons. Echocardiography was performed at 26-30 weeks gestation and cord blood B-type natriuretic peptide (BNP) was measured at delivery. In both groups, z-scores for echocardiographic parameters were within normal ranges; however the monochorionic group had larger atrial areas (mean (standard deviation) right atria-to-heart ratio: 17.0 (2) vs. 15.9 (1); p = 0.018; left atria-to-heart ratio: 17.0 (3) vs. 15.8 (2); p < 0.001) and signs of concentric hypertrophy (right relative wall thickness: 0.66 (0.12) vs. 0.56 (0.11); p < 0.001; left relative wall thickness: 0.69 (0.14) vs. 0.58 (0.12); p < 0.001). Longitudinal function was increased in twins, leading to higher tricuspid annular plane systolic excursion (6.9 mm (0.9) vs. 5.9 mm (0.7); p < 0.001) and mitral annular plane systolic excursion (4.9 mm (0.8) vs. 4.4 mm (1.1); p < 0.001. BNP levels at birth were also higher in MCDA twins (median [interquartile range]: 20.81 pg/mL [16.69-34.01] vs. 13.14 pg/mL [9.17-19.84]; p < 0.001). Thus, uncomplicated MCDA fetuses have normal cardiac shape and function, but signs of cardiac adaptation were identified by echocardiographic and biochemical parameters, when compared with singletons.

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.

Feasibility of automated fetal fractional shortening measurement with two-dimensional tracking and construction of a reference range for normal fetuses

PURPOSE

To assess the feasibility of an automated fractional shortening (Auto FS) measurement method using two-dimensional tracking and to construct a reference range for normal fetuses.

METHODS

This study was conducted from May 2017 to March 2018. First, cardiac motion in the four-chamber view was recorded in the B-mode. Subsequently, the region of interest was set on the edge of the ventricular septum or ventricular muscle at a point one-third away from the atrioventricular valve toward the cardiac apex. Tracking was automatically performed. Values measured between the ventricular septum and right ventricle were defined as R-Auto FS, whereas those measured between the ventricular septum and left ventricle were defined as L-Auto FS. Those on each ventricular muscle were defined as Combined-Auto FS.

RESULTS

Data were obtained from 131 singleton fetuses. R-Auto FS significantly decreased with an increase in the number of gestational weeks, and L-Auto FS and Combined-Auto FS showed the same tendency (Spearman's correlation analysis: p = - .528, p = - .351, and p = - .636, respectively).

CONCLUSION

We succeeded in defining a reference Auto FS value for normal singleton pregnancies. Auto FS was negatively correlated with gestational age. This novel technique can assess fetal heart contractility.

Maturational patterns in right ventricular strain mechanics from the fetus to the young infant

AIM

To test the hypothesis that right ventricular (RV) function has age-specific patterns of development, we tracked the evolution of RV strain mechanics by 2D-speckle tracking echocardiography (2DSTE) in healthy subjects from mid-gestation through one year of age.

METHODS

We conducted a prospective longitudinal echocardiography study in 50 healthy subjects at five time periods across gestation (16-20 weeks, 21-25 weeks, 26-30 weeks, 31-35 weeks, and 36-40 weeks) and four time periods following delivery (1 week, 1 month, 6 months, and 1 year of age). We characterized RV function by measuring RV global and free wall longitudinal strain and systolic strain rate, and segmental longitudinal strain at the apical-, mid-, and basal- ventricular levels of the free wall. Possible associations of gestational age, postnatal age, estimated fetal weight, body surface area, gender, and heart rate on strain were investigated.

RESULTS

The magnitudes of RV global and free wall longitudinal strain and global strain rate were decreased throughout gestation (p < 0.05 for all). Following birth, the magnitudes of all measures increased from one week through one year (p < 0.001 for all). RV segmental longitudinal strain maintained a base-to-apex gradient (highest-to-lowest) from mid-gestation through one year (p < 0.001). There was no significant difference in strain patterns based on gender or hear rate.

CONCLUSION

The maturational patterns of RV strain are gestational- and postnatal age- 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.

Factors associated to early intrauterine fetal demise after laser for TTTS by preoperative fetal heart and Doppler ultrasound

OBJECTIVE

To determine the prognostic value of fetal Doppler and echocardiographic parameters for intrauterine fetal demise (IUFD) within 24 hours and within 1 week after laser coagulation in monochorionic pregnancies complicated by twin-twin transfusion syndrome.

METHOD

This retrospective study correlated the preoperative hemodynamic and echocardiography parameters to the outcome in fetuses with twin-twin transfusion syndrome undergoing laser therapy.

RESULTS

One hundred and twelve laser coagulations were performed between February 2006 and June 2015. The total (single and double) IUFD rate was 27.7%. Further, 59% of IUFD occurred within 24 hours and 74.4% occurred within 1 week after laser. The following were associated to IUFD within 24 hours: the middle cerebral arterial pulsatility index in the donor, abnormal umbilical artery (UA) end diastolic flow, increased middle cerebral artery peak systolic velocity, and right ventricular myocardial performance index (RV-MPI) z-score in the recipient. For IUFD within 1 week were the pulsatility index in the donor UA and the recipient abnormalities in UA, ductus venosus, middle cerebral artery-peak systolic velocity, and RV-MPI z-score.

CONCLUSION

Following laser was early IUFD that was associated with Doppler findings suggesting donor cerebroplacental redistribution, and recipient overload cardiomyopathy, such as abnormal ductus venosus and UA Dopplers as well as an increase of RV-MPI.

Twenty-four Segment Transverse Ventricular Fractional Shortening: A New Technique to Evaluate Fetal Cardiac Function

OBJECTIVES

Because of various fetal and maternal disease states, this study was conducted to evaluate the fractional shortening of 24 transverse segments distributed from the base to the apex of the ventricular chambers.

METHODS

Two hundred control fetuses were examined between 20 and 40 weeks' gestation. The transverse displacement of the ventricular endocardium during the cardiac cycle was computed by using offline software. From the output of the analysis, 24 end-diastolic and end-systolic segments were measured from the base (segment 1) to the apex (segment 24) of the right and left ventricles, and the fractional shortening was computed: [(end-diastolic length - end-systolic length)/end-diastolic length] × 100. Examples of fetal cardiovascular abnormalities were selected to demonstrate the utility of this technique.

RESULTS

The fractional shortening for each segment was independent of gestational age and fetal biometric measurements. There was no significant difference in fractional shortening for segments 1 to 5 between the right and left ventricles. However, the fractional shortening of the left ventricle was significantly greater (P < .0001) than that of the right ventricle for segments 6 to 24, suggesting that the mid and apical segments of the left ventricle have increased displacement toward the center of the chamber compared to the right ventricle. Fetuses with various cardiac structural abnormalities had abnormal fractional shortening values.

CONCLUSIONS

The fractional shortening of 24 segments of the right and left ventricles provides a comprehensive method to examine the contractility of the ventricular chambers.

Intermediate Diastolic Velocity as a Parameter of Cardiac Dysfunction in Growth-Restricted Fetuses

OBJECTIVE

To evaluate the intermediate intracardiac diastolic velocities in fetuses with growth restriction.

METHODS

Doppler waveforms of the two atrioventricular valves were obtained. Peak velocities of the E (early) and A (atrial) components, and the lowest intermediate velocity (IDV) between them, were measured in 400 normally grown and in 100 growth-restricted fetuses. The prevalence of abnormal IDV, E/IDV, and A/IDV ratios in fetuses presenting with perinatal death or acidemia at birth (pH ≤7.1) was estimated.

RESULTS

IDV was significantly lower and E/IDV ratios significantly higher in the two ventricles of growth-restricted fetuses with reduced diastolic velocities in the umbilical artery (p < 0.05). In 13 fetuses presenting with perinatal death or acidemia at birth, 11 (85%) had either an E/IDV or A/IDV ratio >95th percentile, whereas 5 (38%) showed absent or reversed atrial velocities in the ductus venosus (DV-ARAV; p < 0.04). Fetuses without DV-ARAV but with elevated E/IDV ratios in either ventricle were nearly 7-fold more likely to have perinatal demise or acidemia at birth (OR 6.9, 95% CI 1.4-34) than those with E/IDV ratios <95th percentile.

CONCLUSION

The E/IDV and A/IDV ratios in the two cardiac ventricles might provide information about the risk of perinatal demise or acidemia in growth-restricted fetuses.

Fetal ventricular shortening fraction in hydrops fetalis

OBJECTIVE

To estimate fetal ventricular shortening fraction, representing cardiac contractility, derived from cardiospatiotemporal image correlation with M-mode display "STIC-M" in fetuses with hydrops fetalis secondary to high-output (fetal anemia) and low-output causes (congenital heart defects).

METHODS

A cross-sectional study was conducted in normal fetuses (group 1), fetuses with hemoglobin Bart's disease with (group 2) and without (group 3) hydrops fetalis, and those with hydrops fetalis resulting from cardiac defects (group 4). Volume data sets of cardiospatiotemporal image correlations were acquired for each group for subsequent offline analysis with cardiospatiotemporal image correlation with M-mode display. Group 1 data were used to construct reference ranges of left and right ventricular shortening fraction for assessment of fetuses in the remaining groups.

RESULTS

A total of 606 measurements, 15-35 per week, were performed in normal fetuses to construct reference ranges as well as Z-scores of left and right ventricular shortening fraction. Both parameters were decreased with increasing gestation with weak correlation (r2=0.141, P<.001 and r2=0.055, P<.001, respectively). Shortening fraction did not significantly change among 111 fetuses with hemoglobin Bart's disease with and without hydrops. However, left and right ventricular shortening fraction were significantly decreased (mean Z-scores 5 standard deviations and 8 standard deviations below the mean, respectively) in 21 hydropic fetuses as a result of congenital heart defects (P<.001).

CONCLUSION

Fetuses with hydrops fetalis secondary to cardiac defects and anemia have a different pattern of shortening fraction. Hydrops fetalis resulting from cardiac defect is primarily caused by cardiac decompensation; whereas in fetal anemia, it is probably caused by hypervolemia with cardiac decompensation occurring when the cardiac compensatory mechanism is exhausted.

LEVEL OF EVIDENCE

II.

Aortic regurgitation associated with critical aortic stenosis in a fetus

Aortic regurgitation in association with aortic stenosis is rare in the fetus. Findings have shown that severe aortic regurgitation is worsened by the increase in systemic vascular resistance after birth, resulting in low cardiac output, hypoxemia, and neonatal death. This report describes a unique case of aortic regurgitation with aortic stenosis, severe mitral regurgitation, retrograde flow in the aortic arch, and an enormous left atrium with a restrictive foramen ovale in a fetus. In this case, aortic regurgitation was diminished immediately after birth, indicating that spontaneous improvement in aortic regurgitation after birth should be taken into account when the final prognosis is predicted.

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study

Background

Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI).

Methods

TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201–273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis.

Results

Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E’/A’ ratio also increased with gestational age, while a longitudinal shortening was demonstrated.

Conclusions

Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.

Critical Ebstein anomaly in a fetus successfully managed by elective preterm delivery and surgical intervention without delay after birth

This report describes a case of Ebstein anomaly in a fetus with cardiomegaly, severe tricuspid regurgitation, pulmonary regurgitation, and retrograde ductal flow that showed a marked increase in the size of the right atrium with advancing gestational age. Elective preterm delivery was performed at 35 weeks gestation. The prostaglandin E1 infusion resulted in more pronounced systemic hypotension and acidosis secondary to circular shunt across the patent ductus arteriosus as well as pulmonary regurgitation and tricuspid regurgitation. Emergency surgical intervention consisting of main pulmonary artery ligation, ductus arteriosus ligation, central shunt creation, and plication of the right atrium without cardiopulmonary bypass was performed 4 h after birth. At the age of 16 days, the Starnes procedure was performed. The infant's postoperative course was uneventful. A fetus that has Ebstein anomaly associated with pulmonary regurgitation is at risk for circular shunt across the patent ductus arteriosus after delivery. Planned delivery and surgical intervention without delay after birth are useful for the treatment of such cases.

Shortening fraction of the right ventricle: a comparison between euploid and trisomy 21 fetuses at week 11 to week 13 and 6 days of gestation

OBJECTIVES

This study was designed to compare the first trimester shortening fraction of the right ventricle (SFRV) values between euploid fetuses and fetuses with trisomy 21.

METHODS

SFRV was measured in 58 first trimester fetuses between September 2008 and February 2010. The stored M-mode images were used to obtain the right ventricular diastolic diameter (RVDD) and right ventricular systolic diameter (RVSD) measurements offline.

RESULTS

The SFRV values were found to be significantly greater in the 9 fetuses with trisomy 21 as compared to the group of 49 euploid fetuses (mean: 48.6 mm; range: 36-56.25 mm vs mean: 34.11 mm; range: 22.73-43.48 mm) (p < 0.0001). The RVDD measurements were also found to be significantly greater in the fetuses with trisomy 21 than in the euploid fetuses (mean: 3.08 mm; range: 2.2-4.7 mm vs mean: 2.54 mm; range: 1.9-3.6 mm) (p = 0.03).There was no difference in the RVSD measurements between the two groups [mean: 1.56 mm; range: 1.2-2.3 mm (trisomy 21 fetuses) vs mean: 1.67 mm; range: 1.3-2.4 mm (euploid fetuses)] (p = 0.17).

CONCLUSIONS

The SFRV values in fetuses with trisomy 21 appear to be significantly greater than in the euploid fetuses. The RVDD also appears to be greater in fetuses with trisomy 21 than in the euploid fetuses.

Fetal cardiac dimensions at 14-40 weeks' gestation obtained using cardio-STIC-M

OBJECTIVES

To establish normative reference ranges of fetal cardiac dimensions derived from volume datasets acquired using spatiotemporal image correlation with M-mode display (cardio-STIC-M).

METHODS

A cross-sectional study was undertaken on singleton pregnancies with normal fetuses and accurate gestational ages. Cardio-STIC volume datasets were acquired by experienced operators using a high-resolution ultrasound machine; these were maneuvered to obtain a four chamber-view with exactly horizontal interventricular septum (IVS). Cardiac dimensions were measured in STIC-M-mode using 4D View software.

RESULTS

A total of 657 measurements, at a rate of between 15 and 37 per week, were obtained. Normal reference ranges for biventricular outer diameter, left and right ventricular inner diameter, left and right ventricular wall thickness, IVS thickness, left to right ventricular diameter ratio and left and right ventricular shortening fractions were constructed based on best-fit equations as a function of gestational age, fetal head circumference and biparietal diameter. Thirty-four volume datasets of abnormal fetal hearts were also separately assessed, many of which showed abnormal cardiac dimensions.

CONCLUSIONS

This is the first report on normal ranges of fetal cardiac dimensions constructed using the new cardio-STIC-M technology. Preliminary evaluation suggests that these reference ranges may be a useful tool in the assessment of fetal cardiac abnormalities.

Left ventricle shortening fraction: a comparison between euploid and trisomy 21 fetuses in the first trimester

OBJECTIVES

Measurement of the shortening fraction of the left ventricle (SFLV) is an objective way to assess systolic performance. The aim of the study was to compare first trimester SFLV values in euploid fetuses to those in fetuses with trisomy 21.

METHODS

We measured SFLV in 56 fetuses from 11 weeks to 13 weeks 6 days. The left ventricular diastolic diameter (LVDD) and left ventricular systolic diameter (LVSD) were measured offline, and SFLV was calculated. The data were analyzed using Mann-Whitney U test.

RESULTS

We found a significant difference in the SFLV measurements between the group of 49 euploid fetuses and the 7 fetuses with trisomy 21 [38.00 (95% CI: 33.72-42.27) vs 49.93 (95% CI: 43.72-56.13)] (p < 0.05). There was also a significant difference in the nuchal translucency measurements between the two groups: 1.78 mm (95% CI: 1.08-2.48 mm) in the euploid population versus 5.06 mm (95% CI: 3.61-6.71 mm) in the fetuses with trisomy 21 (p < 0.05). There were no significant differences between the group of euploid fetuses and the group of trisomy 21 fetuses in the following parameters: CRL (chorionic villus sampling), LVDD and LVSD.

CONCLUSIONS

SFLV is a well-defined, simple measurement of systolic function of the fetal myocardium. SFLV values in fetuses with trisomy 21 appear to be significantly higher than in euploid fetuses.

Preload index of the inferior vena cava as a possible predictive marker of hydropic changes in fetuses with Ebstein anomaly

OBJECTIVE

We aimed to investigate whether the preload index of the inferior vena cava (PLI-IVC) is of diagnostic value in predicting hydropic changes in fetuses with Ebstein anomaly.

METHODS

Five cases of prenatally diagnosed Ebstein anomaly, which were managed at our institution between 1999 and 2008, were retrospectively reviewed. The PLI-IVC was calculated as the ratio between the reversed flow velocity from the right atrium and the forward velocity of the IVC.

RESULTS

The PLI-IVC was high in all the cases. In 2 cases, PLI-IVC values tended to increase gradually before hydropic changes were recognized. In the cases without hydrops, PLI-IVC values exhibited a nonlinear trend throughout gestation and did not show any apparent increase.

CONCLUSIONS

The upward trend of the PLI-IVC rather than the maintenance of a high value can be considered a sign of cardiac failure. The blood flow pattern in the IVC should be carefully monitored in fetuses with Ebstein anomaly for the early identification of fetal impairment.

Validation of the fetal myocardial performance index in the second and third trimesters of gestation

OBJECTIVES

To test the validity of the myocardial performance index (MPI) and its components against the more conventional methods of fetal cardiac function assessment: the ejection fraction (EF) for systolic function and the E/A index (ratio of transmitral flow during early (E) ventricular filling to flow during atrial (A) contraction) for diastolic function, both in a normal population and in a population at risk for cardiac failure because of volume overload (recipient fetuses in cases of twin-twin transfusion syndrome (TTTS)).

METHODS

The MPI was measured prospectively in addition to more commonly used indices of systolic (EF) and diastolic (E/A index) cardiac function in 117 healthy fetuses (gestational age range, 20-36 weeks) and in 14 fetuses suspected of cardiac failure because of the presence of TTTS. Nomograms were constructed for all variables, and correlations between the MPI, EF and E/A index were assessed. The time taken to obtain the measurements as well as the interobserver and intraobserver variability were determined for the MPI and EF.

RESULTS

In healthy fetuses, the MPI and EF were independent of gestational age, whereas the E/A index and isovolumetric relaxation time (IRT) increased with gestational age. The MPI correlated inversely with the EF (P<0.001). The IRT showed a trend towards an inverse correlation with the E/A index (P=0.10). The mean+/-SD time needed to measure the MPI and EF was 140+/-65 s and 185+/-187 s, respectively (P=0.43). Interobserver and intraobserver intraclass correlation coefficients for the MPI were 0.98 (95% CI, 0.85-0.99) and 0.82 (95% CI, 0.14-0.95), respectively; those for the EF were 0.58 (95% CI, -0.16 to 0.85) and 0.51 (95% CI, -0.46 to 0.83), respectively; and those for the E/A index were 0.97 (95% CI, 0.88-0.99) and 0.91 (95% CI, 0.66-0.98), respectively. All variables, except ejection time, were significantly different between normal fetuses and those with TTTS.

CONCLUSIONS

The MPI is an indicator of the systolic component of fetal left ventricular function that can be easily acquired and reproduced. The MPI is strongly correlated with the EF but shows less interobserver and intraobserver variability.

Cardiovascular assessment of fetal mice by in utero echocardiography

To establish a developmental profile of fetal mouse cardiovascular parameters, we analyzed a large body of ultrasound measurements obtained by in utero echocardiography of C57BL/6J fetal mice from embryonic day 12.5 to 19.5 (term). Measurements were obtained using two-dimensional (2D), spectral Doppler and M-mode imaging with standard clinical cardiac ultrasound imaging planes. As these studies were conducted as part of a large scale mouse mutagenesis screen, stringent filtering criteria were used to eliminate potentially abnormal fetuses. Our analysis showed heart rate increased from 190 to 245 beats per minute as the mouse fetus grew from 8 mm at embryonic day 12.5 to 18.7 mm at term. This was accompanied by increases in peak outflow velocity, E-wave, E/A ratio and ventricular dimensions. In contrast, the A-wave, myocardial performance index and isovolemic contraction time decreased gradually. Systolic function remained remarkably stable at 80% ejection fraction. Analysis of intra- and interobserver variabilities showed these parameters were reproducible, with most comparing favorably to clinical ultrasound measurements in human fetuses. A comprehensive database was generated comprising 23 echocardiographic parameters delineating fetal mouse cardiovascular function from embryonic day 12.5 to term. This database can serve as a standard for evaluating cardiovascular pathophysiology in genetically altered and mutant mouse models.

The twin-twin transfusion syndrome: spectrum of cardiovascular abnormality and development of a cardiovascular score to assess severity of disease

OBJECTIVE

Current means of grading twin-twin transfusion syndrome does not characterize cardiovascular aspects adequately. We sought to develop a score that describes the magnitude of cardiovascular severity in twin-twin transfusion syndrome.

STUDY DESIGN

Fetal echocardiograms of 150 monochorionic/diamniotic twins were reviewed. Blinded to Quintero stage, we applied a cardiovascular score to each twin set and compared it to the Quintero grade. The score is a composite of variables that include ventricular hypertrophy, dilation, function, valve regurgitation, great artery size, and diastolic properties in the recipient and umbilical artery flow in the donor. Doppler indices of vascular and ventricular function were measured.

RESULTS

Mean age was 21 +/- 3 weeks. Discrepancy was noted in degree of severity between Quintero and cardiovascular stages. The score correlated well with myocardial performance index of the recipient right ventricle (r2 = .65).

CONCLUSION

We describe the spectrum of cardiovascular abnormalities that are seen in twin-twin transfusion syndrome and propose a scoring system for assessment of severity.

Fetal cardiac contractility before and after intrauterine transfusion

OBJECTIVE

To evaluate the effect of fetal anemia and intrauterine transfusion on ventricular shortening fraction.

METHODS

The end-diastolic and end-systolic transverse dimensions of the left and right ventricles were obtained using M-mode ultrasonography. The shortening fractions of both ventricles were calculated at three time points: before, immediately after and one day after intrauterine transfusion. The blood volume given at intrauterine transfusion was expressed as a percentage of estimated fetoplacental blood volume.

RESULTS

Complete measurements were obtained from 49 transfusions in 23 fetuses. Intrauterine transfusion was performed at a median gestational age of 31 (range, 19-35) weeks. Median hemoglobin concentration before and after intrauterine transfusion was 7.9 (range, 2.7-13.7) g/dL and 14.3 (range, 12.7-16.1) g/dL, respectively. Both left and right ventricular shortening fractions differed significantly between the three time points. Left ventricular shortening fraction decreased immediately after transfusion in 43 (88%) of the 49 procedures. Right ventricular shortening fraction decreased immediately after transfusion in 42 (86%) of the 49 procedures. At the first intrauterine transfusion, there was only a weak correlation between the decrease in shortening fraction of both ventricles and the transfused volume (left: R(2) = 0.15; P = 0.20/right: R(2) = 0.005; P = 0.81).

CONCLUSION

Transfusion significantly decreases the shortening fraction of both ventricles of the fetal heart. There is, however, little correlation between the decrease in shortening fraction and the volume of red cells given at intrauterine transfusion. Published by John Wiley & Sons, Ltd.

Application of free-hand three-dimensional echocardiography in the evaluation of fetal cardiac ejection fraction: a preliminary study

OBJECTIVE

To investigate the feasibility of using free-hand three-dimensional (3D) echocardiography to evaluate fetal cardiac function.

METHODS

3D cardiac data were collected during screening examinations for 37 normal fetuses with gestational ages of between 16 and 26 weeks. Processing of the 3D volumes included separation of the end-diastolic and end-systolic slices, segmentation of right and left ventricles, measurement of end-diastolic and end-systolic volumes, and calculation of the ejection fraction (EF) for each ventricle. In 21 fetuses at 21-24 weeks, right and left ventricle volumes and EF were compared.

RESULTS

Twenty-five cases were appropriate for final statistical analysis. The volume of the ventricles increased with gestational age and estimated fetal weight. There was no significant trend in the difference between the volumes and EF of the right and left ventricles in the 21-24-week subgroup. The mean right and left ventricular EF were 54 +/- 11.2% and 57.5 +/- 14.6%, respectively. The mean combined EF of ventricles during gestation was 55.1 +/- 10.7% and seemed to remain constant during the gestational ages studied.

CONCLUSIONS

3D echocardiography can provide estimates of ventricular volume and function and may in future be used for evaluation of fetuses with congenital heart disease and cardiac dysfunction.

Cardiac function monitoring of fetuses with growth restriction

OBJECTIVE

To describe the time sequence of changes in cardiac function in intrauterine growth restriction.

STUDY DESIGN

This was a prospective longitudinal study on 22 singleton pregnancies with growth-restricted fetuses. Pulsatility indices of fetal arterial and venous Doppler waveforms, systolic peak velocity in the aorta and pulmonary artery, right and left ventricular shortening fraction and atrioventricular flow E/A ratio were assessed at each monitoring session. Logistic regression was used for modeling the probability of abnormality of a variable in relation to the time interval before delivery. Trends over time were analyzed by Mann-Withney U-test.

RESULTS

Umbilical artery pulsatility index was the first variable to become abnormal, followed by the middle cerebral artery, right diastolic indices (right E/A, ductus venosus), right systolic indices and, finally, both diastolic and systolic left cardiac indices.

CONCLUSION

We have found an earlier and more pronounced right than left and diastolic than systolic fetal cardiac function deterioration in growth restricted fetuses monitored longitudinally.