Evaluation of Fetal Left Ventricular Size and Function Using Speckle-Tracking and the Simpson Rule

Umbilical Vein Flows and Cardiac Size, Shape, and Ventricular Contractility in Fetuses With Estimated Weight Less-Than 10th Centile

OBJECTIVES

In a cohort of patients with estimated fetal weights (EFWs) <10th centile, we aimed 1) to compare the prevalence of abnormalities of fetal 4-chamber view (4CV) cardiac size, shape, and ventricular contractility in fetal growth restricted (FGR) and small-for-gestational-age (SGA) fetuses and 2) to compare umbilical vein flow (UVF) measurements to standard Doppler surveillance in predicting abnormalities of cardiac function.

METHODS

Prospective observational cohort study of fetuses with EFW <10th percentile. Measurements of size and shape used were 4CV transverse width, 4CV cardiac area, 4CV global sphericity index, and right-to-left ventricular mid-chamber width ratio. Variables of contractility used were fractional shortening change at the mid-ventricle chamber, global longitudinal strain, fractional area change, and left ventricular cardiac output. The UVF and standard Doppler surveillance including umbilical artery (UA), middle cerebral artery, and cerebroplacental ratio (CPR) were collected. Control data were from previously published studies.

RESULTS

A total of 95 fetuses with EFWs <10th centile were included in the study. The rates of abnormalities of cardiac size and shape and ventricular contractility were all significantly elevated compared with normally grown control fetuses but similar between FGR and SGA fetuses. In a subset of 76 patients with UVF data, evaluation UVF identified more patients with any abnormality of contractility compared with UA (37.9 vs 17.2%, P = .02).

CONCLUSIONS

The addition of UVF doubled the detection rate of ventricular contractility abnormalities. The addition of UVF should be considered in the surveillance of FGR and SGA fetuses to further stratify the severity of hypoxemia and to identify those at greater risk for future cardiovascular dysfunction.

Evaluation of Fetal Heart Using Fetal Heart Quantification (fetalHQ) Technique in an Indian Cohort

OBJECTIVE

To evaluate the intra- and interobserver reproducibility of parameters used to determine cardiac morphometry and deformation using FetalHQ in Indian population.

METHODOLOGY

Two operators blinded to each other performed FetalHQ analysis independently on 35 normal fetuses of gestational age between 18 + 0 and 37 + 0 weeks and days. Intra- and interobserver correlation coefficient and limits of agreement were ascertained for parameters obtained from HQ analysis.

RESULTS

Excellent reproducibility (ICC > 0.9) was observed for global morphometric parameters. Ejection fraction, stroke volume, stroke volume/kg demonstrated excellent reliability (ICC > 0.9), cardiac output, fractional area change showed a lower correlation (ICC < 0.8), and right and left ventricular global strain showed no correlation. Twenty-four segment sphericity index of left ventricle (LV) and right ventricle (RV) showed low to moderate correlation (LV-ICC 0.48-0.79; RV-ICC 0.43-0.82). Fractional shortening (FS) showed poor intraobserver reliability in RV.

CONCLUSION

FetalHQ provides reliable estimates of the global cardiac morphometry but not for global cardiac strain. Regional transverse contractility represented by FS has poor correlation in right ventricle, especially in the apical region, possibly due to moderator band. Nevertheless, it is a promising tool which requires technical advancements and validation to improve its accuracy and reliability.

Myocardial biomechanical effects of fetal aortic valvuloplasty

Fetal critical aortic stenosis with evolving hypoplastic left heart syndrome (CAS-eHLHS) can progress to a univentricular (UV) birth malformation. Catheter-based fetal aortic valvuloplasty (FAV) can resolve stenosis and reduce the likelihood of malformation progression. However, we have limited understanding of the biomechanical impact of FAV and subsequent LV responses. Therefore, we performed image-based finite element (FE) modeling of 4 CAS-eHLHS fetal hearts, by performing iterative simulations to match image-based characteristics and then back-computing physiological parameters. We used pre-FAV simulations to conduct virtual FAV (vFAV) and compared pre-FAV and post-FAV simulations. vFAV simulations generally enabled partial restoration of several physiological features toward healthy levels, including increased stroke volume and myocardial strains, reduced aortic valve (AV) and mitral valve regurgitation (MVr) velocities, reduced LV and LA pressures, and reduced peak myofiber stress. FAV often leads to aortic valve regurgitation (AVr). Our simulations showed that AVr could compromise LV and LA depressurization but it could also significantly increase stroke volume and myocardial deformational stimuli. Post-FAV scans and simulations showed FAV enabled only partial reduction of the AV dissipative coefficient. Furthermore, LV contractility and peripheral vascular resistance could change in response to FAV, preventing decreases in AV velocity and LV pressure, compared with what would be anticipated from stenosis relief. This suggested that case-specific post-FAV modeling is required to fully capture cardiac functionality. Overall, image-based FE modeling could provide mechanistic details of the effects of FAV, but computational prediction of acute outcomes was difficult due to a patient-dependent physiological response to FAV.

Measuring Atrial Size, Shape, and Contractility of the Fetal Heart Using FetalHQ: A New Technique Using Speckle Tracking Analysis

Measurements of fetal atrial size, shape, and contractility have been previously reported using the TomTec fetal heart speckle tracking analysis software, which currently is no longer available in the marketplace. At the present time, the only software available for speckle-tracking analysis of the fetal heart is fetalHQ, which analyzes the fetal heart ventricles using the same algorithms as the TomTec software used for speckle-tracking analysis. This communication will review how to use the fetalHQ software to measure the size, shape, and contractility of the atrial chambers.

Review of speckle tracking analysis to measure the size, shape, and contractility of the fetal heart in fetuses with congenital heart defects

Evaluation of the fetal heart involves two approaches. The first describes a screening protocol in which the heart is imaged in transverse planes that includes the four-chamber view (4CV), left and right outflow tracts, and the 3-vessel-tracheal view. The second approach is a fetal echocardiogram that requires additional cardiac images as well as evaluating ventricular function using diagnostic tools such as M-mode and pulsed Doppler ultrasound. Speckle tracking analysis of the ventricular and atrial endocardium of the fetal heart has focused primarily on computing longitudinal global strain. However, the technology enabling this measurement to occur has recently been adapted to enable the clinician to obtain numerous additional measurements of the size, shape, and contractility of the ventricles and atrial chambers. By using the increased number of measurements derived from speckle tracking analysis, we have reported the ability to screen for tetralogy of Fallot, D-transposition of the great arteries (D-TGA), and coarctation of the aorta by only imaging the 4CV. In addition, we have found that measurements derived from speckle tracking analysis of the ventricular and atrial chambers can be used to compute the risk for emergent neonatal balloon atrial septostomy in fetuses with D-TGA. The purpose of this review is to consolidate our experience in one source to provide perspective on the benefits of speckle tracking analysis to measure the size, shape, and contractility of the ventricles and atria imaged in the 4CV in fetuses with congenital heart defects.

Reference Ranges and Development Patterns of Fetal Myocardial Function Using Speckle Tracking Echocardiography in Healthy Fetuses at 17 to 24 Weeks of Gestation

OBJECTIVE

The purposes of the study were to develop reference ranges and maturation patterns of fetal cardiac function parameters measured by speckle tracking echocardiography (STE) using multiple biometric variables at 17 to 24 weeks' gestation among Thai fetuses and to compare with other previous reports.

STUDY DESIGN

The four-chamber view of the fetal heart in 79 healthy fetuses was suitably analyzed by STE to establish the best-fit regression model. The 95% reference intervals and Z-score equations of fetal cardiac function parameters were computed.

RESULTS

The fractional area change of both ventricles, left ventricular (LV) end-diastolic and end-systolic volumes, LV stroke volume, LV cardiac output (CO), and LV CO per kilogram were all increased according to gestational age (GA) and five fetal biometric measurements. However, the global longitudinal strain, basal-apical length fractional shortening (BAL-FS), BAL annular free wall and septal wall FS, BAL free wall and septal wall annular plane systolic excursions, 24-segment transverse width FS, as well as LV ejection fraction were all independent of GA or other somatic characteristics. There were varying development patterns between fetal right and left ventricles of these cardiac function indices across the gestation period.

CONCLUSION

Our study created Z-score and corresponding centile calculators, 5th and 95th centile reference tables, and corresponding graphs and determined the normal evolution across gestation using multiple somatic growth and age variables between 17 and 24 gestational weeks. These nomograms serve as an essential prerequisite for quantitatively evaluating fetal cardiac contractility and allow for precisely detecting early changes in the fetal heart function.

KEY POINTS

· Most fetal cardiac function measurements were correlated with all the independent variables.. · Fetal ventricular function parameters have their own characteristic maturation changes.. · Racial variability may not occupy an important place for fetal myocardial function during these GA..

Comparison of Left Ventricular Stroke Volume in 2nd- and 3rd-Trimester Fetuses Measured by the Product of VTI and Aortic Annular Area With That Assessed by Simpson's Single-Plane Rule Using the STE Technique

OBJECTIVES

The aim of the study was to compare left ventricle stroke volume in healthy, eutrophic fetuses in the 2nd and 3rd trimesters evaluated using the velocity time integral and aortic annulus area with left ventricular stroke volume measured using Simpson's single-plane rule and to determine the discrepancy equation.

METHODS

The study included 354 fetuses. In each fetus, during the same examination, simultaneous assessment of stroke volume was performed by pulsed-wave Doppler using the product of the velocity time integral and aortic annulus area and by the fetalHQ® software using Simpson's single-plane rule. The Mann-Whitney U test was used to compare the "product-derived" stroke volume and stroke volume using fetalHQ® software values in the 2nd and 3rd trimesters separately. The agreement between the two methods were verified using Bland-Altman analysis. A linear regression model was used to obtain the discrepancy equation.

RESULTS

In the 2nd trimester, the mean percentage difference between both the techniques showed that the stroke volume values determined using pulsed-wave Doppler were, on average, 88% higher than the stroke volume values determined using fetalHQ®. The upper limit of agreement between the compared techniques was approximately 146% and the lower limit of agreement was equal to 29.6%. In the 3rd trimester, the results indicated that the stroke volume values determined using pulsed-wave Doppler were, on average, 76% higher than the stroke volume values determined using fetalHQ®. The upper limit of agreement between the compared techniques was approximately 129% and the lower limit of agreement was 23%. Based on the results of the linear regression models, discrepancy formulas of the stroke volume values were obtained. The equations to calculate the predicted mean and standard deviations were used to compute the reference intervals for the mean, 5th and 95th centiles.

CONCLUSION

The calculation of left ventricular stroke volume using pulsed Doppler has higher result in relation to stroke volume determined using Simpson's rule significantly. The aortic annulus area showed a higher correlation regarding stroke volume than the velocity time integral in both the 2nd and 3rd trimesters. Stroke volume increased with the increase in aortic annulus area, whereas the velocity time integral remained relatively constant. The retrospective analysis of the collected material enabled the determination of the discrepancy equation.

Reference Values for Fetal Cardiac Dimensions, Volumes, Ventricular Function and Left Ventricular Longitudinal Strain Using Doppler Ultrasound Gated Cardiac Magnetic Resonance Imaging in Healthy Third Trimester Fetuses

BACKGROUND

Recent advances in hardware and software permit the use of cardiac MRI of late gestation fetuses, however there is a paucity of MRI-based reference values.

PURPOSE

To provide initial data on fetal cardiac MRI-derived cardiac dimensions, volumes, ventricular function, and left ventricular longitudinal strain in healthy developing fetuses >30 weeks gestational age.

STUDY TYPE

Prospective.

POPULATION

Twenty-five third trimester (34 ± 1 weeks, range of 32-37 weeks gestation) women with healthy developing fetuses.

FIELD STRENGTH/SEQUENCE

Studies were performed at 1.5 T and 3 T. Cardiac synchronization was achieved with a Doppler ultrasound device. The protocol included T2 single shot turbo spin echo stacks for fetal weight and ultrasound probe positioning, and multiplanar multi-slice cine balanced steady state free precession gradient echo sequences.

ASSESSMENT

Primary analyses were performed by a single observer. Weight indexed right ventricular (RV) and left ventricular (LV) volumes and function were calculated from short axis (SAX) stacks. Cardiac dimensions were calculated from the four-chamber and SAX stacks. Single plane LV longitudinal strain was calculated from the four-chamber stack. Interobserver variability was assessed in 10 participants. Cardiac MRI values were compared against available published normative fetal echocardiogram data using z-scores.

STATISTICAL TESTS

Mean and SDs were calculated for baseline maternal/fetal demographics, cardiac dimensions, volumes, ventricular function, and left ventricular longitudinal strain. Bland-Altman and intraclass correlation coefficient analysis was performed to test interobserver variability.

RESULTS

The mean gestational age was 34 ± 1.4 weeks. The mean RV and LV end diastolic volumes were 3.1 ± 0.6 mL/kg and 2.4 ± 0.5 mL/kg respectively. The mean RV cardiac output was 198 ± 49 mL/min/kg while the mean LV cardiac output was 173 ± 43 mL/min/kg.

DATA CONCLUSION

This paper reports initial reference values obtained by cardiac MRI in healthy developing third trimester fetuses. MRI generally resulted in slightly larger indexed values (by z-score) compared to reports in literature using fetal echocardiography.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

How automated techniques ease functional assessment of the fetal heart: Applicability of two-dimensional speckle-tracking echocardiography for comprehensive analysis of global and segmental cardiac deformation using fetalHQ®

BACKGROUND

Prenatal echocardiographic assessment of fetal cardiac function has become increasingly important. Fetal two-dimensional speckle-tracking echocardiography (2D-STE) allows the determination of global and segmental functional cardiac parameters. Prenatal diagnostics is relying increasingly on artificial intelligence, whose algorithms transform the way clinicians use ultrasound in their daily workflow. The purpose of this study was to demonstrate the feasibility of whether less experienced operators can handle and might benefit from an automated tool of 2D-STE in the clinical routine.

METHODS

A total of 136 unselected, normal, singleton, second- and third-trimester fetuses with normofrequent heart rates were examined by targeted ultrasound. 2D-STE was performed separately by beginner and expert semiautomatically using a GE Voluson E10 (FetalHQ®, GE Healthcare, Chicago, IL). Several fetal cardiac parameters were calculated (end-diastolic diameter [ED], sphericity index [SI], global longitudinal strain [EndoGLS], fractional shortening [FS]) and assigned to gestational age (GA). Bland-Altman plots were used to test agreement between both operators.

RESULTS

The mean maternal age was 33 years, and the mean maternal body mass index prior to pregnancy was 24.78 kg/m2. The GA ranged from 16.4 to 32.0 weeks (average 22.9 weeks). Averaged endoGLS value of the beginner was -18.57% ± 6.59 percentage points (pp) for the right and -19.58% ± 5.63 pp for the left ventricle, that of the expert -14.33% ± 4.88 pp and -16.37% ± 5.42 pp. With increasing GA, right ventricular endoGLS decreased slightly while the left ventricular was almost constant. The statistical analysis for endoGLS showed a Bland-Altman-Bias of -4.24 pp ± 8.06 pp for the right and -3.21 pp ± 7.11 pp for the left ventricle. The Bland-Altman-Bias of the ED in both ventricles in all analyzed segments ranged from -.49 mm ± 1.54 mm to -.10 mm ± 1.28 mm, that for FS from -.33 pp ± 11.82 pp to 3.91 pp ± 15.56 pp and that for SI from -.38 ± .68 to -.15 ± .45.

CONCLUSIONS

Between both operators, our data indicated that 2D-STE analysis showed excellent agreement for cardiac morphometry parameters (ED and SI), and good agreement for cardiac function parameters (EndoGLS and FS). Due to its complexity, the application of fetal 2D-STE remains the domain of scientific-academic perinatal ultrasound and should be placed preferably in the hands of skilled operators. At present, from our perspective, an implementation into clinical practice "on-the-fly" cannot be recommended.

Pre-intervention myocardial stress is a good predictor of aortic valvoluplasty outcome for fetal critical aortic stenosis and evolving HLHS

Fetal critical aortic stenosis with evolving hypoplastic left heart syndrome (CAS-eHLHS) causes biomechanical and functional aberrations, leading to a high risk of progression to hypoplastic left heart syndrome (HLHS) at birth. Fetal aortic valvuloplasty (FAV) can resolve outflow obstruction and may reduce progression risk. However, it is currently difficult to accurately predict which patients will respond to the intervention and become functionally biventricular (BV) at birth, as opposed to becoming functionally univentricular (UV). This prediction is important for patient selection, parental counselling, and surgical planning. Therefore, we investigated whether biomechanics parameters from pre-FAV image-based computations could robustly distinguish between CAS-eHLHS cases with BV or UV outcomes in a retrospective cohort. To do so we performed image-based finite element biomechanics modelling of nine CAS-eHLHS cases undergoing intervention and six healthy fetal control hearts, and found that a biomechanical parameter, peak systolic myofibre stress, showed a uniquely large difference between BV and UV cases, which had a larger magnitude effect than echocardiography parameters. A simplified equation was derived for quick and easy estimation of myofibre stress from echo measurements via principal component analysis. When tested on a retrospective cohort of 37 CAS-eHLHS cases, the parameter outperformed other parameters in predicting UV versus BV outcomes, and thus has a high potential of improving outcome predictions, if incorporated into patient selection procedures. Physiologically, high myocardial stresses likely indicate a healthier myocardium that can withstand high stresses and resist pathological remodelling, which can explain why it is a good predictor of BV outcomes. KEY POINTS: Predicting the morphological birth outcomes (univentricular versus biventricular) of fetal aortic valvuloplasty for fetal aortic stenosis with evolving HLHS is important for accurate patient selection, parental counselling and management decisions. Computational simulations show that a biomechanics parameter, pre-intervention peak systolic myofibre stress, is uniquely robust in distinguishing between such outcomes, outperforming all echo parameters. An empirical equation was developed to quickly compute peak systolic myofibre stress from routine echo measurements and was the best predictor of outcomes among a wide range of parameters tested.

Comparison of the left and right ventricular size and systolic function of low-risk fetuses in the third trimester: Which is more dominant?

Objective

To quantify fetal cardiovascular parameters utilizing fetal-specific 2D speckle tracking technique and to explore the differences in size and systolic function of the left and right ventricles in low-risk pregnancy.

Methods

A prospective cohort study was performed in 453 low-risk single fetuses (28+0–39+6 weeks) to evaluate ventricular size [i.e., end-diastolic length (EDL), end-systolic length (ESL), end-diastolic diameter (ED), end-systolic diameter (ES), end-diastolic area, end-systolic area, end-diastolic volume (EDV), and end-systolic volume (ESV)] and systolic function [i.e., ejection fraction (EF), stroke volume (SV), cardiac output (CO), cardiac output per kilogram (CO/KG), and stroke volume per kilogram (SV/KG)].

Results

This study showed that (1) the reproducibility of the interobserver and intraobserver measurements was good to excellent (ICC 0.626–0.936); (2) with advancing gestation, fetal ventricular size and systolic function increased, whereas right ventricular (RV) EF decreased and left ventricular (LV) EF was not significantly changed; (3) LV length was longer than RV length in diastole (2.24 vs. 1.96 cm, P &lt; 0.001) and systole (1.72 vs. 1.52 cm, P &lt; 0.001); (4) LV ED-S1 and ES-S1 were shorter than the RV ED-S1 and ES-S1 (12.87 vs. 13.43 mm, P &lt; 0.001; 5.09 vs. 5.61 mm, P &lt; 0.001); (5) there were no differences between the LV and RV in EDA or EDV; (6) the mean EDV ratio of right-to-left ventricle was 1.076 (95% CI, 1.038–1.114), and the mean ESV ratio was 1.628 (95% CI, 1.555–1.701); (7) the EF, CO and SV of the LV were greater than the RV (EF: 62.69% vs. 46.09%, P &lt; 0.001; CO: 167.85 vs. 128.69 ml, P &lt; 0.001; SV: 1.18 vs. 0.88 ml, P &lt; 0.001); (8) SV and CO increased with ED-S1 and EDL, but EF was not significantly changed.

Conclusion

Low-risk fetal cardiovascular physiology is characterized by a larger RV volume (especially after 32 weeks) and greater LV outputs (EF, CO, SV, SV/KG and CO/KG).

Speckle Tracking Analysis in Fetuses with D-Transposition: Predicting the Need for Urgent Neonatal Balloon Atrial Septostomy

INTRODUCTION

Speckle tracking analysis of the endocardium of the right (RV) and left (LV) ventricles was used to evaluate the size, shape, and contractility of these chambers in fetuses with D-Transposition of the great arteries (D-TGA) to identify fetuses that would require emergent balloon atrial septostomy (BAS) after birth.

METHODS

This was a retrospective analysis of fetuses with D-TGA and intact ventricular septum that were divided into 2 groups. Group 1 underwent urgent BAS after birth because of a restrictive atrial septum and group 2 did not. Using speckle tracking analysis, the end-diastolic and end-systolic RV and LV areas, lengths, widths, sphericity indices, and contractility were computed. Logistic regression analysis was performed to identify fetuses who would require urgent neonatal BAS.

RESULTS

Of the 39 fetuses with D-TGA, 55% (n = 22) required urgent neonatal BAS (group 1) and 45% (n = 17) (group 2) did not. When comparing D-TGA groups 1 and 2, differences were seen in RV and LV area, sphericity index for segment 1 of the LV, LV fractional area of change and free wall annular plane systolic excursion, fractional shortening for LV segment 12, and RV free wall strain. Regression analysis of these measurements identified 91% of neonates who underwent BAS, with a false-positive rate of 12%.

CONCLUSION

Using speckle tracking analysis to evaluate the RV and LV, measurable differences were identified for the RV and LV size, shape, and contractility between fetuses who underwent neonatal urgent BAS vs. those who did not require this procedure.

Abnormalities of the Width of the Four-Chamber View and the Area, Length, and Width of the Ventricles to Identify Fetuses at High-Risk for D-Transposition of the Great Arteries and Tetralogy of Fallot

OBJECTIVES

The prenatal detection of D-Transposition of the great arteries (D-TGA) and tetralogy of Fallot (TOF) has been reported to be less than 50% to as high as 77% when adding the outflow tracts to the four-chamber screening protocol. Because many examiners still struggle with the outflow tract examination, this study evaluated whether changes in the size and shape of the heart in the 4CV as well as the ventricles occurred in fetuses with D-TGA and TOF could be used to screen for these malformations.

METHODS

Forty-four fetuses with the pre-and post-natal diagnosis of D-TGA and 44 with TOF were evaluated between 19 and 36 weeks of gestation in which the 4CV was imaged. Measurements of the end-diastolic width, length, area, and global sphericity index were measured for the four-chamber view and the right and left ventricles. Using z-score computed values, logistic regression was performed between the 88 study and 200 control fetuses using the hierarchical forward selection protocol.

RESULTS

Logistic regression identified 10 variables that correctly classified 83/88 of fetuses with TOF and TGA, for a sensitivity of 94%. Six of 200 normal controls were incorrectly classified for a false-positive rate of 3%. The area under the receiver operator classification curve was 98.1%. The true positive rate for D-TGA was 93.2%, with a false-negative rate to 6.8%. The true positive rate for TOF was 95.5%, with a false negative rate of 4.5%.

CONCLUSIONS

Measurements of the 4CV and of the RV and LV may help identify fetuses at risk for D-TGA or TOF.

Evaluation of changes of cardiac morphology and function in fetuses with ductus arteriosus constriction by Speckle-tracking echocardiography

BACKGROUND

Premature ductus arteriosus constriction (DA Con) can result in right ventricular enlargement, right ventricular hypertrophy, and tricuspid regurgitation.

METHOD

This study retrospectively analyzed 34 singleton fetuses that underwent fetal echocardiography with a diagnosis of DA Con (16 cases with mild to moderate, and 18 cases with moderate to severe) and 45 healthy fetuses. The morphology and function parameters of cardiac, as well as the 24-Segment of ventricles, were compared between the DA Con group and controls, and between the mild to moderate and moderate to severe groups, using the fetal heart quantification (FHQ) technology.

RESULTS

There were no significant difference in left ventricular parameters in DA Con group when compared to controls. Moreover, fetal 4CV-GSI was significantly reduced, as well as the sphericity index (SI), fractional shortening (FS), global longitudinal strain (GS) and fractional area change (FAC) of right ventricle, especially in the basal-middle segments. Compared with the mild to moderate group, LV-FS increased and RV-FS decreased in moderate to severe group.

CONCLUSION

The results showed that the fetal heart in the DA Con group was different from the controls in morphology and function. FHQ technology provides a comprehensive assessment for the evaluation of cardiac morphological and functional changes in DA Con fetuses.

The dependency of fetal left ventricular biomechanics function on myocardium helix angle configuration

The helix angle configuration of the myocardium is understood to contribute to the heart function, as finite element (FE) modeling of postnatal hearts showed that altered configurations affected cardiac function and biomechanics. However, similar investigations have not been done on the fetal heart. To address this, we performed image-based FE simulations of fetal left ventricles (LV) over a range of helix angle configurations, assuming a linear variation of helix angles from epicardium to endocardium. Results showed that helix angles have substantial influence on peak myofiber stress, cardiac stroke work, myocardial deformational burden, and spatial variability of myocardial strain. A good match between LV myocardial strains from FE simulations to those measured from 4D fetal echo images could only be obtained if the transmural variation of helix angle was generally between 110 and 130°, suggesting that this was the physiological range. Experimentally discovered helix angle configurations from the literature were found to produce high peak myofiber stress, high cardiac stroke work, and a low myocardial deformational burden, but did not coincide with configurations that would optimize these characteristics. This may suggest that the fetal development of myocyte orientations depends concurrently on several factors rather than a single factor. We further found that the shape, rather than the size of the LV, determined the manner at which helix angles influenced these characteristics, as this influence changed significantly when the LV shape was varied, but not when a heart was scaled from fetal to adult size while retaining the same shape. This may suggest that biomechanical optimality would be affected during diseases that altered the geometric shape of the LV.

Measuring the Area of the Interventricular Septum in the 4-Chamber View: A New Technique to Evaluate the Fetus at Risk for Septal Hypertrophy

OBJECTIVES

One of the problems for the clinician who desires to measure the interventricular septum (IVS) in a high-risk fetus is to know where to make the measurement. The purpose of this study was to use speckle-tracking analysis to measure the IVS area, 24-segment widths, and length at end-diastole (ED) and end-systole (ES) in normal fetuses.

METHODS

From the 4-chamber view, speckle-tracking analysis was performed at ED and ES on the IVS in 200 normal fetuses. The following were computed and regressed against gestational age (GA) and fetal biometric (FB) measurements: area, length, and the 24-segment transverse widths from the apex to the crux. The 24-segment width/length ratio was also measured. The speckle-tracking measurements of the ED area and length were compared using a point-to-point measurement tool available on all ultrasound machines.

RESULTS

The ED and ES areas, lengths, and 24-segment widths increased with GA and FB. The ED and ES areas were virtually identical. The 24-segment width/length ratio decreased from the apex to the crux of the septum. There was no significant difference in the measurement of the ED area and the length between speckle-tracking and the point-to-point measurements.

CONCLUSIONS

Measurement of the area and length of the IVS are simple to obtain and provide a new diagnostic tool to evaluate the fetus at risk for IVS hypertrophy which may be observed in fetuses of mothers with pregestational and gestational diabetes.

Speckle-Tracking Analysis in Fetuses With Tetralogy of Fallot: Evaluation of Right and Left Ventricular Contractility and Left Ventricular Function

OBJECTIVES

This study examines fetuses with tetralogy of Fallot (TOF) and evaluates the right (RV) and left (LV) ventricular contractility and LV function using speckle-tracking analysis of the endocardium.

METHODS

The study group consisted of 44 fetuses with TOF, of which 34% had pulmonary valve atresia (N = 15) and 59% (N = 26) had pulmonary valve stenosis. The RV and LV global fractional area change, longitudinal contractility (longitudinal strain, free wall strain, septal strain, free wall and septal annular fractional shortening, and free wall and septal wall annular plane systolic excursion), and transverse contractility (24-segment fractional shortening) as well as LV functional assessment (stroke volume, cardiac output, and ejection fraction) were measured using speckle-tracking analysis. The z-scores of the measurements were compared to 200 controls.

RESULTS

Compared to controls, measurements of LV contractility in fetuses with TOF demonstrated significantly abnormal values for global contractility, longitudinal contractility, and transverse contractility of the mid and apical segments. LV function was abnormal for stroke volume (SV), cardiac output (CO), and ejection fraction (EF). In comparison, RV contractility demonstrated no significant difference between TOF and control z-score values for RV global contractility. Only two RV measurements were found to be abnormal: longitudinal contractility and transverse contractility of the apical segments.

CONCLUSION

Using multiple measurement tools to evaluate global, longitudinal, and transverse contractility, this study identified significant differences between fetuses with TOF and healthy controls, with greater contractility abnormalities seen in the LV than in the RV.

Prenatal Diagnosis of Right-Sided Congenital Ventricular Diverticulum (CVD) Assisted by Spatiotemporal Image Correlation (STIC) Acquisition and the Speckle-Tracking Technique to Assess Fetal Cardiac Function: A Case Report

Congenital ventricular diverticulum (CVD) is a cardiac malformation defined as an outpouching lesion of a ventricle with normal contractility and thickness, and the advancement of prenatal sonography has led to its prenatal diagnosis. In the prenatal period, CVD is reported in association with pericardial effusion, arrhythmia, and fetal hydrops or as an isolated condition. With the development of prenatal echocardiography, CVD can be diagnosed from the early stage of pregnancy, and prenatal procedures, such as pericardiocentesis, are also possible. Spatiotemporal image correlation (STIC) acquisition, a novel approach for the clinical evaluation of fetal hearts, provides easy-to-use techniques for acquiring data from fetal hearts and helping visualization with two-dimensional and three-dimensional (3D) cine sequences. Furthermore, the speckle-tracking technique enables a more comprehensive evaluation of the shape, continuity, and function of the fetal heart. These recent techniques have never been used for CVD diagnosis and evaluation. Here, we present a case of right-sided CVD, which is the first in which STIC acquisition and cardiac function assessment with the speckle-tracking technique were used to assist in the diagnosis and evaluation.

A preliminary study on fetal cardiac morphology and systolic function of normal and anemic pregnant women by fetal heart quantification technology

BACKGROUND

Maternal anemia is a common nutritional problem during pregnancy. Fetal heart quantification (fetal HQ) technology is used to quantitatively evaluate the size, shape, and contractile function of the fetal heart, which can reflect the development of the fetus in the uterus.

METHODS

We used fetal HQ technology to evaluate the basal-apical length (BAL), the transverse width (TW) and the area (A) of the four chamber view at end-diastole in 77 normal fetuses and 40 fetuses of women with anemia. We analyzed the changes of fetal heart size and measured the global sphericity index (GSI), the fraction area change (FAC), and the global longitudinal strain (GLS). The sphericity index (SI) and the fractional shortening (FS) of 24 segments were analyzed to identify any changes of fetal heart morphology and systolic function. The normal range of Z value was set at -2 to 2.

RESULTS

Fetal BAL, TW, A, and gestational age (GA) were positively linearly correlated, while GSI, GLS, and FAC had no significant correlation with GA. There was no significant difference in fetal BAL, TW, A, GLS, and FAC between the two groups (P>0.05). There was no significant difference in the FS of the 24 segments of the left and right ventricles between the two groups (P>0.05). There was no significant difference in the SI of the 1-24 segments of the right ventricle between the two groups (P>0.05). The difference in fetal GSI between the two groups was statistically significant (P<0.05). There was no significant difference in SI between the 1-22 segments of the left ventricle between the two groups (P>0.05), but there was a statistically significant difference between the 23-24 segments (P<0.05).

CONCLUSIONS

The fetal HQ analysis technology can quickly and simply quantitatively assess the size, shape, and contractility of the fetal heart. Anemia in pregnant women has no significant effect on fetal heart size and systolic function; it only affects the morphology of the heart, showing that the heart tends to be spherical as a whole and some segments of the apical segment of the left ventricle are abnormal.

Speckle Tracking Analysis to Evaluate the Size, Shape, and Function of the Atrial Chambers in Normal Fetuses at 20-40 Weeks of Gestation

OBJECTIVES

The purpose of this study was to use speckle tracking analysis to evaluate the size, shape, and function of the atrial chambers in normal fetuses and develop a z-score calculator that can be used in future studies in fetuses at risk for cardiovascular disease.

METHODS

The control group consisted of 200 normal fetuses examined between 20 and 40 weeks of gestation in which speckle tracking analysis of right (RA) and left (LA) atrial chambers was performed. The atrial end-diastolic and end-systolic endocardial borders for each chamber were identified from which measurements of atrial length, width, area, and volume were computed. Equations were derived using fractional polynomial regression analysis to compute z-score equations.

RESULTS

The LA end-diastolic volume, RA and LA end-diastolic area, length, base width, and mid-chamber widths increased with gestational age and fetal size. Left atrial emptying and ejection volumes increased with gestational age and fetal size. The fractional area change was significantly less for the RA than the LA. The LA base and mid-chamber fractional shortening were significantly greater than the RA. There was a significant difference between the RA and LA global contractile strain.

CONCLUSION

Mean and standard deviation equations for each of the measurements described in this study were computed to create a z-score calculator that can be utilized in the clinical environment when evaluating fetuses with suspected atrial pathology that could alter the size, shape, and function of the atrial chambers.

Incremental value of myocardial deformation in predicting postnatal coarctation of the aorta: establishment of a novel diagnostic model

BACKGROUND

Prenatal detection of coarctation of the aorta (CoA) still suffers from high false-positive and false-negative rates. The objective of this study was to develop a novel model to improve the diagnostic accuracy of fetal CoA.

METHODS

A retrospective study was conducted in 122 fetuses with suspected CoA who also had postnatal follow-ups. Fetuses with confirmed diagnosis of CoA after birth were defined as CoA group, and Non-CoA group were those false-positives. Conventional fetal echocardiographic measurements, including great arterial dimensions and flow characteristics were obtained. Left ventricular (LV) functional parameters were determined using two-dimensional speckle tracking echocardiography. A novel multi-parametric diagnostic model, including gestational age (GA) at diagnosis, aortic isthmus (AOI) Z-score and LV longitudinal strain (LVLS), was developed by univariate and multivariate logistic regression analyses. The model was validated prospectively by a validation cohort of 48 fetuses.

RESULTS

CoA was confirmed in 62/122 (50.8%) cases after birth. Fetuses with postnatal CoA were diagnosed significantly earlier than false-positives (median (interquartile range), 24.5 (23.3-26.4) vs 27.8 (24.5-30.4) weeks; P < .001). The Z-scores of aortic dimensions (aortic valve annulus, ascending aorta, transverse aortic arch and AOI) were significantly smaller (all P < .001), while the Z-scores of pulmonary dimensions (pulmonary valve annulus and main pulmonary artery) were significantly greater (all P < .05), in cases of confirmed CoA than false-positives. Compared with Non-CoA group, CoA group displayed lower LV ejection fraction (P = .005), LV fractional area change (P < .001) and LVLS (P < .001). A multivariate logistic regression model incorporating GA (odds ratio (OR): 0.74, 95% confidence interval (CI): 0.60-0.88; P = .001), AOI Z-score (OR: 0.20, 95% CI: 0.08-0.41; P < .001) and LVLS (OR: 1.79, 95% CI: 1.41-2.42; P < .001) was established to diagnose CoA more accurately (Akaike information criterion: 81.77, C-statistics: 0.945). The performance of this model was confirmed prospectively in the validation cohort.

CONCLUSIONS

In fetuses with suspected CoA, speckle tracking analysis of LVLS may have an incremental value in predicting postnatal CoA. Our diagnostic model, including GA, AOI Z-score and LVLS, may provide a good tool for the stratification of the risk in fetal CoA and contribute to patient-specific perinatal management.

Feasibility of 4D-Spatio Temporal Image Correlation (STIC) in the Comprehensive Assessment of the Fetal Heart Using FetalHQ®

Fetal Heart Quantification (FetalHQ®) is a novel speckle tracking software that permits the study of global and regional ventricular shape and function from a 2D four-chamber-view loop. The 4D-Spatio Temporal Image Correlation (STIC) modality enables the offline analysis of optimized and perfectly aligned cardiac planes. We aimed to evaluate the feasibility and reproducibility of 4D-STIC speckle tracking echocardiography (STE) using FetalHQ® and to compare it to 2D STE. We conducted a prospective study including 31 low-risk singleton pregnancies between 20 and 40 weeks of gestation. Four-chamber view volumes and 2D clips were acquired with an apex pointing at 45° and with a frame rate higher than 60 Hz. Morphometric and functional echocardiography was performed by FetalHQ®. Intra- and interobserver reproducibility were evaluated by the intraclass correlation coefficient (ICC). Our results showed excellent reproducibility (ICC > 0.900) for morphometric evaluation (biventricular area, longitudinal and transverse diameters). Reproducibility was also good (ICC > 0.800) for functional evaluation (biventricular strain, Fractional Area Change, left ventricle volumes, ejection fraction and cardiac output). On the contrary, the study of the sphericity index and shortening fraction of the different ventricular segments showed lower reproducibility (ICC < 0.800). To conclude, 4D-STIC is feasible, reproducible and comparable to 2D echocardiography for the assessment of cardiac morphometry and function.

Fetal cardiac geometry and function in pregnancies with well-controlled gestational diabetes mellitus using Fetal HQ

OBJECTIVE

To determine whether abnormal cardiac shape and ventricular global, transverse, and longitudinal contractility are present in fetuses of women with well-controlled GDM.

METHODS

A prospective observational study was performed on 80 fetuses of women with well-controlled GDM and 90 control fetuses. Using Fetal HQ, a new speckle-tracking technique, cardiac shape, global contractility, transverse contractility, and longitudinal contractility were calculated. The number and percentage of fetuses with z score values below 5th or above 95th were computed.

RESULTS

Compared with controls, there were no significant differences in the frequency of cardiac geometric abnormalities in GDM fetuses. Despite good glycemic control, 60.0% of fetuses in the well-controlled GDM group had one or more types of global, longitudinal, and transverse contractility abnormalities of one or both ventricles, but more frequent on the right ventricle (RV, 50%). The most frequent abnormality of the RV occurred in the transverse contractility (35%), followed by abnormalities of global contractility (25%), and longitudinal contractility (21.3%), compared with controls. The left ventricle (LV) analysis demonstrated that the percentage of study fetuses with only transverse contractility abnormality (18.8%) was significantly higher.

CONCLUSIONS

Despite good glycemic control, abnormal ventricular contractility was present in fetuses of women with GDM, but more frequent in the RV. For both the RV and LV, transverse ventricular contractility abnormality were more prevalent than abnormal global and longitudinal contractility. Fetuses of women with GDM should be evaluated for ventricular contractility abnormality and have more follow-ups despite good glycemic control.

Comparing the Non-Quiver and Quiver Techniques for Identification of the Endocardial Borders Used for Speckle-Tracking Analysis of the Ventricles of the Fetal Heart

This study compared the non-quiver with the quiver technique for identifying the end-systolic and end-diastolic endocardium of the fetal right ventricle (RV) and left ventricle (LV) used for speckle-tracking analysis. Bland-Altman and t test analyses showed no significant differences in measurements between the techniques for the RV and LV. The difference in the time required to perform the non-quiver analysis was significantly longer (P < .001) for the RV and LV than the quiver technique. The quiver technique allows the examiner to efficiently identify the endocardial borders of the fetal heart compared with the non-quiver method.

Association between non-culprit healed plaque and plaque progression in acute coronary syndrome patients: an optical coherence tomography study

BACKGROUND

Healed plaques are frequently found in patients with acute coronary syndrome, but the prognostic value is debatable. This study investigated the clinical features of non-culprit healed plaques detected by optical coherence tomography (OCT) with the aim of predicting plaque progression of healed plaques.

METHODS

This study retrospectively analyzed 113 non-culprit lesions from 85 patients who underwent baseline OCT imaging and follow-up angiography from January 2015 to December 2019. Plaque progression predictors were assessed by multivariate analysis.

RESULTS

Among 113 non-culprit lesions, 27 healed plaques (23.9%) were identified. Patients with non-culprit healed plaques had prior antiplatelet therapy (65.0% vs. 33.8%, P = 0.019), hypertension (85.0% vs. 50.7%, P = 0.009), and dyslipidemia (70.0% vs. 41.5%, P = 0.04) which were more frequently than those without healed plaques. The thickness (r = 0.674, P < 0.001), arc ( r = 0.736, P < 0.001), and volume ( r = 0.541, P = 0.004) of healed plaque were correlated with minimum lumen diameter changes. At a mean follow-up of 11.5 months, the non-culprit healed plaques had a lower minimum lumen diameter (1.61 ± 0.46 mm vs. 1.91 ± 0.73 mm, P = 0.016), lower average lumen diameter (1.86 mm vs. 2.10 mm, P = 0.033), and a higher degree of diameter stenosis (41.4% ± 11.9% vs. 35.5% ± 13.1%, P = 0.031) when compared to baseline measurements. The plaque progression rate was higher in the healed plaque group (33.3% vs. 8.1%, P = 0.002), and multivariate analysis identified healed plaques [odds ratio (OR) = 8.49, 95% CI: 1.71-42.13] and lumen thrombus (OR = 10.69, 95% CI: 2.21-51.71) as predictors of subsequent lesion progression.

CONCLUSIONS

Healed plaques were a predictor for rapid plaque progression. The quantitative parameters of healed plaque showed a good agreement with plaque progression. Patients with healed plaque were associated with prior antiplatelet therapy and high level of low-density lipoprotein cholesterol. Bifurcation lesions might be the predilection sites of healed plaques.

Cardiac Measurements of Size and Shape in Fetuses With Absent or Reversed End-Diastolic Velocity of the Umbilical Artery and Perinatal Survival and Severe Growth Restriction Before 34 Weeks' Gestation

OBJECTIVES

The purpose of this study was to evaluate the end-diastolic size and shape of the 4-chamber view as well as the right ventricle (RV) and left ventricle (LV) in growth-restricted fetuses before 34 weeks' gestation with absent or reversed end-diastolic velocity of the umbilical artery and compare the results between those with perinatal deaths and those who survived the neonatal period.

METHODS

Forty-nine fetuses with growth restriction and absent or reversed end-diastolic velocity of the umbilical artery were studied. The size, shape, and sphericity index of the 4-chamber view, RV, and LV were assessed. The number and percentage of fetuses with z score values of less than -1.65 and greater than 1.65 were computed.

RESULTS

Of the 49 fetuses, there were 13 perinatal deaths (27%) and 36 (63%) neonatal survivors. Measurements that were unique for neonatal survivors were an increased RV apical transverse width and decreased measurements of the following: LV and RV widths, LV and RV areas, as well as RV sphericity indices.

CONCLUSIONS

Fetuses with a smaller RV and LV size and area and those with a globular-shaped RV were at significantly lower risk for perinatal death.

Improved detection of coarctation of the aorta using speckle-tracking analysis of fetal heart on last examination prior to delivery

OBJECTIVE

The false-positive rate for prenatal diagnosis of coarctation of the aorta (FP-CoA) commonly exceeds 50%, with an accurate detection rate of < 50%. This study was conducted to determine if the sensitivity for prenatal detection of true CoA and the FP-CoA rate could be improved by evaluating the fetal epicardial size and shape in the four-chamber view (4CV) and the endocardial right (RV) and left (LV) ventricular size, shape and contractility.

METHODS

We analyzed retrospectively Digital Imaging and Communications in Medicine (DICOM) clips of the 4CV from the last examination prior to delivery in a series of 108 fetuses with CoA suspected prenatally by pediatric cardiologists using traditional diagnostic criteria. Postnatal evaluation distinguished those fetuses which subsequently required CoA surgery (true positives; true CoA) from those that were FP-CoA. Postnatal cardiac abnormalities were identified for each group. For the prenatal evaluation, we measured the 4CV end-diastolic epicardial area, circumference, length, width and global sphericity index. Speckle-tracking analysis was used to compute the endocardial RV and LV end-diastolic area, length, 24-segment sphericity index, 24-segment transverse width and the following functional parameters: fractional area change; global longitudinal, free-wall and septal-wall strain; basal-apical-length, basal free-wall and basal septal-wall fractional shortening; septal-wall annular plane systolic excursion; 24-segment transverse-width fractional shortening; and LV end-diastolic and end-systolic volumes, stroke volume, cardiac output and ejection fraction. In addition, the RV/LV end-diastolic area ratio was computed. Using a control group of 200 normal fetuses, the mean and SD for each of the above cardiac measurements was used to compute the Z-scores for each measurement in each of the 108 study fetuses. Logistic regression analysis was then performed on the Z-score values to identify variables that separated the true CoA group from the FP-CoA group.

RESULTS

Of the 108 study fetuses, 54 were confirmed postnatally to have true CoA and 54 were FP-CoA. Right/left area disproportion > 90^th  centile was present in 80% (n = 43) of the true-CoA fetuses and 76% (n = 41) of the FP-CoA fetuses. Fetuses with true CoA had a significantly greater number of associated cardiac abnormalities (93%, n = 50) compared with the FP-CoA fetuses (61%, n = 33) (P < 0.001). The most common associated malformations were bicuspid aortic valve (true CoA, 46% (n = 25) vs FP-CoA, 22% (n = 12); P < 0.01), aortic arch hypoplasia (true CoA, 31% (n = 17) vs FP-CoA, 11% (n = 6); P < 0.01), ventricular septal defect (true CoA, 33% (n = 18) vs FP-CoA, 11% (n = 6); P < 0.05) and mitral valve abnormality (true CoA, 30% (n = 16) vs FP-CoA, 4% (n = 2); P < 0.01). Logistic regression analysis identified 28 variables that correctly identified 96% (52/54) of the fetuses with true CoA, with a false-positive rate of 4% (2/54) and a false-negative rate of 4% (2/54). These variables included the epicardial size in the 4CV, size and shape of RV and LV, and abnormal contractility of RV and LV. The area under the receiver-operating-characteristics curve was 0.98 (SE, 0.023; 95% CI, 0.84-1). There was no significant difference in the percent of fetuses with RV/LV area disproportion between those with CoA and those that were FP-CoA.

CONCLUSIONS

Speckle-tracking analysis of multiple ventricular measurements may be helpful to refine the diagnosis in fetuses that are suspected to have CoA prenatally. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Behavior of fetal longitudinal myocardial fibers assessed by speckle tracking to obtain strain and strain rate values for low-risk pregnancies

Objective To analyze the behavior of fetal longitudinal myocardial fibers assessed by speckle tracking (STE) after fetal viability. Methods A cross-sectional study was performed in 156 women with normal singleton pregnancies from 22 to 31 weeks of gestation. Strain (S) and strain rate (SR) values were measured in both ventricles during the fetal cardiac cycle. The population was divided into five gestational age groups based on 2-week intervals. The correlations of maternal variables with the S and SR variables and intra-observer analysis were performed. Results There was a significant difference in the S and SR values of the left ventricle (LV) among the gestational age groups (P = 0.007). Significantly higher S and SR values were observed in early age groups demonstrating reductions in LV S and SR values at 26 weeks, followed by stabilization. For the right ventricle (RV), there was no significant difference between gestational age groups. Significant intra-observer agreement was observed for S values of the RV (P = 0.008) and LV (P = 0.0004) and SR values of the RV (P = 0.0001) and LV (P = 0.015). Conclusion Decreases in the S and SR values of the LV occurred after 26 weeks, followed by stabilization. No significant difference was observed in the S or SR value of the RV among the gestational age groups, and no significant association of any maternal variable evaluated with S and SR values was observed. Significant intra-observer agreement was obtained among the results.

Fetal cardiac rhabdomyomas treated with maternal sirolimus

OBJECTIVE

To review the pathophysiology of rhabdomyomas and the emerging option of prenatal treatment of fetal cardiac rhabdomyomas.

METHODS

We present a case of fetal rhabdomyomas causing significant hemodynamic compromise that received in utero treatment of maternal sirolimus. Genetic amniocentesis confirmed a TSC2 mutation. A treatment program was initiated with a 10-mg loading dose titrated to a goal maternal trough of 10 to 15 ng/dL. In order to follow fetal cardiac function, a sophisticated method of speckle tracking echocardiography was used before and after treatment. Obstetric ultrasound was used to monitor fetal growth, and clinical surveillance, echocardiography, and brain MRI were used to monitor postnatal growth and development through 6 months of neonatal life.

RESULTS

Sirolimus was initiated from 28 to 36 weeks of gestation with improvement of cardiac status. During this period, intrauterine growth restriction developed. Postnatally, the infant has had stable rhabdomyomas and cardiac function without reinitiating sirolimus. Brain MRI demonstrated scattered cortical tubers and subependymal nodules, and the infant has not had seizure-like activity. At 6 months of age, the infant has achieved appropriate developmental milestones.

CONCLUSION

In counseling cases of prenatal onset large obstructing rhabdomyomas and cardiac compromise, in utero sirolimus treatment can be considered.

Assessment of ventricular contractility in fetuses with an estimated fetal weight less than the tenth centile

OBJECTIVE

To determine whether abnormal global, transverse, and longitudinal ventricular contractility of the heart in fetuses with an estimated fetal weight <10th centile is present, irrespective of Doppler studies of the umbilical artery and cerebroplacental ratio.

STUDY DESIGN

This was a retrospective study of 50 fetuses with an estimated fetal weight <10th centile that were classified based on Doppler results from the pulsatility indices of the umbilical artery and middle cerebral artery, and the calculated cerebroplacental ratio (pulsatility indices of the umbilical artery/middle cerebral artery). Right and left ventricular measurements were categorized into 3 groups: (1) global ventricular contractility (fractional area change), (2) transverse ventricular contractility (24-segment transverse fractional shortening), and (3) basal-apical longitudinal contractility (longitudinal strain, longitudinal displacement fractional shortening, and basal lateral and septal wall annular plane systolic excursion). Z scores for the above measurements were computed for fetuses with an estimated fetal weight <10th centile using the mean and standard deviation derived from normal controls. Ventricular contractility measurements were considered abnormal if their Z score values were <5th centile (z score <-1.65) or >95th centile (Z score >1.65), depending on the specific ventricular measurement.

RESULTS

The average gestational age at the time of the examination was 32 weeks 4 days (standard deviation 3 weeks 4 days). None of the 50 study fetuses demonstrated absent or reverse flow of the umbilical artery Doppler waveform. Eighty-eight percent (44/50) of fetuses had one or more abnormal measurements of cardiac contractility of 1 or both ventricles. Analysis of right ventricular contractility demonstrated 78% (39/50) to have 1 or more abnormal measurements, which were grouped as follows: global contractility 38% (19/50), transverse contractility 66% (33/50); and longitudinal contractility 48% (24/50). Analysis of left ventricular contractility demonstrated 1 or more abnormal measurements in 58% (29/50) that were grouped as follows: global contractility 38% (19/50); transverse contractility 40% (20/50); and longitudinal contractility 40% (20/50). Of the 50 study fetuses, 25 had normal pulsatility index of the umbilical artery and cerebroplacental ratios, 80% of whom had 1 or more abnormalities of right ventricular contractility and 56% of whom had 1 or more abnormalities of left ventricular contractility. Abnormal ventricular contractility for these fetuses was present in all 3 groups of measurements; global, transverse, and longitudinal. Those with an isolated abnormal pulsatility index of the umbilical artery (n=11) had abnormalities of transverse contractility of the right ventricular and global contractility in the left ventricle. When an isolated cerebroplacental ratio abnormality was present, the right ventricle demonstrated abnormal global, transverse, and longitudinal contractility, with the left ventricle only demonstrating abnormalities in transverse contractility. When both the pulsatility index of the umbilical artery and cerebroplacental ratio were abnormal (3/50), transverse and longitudinal contractility measurements were abnormal for both ventricles, as well as abnormal global contractility of the left ventricle.

CONCLUSIONS

High rates of abnormal ventricular contractility were present in fetuses with an estimated fetal weight <10th centile, irrespective of the Doppler findings of the pulsatility index of the umbilical artery, and/or cerebroplacental ratio. Abnormalities of ventricular contractility were more prevalent in transverse measurements than global or longitudinal measurements. Abnormal transverse contractility was more common in the right than the left ventricle. Fetuses with estimated fetal weight less than the 10th centile may be considered to undergo assessment of ventricular contractility, even when Doppler measurements of the pulsatility index of the umbilical artery, and cerebroplacental ratio are normal.

Size and shape of the four-chamber view of the fetal heart in fetuses with an estimated fetal weight less than the tenth centile

BACKGROUND

Fetuses with an estimated fetal weight below the 10^th centile have an increased risk of adverse perinatal and long-term outcomes as well as increased rates of cardiac dysfunction, which often alters cardiac size and shape of the 4-chamber view and the individual ventricles. As a result, a simple method has emerged to screen for potential cardiac dysfunction in fetuses with estimated fetal weights <10^th centile by measuring the size and shape of the 4-chamber view and the size of the ventricles.

OBJECTIVE

To determine the number of fetuses with an abnormal size and shape of the 4-chamber view and size of the ventricles in fetuses with an estimated fetal weight <10^th centile.

MATERIALS AND METHODS

This was a retrospective study of 50 fetuses between 25 and 37 weeks of gestation with an estimated fetal weight <10^th centile. Data from their last examination were analyzed. From an end-diastolic image of the 4-chamber view, the largest basal-apical length and transverse width were measured from their corresponding epicardial borders. This allowed the 4-chamber view area and global sphericity index (4-chamber view length/4-chamber view width) to be computed. In addition, tracing along the endocardial borders with speckle tracking software enabled measurements of the right and left ventricular chamber areas and the right ventricle/left ventricle area ratios to be computed. Doppler waveform pulsatility indices from the umbilical (umbilical artery pulsatility index) and middle cerebral arteries (middle cerebral artery pulsatility index) were analyzed, and the cerebroplacental ratio (middle cerebral artery pulsatility index/umbilical artery pulsatility index) computed. Umbilical artery pulsatility indices >90^th and cerebroplacental ratios <10^th centile were considered abnormal. Using data from the control fetuses, the centile for each of the cardiac measurements was categorized by whether it was <10^th or >90^th centile, depending upon the measurement.

RESULTS

Of the 50 fetuses with estimated fetal weight <10^th centile, 50% (n = 25) had a normal umbilical artery pulsatility index and cerebroplacental ratio. These fetuses had significantly more (P < 0.02 to <0.0001) abnormalities of the size and shape of the 4-chamber view than controls. In all, 44% had a 4-chamber view area >90^th centile, 32% had a 4-chamber view global sphericity index <10^th centile, 56% had a 4-chamber view width >90^th centile, and 80% had 1 or more abnormalities of size and/or shape. The remaining 50% of fetuses (n = 25) had abnormalities of 1 or both for the umbilical artery pulsatility index and/or cerebroplacental ratio. These fetuses had significantly higher rates of abnormalities (P <0.05 to <0.0001) than controls for the following 4-chamber view measurements: 36% had a 4-chamber view area >90^th centile; 28% had a 4-chamber view global sphericity index <10^th centile; and 68% had a 4-chamber view width >90^th centile. Only those fetuses with an abnormal umbilical artery pulsatility index had significant changes in ventricular size; 56% had a left ventricular area <10^th centile; 28% had a right ventricular area <10^th centile; 36% had right ventricular/left ventricular area ratio >90^th centile. One or more of the above abnormal measurements were present in 92% of the fetuses.

CONCLUSION

Higher rates of abnormalities of cardiac size and shape of the 4-chamber view were found in fetuses with an estimated fetal weight <10^th centile, regardless of their umbilical artery pulsatility index and cerebroplacental ratio measurements. Those with a normal umbilical artery pulsatility index and an abnormal cerebroplacental ratio had larger and wider measurements of the 4-chamber view. In addition, the shape of the 4-chamber view was more globular or round than in controls. These fetuses may have an increased risk of perinatal complications and childhood and/or adult cardiovascular disease. Screening tools derived from the 4-chamber view, acting as surrogates for ventricular dysfunction, may identify fetuses who could benefit from further comprehensive testing and future preventive interventions.

Aortic Coarctation: A Comprehensive Analysis of Shape, Size, and Contractility of the Fetal Heart

BACKGROUND

An integrated assessment of the size and shape of the 4-chamber view (4-CV) and right and left ventricles (RV and LV) as well as the function of the RV and LV in fetuses with coarctation of the aorta (CoA) has not yet been conducted.

OBJECTIVES

We evaluated the size and shape of the 4-CV, RV, and LV, and function of the RV and LV, to identify a profile for fetuses with CoA when compared to a control population.

METHODS

50 CoA fetuses were compared to 200 controls. This was a retrospective case series comparing the 4-CV of CoA fetuses and controls. The 4-CV end-diastolic area, length, width, and sphericity index were measured to determine the configuration of the 4-CV. Speckle-tracking analysis was used to compute the RV and LV end-diastolic area, length, 24-segment sphericity index, 24-segment transverse width, and the following functional parameters: (1) fractional area change; (2) global, lateral, and septal strain; (3) basal-apical, lateral, and septal annular displacement and fractional shortening; and (4) 24-segment transverse width fractional shortening. Using 5 and 95% reference intervals, the CoA fetal measurements were classified; from these, the odds ratio was computed between the fetuses with CoA and the controls. p < 0.05 was considered significant.

RESULTS

In fetuses with CoA, the 4-CV was spherical in shape, increased in area and width, and decreased in length. Abnormal CoA sphericity indices reflected a flatter LV and a more spherical RV. The LV area, length, and width, and RV length were decreased. The transverse width of the RV was increased. RV and LV global, longitudinal, and transverse contractility were depressed.

CONCLUSIONS

The results demonstrate previously unappreciated differences in the shape, size, and function of the heart in fetuses with CoA. These differences may assist examiners in identifying fetuses with CoA.

Functional cardiac measurements performed by two-dimensional Doppler echocardiography in normal fetuses: Determination of Z-scores and future prospects

Two-dimensional (2D) echocardiogram with the aid of color Doppler and pulsed Doppler allows one to record blood flow waveforms in several structures of the heart. The determination of normal values of these flows in the fetus can help understand cardiac hemodynamics. Given this importance, numerous surveys have been conducted with various existing echocardiographic techniques in order to improve the functional evaluation and consequently, planning of delivery. The aim of this review was to discuss the findings of the reference values of blood flows obtained by 2D echocardiography with Doppler, the current trend of the determination of Z-scores in the functional measurements, and their future prospects.