Speckle tracking analysis to evaluate the size, shape, and function of the atrial chambers in fetuses with d-transposition of the great arteries to predict the need for neonatal urgent balloon atrial septostomy

Transversal cardiac diameter is increased in fetuses with dextro-transposition of the great arteries older than 28th weeks of gestation

OBJECTIVES

In majority of congenital heart defects the size of the fetal heart is normal (without cardiomegaly). Aim of this study was to establish normal ranges of fetal transversal cardiac diameter (4CV TW ED) and to compare fetal dextro-transposition of the great arteries (d-TGA) with normal ranges for 4CV TW ED.

METHODS

Retrospectively of 3,553 records we analyzed and included 1,154 healthy singleton fetuses as a control group. Consecutive percentiles for 4CV TW ED diameter according to the gestational age (GA) were calculated. 74 fetuses with d-TGA were analyzed in 3rd trimester.

RESULTS

The -2, -1, +1 and +2 Z-scores of 4CV TW ED between weeks 18 and 37 of gestation were calculated. In the group of fetuses with d-TGA 68 % of them had 4CV TW ED > +2 Z-score fitted for GA. Rashkind procedure during first 24 h after birth was performed in 63 % cases. Increased 4CV TW ED was more frequently seen in fetuses who needed Rashkind procedure after birth, but without statistical significance.

CONCLUSIONS

4CV TW ED measurement during the third trimester scans as a cardiac screening tool in obstetrical practice may potentially help to detect d-TGA and indicate further echocardiographic examination in case of d-TGA suspicion. 4CV TW ED was not helpful to predict the necessity for neonatal Rashkind procedure.

Assessment of Atrial Size, Shape, and Contractility in Growth-Restricted and Small-for-Gestational-Age Fetuses

OBJECTIVES

The size, shape, and contractility of the heart's atrial chambers have not been evaluated in fetuses with growth restriction (FGR) or who are small-for-gestational-age (SGA) as defined by the Delphi consensus protocol. This study aimed to examine the atrial chambers using speckle tracking analysis to identify any changes that may be specific for either growth disturbance.

METHODS

Sixty-three fetuses were evaluated with an estimated fetal weight <10th percentile who were classified as FGR or SGA based on the Delphi consensus protocol. The atrial cardiac cycle was defined as end-diastole, end-systole, and end-diastole, equivalent to ventricular end-systole, end-diastole, and end-systole. The atrial size, shape, and contractility were computed from 24 transverse segments and one length measurement identified from speckle tracking analysis of the endocardium at end-diastole and end-systole. The z-score for each atrial measurement was computed using the mean and standard deviation equations from a control group of 200 fetuses. The z-score values were compared between the control and FGR/SGA fetuses as well as between FGR and SGA fetuses using the Kruskal-Wallis test. A P-value of <.05 was considered significant.

RESULTS

Of the 63 fetuses with an estimated fetal weight (EFW) <10th percentile, 60% (38/63) were classified as FGR and 40% (25/63) as SGA. The following abnormal atrial measurements were unique to FGR fetuses: decreased end-diastolic left atrial (LA) area, decreased LA base and mid-chamber end-diastolic width, decreased LA base sphericity index, decreased right atrial (RA) mid-chamber sphericity index, decreased LA ejection volume, and decreased LA emptying volume. The following were unique to the SGA fetuses: Increased RA mid-chamber length, decreased LA fractional area change, decreased RA reservoir strain, decreased RA basal-apical length fractional shortening, and decreased LA base width transverse fractional shortening. The significant difference was an increased LA mid-chamber length in the SGA fetuses.

CONCLUSIONS

Fetuses with an EFW <10th percentile who are classified as either SGA or FGR demonstrate unique abnormalities of atrial size, shape, and contractility, thus allowing the examiner to differentiate between FGR and SGA fetuses.

Assessing Fetal Heart Morphology and Function in Fetuses With Right Ventricular Outflow Obstruction by Fetal Heart Quantitative Technique

OBJECTIVES

To investigate the clinical utility of the fetal heart quantification (Fetal HQ) technique in the assessment of morphological and functional changes in fetuses with right ventricular outflow obstruction (RVOTO).

METHODS

This study included 53 fetuses with RVOTO and 30 age-matched normal controls. The RVOTO fetuses were divided into 2 groups based on the occurrence of other cardiovascular malformations: the simple pulmonary stenosis (PS group) and the conotruncal defects (CTD group). Size, shape, and contractility parameters of the fetal heart in 4-chamber view (4CV), left ventricle, and right ventricle (LV and RV) detected by fetal HQ.

RESULTS

Fetuses with RVOTO exhibited an increased 4CV-width, with normal 4CV-Length. The end-diastolic diameter (ED) of the LV segments 1-22 was significantly greater in RVOTO fetuses. The sphericity index (SI) of the LV 24-segment was significantly smaller in the CTD and PS groups. Global longitudinal strain (GLS) and fractional area change (FAC) of the LV and RV were reduced in RVOTO fetuses.

CONCLUSION

Our results suggested that the characteristic changes in the morphology and function of the RVOTO fetal heart could be detected early by the HQ technique, which has clinical utility in analyzing the morphology of the RVOTO fetal heart in a quantitative manner.

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.

Left atrial strain in fetal echocardiography - could it be introduced to everyday clinical practice?

OBJECTIVES

Prenatal cardiology is a part of preventive cardiology based on fetal echocardiography and fetal interventional cardiology, which facilitates treatment of congenital heart defects (CHD) in pediatric patients and consequently in adults. Timely prenatal detection of CHD plays a pivotal role in facilitating the appropriate referral of pregnant women to facilities equipped to provide thorough perinatal care within the framework of a well-structured healthcare system. The aim of this paper is to highlight the role of left atrial strain (LAS) in prenatal evaluation of fetal heart and prediction of structural and functional disorders.

METHODS

We conducted a comprehensive literature review searching PubMed for articles published from inception up until August 2023, including the search terms "left atrial strain", "fetal echocardiography", and "prenatal cardiology" combined through Boolean operators. In addition, references lists of identified articles were further reviewed for inclusion.

RESULTS

Our review underscores the significance of LAS parameters in fetal echocardiography as a screening tool during specific gestational windows (starting from 11 to 14 weeks of gestation, followed by better visualization between 18 and 22 weeks of gestation). The left atrial strain technique and its parameters serve as valuable indicators, not only for identifying cardiac complications but also for predicting and guiding therapeutic interventions in cases of both cardiac and noncardiac pregnancy complications in fetuses. Evidence suggests establishment of second-trimester reference strain and strain rate values by speckle-tracking echocardiography in the healthy fetal cohort is essential for the evaluation of myocardial pathologies during pregnancy.

CONCLUSIONS

Finding of LAS of fetal heart is feasible and probably can have potential for clinical and prognostic implications.

Evaluation of the changes in cardiac morphology of fetuses with congenital heart disease using fetalHQ

Objective: To evaluate the changes in cardiac morphology of fetuses with congenital heart disease (CHD) using the fetal heart quantitative technique (fetalHQ).Methods: A total of 20 normal pregnant women (control group) and 20 pregnant women suspected of fetal CHD (case group) were included in this study. The dynamic images of the four-chamber view of the fetal heart were recorded and analyzed using fetalHQ. The global sphericity index (GSI) and 24-segment SI of the two groups were compared. The differences in the left and right ventricular 24-segment SI for each group were investigated.Results: There was no statistically significant difference in the GSI between the two groups (p > 0.05). The difference in the SI values of left ventricular segments 1-2 between the case group and control group was statistically significant (all p < 0.05), while the intergroup difference in SI of left ventricular segments 3-24 was not significant (all p > 0.05). The SI of the 24 segments of the right ventricle showed no significant intergroup difference (all p > 0.05). The difference in the left and right ventricular 24-segment SI in the case group did not reach statistical significance (all p > 0.05). In the control group, the SI values between the left and right ventricles were significantly different in segments 18-24 (all p < 0.05), and no significant difference was found in segments 1-17 (all p > 0.05). There was a statistically significant intergroup difference in the percentage of unusual left ventricular SI, determined based on Z-score (p < 0.05), and the percentage of outliers for the right ventricle between the two groups showed no significant difference (p > 0.05).Conclusion: The fetalHQ is regarded as a straightforward and reliable approach for assessing the cardiac GSI and 24-segment SI of left and right ventricles in fetuses diagnosed with CHD. While CHD may not significantly impact the overall shape of the fetal heart or the geometric shape of the right ventricle, in this study, a notable increase in SI values for the left ventricular 1-2 segments was observed, indicating a more flattened ventricular chamber. Additionally, the morphological distinctions between the left and right ventricles in fetuses with CHD are no longer discernible.