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An atrioventricular septal defect (AVSD) is diagnosed with prenatal sonography using the 4‐chamber view (4CV) of the fetal heart. Prenatal 2D sonographic imaging of normal and AVSD short axis (SAX) atrioventricular (AV) valve views have not been well described. The aim is to describe the 2D sonographic 4‐chamber and SAX view of the AV valves when an AVSD is present compared to normal AV valves. The 4CV AVSD heart demonstrates no offset of AV valves due to the abnormal valve structure. Complete and intermediate AVSD has a septum primum defect and inlet ventricular septal defect (VSD). The partial AVSDs have either a septum primum defect or just an inlet VSD with an intact primum septum. The SAX view of AVSD demonstrates the common AV junction and the bridging leaflets. In ventricular diastole valves have a "figure 8" and "dumbbell" shape in partial and complete AVSD, respectively. These appearances are not seen in the normal heart in SAX as both tricuspid and mitral valve are separate valves. The SAX view can be obtained by locating a sagittal aortic arch view and then scanning slightly towards the left side of the fetus, near the base of the heart and the AV valves. An in‐depth interrogation of the abnormal fetal heart is obtained without specialised 4D capable ultrasound machines providing information to assist in counselling during the pregnancy and for postnatal surgical planning. Future research to assess the feasibility of incorporating the SAX view into routine practice and by general sonographers is suggested. [ABSTRACT FROM AUTHOR]

Objective: Atrioventricular septal defect is associated with a high risk of a chromosomal abnormality, particularly trisomy 21. The aim of this study is to assess the rate of trisomy 21 in fetuses diagnosed with an atrioventricular septal defect and to examine the influence of prior screening on the rate of trisomy 21.Methods: Electronic ultrasound database was searched to identify fetuses diagnoses with an atrioventricular septal defect from 2002 to 2014. Rate of trisomy 21 and other aneuploidies was calculated among fetuses with normal situs. The prevalence of trisomy 21 and other aneuploidies was assessed in women with low and high first trimester risk for trisomy 21, using a cut-off value of 1:150 and 1:250.Results: A total 110 fetuses with a diagnosis of atrioventricular septal defect were identified. Among the 98 fetuses with normal situs, the prevalence of trisomy 21 was 46% (95% CI: 36-56%). Using a 1:150 threshold, the rate of trisomy 21 within the low-risk group was 41% (95% CI: 27-57%) while in the high-risk group it was 70% (95% CI: 52-83%), significantly higher than in the low risk group (p=0.028). Similar results were obtained when the 1:250 threshold was applied (66% versus 41%, p=0.055).Conclusions: The rate of trisomy 21 among fetuses identified with an atrioventricular septal defect in the second trimester is high even in those that undergo first trimester combined screening. Some fetuses with a high-risk screening result show a normal karyotype. Therefore, an offer of an invasive procedure to check fetal karyotyping is indicated. Knowledge of these rates may be helpful for parents in the decision making process. [ABSTRACT FROM AUTHOR]

Objectives: To assess the feasibility and clinical potential of 4D volume rendering of the atrioventricular (AV) valve junction, to standardize the acquisition method, and to display the AV valve junction morphology in normal fetuses and in those with a complete atrioventricular septal defect (AVSD). Methods: We performed sonography in 40 normal fetuses and 10 fetuses with complete AVSD, and volume datasets were acquired from apical and lateral four-chamber views. The render box was placed systematically. First, it included the AV valves, with the reference dot at the level of the crux of the heart. Then, it included the papillary muscles, with the reference dot in the interventricular septum at the level of the distal opening of the tricuspid valve leaflet. Results: Volume acquisition and rendering were technically possible in all cases. Volume rendering of the left ventricle showed the position of the anterolateral and posteromedial papillary muscles in 36/40 normal fetuses (90%). At the level of the right ventricle, the septal, anterior and posterior papillary muscles were visualized in 33/40 normal fetuses (82%). In cases of complete AVSD, the AV valve has five leaflets, with anterosuperior and posteroinferior bridging leaflets straddling the septa. The morphology of the anterosuperior bridging leaflets and the abnormal position of the papillary muscles could be displayed in all cases. Conclusions: Our study suggests that some of the components of the AV junction can be reconstructed easily from sonographic volumes acquired from an apical or lateral four-chamber view. This new technique may have a role in obtaining views that are not easily accessible by standard sonography, enabling a rapid complementary assessment of normal and abnormal intracardiac anatomy. [ABSTRACT FROM AUTHOR]