Atrioventricular septal defect

Last revised by Dr Joshua Yap on 02 Oct 2022

Atrioventricular septal defects (AVSDs), also known as atrioventricular canal defects or endocardial cushion defects, comprise a relatively wide range of defects involving the atrial septum, ventricular septum, and one or both of the tricuspid or mitral valve. They can represent 2-7% of congenital heart defects

The estimated prevalence is at ~3-4 in 10,000 births.

It results from deficient development of the apical portion of the atrial septum, basal portion of the interventricular septum, as well as the atrioventricular valves. All four chambers of the heart communicate, therefore, both left-to-right and right-to-left shunts can occur.

Many have been used but can be broadly divided into:

  • complete 

  • incomplete 

An atrioventricular septal defect may also be balanced or unbalanced 8.

Plain chest radiographic features are often non-specific but may show cardiomegaly +/- features of pulmonary hypertension and mitral valve insufficiency.

Allows direct visualization of the defect spectrum; often a large defect of the midline heart structures is seen. Color Doppler often aids in further visualization of the central opening.

An atrioventricular septal defect can give a classical "Gooseneck" sign on a lateral left ventricular angiogram 3.

Allows direct visualization of the defect spectrum. Can be superior in assessing cardiac chamber dimensions and the presence/extent of ventricular hypoplasia which is a determinant of surgical risk.

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Cases and figures

  • Case 1
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  • Case 2
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  • Case 3
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  •  Case 4
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  • Case 5: fetal echocardiography
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