Atrioventricular septal defect

Atrioventricular septal defects (AVSDs), also known as atrioventricular canal defects or endocardial cushion defects, comprise of 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 inter-ventricular septum, as well as 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 AVSD may also be balanced or unbalanced 8.

Plain chest radiographic features are often not specific but may show have cardiomegaly +/- features of pulmonary hypertension and mitral valve insufficiency.

Allows direct visualisation of the defect spectrum and often a large defect of the midline heart structures are seen. Colour Doppler often aids in further visualisation of the central opening.

An AVSD can give a classical "Gooseneck" sign on a lateral left ventricular angiogram 3.

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

Congenital heart disease

There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorised, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.

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Article information

rID: 7354
Synonyms or Alternate Spellings:
  • Atrioventricular septal defect
  • Endocardial cushion defect
  • AVSD
  • Atrioventricular septal defect (AVSD)
  • Atrioventricular canal defect
  • AV canal defect

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