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:
An AVSD may also be balanced or unbalanced 8.
- trisomy 21 (Down syndrome): may be present in up to 50% of cases 4
- trisomy 18 (Edwards syndrome): may be present in up to 25 % of cases 7
heterotaxy syndromes 7
- may be present in up to 10% of cases of asplenia (Ivemark) syndrome 4
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.
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- 4. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
- 5. Langford K, Sharland G, Simpson J. Relative risk of abnormal karyotype in fetuses found to have an atrioventricular septal defect (AVSD) on fetal echocardiography. Prenat. Diagn. 2005;25 (2): 137-9. doi:10.1002/pd.1037 - Pubmed citation
- 6. Loffredo CA, Hirata J, Wilson PD et-al. Atrioventricular septal defects: possible etiologic differences between complete and partial defects. Teratology. 2001;63 (2): 87-93. doi:10.1002/1096-9926(200102)63:2<87::AID-TERA1014>3.0.CO;2-5 - Pubmed citation
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- 8. Drinkwater DC, Laks H. Unbalanced atrioventricular septal defects. Seminars in thoracic and cardiovascular surgery. 9 (1): 21-5. Pubmed
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.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt