What is an AV septal defect

Atrioventricular Septal Defect (AVSD)

The atrioventricular septal defect (AVSD) is also called the AV canal and is a malformation of the septum between the atria and ventricles as well as the AV valves (atrioventricular valves - valves between the atria and ventricles). All of these structures are formed by fusing the so-called "endocardial pillows". If there is no or inadequate fusion, a hole is created in the lower part of the atrial septum and another hole in the upper part of the ventricular septum. Instead of two AV valves, a common AV valve usually has five leaflets. This heart defect can be associated with other malformations - e.g. B. Fallot tetralogy or Double outlet right ventricle (DORV). Children with trisomy 21 (Down's disease) are particularly often affected.



What are the effects of an atrioventricular septal defect (AVSD)?

The holes in the heart septum create short-circuit connections from the left heart to the right one (left-right shunt). There is a shunt from the left ventricle into the right ventricle as well as between the atria. The common AV valve is often leaky (AV valve insufficiency) and this contributes to further complication of the heart function. If the proportion of the ventricular defect is very large, the pressure in the pulmonary circulation increases (pulmonary arterial hypertension).



The children get sick in the first few weeks of life - "heart failure" occurs. The signs to be observed are shortness of breath, profuse sweating, difficulty drinking - drinking takes a long time, children fall asleep, and there is no weight gain.


How is an atrioventricular septal defect (AVSD) treated?

The primary corrective operation is usually carried out between the 4th and 6th month of life. A diagnostic cardiac catheter examination is usually not necessary and only takes place in the event of a later diagnosis or complex anatomy.
During the operation, the septum defects are closed with a patch and the AV valves are reconstructed. The prerequisite is that both chambers are the same size and the lung pressure is not already too high.
Corrective surgery is not possible if a chamber is too small. In this case one proceeds according to the graduated scheme as with complex heart defects with only one chamber (single ventricle) (see complex heart defects)

Reconstructing the AV valves in AVSD is a high surgical art. Smaller leaks in the valve are common and only if this increases over the course of a few years a valve reconstruction must be attempted again.

In the AVSD, the outlet from the left main chamber is shaped like a goose neck.