Atrioventicular Septal Defect with Fallot's Tetralogy
A small percentage of babies have a complex heart condition which combines the most common defect associated with Down’s Syndrome, the Atrioventricular Septal Defect (AVSD) with another defect called Fallot’s Tetralogy.Generally it is possible to combine the information from different defects to give an overall picture but in this combination it is more difficult as the Atrioventricular Septal Defect (AVSD) causes a left to right flow of blood within the heart whilst Fallot’s Tetralogy produces a right to left flow. This is the reason we have produced a Topic Note specifically for these combined defects.
The Atrioventricular Septal Defect (AVSD) is a hole in the wall between the top chambers (atria) and a hole in the wall between the bottom chambers (ventricles), often with one common valve between the two atria and the two ventricles. In Fallot’s Tetralogy there is a narrowing between the right ventricle (pumping chamber) and the pulmonary (lung) artery, a hole between the two ventricles (VSD), a thickening of the right ventricle and the main blood vessel to the body (the aorta) overrides the VSD.
So in combination these defects result in:
- a hole between the top chambers and a hole between the bottom chambers (AVSD)
- combined mitral and tricuspid valves (common atrioventricular valve)
- narrowed pulmonary artery (from heart to lungs) or the area under or above the valve, or all three
- thickening of the right bottom chamber (ventricle)
