Atrial Septal Defect – ASD

What is an Atrial Septal Defect ?

The two upper chambers of the heart are called the right and left atrium. They are separated by a “wall”, called the ATRIAL SEPTUM. Sometimes, this “wall” is not complete. There is a hole in it.

This hole is called an Atrial Septal Defect – or ASD, in short. ASD’s may be large or small, single or multiple. The heart may be otherwise normal, or there may be other defects too.

What happens when there is an ASD ?

In the normal heart, blood flowing in the right sided chambers (atrium and ventricle) is completely separated from the left sided chambers by the atrial septum. When there is a hole in this “wall”, blood from the left atrium flows through the hole into the right side.

You might well ask, “Why only from left to right ?”

That’s because the pressure of blood in the left atrium is higher than in the right, and as you know, any fluid, including blood, will flow from a place with high pressure to one with a lower pressure.

So what is the effect of this ?

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