Pulmonary Stenosis – PS

Pulmonary Stenosis (PS) is one of the simpler abnormalities of the heart. But even this requires some basic knowledge about the structure of the heart.

What is Pulmonary Stenosis ?

The word “pulmonary” denotes “to do with the lungs”.

The pulmonary valve is located between the right ventricle and the pulmonary artery. It regulates blood flow into the lungs, and prevents blood from leaking back into the right ventricle.

Sometimes, this pulmonary valve is extremely narrow, and blocks the smooth flow of blood into the lungs. This condition is called Pulmonary Stenosis – or PS, in short.

At other times, the pulmonary valve itself is normal, but there is an obstruction to blood flow from the right ventricle at other levels. For instance, there may be abnormal bundles of muscle below the pulmonary valve which obstruct flow. This is called “sub-valvular” pulmonary stenosis.

Or occasionally, there may be a narrowing of the pulmonary artery or its branches above the pulmonary valve. This is called “supra-valvular” pulmonary stenosis.

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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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