What are Pulmonary Veins? Let's understand it simply.

We all know that the heart is the engine of our body. This small organ that pumps blood throughout the body and gives life to every cell is truly amazing. But have you heard about the very important blood vessel system that helps the heart work, especially the one that brings the oxygen-rich blood purified in the lungs back to the heart? That system of vessels is what we call the pulmonary veins, or pulmonary veins . Knowing about these is very important to understand our body.

What is the difference between these pulmonary veins and pulmonary arteries?

Now you may have a question: "When we say veins, we usually think of veins that carry impure blood, that is, blood that is low in oxygen. Arteries carry pure, oxygen-rich blood. So what's so special about these?"

Yes, you're right. That's what happens everywhere else in our bodies. Veins bring oxygen-poor blood to the heart, and arteries carry oxygen-rich blood away from the heart. But in the pulmonary circulation, where blood is exchanged between the lungs and the heart, the story is completely reversed. Here's the most amazing thing about our bodies!

Simply put, there are two main differences:

1. Blood type carried:

• Pulmonary Arteries: These carry oxygen-poor (poor) blood from the heart to the lungs.
• Pulmonary Veins: These carry oxygenated (clean) blood from the lungs to the heart.

2. Direction of blood flow:

• Pulmonary Arteries: Carry blood away from the heart (towards the lungs).
• Pulmonary Veins: Carry blood from the lungs to the heart.

Let's look at this table to explain this further.

What is the function of the pulmonary veins and where are they located?

Think of it like a courier service. The lungs are like the 'blood purification center' in our body. When we breathe, the oxygen we inhale is added to the blood, and the carbon dioxide in the blood is removed from the blood through the lungs. The main job of these pulmonary veins is to bring this 'precious parcel' of purified, freshly oxygenated blood back to the 'main distribution center' called the heart.

These are located right between our lungs and our heart . The small blood vessels in both our right and left lungs join together and emerge from each lung as two pulmonary veins. Then all four of these veins come together and connect to the left atrium of the heart. That is, the chamber on the left side of the heart.

How many pulmonary veins do we have?

Normally, most of us (about 60%-70%) have four of these pulmonary veins.

• Two from the right lung.
• Two from the left lung.

But some people may have three or five. This is not a disease of any kind, nor is it something to be afraid of. It is just a small change in the way our body is made. In medicine, we call this ``Anatomical variations''. This change does not cause any harm to the functioning of the body.

Structure of the pulmonary veins

Here are the four common pulmonary veins:

• Right superior pulmonary vein: Brings blood from the upper and middle parts of the right lung.
• Right inferior pulmonary vein: Brings blood from the lower part of the right lung.
• Left superior pulmonary vein: Brings blood from the upper part of the left lung.
• Left inferior pulmonary vein: Brings blood from the lower part of the left lung.

These four veins open separately into the left atrium of the heart. Oxygenated blood enters the left atrium through these four openings. The blood then goes to the left ventricle, from where it is pumped to the entire body through the aorta.

Variations in pulmonary veins

Some people may have small changes in the structure of their pulmonary veins. Some of these changes are harmless and healthy. But some can be serious conditions that affect the functioning of the heart.

Harmless changes

These do not cause any problems for the body, because ultimately the oxygen-rich blood goes straight to the left atrium.

• Common left-sided trunk: This is when the two veins coming from the left lung join together and join the left atrium as a single tube. It's like two roads joining together to form one.
• Accessory right pulmonary vein: In this case, there may be one more vein in addition to the two normal veins on the right side, meaning there may be three veins in total.

Serious changes affecting heart function

These are usually congenital heart defects. They are caused by a blockage or alteration in the path that oxygen-rich blood takes to the left atrium.

• Total Anomalous Pulmonary Venous Return (TAPVR): This is a very serious condition. In this condition , none of the pulmonary veins connect to the left atrium of the heart. Instead, all of these veins connect to the right atrium of the heart. This causes oxygen-rich blood to mix with oxygen-poor blood. Babies with this condition must undergo surgery to survive.

• Partial Anomalous Pulmonary Venous Return (PAPVR): In this condition, at least one pulmonary vein is connected to the left atrium, allowing some clean blood to flow to the body. Although this is not as serious as TAPVR, these people may still need treatment. Sometimes, the condition may not be diagnosed until adulthood.

Other conditions affecting the pulmonary veins

In addition to birth defects, there are several other medical conditions that affect the pulmonary veins.

• Pulmonary vein obstruction:A vein can be blocked due to a cancerous condition in the lungs or heart.
• Pulmonary vein stenosis: Narrowing of one or more veins. In adults, this condition can sometimes occur as a side effect of catheter radiofrequency ablation, a treatment for irregular heartbeats.
• Pulmonary vein thrombosis: A blood clot in a vein. This is most common in people with lung cancer or who have had a lung transplant.
• Pulmonary venous hypertension: Increased pressure in these veins due to impaired function of the left side of the heart.

The relationship between atrial fibrillation and pulmonary veins

These pulmonary veins, especially where they connect to the left atrium of the heart, are a major site for the onset of atrial fibrillation , or A-Fib, a condition in which the heart beats irregularly. That's why doctors use special treatments for these pulmonary veins when treating A-Fib.

How do you check their health status?

If your doctor suspects a problem with your pulmonary veins, he or she may recommend several tests, such as:

• Chest X-ray
• Echocardiography (a scan of the heart)
• MRI scan
• CT scan

How do you keep your pulmonary veins healthy?

If your doctor has diagnosed you with a pulmonary vein condition, it is important to follow his or her instructions. Often, these problems are caused by other heart or lung conditions. Therefore, it is essential to treat the underlying condition properly and to remain under regular medical supervision.

Talk openly with your doctor about your concerns and symptoms. Ask him or her about ways you can manage your condition at home.

The pulmonary veins are a part of the body that silently, but extremely important in maintaining our lives. Being aware of them is a great help in taking care of our overall health.