Some members of myPHteam have asked about how their pulmonary arterial hypertension (PAH) relates to their hearts and lungs. “What does PAH mean or do to your heart? The shortness of breath is very scary,” one member posted.

Your heart and lungs work together to move blood and oxygen throughout your body. A problem with either of these vital organs can affect your cardiovascular system and the rest of your body.

PAH is one of the five types of pulmonary hypertension (PH). When you’re living with PAH, symptoms often come from problems with the lungs, the heart, or both.

This article provides a general overview of the connection between your heart and lungs and how they work together. To understand one system, you’ll need to understand the other. With this knowledge, you’ll have a better idea of what’s happening in your body with PAH.

How Do Your Heart and Lungs Work Together?

Your lungs and heart work closely together and rely on each other. Blood is constantly moving in and out of these organs to supply your body with the oxygen and nutrients it needs. According to Cleveland Clinic, your heart and lungs circulate about 2,000 gallons of blood every day.

To understand how your heart and lungs work together, we’ll look at how your blood moves through them. This is different from systemic circulation, which moves oxygen-rich blood from your heart to the rest of your body.

From Your Body to the Right Side of the Heart

Your pulmonary circuit begins in your right atrium. This upper right part of your heart takes in blood with low oxygen from two large veins, the superior vena cava and the inferior vena cava. The blood travels through your right atrium and passes through the tricuspid valve. This valve has flaps that open and close to keep blood moving the right way through your heart.

The tricuspid valve controls blood from your right atrium into your right ventricle. This lower chamber then pushes blood through the pulmonary valve and into your pulmonary arteries. They’re the only arteries in your body that carry blood with low oxygen. They branch off into a left artery and a right artery that carry blood to your left lung and right lung.

From Your Lungs to the Left Side of the Heart

Inside the lungs, carbon dioxide from your body is exchanged for oxygen. The blood then moves into your pulmonary veins and left atrium. This chamber pumps blood through the mitral valve and into your left ventricle. This is your blood’s last stop in the journey through your lungs and heart.

The left ventricle pumps oxygen-rich blood to the rest of your body. Blood travels through the aortic valve and into the aorta — the largest artery in your body — and then flows to your other organs, tissues, and cells.

PAH makes it harder for the pulmonary arteries to move blood from your heart to your lungs.

After the blood gives away its oxygen and nutrients, it travels back to your heart through your veins. The cycle then starts over again.

Your heart is a powerful muscle that works fast. It takes less than a minute for blood to travel to a body part and return to the heart.

What Affects Lung and Heart Function?

Your lungs and heart are closely connected. If a problem affects one organ, it may also affect the other.

Studies show that lung function is related to heart health. For example, cardiovascular factors that play a role in lung health include:

• Blood pressure levels
• Cholesterol levels
• Blood glucose (blood sugar) levels
• Smoking status
• Exercise frequency

You can take extra steps to take care of your lungs and heart, especially while living with PAH. Your doctor will likely encourage you to eat a healthy diet, try to limit stress, quit smoking (if you smoke), and exercise regularly.

How Does Pulmonary Arterial Hypertension Affect the Lungs and Heart?

Now that you know how the lungs and heart work together, it’s easier to understand how PAH can affect them. PAH is a type of pulmonary hypertension that happens when you have high blood pressure in your pulmonary arteries, making them stiff and narrow. These blood vessels carry blood with low oxygen from your heart to your lungs.

PAH makes this process harder, which can cause symptoms like:

• Chest pain
• Fatigue
• Cough
• Edema (swelling of the feet, face, or stomach from fluid buildup)

You may have high blood pressure in your pulmonary arteries for several reasons. The World Health Organization (WHO) classifies PH into five groups based on the cause. Some types of PH are caused by heart problems, whereas others are caused by lung diseases that can also strain the heart.

If a problem affects one organ, it may also affect the other.

Group 1 PH refers to pulmonary arterial hypertension, a condition that makes your pulmonary arteries stiff, thick, and narrow. The right side of your heart has to work harder to pump blood to your lungs. Eventually, PAH can lead to right-sided heart failure.

Many cases of PAH are idiopathic, meaning they have no known cause. Other causes of PAH include:

• Genetics — About 15 percent to 20 percent of PAH cases are passed down from one generation to the next.
• Use of certain drugs — PAH can develop from taking diet pills, amphetamines, or certain cancer medications.
• Other diseases — Conditions linked with PAH include heart disease present at birth, lupus, and scleroderma (a disease that hardens and tightens the skin and can also affect internal organs).

Although PAH is a progressive disease, meaning it gets worse over time, PAH medications can help.

How Do PAH Medications Affect the Lungs and Heart?

The goal of PAH medications is to slow disease progression and improve PAH symptoms. Just as PAH can affect the lungs and heart, PAH medications can affect these vital organs, too.

It takes less than a minute for blood to travel around your body and return to the heart.

There are several types of PAH medications, and they work in different ways.

Activin Signaling Inhibitors

Activin signaling inhibitors are a newer type of drug for treating PAH. The first drug in this class has been found to improve PAH symptoms. It may also slow disease progression by stopping the chain of events that leads to increased pressure on the heart.

Anticoagulants

Anticoagulants can help prevent blood clots, which may contribute to disease progression in PAH.

Diuretics

Also called water pills, diuretics help your body get rid of extra fluid and salt. For people with PAH, they can help reduce swelling.

Oxygen Therapy

You may experience hypoxia (low oxygen levels) with PAH. Oxygen therapy can increase oxygen levels in the blood and reduce blood pressure by widening the blood vessels. Some people with PAH need oxygen all the time, whereas others need it only during physical activity, while on an airplane, or when at high altitudes.

Pulmonary Vasodilators

Pulmonary vasodilators can help improve blood flow by opening narrowed blood vessels. This can reduce the pressure on the heart and help ease PAH symptoms.

Calcium Channel Blockers

Calcium channel blockers change the way the body uses calcium. By relaxing the blood vessel walls to encourage more blood flow, these drugs can help lower blood pressure in the pulmonary arteries. Very few people with PAH are treated with calcium channel blockers.

Phosphodiesterase 5 Inhibitors

Phosphodiesterase 5 inhibitors help increase blood flow through the lungs and lower blood pressure.

Prostacyclin

People with PAH may be low in prostacyclin, a hormone released by the lungs that affects how blood vessels dilate. Taking a version of this hormone through a medication can help blood vessels relax, lowering blood pressure.

Endothelin Receptor Antagonists

Endothelin receptor antagonists help decrease blood pressure in the lungs and help the heart work better.

Soluble Guanylate Cyclase Stimulators

Soluble guanylate cyclase stimulators can help lower the pressure in the lungs by relaxing the pulmonary arteries.

Talk to Your Doctor

These are just some of the types of PAH medications your doctor might recommend. According to the Pulmonary Hypertension Association, new PAH treatments continue to improve outcomes and quality of life. Ask your healthcare provider which PAH treatments they recommend and why.

Over time, your healthcare provider will monitor your condition through blood tests, echocardiograms, and other tests and tools. They’ll consider your risk factors, family history, health history, and other medical conditions when deciding your treatment plan. They may also recommend lifestyle changes, like eating less salt and getting regular physical activity.

If your PAH gets worse, your doctor might suggest new or different treatments. Don’t hesitate to ask your doctor any questions about their recommendations or the potential side effects of PAH medications.

The lungs and heart work together to keep the body healthy. Knowing how PAH and PAH medications affect these essential organs can help you talk with your healthcare providers, manage symptoms, and make decisions that may improve your quality of life.

Join the Conversation

On myPHteam, people share their experiences with pulmonary hypertension, get advice, and find support from others who understand.

If you have been diagnosed with pulmonary arterial hypertension, what steps do you take to protect your heart and lungs? Let others know in the comments below.