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What Are Heart Murmurs?

Medically Reviewed by James Beckerman, MD, FACC on August 07, 2020

The "murmur" is the sound of blood flowing. It may be passing through an abnormal heart valve, for instance. Or it may be that a condition makes your heart beat faster and forces your heart to handle more blood quicker than normal.

Within the heart, there are four chambers separated by valves that regulate how much blood enters each chamber at any time. Healthy valves also help prevent blood from flowing in the wrong direction in your heart.

A healthy heart makes a "lub-dub" sound as it beats. The "lub" (systolic sound) happens when part of the heart contracts and the mitral and tricuspid valves close, and the "dub" (diastolic sound) occurs when part of the heart relaxes and the aortic and pulmonic valves close. A heart murmur is an extra sound in the heartbeat -- such as a ''whooshing'' -- that is caused by turbulent blood flow through the heart valves.

Heart murmurs happen in many healthy children, who may outgrow them as adults. They may also happen during pregnancy. Such murmurs are called "innocent" heart murmurs. They are not linked with medical or heart conditions and do not need treatment or lifestyle changes.

But there are exceptions. Murmurs can be linked to a damaged or overworked heart valve. Some people are born with valve problems. Others get them as a part of aging or from other heart problems.

Causes

Common conditions can make your heart beat faster and lead to heart murmurs. They can happen if you're pregnant, or if you have:

A murmur could also be a problem with a heart valve. The valves close and open to let blood flow through the heart's two upper chambers -- called the atria -- and two lower chambers -- the ventricles. Valve problems include:

Mitral valve prolapse: Normally, your mitral valve closes completely when the lower left chamber of your heart contracts. It stops blood from flowing back into your upper left chamber. If part of that valve balloons out so it doesn't close properly, you have mitral valve prolapse. This causes a clicking sound as your heart beats. It's fairly common and often not serious. But it can lead to the blood flowing backward through the valve, which your doctor may call regurgitation.

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Mitral valve or aortic stenosis: Your mitral and aortic valves are on the left side of your heart. If they narrow, which doctors call stenosis, your heart has to work harder to pump blood to the rest of your body. If left untreated, it can wear out your heart and lead to heart failure. You might be born with this. It can also happen as part of aging, or because of scarring from infections such as rheumatic fever.

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Aortic sclerosis and stenosis: One in three elderly people have a heart murmur because of the scarring, thickening, or stiffening of their aortic valve. That’s aortic sclerosis. It's usually not dangerous, since the valve can work for years after the murmur starts. It’s sometimes seen in people who have heart disease. But the valve can narrow over time. This is called stenosis. It can lead to chest pain, shortness of breath, or you may pass out. Sometimes, the valve needs to be replaced.

Mitral or aortic regurgitation: In this case, regurgitation means the blood is going the wrong way through your mitral or aortic valve and back into your heart. To counteract it, your heart must work harder to force blood through the damaged valve. Over time, this can weaken or enlarge your heart and lead to heart failure.

Congenital heart defects: About 25,000 babies are born with heart defects each year. These problems include holes in heart walls or abnormal valves. Surgery can correct many of them.

Symptoms

Many people with heart murmurs have no symptoms. But some murmurs can happen along with these other symptoms:

  • Chest pain
  • Rapid heartbeat (palpitations)
  • Breathlessness
  • Fatigue
  • Bluish skin color or fingertips (sometimes seen in babies with congenital heart defects)

Diagnosis

Usually, doctors find heart murmurs during a physical exam. Your doctor will be able to hear it when listening to your heart with a stethoscope.

Your doctor may order one or more of the following tests to see whether your heart murmur is innocent or if it is caused by acquired valve disease or a defect you were born with:

  • Electrocardiogram (EKG), which measures the electrical activity of the heart
  • Chest X-rays to see if the heart is enlarged due to heart or valve disease
  • Echocardiography, which uses sound waves to map the heart's structure

On further examination, your doctor may find that the heart murmur is innocent. If your heart murmur is related to more serious heart problems, your doctor may refer you to a cardiologist (heart specialist).

Medication or surgery may be recommended to treat the underlying problem. With a thorough physical examination and proper tests, your doctor should be able to tell what causes your heart murmur.

Treatment

Many children and adults have harmless heart murmurs, which don't need treatment.

If another condition, like high blood pressure, is causing yours, your doctor will treat the cause.

Some types of heart valve disease may require:

  • Medicines to prevent blood clots, control irregular heartbeat or palpitations, and lower blood pressure
  • Diuretics to get rid of excess salt and water from your body, making it easier for your heart to pump
  • Surgery to correct heart defects you’re born with
  • Surgery to correct certain types of heart valve disease

It's not common, but doctors sometimes ask people to take antibiotics to help prevent heart infection before dental work or some kinds of surgery.

Prevention?

In most cases, you can't prevent heart murmurs. The exception is that if you treat an underlying condition, such as high blood pressure, or you avoid heart valve infection, heart murmurs are stopped before they start.

When to Call Your Doctor

Get medical help if you feel:

  • Chest pain
  • Breathlessness, fatigue, or fainting for no obvious reason
  • Heart palpitations
WebMD Medical Reference

Sources

SOURCES:

American Heart Association.

National Heart Lung and Blood Institute: "Explore Heart Murmur."

MedlinePlus: "Heart murmurs and other sounds."

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