A heart murmur is an unusual sound heard between heartbeats. It doesn’t necessarily mean you have a heart condition, but it often requires further evaluation.

During a checkup, your doctor will listen to your heartbeat using a stethoscope to determine whether your heart is beating properly and has a normal rhythm. This gives your doctor information concerning your heart’s health.

If your doctor hears a “murmur” or any other abnormal sounds coming from your heart, it may be an early indicator of a heart condition.

This article reviews the different types of heart murmurs, their potential causes, and when to see a doctor.

How serious is a heart murmur, and should you be worried if you or your child has one?

Heart murmurs are fairly common in children and adults. While medical intervention is needed in some instances, many murmurs don’t require any treatment.

The majority of childhood heart murmurs do not have symptoms or structural heart problems, and some resolve with age. Murmurs in adults are often caused by benign changes in blood flow due to conditions like pregnancy, anemia, and fever.

That said, it’s important to have a doctor diagnose the root cause of your heart murmur. They can then recommend treatment if needed.

A normal heartbeat has two sounds, a lub (sometimes called S1) and a dub (S2). These sounds are caused by the closing of valves inside your heart.

If there are problems in your heart, there may be additional abnormal sounds.

The most common abnormal heart sound is a heart murmur. A murmur is a blowing, whooshing, or rasping sound that occurs during your heartbeat.

There are two kinds of heart murmurs:

  • innocent (also called physiological)
  • abnormal

Innocent murmurs

An innocent murmur can occur in children and adults. It’s caused by the sound of blood moving normally through the heart. In adults, an innocent heart murmur may be caused by:

  • physical activity
  • an overactive thyroid
  • fever
  • pregnancy
  • anemia

Abnormal murmurs

An abnormal murmur in a child is due to congenital heart malformations, which means they’re present at birth. It may need to be corrected with surgery.

An abnormal murmur in adults is usually caused by problems with the valves that separate the chambers of your heart. If a valve doesn’t close tightly and some blood leaks backward, this is called regurgitation.

If a valve becomes too narrow or stiff, this is known as stenosis. Stenosis can also cause a murmur.

Galloping rhythms

Other heart sounds include a “galloping” rhythm, which involves additional heart sounds, S3 and S4:

  • An S3 gallop or “third heart sound” is a sound that occurs after the diastole S2 “dub” sound. In young athletes or pregnant women, it’s likely to be harmless. In older adults, it may indicate heart disease or heart failure.
  • An S4 gallop is an extra sound before the S1 systole “lub” sound. It’s always a sign of disease, likely the failure of the left ventricle of your heart.

You can also have both an S3 and an S4 sound. This is called a “summation gallop,” which can occur when your heart is beating very fast. A summation gallop is very rare.

Clicks or rubbing sounds

Clicks or short, high-pitched sounds may also be heard during your regular heartbeat. This could indicate a mitral valve prolapse, when one or both flaps of your mitral valve are too long. This can cause some regurgitation of blood into your left atrium.

Rubbing sounds may be heard in people with certain kinds of infections. A rubbing sound is usually caused by an infection in your pericardium (a sac that surrounds your heart) due to a virus, bacteria, or fungus.

How are heart murmurs graded?

Murmurs are graded according to how loud they are. The scale for grading runs from 1 to 6, where 1 is very faint and 6 is very loud, so loud that it may not need a stethoscope to be heard.

Murmurs are also categorized as occurring during either the first sound (S1), as systolic murmurs, or during the second sound (S2), as diastolic murmurs.

Your heart is made up of four chambers. The two upper chambers are called the atria, and the two lower chambers are called the ventricles.

Valves are located between these chambers. They make sure that your blood always flows in one direction.

  • The tricuspid valve goes from your right atrium to your right ventricle.
  • The mitral valve leads from your left atrium to your left ventricle.
  • The pulmonary valve goes from your right ventricle out to your pulmonary artery.
  • The aortic valve goes from your left ventricle to your aorta.

Your pericardial sac surrounds your heart and protects it.

Problems with these parts of your heart may lead to unusual sounds that your doctor can detect with a stethoscope or by performing an echocardiogram test.

Congenital malformations

Murmurs, especially in children, may be caused by congenital heart malformations.

These can be benign and never cause symptoms, or they can be severe malformations that require surgery or even a heart transplant.

Innocent murmurs include:

  • pulmonary flow murmurs
  • a Still’s murmur
  • a venous hum

One of the more serious congenital problems that causes heart murmurs is called Tetralogy of Fallot. This is a set of four defects in the heart that lead to episodes of cyanosis.

Cyanosis occurs when an infant or child’s skin turns blue due to a lack of oxygen during activity, such as crying or feeding.

Another heart problem that causes a murmur is patent ductus arteriosus, in which a connection between the aorta and the pulmonary artery fails to close correctly after birth.

Other congenital problems include:

Heart valve defects

In adults, murmurs are usually the result of problems with heart valves. This may be caused by an infection, such as infective endocarditis.

Valve problems can also simply occur as part of the aging process, due to wear and tear on your heart.

Regurgitation, or backflow, happens when your valves don’t close properly:

  • Your aortic valve can have aortic regurgitation.
  • Your mitral valve can have acute regurgitation that’s caused by a heart attack or a sudden infection. It can also have chronic regurgitation that’s caused by high blood pressure, infection, mitral valve prolapse, heart failure, or other causes.
  • Regurgitation can also occur in the tricuspid valve, usually caused by the enlargement (dilation) of the right ventricle.
  • Pulmonary regurgitation is caused by the backflow of blood into your right ventricle when your pulmonary valve can’t close completely.

Heart valve stenosis

Stenosis is a narrowing or stiffening of your heart valves. Your heart has four valves, and each valve can have stenosis in a unique way:

  • Aortic stenosis is the most common type of stenosis, especially as people age. It can also occur because of rheumatic fever. Having a bicuspid aortic valve increases your risk of aortic stenosis, which may cause heart failure.
  • Mitral stenosis is usually caused by rheumatic fever, a complication of untreated strep throat, or scarlet fever. It can cause fluid to back up into your lungs, causing pulmonary edema.
  • Tricuspid stenosis can occur because of rheumatic fever or heart injury.
  • Pulmonary valve stenosis is usually a congenital problem and runs in families. Aortic and tricuspid stenosis can also be congenital.
  • Stenosis may also be caused by hypertrophic cardiomyopathy. In this condition, the muscle of your heart thickens, which makes it harder to pump blood through the heart. This is a very serious disease that’s often passed on through families.

In many cases, heart murmurs can only be detected when your doctor listens to your heart using a stethoscope. You may not notice any outward signs or symptoms.

However, in some cases, you may notice signs or symptoms of an underlying heart condition. These can include:

If you have any of the above symptoms, make an appointment with a doctor. They can determine what’s causing your heart murmur and recommend treatment.

To evaluate your heart murmur and determine its cause, a doctor will first listen to your heart with a stethoscope. This medical device can be used to listen to your heart, lungs, and other organs.

If problems are detected, your doctor may order an echocardiogram. This test uses sound waves to create a moving picture of your heart to help your doctor better understand the abnormalities detected.

Your doctor may also order an electrocardiogram (ECG) to check your heart’s rhythm, rate, and electrical activity.

If your doctor hears any abnormal heart sounds, they may ask you questions about your family.

If any of your family members have also had abnormal heart sounds or a history of heart problems, it’s important to tell your doctor. It may make diagnosing the cause of your heart murmur easier.

Your doctor will also ask if you’ve had any other symptoms of heart problems, such as:

  • bluish skin
  • chest pain
  • fainting
  • shortness of breath
  • swelling
  • weight gain

Your doctor may also listen to your lungs and may examine you to see if you have signs of liver enlargement. These symptoms may provide clues about what type of heart problem you’re experiencing.

Treatment for a heart murmur depends on the type of heart murmur you have and its cause.

Innocent heart murmurs typically don’t need treatment. But if a doctor finds that your heart murmur is caused by a problem with your heart or another underlying condition, then that underlying condition will need to be treated.

For example, depending on the cause of your heart murmur, a doctor may recommend lifestyle changes such as:

  • incorporating daily exercise
  • reducing your salt intake
  • limiting alcohol
  • quitting smoking (if you smoke)
  • managing your weight

If your heart murmur is caused by high cholesterol or high blood pressure, your doctor may prescribe medications to manage these conditions.

In some cases, a leaky valve or congenital malformation may need to be surgically repaired or replaced.

Heart murmurs don’t typically influence life expectancy unless they’re caused by an underlying heart condition that has not been treated.

While some heart murmurs may be innocent and not require treatment, it’s still important to follow up with a doctor to determine the underlying cause.

Heart murmurs caused by an underlying heart condition or disease may be treated with lifestyle changes, medication, or, in some cases, surgery.