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

A heart murmur is an unusual sound heard between heartbeats.

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

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

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

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 or abnormal sounds.

Heart murmurs

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

An innocent murmur can be found in children and adults. It’s caused by the sound of blood moving normally through the heart. In adults, innocent heart murmur may be caused by physical activity, fever, or pregnancy.

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 has become too narrow or becomes stiff, this is known as stenosis. It can also cause a murmur.

Murmurs are graded depending on how loud the sound is. The scale for grading runs from 1 to 6, where one is very faint and six 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 systole murmurs, or during the second sound (S2), as diastole murmurs.

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.
  • 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.

Other 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.

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 trunk.
  • 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 by listening to your heart 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 happens when an infant or child’s skin turns blue from 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, or other causes.
  • Your tricuspid valve can also experience regurgitation, usually caused by the enlargement (dilation) of your right ventricle.
  • Pulmonary regurgitation is caused by the backflow of blood into your right ventricle when your pulmonary valve can’t close completely.

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:

Another cause of heart murmurs is stenosis caused by hypertrophic cardiomyopathy. In this condition, the muscle of your heart thickens, which makes it harder to pump blood through your heart. This results in a heart murmur.

This is a very serious disease that’s often passed on through families.

Causes of clicks

Heart clicks are caused by problems with your mitral valve.

Mitral valve prolapse is the most common cause. It occurs when one or both flaps of your mitral valve are too long. This can cause some regurgitation of blood into your left atrium.

Causes of rubs

Heart rubs are caused by friction between layers of your pericardium, a sac around your heart. This is usually caused by an infection in your pericardium due to a virus, bacteria, or fungus.

Causes of galloping rhythms

A galloping rhythm in your heart, with a third or fourth heart sound, is very rare.

An S3 sound is likely caused by an increased amount of blood within your ventricle. This may be harmless, but it can also indicate underlying heart problems, such as congestive heart failure.

An S4 sound is caused by blood being forced into a stiff left ventricle. This is a sign of serious heart disease.

Your doctor will listen to your heart with a stethoscope, a medical device used to listen to your heart, lungs, and other organs in your body.

If they detect problems, your doctor may order an echocardiogram. This is a test that uses sound waves to create a moving picture of your heart to help your doctor get a better understanding of the abnormalities detected.

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 abnormal heart sounds easier.

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

  • bluish skin
  • chest pain
  • fainting
  • distended neck veins
  • 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.

Abnormal heart sounds often indicate some type of underlying heart disease. This may be treated with medication, or it may require surgery.

It’s important to follow up with a heart specialist to learn the details of your condition.