Heart Murmur

Overview

What is a heart murmur?

When your heart beats, valves open and close, allowing blood to flow. When the valves close, they produce two sounds: a “lub” and a “dub.”

If your heart makes a whooshing or swishing sound instead, that’s called a heart murmur. A murmur means blood is flowing abnormally across your heart valves.

A murmur may mean there’s a problem with your heart. But heart murmurs are also present in healthy people who don’t have a heart problem (called “innocent” heart murmurs).

How common are heart murmurs?

Heart murmurs are quite common. In fact, most people had an innocent heart murmur at some point during childhood.

Are there different types of heart murmur?

Heart murmurs are classified based on when they happen in a heartbeat:

  • Systolic: This type of murmur occurs when your heart muscle contracts (tightens).
  • Diastolic: This type of murmur occurs when your heart muscle relaxes.
  • Continuous: A continuous heart murmur happens during both contraction and relaxation of your heart muscle.

Diastolic and continuous murmurs are more likely related to heart disease. But every heart murmur should be evaluated.

How loud is a heart murmur?

You can’t hear a heart murmur with your ear. You need a stethoscope, which makes the sounds loud enough to hear.

Healthcare providers classify murmurs by how intense or loud they are. They use a scale of 1 (the murmur can barely be heard, even with a stethoscope) to 6 (it can be heard clearly, even when the stethoscope isn’t pressing on your skin).

Symptoms and Causes

What causes a heart murmur?

A murmur is caused by turbulent or abnormal blood flow across your heart valves.

If blood is flowing more rapidly than normal, it can cause an innocent heart murmur (also called normal or physiologic). This type of murmur is common during:

  • Childhood.
  • Exercise.
  • Growth spurts.
  • Pregnancy.
  • The first few days after a baby is born.

Innocent heart murmurs can disappear and reappear. They may get louder when your heart beats faster. They often go away eventually, but some last a lifetime. Innocent heart murmurs don’t indicate a problem with your heart.

Some heart murmurs are due to a heart problem or other condition, including:

  • Anemia: or low red blood cell count, can cause a murmur because it affects blood viscosity (thickness). Other signs of anemia include weakness and fatigue (extreme tiredness).
  • Carcinoid syndrome or carcinoid heart disease is a slow-growing tumor (cancer) caused by extra hormones, which can affect your heart. A person with carcinoid syndrome might also experience unexplained weight loss, belly pain, diarrhea or low blood pressure.
  • Congenital heart defect: Your heart may have a structural problem that’s been there since birth. Examples of congenital heart defects include a septal defect (hole in your heart) or tetralogy of Fallot.
  • Endocarditis is a heart infection. Bacteria or other germs get into the bloodstream and attack your heart valves. It usually causes additional symptoms, like fever, chills, rash or sore throat.
  • Heart valve disease means one or more heart valves aren’t working correctly, preventing good blood circulation. For example, a valve may be stiff (valve stenosis). It may not open or close all the way. Or it may allow blood to leak in the wrong direction (valve regurgitation). Other signs include swelling in your ankles or feet, heart palpitations (fluttering), shortness of breath or pressure in your chest.
  • H**yperthyroidism**, also called overactive thyroid, the gland makes too much thyroid hormone. The condition also may cause anxiety, increased appetite, rapid heartbeat and weight loss.
  • Hypertrophic cardiomyopathy is a type of heart disease that makes your heart muscle larger, thicker or stiffer. It can be inherited or develop due to aging or high blood pressure. Other symptoms may include syncope (fainting), chest pain, heart palpitations, fatigue and shortness of breath.

What are the symptoms of a heart murmur?

Some heart murmurs cause no symptoms at all and are discovered during a routine medical exam.

But depending on what’s causing the murmur, you may experience symptoms such as:

  • Bluish skin.
  • Cough that won’t go away.
  • Heart palpitations.
  • Pain or tightness in your chest.
  • Shortness of breath.
  • Syncope or weakness.

Diagnosis and Tests

How is a heart murmur diagnosed?

A healthcare provider can diagnose a heart murmur by listening to your heart. A murmur makes an abnormal swishing sound.

Your provider listens to your heart with a stethoscope from different places on your chest and back. They listen for certain things in your heartbeat:

  • Lub-dub sound instead of swishing.
  • Pitch.
  • Rhythm.
  • Timing.
  • Volume.

Your healthcare provider may ask you to do different things while they listen:

  • Grip your hands.
  • Sit.
  • Squat.
  • Stand suddenly.
  • Lie down.

What tests might I have if a healthcare provider hears a heart murmur?

If a healthcare provider hears a murmur, you may need further testing to rule out a health problem. You may be referred to a cardiologist, a physician who specializes in the heart.

Tests that can determine the cause of a heart murmur are:

  • Chest X-ray: A chest X-ray takes pictures inside your chest to find any structural problems.
  • Echocardiogram: Echocardiogram (also called an echo) uses sound waves to create images of your heart’s valves and chambers. It helps examine your heart’s pumping action. This can be a surface ultrasound or a more specialized ultrasound procedure through your mouth and esophagus, which gives better pictures than the surface ultrasound.
  • Electrocardiogram: Electrocardiogram(also called an ECG or EKG) is a painless test that measures the electrical activity of your heart.

Management and Treatment

How is a heart murmur treated?

Many heart murmurs don’t need any treatment and aren’t a cause for concern. But if a murmur is caused by a more serious condition, you may need:

  • Medications, such as iron to correct anemia or drugs to slow the thyroid gland.
  • Surgery to correct or replace a valve.

Prevention

How can I prevent heart murmurs?

Heart murmurs can’t be prevented. But you can avoid serious problems from a heart condition by getting your heart checked regularly.

Outlook / Prognosis

What is the outlook for people with a heart murmur?

The outlook for people with a heart murmur depends on the condition causing it. Kids often outgrow childhood murmurs, and a murmur with pregnancy usually goes away after childbirth. However, murmurs associated with heart conditions require medical treatment.

Living With

When should I call a healthcare provider?

Seek medical attention if you have any signs of a heart problem, including:

  • Bluish skin.
  • Chest pain or pressure.
  • Heart palpitations.
  • Shortness of breath.
  • Syncope or weakness.

A note from Cleveland Clinic

A heart murmur is a whooshing or swishing sound that occurs when blood moves abnormally over your heart valves. Many heart murmurs are innocent, meaning there’s no cause for concern. But a heart murmur should be evaluated to make sure you don’t have an underlying health problem.

Last reviewed by a Cleveland Clinic medical professional on 05/16/2022.

References

  • American Heart Association. Heart Murmurs. (https://www.heart.org/en/health-topics/heart-murmurs) Accessed 5/16/2022.
  • Merck Manual (Professional Version). Cardiac Auscultation. (https://www.merckmanuals.com/professional/cardiovascular-disorders/approach-to-the-cardiac-patient/cardiac-auscultation) Accessed 5/16/2022.
  • National Heart, Lung, and Blood Institute. Heart Murmur. (https://www.nhlbi.nih.gov/health-topics/heart-murmur) Accessed 5/16/2022.
  • Osmosis. Normal Heart Sounds. (https://www.osmosis.org/learn/Normal_heart_sounds) Accessed 5/16/2022.
  • Thomas SL, Heaton J, Makaryus AN. [Updated 2020 Aug 15]. Physiology, Cardiovascular Murmurs. (https://www.ncbi.nlm.nih.gov/books/NBK525958/) In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Accessed 5/16/2022.

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