What is a heart murmur?

A heart murmur is an abnormal sound that is heard through the stethoscope. It does not always indicate that a medical condition exists.

This answer provided for NATA by the University of Montana Athletic Training Education Program.

A heart murmur is a sound you hear from the blood flow of the heart.

A heart murmur is an extra heart sound. Heart murmurs are thought to be caused by turbulent blood flow through the heart. Some degree of turbulent flow is normal and cannot always be heard. Heart murmurs can generally only be heard by a trained medical professional using a stethoscope to listen to heart sounds. Heart murmurs can be caused by many different things, and most causes of heart murmurs are not of any medical importance. There are, however, heart murmurs caused by heart defects that are significant. Your doctor is trained to know when a heart murmur may be medically important or may require further testing.

A heart murmur is a sound made by blood as it travels through the heart. Heart murmurs may be abnormal, but can often be normal. In some, but not all, cases, a heart murmur is a sign of a problem in the heart and vascular system.

Normally blood flows with a predictable “lub-DUPP” sound pattern that can be heard through a stethoscope. This sound is the heart valves closing. If there is a heart murmur, a healthcare provider may hear an extra or unusual sound that prompts closer evaluation of the heart, sometimes including a referral to a heart specialist.

A heart murmur is an extra or unusual sound heard during a heartbeat. Murmurs range from very faint to very loud. They sometimes sound like a whooshing or swishing noise. Normal heartbeats make a "lub-DUPP" or "lub-DUB" sound. This is the sound of the heart valves closing as blood moves through the heart. Doctors can hear these sounds and heart murmurs using a stethoscope.

There are two types of heart murmurs: innocent (harmless) and abnormal. People who have innocent heart murmurs have normal hearts. They usually have no other signs or symptoms of heart problems. Innocent murmurs are common in healthy children. Many, if not most, children will have heart murmurs heard by their doctors at some time in their lives. People who have abnormal murmurs may have other signs or symptoms of heart problems. Most abnormal murmurs in children are due to congenital heart defects. These are heart defects that are present at birth. In adults, abnormal murmurs are most often due to heart valve problems caused by infection, disease, or aging.

This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.