Heart Murmur

What is a heart murmur?

A heart murmur is an extra sound heard with a stethoscope when listening to the heart. The sound is made by blood flowing through the heart. It is similar to the sound water makes as it flows through a pipe. A heart murmur does not always mean that there is something wrong with the heart.

How does it occur?

Murmurs can result from:

the shape of the heart
abnormalities of heart structures, such as the valves or heart walls, which may have been present since birth
heart muscle damage caused by coronary artery disease
damaged or overworked heart valves resulting from illnesses such as rheumatic fever, or from heart attacks, infective endocarditis, or other problems.

When your heart beats faster, it changes the rate and amount of blood moving through your heart. This can cause heart murmurs. Some of the conditions that cause your heart to beat faster are:

anemia
high blood pressure
pregnancy
fever
stress
thyroid problems.

Most heart murmurs are innocent and are found in people with normal hearts. Innocent heart murmurs - also called functional, normal, vibratory, or physiologic murmurs - are harmless. They are common in children. Innocent heart murmurs cause no problems, and most go away by the time a child is an adult.

What are the symptoms?

Innocent murmurs do not cause any symptoms.

Heart problems that cause heart murmurs may not cause other symptoms for many years. Possible symptoms include:

shortness of breath
lightheadedness
decreased ability to exert yourself, for example, during activities such as climbing the stairs or even making a bed
frequent episodes of rapid heart rate
chest pain.

How is it diagnosed?

A heart murmur is usually detected when your health care provider listens to your heart through a stethoscope. The following tests may be done to look for the cause of the murmur:

An electrocardiogram, which records the heart's electrical activity.
A chest x-ray to look for an enlarged heart, signs of heart muscle failure, and birth defects.
An echocardiogram, which uses sound waves to create images of the heart structure. The images may show a hole in the wall of the heart or an abnormal valve.
Cardiac catheterization. A thin tube (catheter) is passed into one of your blood vessels and into your heart. A dye is injected through the catheter so your health care provider can see the blood vessels or chambers of your heart on x-rays. This procedure also allows measurement of the pressures in the heart chambers and of valve function.

How is it treated?

Innocent murmurs do not need treatment. However, if you have a heart murmur, check with your healthcare provider before having any dental work or surgery. You may need to take antibiotics to prevent infection of your heart valves.

Treatment of other types of murmurs depends on:

your symptoms
the risk of heart damage over time if the abnormality is not corrected
the risk of sudden complications, such as stroke or cardiac arrest.

Treatment for heart murmurs also depends on the cause. For example, if the murmur is caused by high blood pressure, lifestyle changes, such as a low-fat, low-salt diet and more exercise, may help. Medicines may also be prescribed to lower blood pressure. If the murmur is caused by a valve problem, you may need surgery.

What can be done to help prevent heart murmurs?

Little is known about how to prevent the birth defects that cause heart murmurs. However, problems such as coronary artery disease or hypertension, which can cause heart muscle damage, can sometimes be prevented, delayed, or minimized by healthy diet and exercise habits, and by not smoking.

Always get prompt treatment for strep infections to prevent rheumatic heart disease.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File CRD3628F.HTM Release 9.0/2006