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HealthInfo Canterbury

Heart murmurs in children

Doctor listening to boys heartA heart murmur is a sound made by blood flowing in or near the heart. Your doctor or nurse can hear these sounds when listening to your child’s chest with a stethoscope.

Heart murmurs can be present at birth (congenital) or develop later in life.

Most heart murmurs are innocent (harmless), caused by blood flowing through different parts of the heart. These are common and don’t need any treatment.

Possible heart problems

Sometimes a heart murmur can be a sign of a problem with the heart. In children this is usually a problem with the valves in the heart or structure of the heart (congenital heart disease). If a child has a heart problem, they may have symptoms such as cyanosis (a bluish tint to the skin, fingernails or lips), fast breathing, poor feeding and poor weight gain. They may be unable to exercise and they may sweat excessively.

If your child has symptoms of a heart problem or if your doctor is concerned about a heart murmur they'll arrange further tests. These will include an echocardiogram which uses ultrasound to get a picture of the heart.

Innocent heart murmurs

If doctors listen to children's hearts in quiet conditions, they often hear innocent murmurs. These murmurs come and go and vary with breathing, heart rate and the position of the child. Innocent murmurs are louder when the heart is beating faster than usual, such as when your child's anxious or has a temperature.

These murmurs are caused by the sound of blood flowing through different parts of the heart. As children's hearts are smaller and beat faster than adults' hearts, these noises are more likely to be heard. The murmurs usually disappear later in childhood.

An experienced doctor will recognise the noise of an innocent heart murmur as being different to one caused by a heart defect. Further testing is not needed but sometimes the doctor will ask to listen to the child's heart again when they're well or older.

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Written by HealthInfo clinical advisers. Last reviewed July 2021.

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Page reference: 120671

Review key: HIHMC-120671