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Heart Murmurs

What is it?

Heart murmurs are the sounds (whooshing, rasping, blowing) heard when a health care provider listens to the heart through a stethoscope.

The sounds are from blood as it moves through the heart chambers, arteries and blood vessels.

The normal sounds heard are from valves closing. Valves control the blood flow between the ventricles and atria.

Most murmurs in children are normal or innocent. Only a small number of children with a murmur will have a problem with their heart. Murmurs in children may be caused by birth defects including:

Not all murmurs are signs of heart disease. Sometimes a murmur is heard in a child who has a fever or who is anemic (has blood that doesn't carry enough oxygen through the body), and the murmur goes away when the child is treated.

Murmurs are graded on how easily they're heard by the health care provider. The grading is on a scale of one to six with grade six being the loudest.

A grade six can be heard from a stethoscope removed from the chest. Also, a murmur is described by the stage of the heartbeat when the murmur is heard.

There are four kinds of murmurs — innocent, systolic, diastolic and continuous:

  • Innocent murmurs are not from birth defects and usually go away by the time a child becomes an adult.
  • Systolic murmurs happen during the contraction of a heart muscle. One of the common causes of a systolic murmur is aortic stenosis, a narrowing of the aorta
  • Diastolic murmurs are caused by aortic and pulmonary valve leakage or narrowing of the mitral and tricuspid valves.
  • A continuous murmur happens throughout the heartbeat cycle. The most common cause is a patent ductus arteriosus.

How is it treated?

Tests may be needed to learn more about a heart murmur. Many children with a murmur do not need any testing other than a history and physical evaluation.