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Clinical Reference Systems: Pediatric Advisor 10.0

Innocent Heart Murmurs of Childhood

What is an innocent heart murmur?

Heart murmurs are extra noises heard with each heartbeat. Some murmurs occur even though the heart and blood vessels are completely normal. These murmurs are called innocent murmurs. There are several different types of innocent murmurs that occur in childhood. Some occur when the child is very young, and others are heard later in childhood.

What causes innocent heart murmurs?

The heartbeat has two distinct sounds that you can hear with a stethoscope. These two thumping sounds are the sounds of the heart valves closing. A heart murmur is heard in between these two normal valve sounds. The murmur sound is caused by blood flowing turbulently through the heart, like the sound of a stream flowing into a whitewater pool. A murmur can occur in several different parts of the heart and blood vessels even though the heart is completely normal.

Are innocent murmurs common?

Innocent murmurs occur in about half of all children at some time during childhood.

How are innocent murmurs diagnosed?

To diagnose an innocent murmur, your doctor will ask about your child's growth, and listen carefully to the heart. Your doctor may want to know if your child is able to exercise as much as other children the same age.

Innocent murmurs have a very distinctive sound. Your doctor can usually tell the difference between an innocent murmur and a murmur that can cause problems. It is not necessary to have any tests done when an innocent murmur is diagnosed, unless advised by your doctor.

How long do innocent murmurs last?

Some innocent murmurs begin in early infancy and last less than 6 months. Other innocent murmurs begin in childhood and last until the teenage years. Still other innocent murmurs occur at any age. Ask your doctor if and when she expects your child's murmur to go away.

Is any treatment necessary for innocent murmurs?

No special treatments or restrictions are necessary. Children with innocent murmurs can safely participate in sports and other vigorous activities.

Call your physician during office hours if:

  • You have additional questions about innocent heart murmurs.

Written by Robert M. Brayden, MD, Associate Professor of Pediatrics, University of Colorado School of Medicine.
Copyright 1999 Clinical Reference Systems