Innocent Heart Murmurs of Childhood

What is an innocent heart murmur?

A heart murmur is a sound that occurs between beats of the heart. Your heart makes sounds ("lub-dub") when the heart valves close. Normally it is silent between beats. An innocent murmur is a sound that occurs between beats of the heart even though the structure of the heart and blood vessels is normal.

Most adults do not have heart murmurs, but many children do. Several different types of innocent murmurs can happen in childhood. Some happen when a child is very young. Others are heard later in childhood.

Innocent heart murmurs are also called functional, normal, vibratory, or physiologic murmurs. They do not cause any problems.

How does it occur?

A murmur is a sound made by blood flowing through the heart, like the sound water makes as it flows through a hose. When the heart beats faster, it changes the rate and amount of blood moving through the heart. This can cause heart murmurs. Some of the conditions that might cause a child's heart to beat faster are:

• anemia
• fever
• stress.

What are the symptoms?

Innocent heart murmurs do not cause any symptoms.

How is it diagnosed?

A heart murmur is usually discovered when your healthcare provider listens to the heart with a stethoscope. Innocent murmurs have a distinctive sound. Your healthcare provider can usually tell the difference between an innocent murmur and a murmur that may be caused by a medical problem.

Your provider will ask about your child's growth and may ask if your child is able to exercise as much as other children of the same age. Usually no tests are needed when an innocent murmur is diagnosed.

How is it treated?

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

How long do innocent murmurs last?

Innocent heart murmurs may come and go during childhood. 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.

When fever or anemia causes a murmur, the murmur goes away when the fever or anemia goes away. Most murmurs go away for good as a child nears adulthood.

Ask your healthcare provider if and when he or she expects your child's murmur to go away.

How can I help take care of my child?

Make sure that your child has a physical exam every year.

When should I call my child's healthcare provider?

Call during office hours if:

• Your child is not able to be as physically active as he or she used to be.
• You have more questions about innocent heart murmurs.