What is a heart murmur?

The heart is a muscular organ with four chambers. It pumps blood out to the lungs to pick up oxygen, and out through the body to deliver oxygen. Four valves control the flow of blood through the chambers of the heart and out of the heart.

The heartbeat sounds are the sounds of the valves closing. A heart murmur is an extra sound heard when a doctor listens with a stethoscope. This extra sound is created by turbulent blood flow.

A heart murmur in children caused by turbulent blood flow can be either normal or abnormal:

• In normal heart murmurs, the flow can be heard pumping through the heart normally. This normal blood flow is called an innocent, or normal, murmur. More than 66 percent of all children, and approximately 75 percent of all newborns, have normal heart murmurs.
• Abnormal blood flow suggests a structural heart problem or defect, which requires further evaluation.

Normal heart murmurs are usually louder when the child has a cold or fever, and typically disappear by adolescence (though not always). However, normal heart murmurs are still associated with a structurally normal heart; they do not cause any exercise restrictions or precautions, do not require antibiotics before a dental-cleaning, and do not require further cardiology evaluation.

Testing and diagnosis of heart murmur in children

Doctors can evaluate many characteristics of the murmur to determine if it is normal or abnormal, including:

• If it is loud or soft
• If it is high- or low-pitched
• Where on the chest or back it can be heard
• If there are differences in the sound based on your child's position
• When the murmur occurs relative to the first and second heart sounds

If your child's primary doctor thinks that the murmur is normal or innocent, he or she will note the murmur on the patient chart and listen again at later checkups for changes. If you switch doctors, make sure to tell the new doctor about the innocent murmur. If your child's doctor feels comfortable that the murmur is normal, there is no need for further cardiology evaluation.

Sometimes the doctor will be concerned that the murmur is not normal. In these cases, you may be referred to a pediatric cardiologist, a doctor who specializes in heart problems in children. It is very important to see the pediatric cardiologist if your child's doctor tells you to do so.

A pediatric cardiologist will perform a full evaluation of your child's health, including getting a history and performing an examination, as well as possibly ordering heart tests such as:

• Electrocardiogram: a record of the electrical activity of the heart
• Echocardiogram (also called "echo" or cardiac ultrasound): sound waves create an image of the heart
• A chest X-ray

Not all tests will need to be performed, as pediatric cardiologists are specially trained to tell whether these murmurs are normal or abnormal. Based on your child’s evaluation, doctors will come up with a plan for treating your child.

Sometimes, abnormal murmurs don't show up right away, and develop later. Also, there are some heart abnormalities that don't even have murmurs. See our list of symptoms that might indicate a heart problem. If your child has any of them, make sure to tell your primary care doctor.