Heart Murmurs and Your Child

Many parents fear the worst when their child is diagnosed with a heart murmur, but this diagnosis is actually extremely common. In fact, many kids are found to have a heart murmur at some point during their lives. Most murmurs are not a cause for concern and do not affect the child's health at all.

What exactly is a heart murmur? By itself, the term heart murmur isn't a diagnosis of an illness or disorder. To better understand what it does mean, it's important to know how the heart works.

How the Heart Works

The normal heart has four chambers and four valves (which function like one-way doors). The two lower pumping chambers of the heart are called the ventricles, and the two upper filling chambers are the atria (singular is atrium).

Here's how blood moves in normal circulation: Blood that returns from the body to the filling chamber on the right side (the right atrium) is low in oxygen. This blood passes across a valve (the tricuspid valve) to the pumping chamber on the right side (the right ventricle) and then travels across the pulmonary valve to the lungs to receive oxygen. The oxygen-enriched blood returns to the filling chamber on the left side (the left atrium), then across a valve (the mitral valve) to the pumping chamber on the left side (the left ventricle). The blood is then pumped across the aortic valve out to the body through the aorta, a large blood vessel that carries blood to the smaller blood vessels in the body to deliver oxygen.

Using a stethoscope, a doctor examines the heart by listening to the sounds it makes. The familiar "lub-dub" sound of a normal heartbeat is caused by the closing sound of the valves as the heart squeezes to push blood through the body. A heart murmur describes an extra sound in addition to the "lub-dub." Sometimes these extra sounds are simply the sound of normal blood flow moving through a normal heart. Other times, a murmur may be a sign of a heart problem.

How Are Heart Murmurs Diagnosed?

A murmur is heard during the heart listening exam, using a stethoscope held at different areas on the front of the chest as the heart beats. Heart murmurs can be heard in infants as well as older children and teens. Of course, if the child is crying, uncooperative to the examiner, or breathing loudly, it may not be possible to hear a murmur. It helps if the child is quiet when the doctor listens, since some heart murmurs are very soft. The doctor may have a parent help by calming the child or having the child sit in the parent's lap during the exam.

Heart murmurs are rated on a scale from 1 to 6 in intensity (loudness). Grade 1 is barely audible, whereas grade 6 is very loud. Your child's doctor will note where on the chest the murmur is best heard, the characteristics of the murmur (for example, whether it's harsh and high-frequency or soft and blowing), where it occurs in the heartbeat cycle, and whether it changes when your child changes position. After this initial discovery, the doctor may refer your child to a pediatric cardiologist for further evaluation.