Heart murmurs

What is a heart murmur? 

Murmurs are sounds that the heart makes. The sound is made by the movement of the blood through the heart. A regular heartbeat makes a “lub-dub” sound. When there is a murmur, a “swooshing,” or vibrating sound can be heard in addition to the “lub-dub.” These sounds are all heard through a stethoscope placed on the chest. The type of sound the heart makes will help your child’s health-care provider determine whether the murmur is innocent or whether more information is needed.  

Heart murmurs are quite common in children, occurring in about one in every two children. In fact, it is possible to hear a murmur in just about all children at some time or another in their young lives. It is more common to hear a murmur when a child is excited or has a fever. 

Most murmurs are normal and are often referred to as innocent murmurs. Only about one in 100 murmurs indicates a problem with the heart. 

Heart murmurs are rated on a scale from 1 to 6. Grade 1 means it can barely be heard, while grade 6 means it is very loud. 

What are innocent murmurs? 

Innocent murmurs don’t cause problems for a child and do not require treatment. They are also called functional, physiological or benign murmurs, or flow murmurs because they reflect the sound of regular blood flow through the heart. 

Innocent murmurs can usually be heard when the child is between the ages of two and six. At this age, they are simply easier to hear than they were when the child was younger. 

If a child is found to have an innocent murmur, it means they are healthy and do not need any treatment or activity restrictions. A heart murmur is also no indication that a child will have heart disease later in life. 

The most common innocent murmur is Still’s murmur. Other murmurs include benign pulmonary outflow murmur, carotid bruit, and venous hum. 

How does a health-care provider determine whether a murmur is innocent? 

By listening to your child’s heart, their heath-care provider will check to see where the heart murmur is heard, the type of noise it makes (for example, clicking or blowing), whether it changes when the child moves, and when it occurs in relation to the sounds the heartbeat. Often a health-care provider will be able to tell just by listening whether it needs to be examined further. 

What might indicate a serious murmur? 

A health-care provider may want to investigate a murmur if it was accompanied by other symptoms. These might include bluish skin or lip (cyanosis) and breathing difficulties or poor weight gain. If a serious murmur is suspected, several tests may be done to gather more information, including checking oxygen saturation (measuring oxygen levels in the blood), measuring blood pressure, chest X-ray, electrocardiogram and an echocardiogram. If a diagnosis of a heart abnormality is confirmed with these tests, then a referral may be made to pediatric cardiologist. 

What causes serious murmurs? 

Serious murmurs are generally caused by congenital heart disease, including abnormalities of the heart valves or a hole between two chambers of the heart. 

How are murmurs treated? 

No treatment is necessary for innocent murmurs. The treatment for a murmur caused by an abnormality of the heart will vary depending on the diagnosis.