Heart Murmur
Source: Caring for Your Baby and Young Child: Birth to Age 5 (Copyright © 2009 American Academy of Pediatrics)
What is a heart murmur?
Technically, a heart murmur is simply a noise heard between the beats of the heart. When a doctor listens to the heart, she hears a sound something like lub-dub, lub-dub, lub-dub. Most often, the period is silent. If there is any sound during this period, it is called a murmur. Although the word is unsettling, murmurs are extremely common, and usually normal (that is, the sounds are caused by a healthy heart pumping blood normally). It is important to note that a murmur is just a sound, and we listen to make sure that the sound isn’t being caused by a true heart problem.
“Innocent” murmurs
In preschool and school-age children, heart murmurs are almost always not a concern; the children require no special care, and the sound eventually disappears. The murmur is just an extra sound of blood flowing through a structurally normal, healthy heart—we believe that growing children with fast-beating hearts just make these sounds at some point in childhood as a normal part of their development.
If your child has such a murmur it may be discovered between the ages of one and five or older during a routine examination. The doctor will then listen carefully to determine if this sounds like one of the common “normal/functional/benign” heart murmurs or one that might indicate a problem. Usually, just by listening to its sound, the pediatrician will be able to tell if a murmur is something to be concerned about. One of the most common types of innocent childhood murmurs is called a “Still’s murmur.”
On rare occasions, a pediatrician will hear a murmur that sounds abnormal and suggest that your child be referred to a pediatric cardiologist to enable a precise diagnosis to be made. Even when the sound is concerning to the pediatrician, most children that are screened by the cardiologist end up having a normal heart.
Heart murmurs and infants
A heart murmur that occurs soon after birth or during the first 6 months of life would be less likely to be an “innocent murmur,” and most likely these murmurs will require the attention of a pediatric cardiologist. They may be due to abnormal connections between the pumping chambers (septal defects) or the major blood vessels coming from the heart (e.g., transposition of vessels). He also may undergo additional tests, such as a chest X-ray, electrocardiogram (ECG), and an echocardiogram. The echocardiogram is an ultrasound of the heart—it creates a picture of the inside of the heart by using sound waves. The cardiologist and pediatrician together will make a decision as to the next steps depending on the results of these tests.
Treatment
Innocent heart murmurs are normal and therefore require no treatment. Children with these innocent heart murmurs do not need repeated evaluation or long-term follow-up care from the cardiologist, nor do they require restrictions on sports or other physical activities.
Innocent heart murmurs generally disappear by mid-adolescence. Cardiologists don’t know why they go away, any more than we now why they appear in the first place. In the meantime, don’t be discouraged if the murmur is softer on one visit to the pediatrician and loud again on the next. This may simply mean that your child’s heart is beating at a slightly different rate each time.