The human heartbeat is usually steady: lub-dub, lub-dub. In some people, though,
the blood makes an extra noise as it flows through the heart. This sound is called
Doctors hear a heart murmur as a whooshing sound between heartbeats. The whoosh
is just an extra noise that the blood makes as it flows through the
What Happens in a Heart Murmur?
Depending on a person's age, the heart beats about 60 to 120 times every minute.
Each heartbeat is really two separate sounds. The heart goes "lub" with the closing
of the valves that control blood flow from the upper chambers to the lower chambers.
Then, as the valves controlling blood going out of the heart close, the heart goes
A heart murmur describes an extra sound heard 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.
Who Gets Heart Murmurs?
Parents might worry if they're told that their child has a heart murmur. But heart
murmurs are very common, and many kids are found to have one at some point. Most murmurs
are not a cause for concern and won't affect a child's health at all.
How Are Heart Murmurs Diagnosed?
Doctors listen to the heart by putting a stethoscope on different areas of the
chest. It helps if kids are quiet as the doctor listens, because some heart murmurs
are very soft. It's not unusual for a murmur to be noticed during a routine checkup,
even if none was heard before.
Heart murmurs are rated on a scale from 1 to 6 based on how loud they are. Grade
1 is very soft, whereas grade 6 is very loud. If a murmur is found, the doctor may
refer a child to a pediatric cardiologist for further evaluation.
What Causes Heart Murmurs?
Innocent Heart Murmurs
The most common type of heart murmur is called functional or innocent.
An innocent heart murmur is the sound of blood moving through a normal, healthy heart
in a normal way. Just as you might hear air moving through an air duct or water flowing
through a pipe, doctors can hear blood moving through the heart even when there's
no heart problem.
An innocent heart murmur can come and go throughout childhood. Kids with these
murmurs don't need a special diet, restriction of activities, or any other special
treatment. Those old enough to understand that they have a heart murmur should be
reassured that they aren't any different from other kids.
Most innocent murmurs will go away on their own as a child gets older.
Congenital Heart Defects
Some murmurs can indicate a problem with the heart. In these cases, doctors will
have a child see a pediatric cardiologist. The cardiologist will order tests such
a chest X-ray: a picture of the heart and surrounding
an EKG: a record of
the heart's electrical activity
an echocardiogram: a picture of the heart made using sound waves
About 1 out of every 100 babies is born with a structural heart problem, or congenital heart defect. These babies may show signs of the
defect as early as the first few days of life or not until later in childhood. Some
kids won't have any symptoms beyond a heart murmur, while others will such signs as:
have trouble exercising or doing physical activity
have chest pain
Call your doctor if your child has any of these symptoms.
Pregnant women have a higher risk of having a baby with a heart defect if they
get rubella (German
measles), have poorly controlled diabetes, or have PKU (phenylketonuria, a genetic
error of the body's metabolism).
Common Heart Defects
Several kinds of heart problems can cause heart murmurs, including:
Septal defects, which involve the walls (or septum) between
the upper or lower chambers of the heart. A hole in the septum can let blood flow
through it into the heart's other chambers. This extra blood flow may cause a murmur.
It can also make the heart work too hard or become enlarged. Bigger holes can cause
symptoms besides a heart murmur; smaller ones may eventually close on their own.
Valve abnormalities, caused by heart valves that are narrow,
too small, too thick, or otherwise abnormal. These valves don't allow smooth blood
flow across them. Sometimes, they can allow backflow of blood within the heart. Either
problem will cause a murmur. Outflow tract obstruction might be caused
by extra tissue or heart muscle that blocks the smooth flow of blood through the heart.
Heart muscle disorders(cardiomyopathy), which
can make the heart muscle abnormally thick or weak, hurting its ability to pump blood
to the body normally.
Your doctor and a pediatric cardiologist can determine if the murmur is innocent
(which means your child is perfectly healthy) or if there is a specific heart
problem. If there is a problem, the pediatric cardiologist will know how best to take
care of it.