You know the sound of your heartbeat: lub-dub, lub-dub. In some people, there's an extra noise that the blood makes as it flows through the heart. It sounds sort of like the noise of water flowing through a hose. This sound is called a murmur (say: mer-mer).
Most murmurs don't mean anything is wrong. But sometimes they are a sign of a problem with the heart.
The Heart and How It Works
The heart is a strong muscle about the size of your fist that pumps blood around the body. It sits inside the chest and is protected by the ribcage. The heart has four different areas, or chambers. These chambers are connected to each other by valves that control how much blood enters each chamber at any one time. The valves open and shut with every beat. As the valves shut to control the flow of blood through the heart, they make the sound you recognize as your heartbeat.
Depending on a person's age, the heart beats about 60 to 120 times every minute. Each heartbeat is really two separate sounds: lub-dub, lub-dub. Your 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, your heart goes "dub."
What Is a Heart Murmur?
A heart murmur is a whooshing sound between the beats that a doctor hears through a stethoscope. The whoosh is just an extra noise that the blood makes as it flows through the heart. Doctors usually discover murmurs during regular checkups or when kids see the doctor because they're sick.
Just like kids, murmurs have grades. Grade 1 is the softest-sounding murmur, and Grade 6 is the loudest. A murmur graded 4, 5, or 6 is so loud you can actually feel a rumbling from it under the skin if you put your hand on the person's chest.
What Happens If You Have a Murmur?
More than half of all children have a heart murmur at some time in their lives and most heart murmurs don't mean anything is wrong. Doctors may call these "innocent," "functional," or "normal" murmurs. They are caused by blood rushing through the valves in a normal heart and are nothing to worry about.
One common type of normal murmur is Still's murmur, named for the doctor who first described it. This murmur is most often heard in healthy children ages 3 to 7.
A normal murmur can get louder when the blood flows faster through the heart, like when kids have a fever or run around. That's because an increase in body temperature or activity makes the heart pump more blood. When your temperature goes down, the murmur may get quieter or even disappear.
It can be easier to hear heart murmurs in kids because they have less fat, muscle, and bone between the murmur and the doctor's stethoscope. Many normal murmurs become harder to hear as children grow older, and some eventually disappear.
Even though most murmurs do not mean anything is wrong, sometimes a heart problem can cause a murmur. The heart may have a hole in it, a heart valve may leak, or a valve may not open all the way. If your doctor thinks your heart murmur could be due to a heart problem, you will need to see a pediatric cardiologist (say: pee-dee-at-rik car-dee-ol-uh-jist). This kind of doctor knows a lot about children's hearts.
What Do Doctors Do?
A pediatric cardiologist will ask questions to see if you've ever been short of breath, had chest pain, felt dizzy, or fainted. The doctor also will listen to your heart with a stethoscope, check your pulse, and listen to your lungs. Sometimes the doctor might want you to get a chest X-ray to see if the heart looks bigger than normal. You also might get an electrocardiogram (EKG), which measures electrical activity of the heart. None of these tests hurt.
Another test the cardiologist might do is an echocardiogram. This test uses sound waves to make a picture of the heart as blood is pumped through its chambers and valves. It takes about 20 minutes and it doesn't hurt either.
The doctor will take the information from the tests and exam and determine if your murmur is likely to cause a problem for you. A kid with a heart murmur might need to be careful about getting infections that could travel to the heart. To prevent this, your doctor may prescribe antibiotics for you to take before you get your teeth cleaned at the dentist or have any surgery.
The doctor also may prescribe medicine to help the heart squeeze harder, prevent blood clots (bits of thick blood that can block blood vessels), remove extra fluid from the body, or lower your blood pressure.
In some cases, surgery is necessary to fix the problem. Depending on the problem, doctors can patch a hole in the heart, fix a valve, rebuild a blood vessel, or stretch open a blood vessel that's too narrow.
But most of the time, a heart murmur isn't a big problem. And most kids with heart murmurs can run, jump, and play just like everybody else. A heart murmur is simply a sound. It's not always the sign of a heart problem. Usually, it's just your heart whistling while it works.
Reviewed by: Steven Dowshen, MD
Date reviewed: November 2009