Heart Murmurs

What are heart murmurs?

Heart murmurs are sounds that a healthcare provider may hear when they listen to your child’s heart through a stethoscope. A murmur may sound like whooshing, rasping or blowing. These sounds come from blood moving through the heart.

Most heart murmurs in children are harmless. Some are a sign of a heart problem or other illness, so it’s important to have abnormal sounds checked.

What causes heart murmurs?

Most heart murmurs in children are the kind called innocent murmurs. There may be no clear cause, but the murmur is harmless and usually goes away on its own by the time the child becomes an adult. It is common for innocent murmurs to come and go or to be louder sometimes and quieter other times.

Sometimes, a murmur is heard in a child who has a fever or a low level of red blood cells (anemia). These murmurs go away when the child gets treatment for the condition that caused it. Usually, these murmurs are harmless and became louder and easier to hear because more blood flows through the heart when the child is sick.

Less often, a murmur is from a structural heart defect or a problem with 1 of the heart valves. More than half of all children will have a heart murmur at some time, but less than 1% of all children have a structural heart defect that may cause a murmur.
What is the grading scale for murmurs?

Murmurs are graded on how easy they are for a healthcare provider to hear. The grading is on a scale of 1 to 6, with grade 6 being the loudest. Just because a murmur is louder does not mean that the murmur is something to worry about.

Heart Center at Seattle Children's

Our pediatric cardiologists and cardiac surgeons have more advanced training and experience operating and performing procedures on babies, children and teens than at any other children's hospital in the Pacific Northwest.

Whare the symptoms of a heart murmur?

By itself, a heart murmur does not cause symptoms. If some condition, like a heart defect or problem with a heart valve, caused the heart murmur, your child might have other signs or symptoms. These would depend on the heart condition and how severe it is.

How is a heart murmur diagnosed?

If your child’s doctor hears a murmur when listening to your child’s heart, they will listen for details about the sound. These details can give clues about the cause.

Your child’s doctor will listen for details like:

When the sound happens
Where in the chest they can hear it
The pitch and tone of the heart murmur
How long it lasts
How it sounds when your child does certain movements or gets in certain positions

The doctor will examine your child and ask about their health history and your family health history. For many children with a murmur, these steps may be all they need to tell if a murmur is innocent or from a structural heart problem.

To get more information about how your child’s heart looks and works, your child may also need tests. These may include:

How is a heart murmur treated?

Your child does not need any treatment just for a heart murmur.

Most heart murmurs in children do not mean there’s a problem. They will go away on their own as the child gets older.

If your child’s heart murmur is from a structural heart problem, like a ventricular septal defect (VSD), or some other health problem, like anemia, your child may need treatment for that condition.

Children who have a heart defect that caused their murmur may need more imaging tests and follow-up visits with a cardiologist. They sometimes need medicines, cardiac catheterization or heart surgery.

Why choose Seattle Children's for heart murmur treatment?

The experts you need are here
- Our team of more than 40 pediatric cardiologists has experience diagnosing and treating every kind of heart problem. Often, we can tell if a murmur is harmless by just listening to it. When needed, we perform tests.
- For the rare cases when a heart defect causes a murmur, we have deep experience with diagnosis and treatment options, like cardiac catheterization or heart surgery.
- Our pediatric cardiac surgeons perform more than 500 procedures yearly. We also have a pediatric cardiac anesthesia team and a Cardiac Intensive Care Unit ready to care for children who need heart surgery.
- Our surgical outcomes are among the best in the nation year after year.
Care from birth through young adulthood
- Seattle Children’s cardiologists see babies, children and teens with heart murmurs. We have experience checking heart murmurs in kids of all ages to tell whether they need treatment.
- For children with a valve problem, structural defect or other illness, we create a custom treatment plan. As your child grows, we closely check their needs to make sure they get the care that is right for them at every age.
- If your child was born with a heart defect, we have a special Adult Congenital Heart Disease Program to meet your child’s long-term healthcare needs. This program, shared with the University of Washington, transitions your child to adult care when they are ready.
Support for your whole family
- We are committed to your child’s overall health and well-being and to helping your child live a full and active life.
- Whatever types of care your child needs, we will help your family through this experience. We will discuss your child’s condition and treatment options in ways you understand and involve you in every decision.
- Our Child Life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.
- Seattle Children’s has many resources, from financial to spiritual, to support your child and your family and make the journey as smooth as possible.
- Many children and families travel to Seattle Children’s for heart surgery or other care. We help you coordinate travel and housing so you can stay focused on your child.
- Read more about the supportive care we offer.