Heart Murmurs

What are heart murmurs?

Heart murmurs are sounds that a healthcare provider may hear when listening to the heart through a stethoscope. A murmur may sound like whooshing, rasping or blowing and comes from blood moving through the heart.

Most heart murmurs in children are innocent, or harmless. Occasionally a murmur is from a structural heart defect. It’s important to have abnormal sounds checked because they might mean there’s a problem in the heart.

Murmurs are graded on how easily they’re heard by the healthcare provider. The grading is on a scale of 1 to 6, with grade 6 being the loudest. Just because a murmur is louder does not necessarily mean that the murmur is something to be worried about.

  • The majority of murmurs heard in children are just the sounds of blood moving through the heart. 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.

    Not all murmurs are signs of a heart problem. Sometimes, a murmur is heard in a child who has a fever or who has a low level of red blood cells (anemic), and the murmur goes 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 of increased blood flow through the heart when the child is sick.

Heart Murmurs at Seattle Children’s

  • Seattle Children’s Heart Center is one of the best pediatric cardiology programs in the United States and is the top-ranked program in the Northwest, according to U.S. News & World Report. With more than 40 pediatric cardiologists, we have experience diagnosing and treating every kind of heart problem.

    Our heart team has evaluated many children with heart murmurs. We have extensive experience with the conditions that can cause heart murmur and with the treatments they may require. Often we can tell if a murmur is harmless by just listening to it. When needed, we perform tests as part of the evaluation.

    Children who have a heart defect that caused their murmur may need medicines, cardiac catheterization or heart surgeryto treat their condition. We have a team of specially trained cardiologists (physicians), nurses and technicians who have expertise in evaluating and treating children with heart defects. We have a pediatric cardiac anesthesia team and a Cardiac Intensive Care Unit ready to care for children who undergo heart surgery.

    Seattle Children’s has been treating children since 1907. Our team members are trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia (sedation) are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialistsknow how to help children understand their illnesses and treatments in ways that make sense for their age.

  • When you come to Seattle Children’s, a team of people will take care of your child. Along with your child’s heart doctor (cardiologist), you are connected with newborn specialists (neonatologists), lung doctors (pulmonologists), nurses, child life specialists, social workers and others, if their expertise is needed. We work together to meet all of your child’s health needs and help your family through this experience.

    We’re committed to your child’s overall health and well-being. We’ll discuss treatments in ways you can understand and involve you in every decision.

    Read more about the supportive care we offer.

Symptoms of Heart Murmur

Most heart murmurs in children are the kind called innocent murmurs. They don’t mean there’s a problem with the heart or anything else in the body. They are harmless and usually go away on their own by the time the child becomes an adult.

By itself, a heart murmur doesn’t cause symptoms, particularly if it is one of the innocent murmurs. If some condition, like a heart defect or problem with heart valves, caused the heart murmur, this condition might cause other signs or symptoms. These signs and symptoms would depend on the heart condition and how severe it is.

Diagnosing Heart Murmur

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 it can be heard, the pitch and the tone of the heart murmur, how long it lasts and 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 determine 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: 

Treating Heart Murmur

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 ventricular septal defect (VSD), or some other health problem, like anemia, your child may need treatment for that condition.

Contact Us 

Contact the Heart Center at 206-987-2515 to request an appointment, a second opinion or more information.

Providers, see how to refer a patient.