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Heart Murmur in Kids

What Is A Heart Murmur?

A heart murmur is the sound of blood flow in the chest heard with the stethoscope. If it is heard elsewhere, it is called a bruit. It does not necessarily mean there is an abnormality, just that it is detected. (Similar to hearing water going through a pipe — you hear it — and just because you hear it does not mean it is abnormal.)

The term “murmur” should not be confused with the term “abnormal murmur” just as the word “temperature” should not be confused with the term “fever.” However, people often mistakenly use both terms interchangeably.

The infographic and information below explain heart mumurs.



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Please feel free to share this infographic on your own blog or website. When you do, please give credit and link to Ann & Robert H. Lurie Children’s Hospital of Chicago.

Murmurs are not always significant; they may be normal or innocent. Innocent murmurs are usually found incidentally during a physical exam. They require no further evaluation. Pathologic murmurs are due to abnormal blood flow, usually as a result of a cardiac abnormality. These ought to be referred to a pediatric cardiologist (even prior to testing to avoid duplication and the improper performance of tests).

The classification of heart murmurs is based on their loudness, where in the heart pumping cycle they occur, and where on the chest they are best heard. From these characteristics, the likely cause of a murmur can be predicted.

Each pump of the heart is a two-phase process:

  • Systole is the name for the pumping phase
  • Diastole is the name for the resting, filling phase

A murmur heard during systole is systolic; likewise, a murmur heard during diastole is diastolic.

The intensity and timing of a murmur, particularly when accompanied by symptoms, may suggest that the murmur is significant. Such a murmur needs to be evaluated to determine the underlying structural problem. Many heart abnormalities can be corrected before the heart muscle is permanently damaged.

How Common Are Heart Murmurs in Children?

Heart murmurs are very common. You shouldn’t be surprised if a pediatrician says they hear a murmur. In most cases, the murmur is likely normal. The important part is for your pediatrician or healthcare provider to determine whether this is something that is abnormal or requires further expertise.

How Serious Is a Heart Murmur in a Child?

The level of severity depends on whether the murmur is normal or not. If it’s abnormal, that means there is something wrong with the heart and a cardiologist will need to figure out the cause. If the murmur is abnormal, it could be benign or something more serious – you can’t tell by using the term “murmur” in and of itself. A cardiologist typically considers the murmur and other findings during an exam and puts it together to determine if any additional testing is needed. All the information from the exam and testing is then reviewed to decide what needs to be done next; if anything needs to be done at all.

What Causes A Heart Murmur?

The sound is the result of noisy or turbulent blood flow in the heart. This turbulence may be a normal amount, but louder due to the acoustics which vary from patient to patient (just like concert halls vary in their acoustics). The turbulence may also be abnormal due to abnormal areas of blood flow from abnormalities in the heart. Abnormal heart murmurs can be caused by congenital abnormalities (that is, abnormalities present at birth). Abnormal murmurs can also result from heart infections. These murmurs are usually due to valve leakiness or thickening. Some abnormal murmurs arise from heart muscle damage resulting from coronary artery disease, hypertension or a cardiomyopathy.

What Are the Symptoms of a Heart Murmur?

The symptoms of a significant heart murmur depend on the heart abnormality and its severity. Possible symptoms include:

  • Shortness of breath
  • Lightheadedness
  • Inability to tolerate exertion or poor feeding and weight gain in infants
  • Frequent episodes of rapid heart rate
  • Chest pain

How Is a Heart Murmur Diagnosed?

Technology has made great progress beyond the simple stethoscope in the diagnosis of heart murmurs. For example:

  • An electrocardiogram can detect any associated electrical abnormalities
  • A chest x-ray screens for an enlarged heart, signs of heart muscle failure and certain congenital abnormalities
  • An echocardiogram uses sound waves to create images of the heart structure. The images may show a hole in the wall of the heart or an abnormal valve.
  • In some cases, cardiac catheterization may be necessary to determine the structural problem. This technique also allows measurement of the pressures in the heart chambers and of valve function.

How Is a Heart Murmur Treated?

Not all abnormal murmurs require treatment. The decision for treatment depends on several factors:

  • The symptoms
  • The risk of heart damage over time if the abnormality is not corrected
  • The risk of sudden complications, such as stroke or cardiac arrest

The treatment for correcting significant heart murmur may be an interventional procedure in the cardiac catheterization laboratory or a surgical operation.

Most abnormal murmurs should be followed by a pediatric cardiologist familiar with the cardiac abnormality causing the murmur and the long-term management of it.

Do Kids Grow Out of Heart Murmurs?

The simple answer is no. You always have blood flow so, technically, you should always hear a murmur. When you grow, you may not be able to hear the murmur but the blood flow is still there.

Can Heart Murmurs Get Worse Over Time?

If it’s a normal murmur, it may be louder or softer at different points in time, but it shouldn't be of concern. While blood flow doesn’t get worse, a change in an abnormal murmur over time could mean there is a change in the underlying heart defect. That would need to be determined by a cardiologist who will then need to take a look at your child's overall medical history.  


Heart Center Family Resource Guide

To help prepare families for their care with Lurie Children's Heart Center, we have compiled a list of resources about treatment and recovery. Learn how to get ready for an inpatient stay or outpatient visit, and read about our support services for patients and families.

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