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Heart Murmurs in Children

What is a heart murmur?

Murmurs are extra or unusual sounds made by blood circulating through the heart's chambers or valves, or through blood vessels near the heart.

What causes a heart murmur?

Heart murmurs may be heard in a normal healthy heart of a child, or they may be caused by a number of factors or diseases, including the following:

  • Defective heart valves

  • Holes in the interior heart walls (atrial septal defect or ventricular septal defect)

  • Structural heart defects (congenital or present at birth) 

  • Fever

  • Anemia

What are the different types of murmurs?

Your child's health care provider will evaluate a murmur based on several factors. Murmurs are analyzed for pitch, loudness, location, and duration. They also are graded according to their intensity (on a scale of one to six, with one being very faint and six being very loud).

Types of murmurs include the following:

  • Systolic murmur. A heart murmur that occurs during a heart muscle contraction.

  • Diastolic murmur. A heart murmur that occurs during heart muscle relaxation between beats.

  • Continuous murmur. A heart murmur that occurs throughout the cardiac cycle.

Heart murmurs can change and be heard or not heard at different times. Some large heart defects have almost no murmur in the newborn due to normal persistence of fetal circulation and pressure in the blood vessels of the lungs and body. Murmurs may be inconsistent and difficult to hear in an infant who is agitated or crying. Thus, murmurs may be missed or not detected. For these reasons, your doctor will listen and evaluate your child's heart sounds multiple times throughout your child's growth and development.  

Do all murmurs signify heart disease?

Not all heart murmurs are symptoms of heart disease. Sometimes, a murmur may be heard in a normal child as the strong, healthy heart pumps blood into the vessels. This is known as an "innocent murmur." It usually resolves as the child grows. 

Murmurs can also be heard in a child with no heart disease but who has a fever or who is anemic; these murmurs often go away when the underlying problem is treated.

What tests may be used to evaluate a heart murmur?

  • Chest X-ray. This helps evaluate the size of the heart. 

  • Echocardiography (echo). An ultrasound procedure that evaluates the structure and function of the heart. 

  • Electrocardiogram (EKG). A simple test using stickers placed on the chest that can detect and record the electrical activity of the heart.      

What is the treatment for a heart murmur?

Some heart murmurs resolve over time. Even if there is a hole or structural defect found in the heart, it may close as your child grows. However, some defects will require surgery to correct, and some are caused by conditions not related to the heart, such as anemia. In these cases, the underlying problem will be treated and the heart murmur will be monitored closely to ensure that it resolves.