Heart murmur symptoms & causes in children

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What is a heart murmur?

Murmurs are 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 caused by a number of factors or diseases, including:

  • defective heart valves
  • holes in the heart walls
  • surgical repair of congenital (present at birth) heart defects
  • fever
  • anemia (a decrease in the red cells in the blood)

What are the different types of murmurs?

A physician will evaluate your child’s murmur based on several factors. Murmurs are analyzed for pitch, loudness and duration. They also are graded according to their intensity (on a scale of one to six, with one being faint and six being very loud).

Types of murmurs include: 

  • systolic murmur
    • occurs during a heart muscle contraction
    • are divided into ejection murmurs (due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs (due to mitral or tricuspid regurgitation where the blood leaks back into the atria from the ventricles).
  • diastolic murmur
    • occurs during heart muscle relaxation between beats
    • are due to a narrowing of the mitral or tricuspid valves or regurgitation of the aortic or pulmonary valves
  • continuous murmur
    • occurs throughout the cardiac cycle

Murmurs related to a congenital (present at birth) heart defect or other problem involving the heart structures will be heard the loudest in the area of the chest where the problem occurs.

Do all murmurs mean that my child has heart disease?

Not all heart murmurs are symptoms of heart disease. Sometimes, a child may have a murmur if she has a fever or is anemic; these murmurs often go away when the underlying problem is treated.

Some children have what’s known as an innocent murmur. These murmurs are not related to congenital heart defects and usually resolve by the time a child reaches adulthood. If your child's physician hears an innocent murmur, he may want to perform additional tests to ensure that he doesn’t have a heart defect. A child with an innocent murmur can live a normal life and be as active as any other healthy child.

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