Heart murmurs

Heart murmurs are sounds made by blood as it flows through the heart or blood vessels near the heart. Most of the time a heart murmur is just the normal sounds of blood flow, but sometimes it can indicate that there is a heart problem.

What causes a heart murmur?

Heart murmurs may be caused by a number of factors or diseases, including the following:

  • 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?

Your child's physician will evaluate a 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 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. Systolic murmurs are divided into ejection murmurs (due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs.
  • Diastolic murmur - a heart murmur that occurs during heart muscle relaxation between beats. Diastolic murmurs are due to a narrowing of the mitral or tricuspid valves, or regurgitation of the aortic or pulmonary valves.
  • Continuous murmur - a heart murmur that 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 signify heart disease?

Not all heart murmurs are symptoms of heart disease. Many children have what is 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/she may want to perform additional tests to ensure a heart defect is not present. A child with an innocent murmur can live a normal life and be as active as any other healthy child.

Sometimes, a murmur may be heard in a normal child who has a fever or who is anemic; these murmurs often go away when the underlying problem is treated.

Caring for children with heart murmurs

Pediatric cardiologists at Children’s are experts at diagnosing the cause of heart murmurs. If fever or anemia is to blame, treating the conditions medically may result in disappearance of the murmur. If your child has an innocent murmur, it is likely that no treatment beyond routine monitoring will be needed. Surgery may be required if a congenital heart defect is discovered.

Herma Heart Center has the most experienced and the only board-certified congenital heart disease surgeons in Wisconsin. Learn more.