Heart Murmur in Children

The sound of a human heartbeat is usually steady: lub-dub, lub-dub. In some people, the blood makes an extra noise as it flows through the heart. This extra sound is called a murmur. Doctors hear a heart murmur as a “whooshing” sound between heartbeats.

The specialists at Norton Children’s Heart Institute, affiliated with the UofL School of Medicine — the leading providers of pediatric heart care in Louisville and Southern Indiana — can help children with heart murmurs. The board-certified and fellowship-trained specialists at Norton Children’s Heart Institute have the skills and experience to provide a pinpoint diagnosis and develop a customized treatment plan for children with heart murmurs.

What Happens With a Heart Murmur?

Depending on a person’s age, the heart beats about 60 to 120 times every minute. Each heartbeat really is two separate sounds. The heart goes “lub” with the closing of the valves that control blood flow from the upper chambers to the lower chambers. Then, as the valves controlling blood going out of the heart close, the heart goes “dub.”

A heart murmur describes an extra sound heard in addition to the “lub-dub.” Sometimes these extra sounds are from normal blood flow moving through a normal heart. Other times, a murmur may be a sign of a congenital heart defect or other issue.

Heart Murmur Symptoms

About one out of every 100 babies is born with a structural heart issue, or congenital heart defect. These babies may show signs of the defect as early as the first few days of life or not until later in childhood. Some children won’t have any symptoms beyond the heart murmur itself. Other children may have symptoms such as:

  • Blueness in the lips (cyanosis)
  • Difficulty feeding
  • Failure to thrive
  • Rapid breathing

An older child or teen might:

  • Be very tired
  • Have trouble exercising or doing physical activity
  • Have chest pain

Call your doctor if your child has any of these symptoms.

Heart murmurs are very common. Many children may have one at some point.

The most common type of heart murmur is the functional or “innocent” type. An innocent heart murmur is the sound of blood moving through a normal, healthy heart in a normal way.

Other heart murmurs are caused by heart defects. Pregnant women have a higher risk of having a baby with a heart defect if they had rubella (German measles), have poorly controlled diabetes or have phenylketonuria (PKU), a genetic error in the body’s metabolism.

Several kinds of heart defects can cause heart murmurs, including:

  • Septal defects, which involve the wall (septum) between the upper or lower chambers of the heart: A hole in the septum can let blood flow through it into the heart’s other chambers. This extra blood flow may cause a murmur. It also can make the heart work too hard or become enlarged. Bigger holes can cause symptoms besides a heart murmur; smaller ones may eventually close on their own.
  • Heart valves that are narrow, too small, too thick or otherwise abnormal: These valves don’t allow smooth blood flow across them. Sometimes, they allow backflow of blood within the heart. Either issue will cause a murmur.
  • Outflow tract obstruction might be caused by extra tissue or heart muscle that blocks the smooth flow of blood through the heart.
  • Heart muscle disorders (cardiomyopathy): These disorders can make the heart muscle abnormally thick or weak, hurting its ability to pump blood to the body.

Diagnosing a Heart Murmur

It’s not unusual for a murmur to be noticed during a routine checkup, even if none was heard before. Heart murmurs are rated on a scale from 1 to 6 based on how loud they are. Grade 1 is very soft, and grade 6 is very loud. If a murmur is found, the doctor may refer a child to a pediatric cardiologist for further evaluation.

Your doctor and a pediatric cardiologist can determine if the murmur is innocent (which means your child does not have a heart disorder) or if there is a specific heart condition causing the murmur. If a disorder or defect is present, the pediatric cardiologist will know how best to take care of it. The cardiologist will order tests such as:

  • Chest X-ray: This shows a picture of the heart and surrounding organs.
  • Electrocardiogram (ECG or EKG): This test checks the heart’s electrical activity to show damage or irregular rhythms.
  • Echocardiogram (echo): This test uses sound waves (ultrasound) to produce images of the heart and blood vessels’ structures on a screen. It can show the structure and function of the heart. Norton Children’s Heart Institute has 28 tele-echo locations throughout Kentucky and Southern Indiana.

Heart Murmur Treatments

Innocent heart murmurs can come and go throughout childhood. Children with these murmurs don’t need a special diet, restriction of activities or any other special treatment. Those old enough to understand that they have a heart murmur should be reassured that they aren’t any different from other kids. Most innocent murmurs will go away as a child gets older.

If your child has a structural issue in his or her heart, that does not mean he or she will need surgery. Some murmurs are caused by small holes between the two lower chambers of the heart. These holes often do not get bigger and eventually close on their own. Other children with murmurs caused by the narrowing or mild leaking of one of the heart’s valves can also expect to lead healthy, active lives.

Our specialists at Norton Children’s Heart Institute will fully evaluate your child’s heart murmur and let you know the best way to address your child’s murmur so they can live a healthy and happy life.

Why Choose Norton Children’s Heart Institute

The Adult Congenital Heart Association has recognized Norton Children's Heart Institute for its expertise treating adult congenital heart disease.

  • Norton Children’s Hospital has been a pioneer in pediatric cardiothoracic surgery, performing Kentucky’s first pediatric heart transplant in 1986 and becoming the second site in the United States to perform an infant heart transplant.
  • The American Board of Thoracic Surgery has certified our cardiothoracic surgeons in congenital heart surgery.
  • The Adult Congenital Heart Association has accredited Norton Children’s Heart Institute’s Adult Congenital Heart Program as the only comprehensive care center in Kentucky and Indiana treating adults born with a heart defect.
  • More than 5,000 children a year visit Norton Children’s Heart Institute for advanced heart care.
  • Norton Children’s Heart Institute has offices across Kentucky and Southern Indiana to bring quality pediatric heart care closer to home.
  • The Jennifer Lawrence Cardiac Intensive Care Unit (CICU) at Norton Children’s Hospital is the largest dedicated CICU in Kentucky, equipped with 17 private rooms and the newest technology available for heart care.
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