Heart Murmur in Children: When It Is Innocent and When It Needs Testing

A heart murmur in children is a sound heard during a heartbeat, and in many cases it is harmless. Some murmurs, however, may suggest an underlying heart condition and need further evaluation.

Overview: What a Heart Murmur Means

A heart murmur in children is an extra or unusual sound heard with a stethoscope during the heartbeat. Instead of the usual “lub-dub” pattern alone, the clinician may hear a whooshing or swishing sound caused by blood moving through the heart or nearby blood vessels. A murmur is not a diagnosis by itself. It is a clue that helps guide whether more evaluation is needed.

Many children have what is called an innocent heart murmur. This means the sound is produced by normal blood flow through a healthy heart. Innocent murmurs are common in infancy and childhood and may come and go as a child grows. They often become easier to hear during fever, crying, exercise, or periods of rapid growth, when blood flow is faster.

Other murmurs are called pathologic or abnormal murmurs. These may be linked to structural heart differences present at birth, valve problems, or less commonly acquired heart conditions. The key question is not simply whether a murmur is present, but whether it sounds harmless or suggests a heart problem that should be investigated.

Innocent vs Abnormal Murmurs

Innocent murmurs usually occur in children who are otherwise well, growing normally, and active without limitations. These murmurs often change with body position and tend to be soft, brief, and limited to certain parts of the heartbeat. They are not associated with signs of poor circulation or strain on the heart. Common innocent murmurs include Still’s murmur, pulmonary flow murmurs, and venous hums.

An abnormal murmur may have features that make a clinician more cautious. It may be louder, harsh, heard throughout more of the heartbeat, or associated with an unusual heart sound. The child may also have symptoms, poor growth, or a family history of congenital heart disease. In newborns and young infants especially, a murmur deserves careful attention because some significant heart conditions can present early.

Abnormal murmurs may be related to congenital heart defects such as holes in the heart walls or narrowing of heart valves or blood vessels. For example, a murmur can occur with atrial septal defect or ventricular septal defect. Some children may also have murmurs from valve conditions or more complex heart abnormalities. The exam helps determine whether the murmur is likely innocent or whether additional testing is the safer next step.

Symptoms That May Need Attention

Most children with innocent murmurs have no symptoms at all. The murmur is often found during a routine checkup, sports physical, or examination for an unrelated illness. In these cases, the child usually eats well, grows normally, and keeps up with play and physical activity.

Symptoms that can suggest an underlying heart problem include trouble feeding in infants, sweating during feeds, poor weight gain, rapid breathing, shortness of breath, unusual tiredness, or a bluish color around the lips or skin. In older children, reduced exercise tolerance, dizziness, fainting, chest pain during exertion, or a racing heartbeat may also need assessment.

Not every one of these symptoms means a serious heart condition is present, because many can happen with common childhood illnesses as well. Still, when a murmur occurs together with these signs, medical evaluation becomes more important. The doctor will consider the whole picture rather than the murmur alone.

• Blue or gray skin color, lips, or nails
• Feeding difficulties or poor growth
• Fast breathing or breathlessness
• Fainting, especially with exercise
• Chest pain or unusual fatigue during activity

Causes and Risk Factors

Innocent murmurs are caused by normal blood flow and are not due to heart damage. A child’s chest wall is thinner than an adult’s, and the heart beats faster, so normal flow sounds may be easier to hear. Fever, anemia, dehydration, and excitement can make these murmurs temporarily louder because the heart is pumping faster or more forcefully.

Abnormal murmurs may be caused by congenital heart disease, meaning a structural heart difference present at birth. These can include defects in the walls between heart chambers, valve narrowing or leakage, or changes in the major blood vessels connected to the heart. Less often, murmurs in children can be related to acquired conditions such as inflammation of the heart, rheumatic disease in some regions, or severe anemia.

Certain factors may increase the likelihood that a murmur will need closer assessment. These include a family history of congenital heart disease, genetic syndromes, maternal illness during pregnancy, or a history of prematurity. In some cases, a child may already be known to have a condition such as congenital heart disease, and the murmur helps track how the condition is changing over time.

How Doctors Diagnose a Heart Murmur

Diagnosis begins with a detailed history and physical examination. The doctor listens for where the murmur is heard best, how loud it is, whether it occurs when the heart contracts or relaxes, and whether it changes with breathing or position. They also assess the child’s growth, oxygen level if needed, pulses, blood pressure, and any signs of breathing difficulty or poor circulation.

If the murmur has the typical features of an innocent murmur and the child is otherwise healthy, no immediate testing may be necessary. The family may simply be reassured, with routine follow-up during regular checkups. If the murmur appears abnormal or there are concerning symptoms or exam findings, the child may be referred to a pediatric cardiologist.

Further evaluation may include an electrocardiogram to look at the heart’s electrical activity, a chest X-ray in selected cases, and especially an echocardiogram. An echocardiogram uses ultrasound to show the heart’s structure, valves, and blood flow in real time and is one of the most useful tests for clarifying the cause of a murmur. In some cases, doctors may recommend echocardiography to determine whether the murmur is innocent or linked to a heart defect.

Treatment Options and Follow-Up

Treatment depends entirely on the cause. Innocent murmurs do not require medicines, procedures, or activity restriction. Children with innocent murmurs can usually take part in normal play, school activities, and sports unless a doctor identifies another reason for caution. Many innocent murmurs become softer or disappear as a child grows.

If testing finds a structural heart problem, management may range from simple monitoring to medication or an interventional procedure. Some defects are small and may close on their own or remain stable without immediate treatment. Others may need closer observation by a pediatric cardiologist to protect heart function and support healthy growth and development.

For certain conditions, doctors may recommend catheter-based or surgical treatment. Depending on the diagnosis, this can include pediatric cardiology care for long-term follow-up or cardiac surgery when repair is needed. Near the end of the care pathway, families seeking international care may also wish to know that Acibadem International’s multidisciplinary specialists and JCI-accredited hospitals diagnose and treat pediatric heart conditions for children from many countries.

Prevention, Self-Care, and When to See a Doctor

There is no way to prevent an innocent murmur, because it is a normal sound rather than a disease. Parents can support heart health by keeping routine pediatric appointments, staying up to date with recommended vaccinations, and seeking medical care when a child seems unusually tired, short of breath, or struggles to feed or grow. Good prenatal care is also important because some congenital heart problems develop before birth.

At home, it helps to pay attention to patterns rather than isolated moments. For example, a child who briefly becomes breathless while playing hard may be fine, but repeated exercise intolerance or frequent dizziness deserves discussion with a doctor. If a murmur has already been diagnosed, families should ask whether any follow-up visits, tests, or activity guidance are needed.

A doctor should assess a newly discovered murmur if the child is a newborn, has symptoms, has a known genetic syndrome, or has a family history of significant heart disease. Urgent medical attention is important if the child has blue lips, severe breathing difficulty, fainting, or poor feeding with lethargy. Prompt evaluation can identify those children who need treatment while reassuring families when the murmur is harmless.

Frequently asked questions

Are most heart murmurs in children dangerous?

No. Many heart murmurs in children are innocent, meaning they are caused by normal blood flow in a healthy heart. A doctor’s examination helps decide whether the murmur is harmless or whether further testing is needed.

Can a child have a heart murmur and still be completely healthy?

Yes. Many healthy children have innocent murmurs and have no symptoms, growth problems, or exercise limitations. These murmurs often change over time and may become less noticeable as the child gets older.

What test is usually used to check a child’s heart murmur?

If a murmur needs further evaluation, an echocardiogram is commonly used. This ultrasound test shows the heart’s structure and blood flow and can help identify or rule out many underlying heart problems.

Does a heart murmur mean a child cannot play sports?

Not necessarily. Children with innocent murmurs can usually take part in normal activities and sports. Restrictions are only considered if testing shows a heart condition or if the child has symptoms that need evaluation.

Can an innocent heart murmur go away?

Yes. Innocent murmurs often become softer or disappear as a child grows. Even if the sound remains, it does not usually cause health problems when the heart is otherwise normal.

When should parents seek urgent care for a child with a murmur?

Urgent care is important if the child has blue lips or skin, severe breathing difficulty, fainting, extreme sleepiness, or poor feeding in infancy. These signs do not always mean a serious heart problem, but they should be assessed promptly.

References

• American Heart Association
• American Academy of Pediatrics
• National Heart, Lung, and Blood Institute
• Centers for Disease Control and Prevention
• European Society of Cardiology

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.