Heart Murmurs: Innocent Sounds, Valve Problems, and When Testing Is Needed

A heart murmur is an extra sound heard during a heartbeat, often detected with a stethoscope during a routine examination. Many murmurs are harmless, but some can signal a valve problem or another heart condition that needs further testing.

Overview

A heart murmur is an additional sound heard between the normal lub-dub sounds of the heartbeat. It is usually detected by a doctor listening with a stethoscope. The sound may be described as blowing, whooshing, swishing, or rumbling, depending on how blood moves through the heart or nearby blood vessels.

Hearing the word murmur can be worrying, but a murmur is not a diagnosis by itself. It is a physical finding. Some murmurs are innocent, meaning the heart is structurally normal and the sound is simply caused by fast or strong blood flow. Others are abnormal and may point to a valve problem, a congenital heart condition, or changes in the heart muscle.

Doctors assess a murmur by considering the person’s age, symptoms, medical history, and what the murmur sounds like. The timing, loudness, location, and whether it changes with body position can all provide clues. When needed, imaging tests can confirm whether the heart is healthy or whether treatment or follow-up is appropriate.

Innocent Heart Murmurs

Innocent, also called functional or physiologic, heart murmurs occur when blood flows normally through a healthy heart but creates an audible sound. They are especially common in children and adolescents because the chest wall may be thinner and blood flow can be relatively brisk. Many innocent murmurs come and go and may become more noticeable during growth, excitement, fever, or physical activity.

Adults can also have innocent murmurs. Situations that increase blood flow or make the heart pump more strongly may produce a temporary murmur. Examples include pregnancy, anemia, fever, overactive thyroid, and intense exercise. Treating the underlying temporary condition, when one is present, often makes the murmur less noticeable or resolves it.

An innocent murmur does not mean the heart is weak, damaged, or at risk of sudden failure. If a doctor is confident that the murmur is innocent and there are no concerning symptoms or examination findings, no specific treatment may be needed. In some cases, a one-time echocardiogram is ordered to document that the heart structure and valves are normal.

Symptoms and Warning Signs

Many people with heart murmurs have no symptoms at all. A murmur may be discovered during a school physical, pregnancy check-up, preoperative assessment, or routine medical visit. When the murmur is innocent, the person usually feels well and has normal exercise capacity.

If a murmur is caused by a valve disorder or another heart condition, symptoms may develop gradually or appear during exertion. These symptoms are not specific to murmurs, but they help doctors decide how urgently evaluation is needed.

• Shortness of breath during activity or while lying flat
• Chest discomfort, pressure, or pain
• Fainting, near-fainting, or unexplained dizziness
• Palpitations or an irregular heartbeat sensation
• Swelling of the ankles, feet, legs, or abdomen
• Unusual fatigue or reduced ability to exercise
• Bluish lips or fingertips, especially in infants or children
• Poor feeding, slow growth, or sweating with feeds in babies

Symptoms such as fainting with exercise, chest pain, severe breathlessness, or blue discoloration should be assessed promptly. In infants and children, feeding difficulty, poor weight gain, rapid breathing, or fatigue with activity should be discussed with a pediatrician or pediatric cardiologist.

Causes and Risk Factors

Abnormal heart murmurs are often related to how blood passes through the heart valves. Valves act like one-way doors between the heart chambers and the major blood vessels. If a valve is narrowed, called stenosis, blood may have to move through a smaller opening. If a valve leaks, called regurgitation or insufficiency, blood can flow backward. Both situations may create a murmur.

Valve problems can be present from birth or develop later in life. Common examples include aortic stenosis, mitral regurgitation, mitral valve prolapse, and a bicuspid aortic valve. Rheumatic heart disease, previous heart infections, age-related valve thickening, high blood pressure, and certain connective tissue conditions can also affect valves. Not every valve change causes symptoms, and some are found only after a murmur is heard.

Other causes include congenital heart defects, such as small holes between heart chambers, changes in heart muscle size or function, and increased blood flow due to non-cardiac conditions. Risk factors that may make careful evaluation more important include a family history of congenital heart disease, previous heart valve disease, past infective endocarditis, radiation treatment to the chest, certain autoimmune conditions, or a history of rheumatic fever.

Diagnosis and Testing

The first step is a careful medical history and physical examination. The doctor listens to the heart in several areas of the chest and may ask the person to breathe, stand, squat, or lie in different positions. These maneuvers can change blood flow and help distinguish certain murmur patterns. Blood pressure, pulse, oxygen levels, and signs of fluid retention may also be checked.

The main test for evaluating a murmur is an echocardiogram, which is an ultrasound scan of the heart. It shows the heart chambers, valves, pumping function, and direction of blood flow. Doppler ultrasound can measure how fast blood moves across valves and whether there is narrowing or leakage. This test is painless and does not involve radiation.

Additional tests may be used depending on symptoms and findings. An electrocardiogram can assess heart rhythm and signs of chamber enlargement. A chest X-ray may show heart size or lung fluid. Blood tests may check for anemia, thyroid disease, infection, or other contributing conditions. In selected cases, exercise testing, cardiac MRI, CT imaging, or transesophageal echocardiography may provide more detailed information.

Not every murmur requires extensive testing. Doctors consider the grade and quality of the murmur, the person’s age, whether symptoms are present, and whether there are other abnormal examination findings. A soft, typical innocent murmur in a well child may be managed differently from a new murmur in an adult with breathlessness.

Treatment Options

Treatment depends on the cause of the murmur rather than the sound itself. Innocent murmurs do not need medication, activity restriction, or procedures. If a murmur is related to anemia, fever, thyroid disease, or pregnancy-related circulation changes, care focuses on the underlying situation and appropriate follow-up.

When a murmur is caused by valve disease, the treatment plan is based on the type and severity of valve involvement, symptoms, heart function, and overall health. Mild valve leakage or narrowing may only require periodic echocardiograms and routine cardiology visits. Blood pressure control, heart rhythm management, and treatment of related conditions can reduce strain on the heart in some patients.

More significant valve disease may require a procedure or surgery if it causes symptoms, affects heart function, or reaches a level where repair or replacement is recommended. Options may include valve repair, valve replacement, or catheter-based procedures for selected patients. The choice depends on the valve involved, anatomy, age, other medical conditions, and the expertise of the treating heart team.

Antibiotics before dental or medical procedures are not recommended for everyone with a murmur. They are reserved for specific high-risk heart conditions to reduce the risk of infective endocarditis. Patients with known valve disease or prior endocarditis should ask their cardiologist whether any special precautions apply to them.

Prevention and Self-care

Many heart murmurs, especially innocent murmurs and congenital valve differences, cannot be prevented. However, general heart-healthy habits can support the cardiovascular system and may help reduce the risk of acquired heart disease. This includes not smoking, maintaining a healthy blood pressure, managing diabetes or cholesterol when present, staying physically active as advised, and following a balanced eating pattern.

Good dental hygiene is important, particularly for people with certain valve problems or previous heart infections. Regular brushing, flossing, and dental care help reduce bacteria in the mouth that can occasionally enter the bloodstream. People who have been told they are at high risk for endocarditis should follow their doctor’s advice about preventive antibiotics before certain dental procedures.

People diagnosed with a valve condition should keep follow-up appointments even if they feel well. Valve disease can change slowly over time, and scheduled echocardiograms help doctors detect changes before complications develop. It is also helpful to keep a record of previous echo reports, medications, allergies, and any procedures when seeing a new healthcare provider or traveling.

When to See a Doctor

A newly detected murmur should be reviewed by a qualified healthcare professional, especially in adults, infants, or anyone with symptoms. A doctor can decide whether the murmur appears innocent or whether testing is needed. People with a known murmur should also seek reassessment if symptoms change or if they are planning pregnancy, major surgery, or a new intensive exercise program.

Medical care should be sought promptly for chest pain, fainting, shortness of breath at rest, sudden swelling, blue lips or fingertips, or rapid worsening of exercise tolerance. Children should be assessed if they have poor feeding, poor growth, excessive sweating, rapid breathing, or fatigue during play. These signs do not always mean a serious heart condition is present, but they deserve timely evaluation.

For international patients who need evaluation of a heart murmur or valve disease, Acibadem International’s multidisciplinary specialists and JCI-accredited hospitals provide diagnostic testing and treatment planning across cardiology, cardiac imaging, and cardiovascular surgery. The most appropriate approach should always be individualized after examination and review of test results.

Frequently asked questions

Is a heart murmur always dangerous?

No. Many heart murmurs are innocent and occur in people with normal heart structure and function. A doctor can usually judge whether the murmur has harmless features or whether an echocardiogram is needed.

What does a heart murmur sound like?

A murmur may sound like a whoosh, swish, blowing, or rumbling sound between the normal heartbeats. Doctors describe it by timing, loudness, pitch, and where it is heard best on the chest.

Can children outgrow heart murmurs?

Yes, many innocent murmurs in children become less noticeable or disappear as the child grows. However, a pediatrician may recommend evaluation if the murmur is loud, unusual, present with symptoms, or associated with other examination findings.

What test is most important for a heart murmur?

An echocardiogram is the main test used when a murmur needs further assessment. It uses ultrasound to show the heart valves, chambers, pumping function, and blood flow patterns.

Can a heart murmur limit exercise?

An innocent murmur usually does not limit exercise. If a murmur is related to valve disease or another heart condition, exercise advice depends on the diagnosis, severity, symptoms, and cardiologist’s recommendations.

Do people with heart murmurs need antibiotics before dental work?

Most people with a murmur do not need preventive antibiotics. They are recommended only for certain high-risk heart conditions, so patients should ask their cardiologist or dentist if this applies to them.

Can a heart murmur appear later in life?

Yes. A new murmur in adulthood can occur because of valve changes, high blood flow states such as anemia or fever, or other heart conditions. It should be assessed by a healthcare professional to determine whether testing is needed.

References

• American Heart Association
• European Society of Cardiology
• Mayo Clinic
• National Heart, Lung, and Blood Institute
• Cleveland Clinic

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.