Heart Murmur: Causes, Symptoms, and When to See a Cardiologist

A heart murmur is one of the most common findings during a routine cardiac examination yet it remains one of the most misunderstood. Many people hear the words “heart murmur” from their doctor and immediately fear the worst. The truth is, most heart murmurs are harmless. But some do require specialist attention.

In this article, I explain exactly what a heart murmur is, what causes it, how it is diagnosed, and when you should seek advice from a cardiologist.

What Is a Heart Murmur?

A heart murmur is an extra or unusual sound heard between normal heartbeats. When a doctor listens to your heart with a stethoscope, they normally hear two distinct sounds often described as “lub-dub.” A heart murmur is an additional whooshing, swishing, or rasping sound that occurs as blood flows through the heart.

It is important to understand that a heart murmur is not a diagnosis in itself it is a finding. It may indicate an underlying condition, or it may be completely benign.

Types of Heart Murmurs

Heart murmurs are broadly classified into two categories:

Innocent (Functional) Heart Murmurs These are harmless sounds caused by blood flowing normally through the heart. They are particularly common in children and can also occur in adults during pregnancy, fever, anaemia, or periods of rapid growth. Innocent murmurs do not require treatment.

Abnormal Heart Murmurs These are caused by structural problems within the heart, such as a defective valve or a hole between heart chambers. Abnormal murmurs may indicate a condition that needs monitoring or treatment.

Common Causes of Heart Murmurs

The most frequent causes of abnormal heart murmurs include:

• Valvular heart disease narrowing (stenosis) or leaking (regurgitation) of the aortic, mitral, pulmonary, or tricuspid valves
• Congenital heart defects structural abnormalities present from birth
• Infective endocarditis infection of the inner lining of the heart
• Hypertrophic cardiomyopathy abnormal thickening of the heart muscle
• Anaemia low red blood cell count causing faster blood flow
• Hyperthyroidism an overactive thyroid that increases heart rate and blood flow
• Pregnancy increased blood volume during pregnancy can produce a murmur

Symptoms Associated with a Heart Murmur

Innocent heart murmurs typically cause no symptoms at all. However, if a murmur is caused by an underlying heart condition, you may experience:

• Shortness of breath, especially during physical activity
• Chest pain or tightness
• Fatigue or persistent tiredness
• Swelling in the legs, ankles, or feet
• Dizziness or lightheadedness
• Fainting or near-fainting episodes
• Rapid or irregular heartbeat (palpitations)
• A bluish tint to the skin (cyanosis) more common in children

If you experience any of these symptoms alongside a known or suspected heart murmur, it is essential to seek a medical evaluation promptly.

How Is a Heart Murmur Diagnosed?

A heart murmur is usually first detected during a routine physical examination when a doctor listens to the heart with a stethoscope. To assess its significance, a cardiologist will typically recommend one or more of the following diagnostic tests:

Echocardiogram (Echo) This is the gold standard for evaluating a heart murmur. An echocardiogram uses ultrasound waves to produce detailed images of the heart’s structure, showing how the valves and chambers are functioning in real time.

Electrocardiogram (ECG) An ECG records the heart’s electrical activity and can identify abnormal rhythms or signs of enlargement that may be associated with the murmur.

Chest X-Ray This can reveal changes in the size or shape of the heart and may show fluid in the lungs if heart function is compromised.

Cardiac MRI or CT Scan For more complex cases, advanced imaging provides highly detailed pictures of the heart’s anatomy and blood flow.

When Should You See a Cardiologist?

You should consult a cardiologist if:

• You have been told you have a heart murmur and have never had a formal cardiac assessment
• You are experiencing symptoms such as breathlessness, chest pain, or palpitations
• A heart murmur has been detected in a child and parental reassurance or further investigation is needed
• You have a known valve condition and are due for a follow-up
• You are pregnant and a murmur has been identified
• You are planning surgery and a pre-operative cardiac clearance is required

Early assessment by a specialist can provide clarity, peace of mind, and — where necessary timely treatment that protects your long-term heart health.

Treatment Options for Heart Murmurs

Treatment depends entirely on the underlying cause.

No Treatment Needed Innocent heart murmurs require no treatment. Regular monitoring may be recommended in some cases.

Medication If the murmur is caused by a condition such as high blood pressure, arrhythmia, or heart failure, medications can help manage the underlying problem and reduce the workload on the heart.

Surgical or Interventional Procedures In cases of significant valvular disease or congenital defects, procedures such as valve repair, valve replacement, or catheter-based interventions may be recommended.

Lifestyle Modifications For many patients, managing risk factors through diet, regular exercise, weight control, and stopping smoking can support overall heart health alongside medical treatment.

Heart Murmurs in Children

Heart murmurs are very common in children in fact, up to 70% of children may have an innocent murmur detected at some point during childhood. These are almost always harmless and resolve on their own. However, a small number of children do have structural heart defects that require treatment. A paediatric cardiologist or specialist consultation can quickly determine whether further investigation is warranted.

Living With a Heart Murmur

For the vast majority of people, a heart murmur does not affect daily life. Those with an innocent murmur can exercise freely, work normally, and live without restriction. Those with an abnormal murmur caused by valve disease or another structural issue may need to attend regular cardiology follow-ups to monitor their heart function over time.

The key is not to ignore a finding. A single echocardiogram can provide definitive answers and allow your cardiologist to advise you with confidence.

Final Thoughts

A heart murmur can sound alarming, but it is not always a cause for concern. What matters is getting the right assessment from a qualified specialist who can accurately diagnose the cause, explain your options, and support you with evidence-based care.

If you or someone you know has been told they have a heart murmur and would like a specialist opinion, I offer same-day consultations and all cardiac tests — including echocardiogram and ECG in a single visit at my clinics across London.

Dr Francesco Lo Monaco is a leading private cardiologist in London and Founder of The National Heart Clinic, Harley Street. He holds 600+ five-star reviews and is a multi-award winning heart specialist, including Cardiologist of the Year at the Forttuna Global Excellence Awards 2025.

📍 Clinics: Harley Street | Brentford | Harrow 📞 +44 7904 594 503 🌐 drlomonacocardiologist.co.uk