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Being told you have a heart murmur can be worrying, but it is simply an extra sound heard during your heartbeat. While many murmurs are completely harmless, some indicate an underlying issue with your heart valves. This guide explains the difference between innocent and abnormal murmurs, and how an echocardiogram provides a definitive diagnosis.
A normal heartbeat makes a "lub-dub" sound as the heart valves close. A heart murmur is an extra, unusual sound — often described as a whooshing or swishing noise — that occurs when blood does not flow smoothly through the heart. This turbulence creates a sound that a doctor can hear using a stethoscope.
Doctors classify murmurs based on when they occur during the heartbeat cycle:
When a doctor listens to your heart, they grade the loudness of the murmur on a scale from 1 to 6:
The most important distinction your doctor will make is whether your murmur is "innocent" (harmless) or "abnormal" (pathological).
| Feature | Innocent Murmur | Abnormal (Pathological) Murmur |
|---|---|---|
| What it means | The heart is structurally normal, but blood is flowing faster than usual. | There is a structural problem with the heart, usually involving the valves. |
| Common causes | Exercise, pregnancy, fever, anaemia, rapid growth in children, or an overactive thyroid. | Valve calcification (ageing), rheumatic fever, congenital heart defects, or valve prolapse. |
| Symptoms | None. The person feels completely healthy. | May cause shortness of breath, chest pain, dizziness, or swelling in the ankles. |
| Treatment | No treatment required. The murmur may disappear on its own. | Requires monitoring via echocardiogram. May eventually need medication or valve surgery. |
While innocent murmurs cause no symptoms, an abnormal murmur indicates that the heart is working harder than it should. If you have been told you have a murmur, you should seek immediate medical assessment if you experience any of the following "red flag" symptoms.
Difficulty breathing, especially during physical exertion or when lying flat in bed at night. This can indicate fluid building up in the lungs due to inefficient heart pumping.
A feeling of pressure, tightness, or pain in the chest. This occurs when the heart muscle itself is not receiving enough oxygen-rich blood.
A sensation that your heart is fluttering, racing, or skipping a beat. Valve issues are closely linked to irregular heart rhythms (arrhythmias).
Noticeable swelling in your ankles, feet, legs, or abdomen. This happens when the heart cannot pump blood effectively, causing fluid to pool in the lower extremities.
Feeling lightheaded or actually fainting (syncope), particularly during exercise. This suggests the brain is temporarily not receiving enough blood flow.
A stethoscope can detect the presence of a murmur, but it cannot definitively show what is causing it. To understand the exact cause, a structural assessment of the heart is required.
An echocardiogram (often called an "echo") is the gold standard diagnostic test for a heart murmur. It is a specialised ultrasound-scan of the heart that uses high-frequency sound waves to create real-time, moving images of your heart muscle and valves.
During an echo, the sonographer can see:
Depending on your symptoms, your doctor may also recommend:
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