Patient guide · Heart and echocardiography
Heart Murmur: What It Means and What an Echo Scan Shows
Understand why heart murmurs happen, which symptoms need attention, and how an echocardiogram examines the heart valves, chambers, pumping function and blood flow.
Medically reviewed by Mr Pedram Aghaei, Co-founder and Medical Writer, London Private Ultrasound · 21 October 2026
If you’ve heard “heart murmur” come up during a routine check-up, a pregnancy appointment or a pre-op assessment—and are left wondering what it is, you’re not alone.
A single word like this, especially when it is related to heart health, can stay with you for days.
But before you go down a rabbit hole of researching what it is or what it means, this guide should be your pit stop.
This article walks you through what a heart murmur is, the difference between a harmless murmur and one that needs a closer look, the symptoms worth paying attention to, and what an echocardiogram—an ultrasound scan of the heart—can actually show you.
What Is a Heart Murmur?
A heart murmur is an extra sound, usually a whooshing or swishing noise, that a doctor hears through a stethoscope when blood doesn’t flow completely smoothly through your heart.
The British Heart Foundation describes it as “an extra, unusual sound heard in your heartbeat”.
A healthy heartbeat makes a “lub-dub” sound as your heart valves snap shut.
A murmur is the faint rush of blood heard alongside or between those sounds, a bit like the difference between water flowing quietly through a wide pipe and water hissing through a kinked hose.
The murmur itself is a clue, so it tells your doctor where to look rather than what’s causing it.
Is a Heart Murmur Serious?
Most heart murmurs aren’t serious, and many people live their whole lives with a harmless murmur that never causes a problem.
Some murmurs, though, are a sign that a heart valve or another part of the heart isn’t working as it should, which is why doctors sort murmurs into two groups.
Innocent heart murmurs
An innocent heart murmur means your heart is healthy and the sound simply comes from blood moving a little faster than usual.
The BHF says innocent murmurs are harmless, can come and go, and don’t need treatment.
Abnormal heart murmurs
An abnormal heart murmur is caused by a problem with the heart itself, most often a valve that’s narrowed or leaking, or a structural difference you were born with.
These are less common, and they’re the ones a doctor will want to look at more closely with a scan.
You can’t tell which type you have from how you feel, and a stethoscope can only hint at the answer. An echocardiogram is the test that shows whether your heart’s structure and valves are normal.
What Causes a Heart Murmur?
A heart murmur is caused either by extra blood flowing through a healthy heart, which gives an innocent murmur, or by a change in the heart’s valves or walls that disturbs the flow, which gives an abnormal murmur.
Here are the most common causes, starting with the harmless ones.
A murmur found during pregnancy, a fever or after exercise
Anything that makes your heart pump harder or faster can create an innocent murmur. The BHF lists pregnancy, fever, exercise, anaemia and an overactive thyroid as common causes, and the murmur often fades once the cause settles.
A valve that doesn’t close tightly
When a valve doesn’t seal properly, a small amount of blood leaks backwards each time your heart beats. Doctors call this regurgitation, and a leaky mitral valve is one of the most common causes of a murmur in adults.
A valve that has become narrow or stiff
As we get older, a valve can thicken or stiffen so it no longer opens fully, and blood has to squeeze through a smaller gap. Aortic stenosis is the best-known example and becomes more common with age.
A heart difference you were born with
Some murmurs come from a congenital heart condition, such as a small hole between the heart’s chambers or an aortic valve with two flaps instead of three. These are often picked up in childhood, but some are only discovered in adulthood.
An infection that has affected the valves
Rarely, an infection such as rheumatic fever, or an infection of the heart lining called endocarditis, can damage a valve and cause a murmur.
Heart Murmur Symptoms to Look Out For
Many people with a heart murmur have no symptoms at all, but when a murmur is linked to a valve problem, the BHF says you might notice these symptoms:
- getting breathless more easily, especially when you’re active or lying flat
- chest pain or tightness
- feeling dizzy, light-headed or fainting
- swelling in your ankles, legs or tummy
- a cough that won’t go away
- feeling unusually tired or sweaty when you’re resting
If any of these sound familiar, mention them to your doctor, even if they seem small. Sharing details like these helps your doctor decide how quickly you need a scan.
When to Worry About a Heart Murmur in Adults
You should worry about a heart murmur in adults when it comes with symptoms such as breathlessness, chest pain, dizziness or fainting, because these can mean a valve problem is putting your heart under strain.
A murmur with none of these is usually far less urgent, though it still deserves a proper look.
The NICE guideline on heart valve disease advises urgent specialist assessment, including an echocardiogram, within two weeks for adults who have a murmur and faint during exercise. NICE also suggests urgent assessment when there’s chest pain or breathlessness on very little effort or at rest.
Call 999 or attend A&E now for current chest pain, especially with breathlessness, sweating, collapse or pain spreading to the arm or jaw. Do not delay emergency care to arrange a routine scan.
What Do Heart Murmur Grades Mean?
Heart murmur grades describe how loud a murmur sounds through a stethoscope, on a scale from 1, which is very faint, to 6, which is loud enough to hear with the stethoscope just off the chest.
This is called the Levine scale, and you might see it written as “grade 2/6” in a letter.
Louder murmurs, from grade 3 upwards, are more likely to be abnormal, and the loudest ones can be felt as a vibration on the chest wall. Doctors also note when the murmur happens:
- A systolic murmur happens as your heart squeezes, and it’s the most common type, including most innocent murmurs.
- A diastolic murmur happens as your heart relaxes and fills, and these are usually checked with an echo because they’re rarely innocent.
A grade gives your doctor a useful clue, but loudness doesn’t always match how serious the cause is. That’s why the next step is often an echocardiogram scan.
Do You Need an Echo for a Heart Murmur?
You’ll usually need an echo for a heart murmur if you’re an adult with a new murmur, especially if you have symptoms, a family history of heart problems, or you’re over 75.
NICE recommends offering an echocardiogram to adults with a murmur when valve disease is suspected, and considering one even when there are no other symptoms.
An echo is a simple ultrasound scan, much like the scans used in pregnancy. You lie on your side while gel and a small probe are moved over your chest, and the images appear on a screen in real time.
Told You Have a Murmur and Want to Know What It Means?
An echocardiogram at London Private Ultrasound is £299 and checks your heart valves, chambers, pumping strength and blood flow. Your scan is performed and interpreted by a GMC-registered cardiologist. You receive a verbal explanation on the day and a written report within 24 hours. No GP referral is needed.
What Does a Heart Murmur Look Like on an Echo?
On an echo, a heart murmur shows up as a valve that looks thickened or doesn’t open fully, a valve that doesn’t close tightly, or a hole between chambers.
Colour Doppler, a feature of the scan, shows blood flow in red and blue, so a leaking valve appears as a jet of colour flowing the wrong way.
The cardiologist will also check:
- the size of your heart’s chambers and the thickness of the walls
- how strongly your heart pumps, measured as the ejection fraction
- the speed of blood through each valve, which shows how narrow a valve is
- the sac around your heart and the first part of the aorta
Your report will say whether any valve problem is mild, moderate or severe.
How Is a Heart Murmur Treated?
An innocent heart murmur doesn’t need any treatment, while an abnormal murmur is treated by managing the condition causing it.
What that looks like depends on which valve is affected and how much. Here’s a quick overview:
Keeping an eye on it
Mild valve problems are often simply monitored, and NICE suggests an echo every 3 to 5 years for mild narrowing of the aortic or mitral valve.
Medicines
These can ease symptoms such as breathlessness or swelling, or help control a related heart rhythm problem.
Repairing or replacing the valve
When a valve problem becomes severe, it can be repaired or replaced, either with open heart surgery or, for some people, a keyhole procedure through a blood vessel.
A specialist will talk you through which option suits you, and many people with a valve problem live full, active lives with the right monitoring.
How Much Does an Echocardiogram Cost in London?
An echocardiogram in London usually starts from £200 onwards and can climb further based on what’s included. At London Private Ultrasound an echocardiogram costs £299, and that’s the full price, with nothing extra to pay afterwards. It includes:
- a full transthoracic echo of your valves, chambers, pumping function and blood flow
- a scan performed and interpreted by a GMC-registered cardiologist
- your findings explained on the day
- a written report within 24 hours, ready to share with your GP or specialist
If you’d also like to sit down with a cardiologist and have an ECG—a recording of your heart’s rhythm—in the same visit, our Echo Plus Cardiologist package is £449, which costs less than booking all three separately.
Book an Echocardiogram for a Heart Murmur in London
Hearing the word “murmur” can leave you with more questions than answers, and you deserve to know what’s going on inside your heart.
An echocardiogram with London Private Ultrasound gives you a clear picture in one short visit.
Here’s why people often go with our clinic for an echo scan:
Cardiologist-led
Your echo is performed and interpreted by a GMC-registered cardiologist in a CQC-registered clinic.
Reports without delay
We explain what we’ve seen while you’re still with us, and your written report follows within 24 hours.
Simple and comfortable
The scan takes 20 to 30 minutes, uses no radiation and needs no preparation.
Seen quickly
Same-day and next-day appointments are often available, 9am to 7pm, seven days a week, with no GP referral.
A clear next step
If you’d like expert advice on the day, the Echo Plus Cardiologist package adds a cardiologist consultation and an ECG.
Trusted by patients
We’re rated 4.8 out of 5 on Google, with over 1,200 reviews.
You’ll find us at 27 Welbeck Street, a short walk from Bond Street station, and at 54–56 Victoria Street, St Albans.
Not Sure Whether Your Murmur Is Innocent or Something More?
A heart echo scan shows how each valve opens and closes and whether any blood is leaking backwards. It takes 20 to 30 minutes, uses no radiation, and needs no preparation, so you can eat, drink and take your usual medicines as normal. Same-day appointments are often available.
Frequently Asked Questions
How long can you live with a heart murmur?
People with an innocent heart murmur have a normal life expectancy, and the murmur doesn’t shorten their lives. For an abnormal murmur, the outlook depends on the cause and how severe it is, and with regular checks and treatment when needed, many people live long and active lives.
Can a heart murmur go away?
A heart murmur can go away when it’s caused by something temporary, such as pregnancy, a fever or anaemia, and many childhood murmurs fade by puberty. A murmur caused by a valve problem usually stays, and your doctor will keep an eye on it.
Can I exercise with a heart murmur?
Most people with an innocent heart murmur can exercise as normal, with no limits. If your murmur is caused by a valve problem, ask your cardiologist which activities are right for you, as advice depends on the valve and how severe the problem is.
Is a heart murmur in pregnancy normal?
A heart murmur in pregnancy is often normal, because your body pumps much more blood than usual to support your baby. If you have symptoms such as breathlessness at rest or chest pain, or the murmur was there before pregnancy, your midwife or doctor may suggest an echo.
Do I need a GP referral for an echocardiogram?
You don’t need a GP referral for a private echocardiogram at London Private Ultrasound, and you can book directly. Your report can then be shared with your GP or specialist.
Medical disclaimer: This article provides general patient information and does not replace individual medical advice. If you have current chest pain, severe breathlessness, collapse, or pain spreading to your arm or jaw, call 999 or attend A&E immediately.