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Health condition · Clinically reviewed

Heart murmurs, from innocent flow sounds to valve disease that needs treating.

Most murmurs are harmless. A few point to valve disease, cardiomyopathy or congenital heart disease that changes the plan entirely.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, ESC and BHF standards you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including echocardiography-led assessment, TAVI and updated endocarditis prophylaxis.

Key facts

Heart murmurs at a glance.

The essentials in plain English - what a murmur is, which ones matter and how they are worked up in the UK.

  • What it is

    An abnormal heart sound caused by turbulent blood flow across a valve, chamber or vessel.

  • Two big families

    Innocent (physiological) murmurs are benign. Pathological murmurs signal underlying cardiac disease.

  • Grading

    Levine scale 1 to 6 - a palpable thrill appears from grade 4 upwards.

  • Timing matters

    Systolic murmurs are common and often benign. Diastolic and continuous murmurs are almost always pathological.

  • Gold-standard test

    Echocardiography characterises the murmur, quantifies severity and guides all further care.

  • Endocarditis

    A key long-term risk in valve disease - dental hygiene and individualised prophylaxis under NICE CG64 are central.

Why this guide matters

Sorting the harmless from the serious.

A murmur on its own is a finding, not a diagnosis. The three points below shape everything else on this page.

  • Timing tells you a lot

    Systolic murmurs are common and often benign. Diastolic and continuous murmurs are almost always pathological.

  • Echocardiography is the pivot

    It confirms whether the murmur is innocent or structural, quantifies severity and decides what happens next.

  • Endocarditis stays on the radar

    For pathological murmurs, dental hygiene and individualised prophylaxis under NICE CG64 remain central to long-term care.

How the diagnosis is made

From first stethoscope to a clear plan.

The steps a UK GP or cardiologist will normally follow - in order - so you know what to expect and why.

  1. 01

    Assessing

    History and red flags

    Symptom review - breathlessness, syncope, chest pain, palpitations - plus family history of sudden death or congenital disease.

  2. 02

    Assessing

    Cardiac auscultation

    Location, timing (systolic, diastolic, continuous), character, intensity, radiation and response to dynamic manoeuvres.

  3. 03

    Assessing

    Dynamic manoeuvres

    Valsalva increases HOCM but decreases aortic stenosis. Squatting and hand-grip help localise the lesion at the bedside.

  4. 04

    Confirming

    ECG

    Screens for left ventricular hypertrophy, arrhythmia and conduction disease that often accompany structural heart disease.

  5. 05

    Confirming

    Echocardiography

    The gold-standard test - specialist commissioned and urgent if the murmur is diastolic, loud or symptomatic.

  6. 06

    Planning

    Cardiac MRI where indicated

    Selective and specialist-led - useful for complex valve disease, cardiomyopathy and congenital anatomy.

  7. 07

    Planning

    Specialist cardiology review

    Specialist commissioned cardiology input with BHF-aligned pathways sets the long-term monitoring and treatment plan.

Typical timeline: a first murmur to a definitive echo report in days to a few weeks.

Symptoms

What a murmur can mean.

Many murmurs are silent - picked up incidentally on examination. Others come with the fingerprints of underlying valve or muscle disease.

  • Innocent flow murmurs

    Still murmur, venous hum, pulmonary flow murmur - soft, systolic, position-dependent and with no other cardiac signs.

  • Systolic murmurs

    The commonest group - includes aortic stenosis, mitral regurgitation, HOCM, VSD and pulmonary stenosis.

  • Diastolic murmurs

    Aortic regurgitation and mitral stenosis - always pathological and warrant urgent specialist review.

  • Continuous murmurs

    Patent ductus arteriosus, arteriovenous fistula and coronary AV fistula - heard through systole and diastole.

  • Palpable thrill

    A thrill appears at Levine grade 4 and above - always signals a significant, pathological lesion.

  • Symptoms of underlying disease

    Breathlessness, exertional syncope, chest pain, palpitations or signs of heart failure need same-week review.

  • High-output states

    Anaemia, fever, thyrotoxicosis and pregnancy can generate flow murmurs that resolve when the driver is corrected.

  • Red flag - new diastolic murmur

    Any new diastolic or loud systolic murmur, especially with fever or embolic signs, needs urgent cardiology review.

Treatment

How murmurs are managed in the UK.

Reassurance for innocent murmurs. Targeted treatment - medical, interventional or surgical - for the underlying lesion. See our related guides on aortic stenosis, mitral valve prolapse, hypertrophic cardiomyopathy and endocarditis.

  • Reassurance for innocent murmurs

    Once echocardiography (or clear clinical criteria) confirms an innocent murmur, no follow-up or restriction is needed.

  • Treat the underlying lesion

    Care is directed by the cause - see our guides on aortic stenosis, mitral valve prolapse, HOCM and endocarditis.

  • TAVI and surgical valve replacement

    For severe aortic stenosis, transcatheter aortic valve implantation and surgical AVR are life-changing options via a heart-team MDT.

  • Mitral repair, replacement and MitraClip

    Severe mitral regurgitation is managed with surgical repair, replacement or percutaneous edge-to-edge repair depending on anatomy.

  • Medical therapy

    Rate and rhythm control, diuretics, ACE inhibitors and anticoagulation - tailored to the specific valve or cardiomyopathy diagnosis.

  • Endocarditis prophylaxis

    Individualised under NICE CG64 - not routine, but considered for high-risk cardiac lesions before high-risk procedures.

  • Serial echocardiography

    Regular specialist-led echo tracks severity and timing of intervention in moderate or asymptomatic severe disease.

  • Cardiac rehabilitation and lifestyle

    Structured rehab after valve surgery, plus dental hygiene, blood-pressure control and safe exercise, all improve outcomes.

Interventional and surgical options are delivered via a specialist heart-team MDT - our TAVR / TAVI clinic, coronary artery bypass, cardiac rehabilitation programme and subcutaneous ICD pages describe the pathways in detail.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or cardiologist knows your heart and history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Prophylaxis against infective endocarditis (CG64).

  • NICE. Heart valve disease presenting in adults (NG208).

  • European Society of Cardiology (ESC). Guidelines for the management of valvular heart disease.

  • British Heart Foundation (BHF). Patient information on heart murmurs and valve disease.

Red flags

When a murmur needs urgent attention.

Many murmurs can be assessed calmly. These are the situations where the clock matters - and where a specialist opinion is needed.

  • New diastolic murmur

    Always pathological - needs urgent specialist commissioned cardiology review and echocardiography, usually within days.

  • Loud systolic murmur with a thrill

    Levine grade 4 or louder implies significant structural disease and warrants same-week review.

  • Exertional syncope or angina

    Classic triad of severe aortic stenosis with breathlessness - urgent cardiology assessment and echocardiography.

  • Fever plus murmur

    Suspect infective endocarditis - urgent bloods, blood cultures and hospital admission for imaging and antibiotics.

  • Signs of heart failure

    Orthopnoea, ankle swelling and paroxysmal nocturnal dyspnoea with a murmur - urgent same-week cardiology.

  • Embolic events

    Stroke, TIA or peripheral embolism with a new murmur can signal endocarditis or intracardiac thrombus.

  • Family history of sudden cardiac death

    Especially with a murmur that varies with Valsalva - consider hypertrophic cardiomyopathy and screen relatives.

  • Cyanosis or clubbing in a child

    Suggests congenital heart disease - urgent paediatric cardiology assessment and echocardiography.

  • Rapid progression of symptoms

    A previously stable valve lesion that worsens over weeks needs re-imaging and specialist review without delay.

Living with it

A monitored condition, with a clear plan.

Four things that make the biggest difference over years - dental hygiene, regular imaging, sensible activity and knowing when to escalate.

A quiet reminder

Small habits, kept up for years, keep valves working.

Structured cardiac follow-up, dental hygiene and paying attention to new symptoms outperform any single intervention.

  1. 01 Dental

    Dental hygiene is not optional

    Poor dental health is the most common preventable driver of endocarditis - regular hygienist visits genuinely lower risk.

  2. 02 Follow-up

    Keep your echo appointments

    Serial echocardiography is how the right moment for surgery or TAVI is caught before symptoms take hold.

  3. 03 Activity

    Move within your plan

    Most valve lesions allow normal activity - your cardiologist will flag the few where competitive sport needs review.

  4. 04 Escalate

    New symptoms mean a new echo

    Breathlessness, blackouts, chest pain or palpitations after a stable murmur should never be watched at home.

Frequently asked

Everything we get asked about heart murmurs.

Quick answers on innocent versus pathological murmurs, echocardiography, TAVI and endocarditis prophylaxis.

  • What is a heart murmur?

    A heart murmur is an abnormal sound heard between the normal heart sounds. It is caused by turbulent blood flow - across a narrowed or leaky valve, through a hole between chambers, or in a high-flow state like anaemia, fever or pregnancy.

  • Is a heart murmur always serious?

    No. Many murmurs are innocent - especially in children and young adults. They come from normal blood flow, have a soft systolic character and no other cardiac signs. Others reflect underlying valve or structural disease and need echocardiography to sort out.

  • How is a murmur graded?

    On the Levine scale from 1 to 6. Grade 1 is very quiet and needs concentration to hear. Grade 4 and above is accompanied by a palpable thrill on the chest wall and always signals significant pathology.

  • What tests will I have?

    Assessment usually starts with a careful history, examination and ECG. Echocardiography is the gold-standard test - it shows the valves and chambers in motion, quantifies severity and guides everything that follows. Cardiac MRI is used selectively for complex cases.

  • When is surgery or TAVI considered?

    When a valve lesion is severe and either causes symptoms or begins to affect the heart muscle. Aortic valve replacement, transcatheter aortic valve implantation (TAVI), mitral repair, MitraClip and mitral valve replacement are all options - the choice is made by a specialist heart-team MDT.

  • Do I need antibiotics before dental work?

    Not routinely. Under NICE guideline CG64, prophylactic antibiotics are considered on an individualised basis for people with high-risk cardiac lesions undergoing high-risk procedures. Excellent dental hygiene is more important than a single antibiotic dose for most people with a murmur.

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