Mitral Valve Stenosis
Mitral valve stenosis overview
The mitral valve controls blood flow from the left upper chamber of the heart (the left atrium) to the left lower chamber (the left ventricle). In mitral valve stenosis, the valve becomes narrowed and stiff, so blood has difficulty passing through. A healthy mitral valve opens to an area of about 4 to 6 cm². In stenosis the opening shrinks, pressure builds up behind it in the left atrium, and that pressure is passed back to the lungs.
Mitral stenosis usually develops slowly over many years. Many people have no symptoms for a long time, and the condition is often found when a doctor hears a murmur or after an echocardiogram. It is less common than a leaking valve (mitral regurgitation) in the UK, but it is important to recognise because it can cause breathlessness, atrial fibrillation and stroke, and it can be treated.
Mitral valve stenosis symptoms and signs
- Breathlessness on exertion, then at rest or when lying flat
- Tiredness and reduced exercise capacity
- Palpitations, particularly from atrial fibrillation
- Cough, sometimes with blood-stained sputum
- Swollen ankles or abdomen if the right side of the heart is affected
- Stroke or TIA from a clot that forms in the left atrium
Symptoms may first appear during pregnancy, an illness with fever, anaemia or a fast heart rate, because these all shorten the time available for blood to cross the narrowed valve.
Complications
- Atrial fibrillation, because the stretched left atrium becomes electrically unstable
- Blood clots in the left atrium, which can cause stroke
- High pressure in the lung arteries (pulmonary hypertension)
- Right-sided heart failure in long-standing disease
Causes and risk factors of mitral valve stenosis
- Rheumatic heart disease is the most common cause worldwide. It follows rheumatic fever, usually in childhood, and the valve damage may appear decades later
- Calcification of the valve ring (mitral annular calcification), mainly in older people and in some people with kidney disease
- Rarely, congenital valve abnormalities, radiation to the chest or inflammatory conditions such as lupus
In the UK, many people with rheumatic mitral stenosis were born or lived in parts of the world where rheumatic fever is still common, such as South Asia, Africa, the Middle East and the Pacific. Rheumatic mitral stenosis is more common in women.
Preventing rheumatic fever
Rheumatic fever follows an untreated streptococcal throat infection. Prompt treatment of sore throats with antibiotics where advised, and long-term penicillin for people who have already had rheumatic fever, help prevent further damage to the heart valves.
When to see a doctor about mitral valve stenosis
See a doctor if you have:
- Unexplained or worsening breathlessness, especially when lying flat or at night
- Palpitations or an irregular heartbeat
- A heart murmur or a past history of rheumatic fever
- Ankle swelling, or reduced ability to exercise
- If you are planning a pregnancy and have been told you have a narrowed mitral valve
Call 999 if you have sudden severe breathlessness, coughing up frothy or bloody sputum, chest pain, or signs of stroke such as facial droop, arm weakness or slurred speech.
How mitral valve stenosis is diagnosed
An echocardiogram is the key test. It shows the shape and movement of the valve, measures the valve area and the pressure difference across it, and assesses the size of the left atrium, the pumping function of the heart and the pressure in the lung arteries.
A valve area of 1.5 cm² or less is usually considered clinically significant, and an area below 1.0 cm² indicates very tight stenosis.
Other tests
- Examination and a typical low-pitched murmur heard at the apex of the heart. Read more about the heart murmur
- ECG to look for atrial fibrillation and left atrial enlargement
- A stress echocardiogram when symptoms and resting scans do not match
- A transoesophageal echo (a probe passed through the gullet) before a balloon procedure, to check for clot in the left atrium and judge whether the valve is suitable
- Chest X-ray, and cardiac CT or MRI in selected cases
We offer a private echocardiogram in Peterborough, Corby and London.
Mitral valve stenosis treatment options
Medicines
- Beta-blockers or rate-limiting calcium blockers to slow the heart rate and give blood more time to cross the valve
- Diuretics (water tablets) to relieve breathlessness and fluid retention
- Anticoagulants to prevent stroke if you have atrial fibrillation, a previous clot, or a clot in the left atrium
In people with rheumatic mitral stenosis, warfarin or a similar vitamin K antagonist is generally advised rather than the newer anticoagulants. In a large trial of people with rheumatic heart disease and atrial fibrillation (INVICTUS, 2022), rivaroxaban gave worse outcomes than a vitamin K antagonist.
Medicines relieve symptoms but do not widen the valve.
Opening or replacing the valve
- Percutaneous mitral balloon valvotomy: a balloon is passed through a vein to the heart and inflated to widen the valve. It suits symptomatic people whose valve is flexible with little calcification and no significant leak or clot
- Surgery: valve repair or replacement when a balloon procedure is not suitable, for example when the valve is heavily calcified
- For heavily calcified valves in older people, treatment is more complex and is planned by a specialist heart team
Treatment is usually advised when stenosis is clinically significant and you have symptoms. It may also be considered without symptoms if there is a high risk of clots, pulmonary hypertension, new atrial fibrillation, a planned pregnancy or major surgery ahead. These procedures are performed in specialist hospitals. A consultation can review your scans and help with referral.
Living with mitral valve stenosis
- Have regular check-ups with a cardiologist and scheduled echocardiograms
- Take rate-control and anticoagulant medicines exactly as prescribed, and keep any blood tests (INR) if you take warfarin
- Stay active within your limits, and rest when symptoms appear
- Reduce salt if you retain fluid, and avoid excess alcohol
- Look after your teeth and gums to reduce the risk of valve infection. Routine antibiotics before dental work are not usually advised, but ask your cardiologist about your own situation
- Tell any doctor treating you about your valve, especially before surgery
Pregnancy
Pregnancy increases blood volume and heart rate, which can make mitral stenosis symptoms worse. If you are planning a pregnancy, see a cardiologist beforehand. Pregnant women with mitral stenosis should be looked after by a specialist team, and treatment may be needed before or during pregnancy.
Mitral valve stenosis prognosis and outlook
Mitral stenosis usually progresses slowly, and many people stay well for years. The outlook depends on how tight the valve is, whether you have symptoms, whether atrial fibrillation or pulmonary hypertension has developed, and whether you receive treatment.
Relieving the narrowing at the right time improves symptoms and long-term outcomes. Untreated severe stenosis can lead to heart failure, atrial fibrillation and stroke, so regular follow-up matters.
Mitral valve stenosis key facts
- Mitral stenosis is a narrowing of the valve between the left upper and lower heart chambers.
- Rheumatic heart disease is the most common cause worldwide.
- It often develops slowly, with symptoms appearing years or decades later.
- An echocardiogram diagnoses it and measures its severity.
- Atrial fibrillation and stroke are the main complications.
- Warfarin, not newer anticoagulants, is usually advised in rheumatic mitral stenosis with atrial fibrillation.
- Balloon valvotomy or surgery relieves significant stenosis.
This page follows current UK and European guidance: NICE NG208 on heart valve disease presenting in adults (investigation and management), the 2021 ESC/EACTS Guidelines for the management of valvular heart disease (Eur Heart J 2022;43:561-632) and the INVICTUS trial (N Engl J Med 2022;387:978-988).
Mitral valve stenosis questions and answers
Is mitral stenosis the same as mitral regurgitation?
No. Stenosis is a narrowing of the valve; regurgitation is a leak. Some people have both. See mitral valve regurgitation.
Can mitral stenosis be cured?
The narrowed valve can be widened with a balloon procedure or replaced with surgery, which relieves symptoms and improves outlook. It is not reversed by medicines, which control symptoms and reduce complications.
Do I need antibiotics before dental work?
Routine antibiotic prophylaxis is not recommended for most valve disease, but maintain good dental hygiene and ask your cardiologist about your own situation.
How often are scans needed?
It depends on severity, from every 3 to 5 years for mild disease to yearly for significant disease.
Can I take the newer blood thinners?
In rheumatic mitral stenosis with atrial fibrillation, warfarin or a similar vitamin K antagonist is generally advised instead. Your cardiologist will advise on the right medicine for you.
Can I exercise?
Most people with mild stenosis and no symptoms can exercise normally. If you have symptoms or significant stenosis, ask your cardiologist what level of exercise is safe.
Questions to ask your cardiologist about mitral valve stenosis
- How tight is my mitral valve, and what is the valve area?
- What is the cause of my mitral stenosis?
- Do I have atrial fibrillation or pulmonary hypertension?
- Do I need a blood thinner, and which one is right for me?
- Am I suitable for a balloon procedure, or will I need surgery?
- When should I have treatment, and what would make you recommend it sooner?
- How often do I need echocardiograms?
- What should I do if I plan a pregnancy?
- Which symptoms should make me contact you urgently?
Mitral valve stenosis diagrams and visual aids
Narrowed valve compared with a leaking valve
Mitral valve stenosis (narrowed) compared with mitral valve regurgitation (leaking).
Image: BruceBlaus / Blausen.com staff, Blausen 0645 MitralValve RegurgitationvsStenosis, Wikimedia Commons. Licensed under CC BY 3.0.
How mitral stenosis affects the heart and lungs
A narrowed mitral valve slows blood flow from the left atrium to the left ventricle. Pressure rises behind the valve, which can cause breathlessness, atrial fibrillation and a risk of clots.
If you have breathlessness or a heart murmur and have been told your mitral valve is narrowed. You can book a video consultation or telephone consultation from anywhere in the UK, or a face to face consultation in Peterborough or Corby. An echocardiogram can be arranged.
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Medically reviewed by Dr Salam Salloum, Consultant Cardiologist. Last reviewed: . This page is for general information and does not replace personal medical advice.