Heart valve disorders
Mitral valve stenosis
What is mitral valve stenosis?
Your mitral valve lies between your left atrium and your left ventricle. It has two leaflets, or flaps, that open to allow re-oxygenated blood to flow from your atrium into your ventricle. The leaflets close again when your ventricle contracts to push the blood into your aorta and out to the rest of your body.
The closing of your mitral valve prevents blood from flowing back into your atrium when your ventricle contracts.
Mitral valve stenosis
For more information about how your heart works, take a look at How your heart pumps.
If you have mitral valve stenosis, that means that your mitral valve, which is the outlet from your left atrium into your left ventricle, is narrowed and blood flow is somewhat blocked.
Mitral valve stenosis is almost always caused by rheumatic heart disease, which is now rare in the developed world but can still be a problem in areas where access to antibiotics is limited.
Long-standing mitral valve stenosis can put a strain on your left atrium, which is forced to over-work to try to push blood through your narrowed mitral valve into your left ventricle. Blood accumulates in the atrium and may pool in the lungs, causing serious problems and ultimately leading to heart failure.
If your mitral valve stenosis is severe, you may need to have surgery to repair or replace your mitral valve.
Mitral valve stenosis is also known as mitral stenosis.
What causes mitral valve stenosis?
Mitral valve stenosis is almost always caused by rheumatic heart disease, which is the result of untreated strep throat and is now rare in the developed world, where antibiotics are freely available. Elsewhere in the world, rheumatic heart disease can still be a significant problem.
Mitral valve stenosis can also be caused by calcium build-up on the valve leaflets, which can happen as we age, and by radiation therapy – although this is rare these days because experts are now aware of the risk.
Other causes are very rare (for example, some autoimmune disorders, mitral annular calcification, and malignant carcinoid syndrome) and we won’t cover them here. If you have mitral valve stenosis, your doctor will tell you more about these disorders if they’re relevant to your condition.
Causes of mitral valve stenosis include:
- Rheumatic heart disease: This is the most common cause
- Calcium build-up on the mitral valve: This can happen with age
- Radiation therapy for certain cancers: Radiation can damage heart valves, and stenosis can develop – usually 20 years or more after the therapy occurred
What are the symptoms of mitral valve stenosis?
If you have mild mitral valve stenosis, you may experience no symptoms at all.
However, if you do have symptoms they should be taken seriously because, even if they are initially quite tolerable, your condition may worsen with time.
The symptoms of mitral valve stenosis mimic those of other heart valve disorders.
Common symptoms of mitral valve stenosis include:
- Shortness of breath when you exercise or lie down
- Palpitations and a fast, fluttering heartbeat
Mitral valve stenosis may lead to left heart failure, and if that happens your symptoms may also include tiredness and swollen feet and ankles.
How is mitral valve stenosis treated?
Your doctor will determine the best course of treatment for your mitral valve stenosis based on the severity of your symptoms.
If you have mild stenosis, you may not need any treatment at all. However, if you are experiencing symptoms, your doctor may prescribe medications to treat heart or circulatory disorders that may be making your condition worse.
To treat severe disease, you will need surgery to repair or replace your narrowed mitral valve.
Treatment options for mitral valve stenosis include:
- Diuretics to reduce your fluid load and limit swelling if heart failure is developing
- Blood-thinning medications to prevent clots. This is especially important if you have developed an arrhythmia, such as atrial fibrillation
- Surgery: You may need surgery or a catheter-based procedure to repair or replace your mitral valve
What are the aims of treatment?
The aims of treatment for people with mild mitral valve stenosis are to stabilize your symptoms and prevent them from worsening.
In severe disease, you will require surgery, and the aim is to restore normal valve function.