The mitral valve is also known as the bicuspid valve. It separates the hearts upper left chamber from the lower left chamber.
Each time your heart beats, the upper chambers (called atria) contract to push blood into the lower chambers (called ventricles). It is the job of the mitral valve to regulate the flow of blood from the left atrium and close when the left ventricle is full, thus preventing a back flow of blood. The valve uses two flaps, called leaflets, to shut the valve. Tendons are attached to these flaps to keep them tight and stop them collapsing through to the other side.
As you will appreciate the mitral valve fulfills a very important function and any problem will make the heart less efficient in pumping blood around the body. Indeed severe problems can result in heart failure unless the valve is surgically replaced or repaired.
With mitral stenosis the valve fails to open wide enough and therefore restricts the blood flow. With mitral incompetence the valve fails to seal and allows the back flow of blood into the atria. Without surgery, the valve can then collapse (mitral valve prolapse). These two conditions can occur singularly or in combination.
Mitral valve stenosis does not always create symptoms, but shortness of breath and an abnormally fast heart rhythm (atrial fibrillation) are common warning signs.
The most common cause is rheumatic fever and it often takes between five and ten years for the heart damage to present itself. Rheumatic fever creates inflammation in the valve and in the years following the flaps in the valve stick together and become thickened, scarred and rigid.
A less common cause of mitral stenosis is calcium deposits forming around the valve.
If you have symptoms, you are at risk of heart failure if you fail to have an operation either to replace the valve or to open up the valve (percutaneous balloon valvuloplasty). Left untreated, moderate to severe mitral stenosis can lead to heart failure.
Mitral incompetence occurs when the mitral valve flaps fail to seal shut, either because of problems with the flaps or a widening of the ring of muscle surrounding the valve (which is called the mitral annulus).
Symptoms include shortness of breath, dizziness, chest pain, tiredness, irregular or abnormally fast heart rate, high pressure inside the vessels carrying blood from the heart to the lungs and heart failure.
Mitral incompetence is more common in older people and is normally the result of changes to the heart with age. For example, the valve may become weaker due to wear and tear or damage may be caused by high blood pressure..
Sometimes mitral incompetence can result from rheumatic heart disease (a complication of rheumatic fever), endocarditis (infection of the inner lining of the heart), cardiomyopathy (a disease of the heart muscle) or congenital heart disease (birth defects affecting the normal function of the heart).
If the condition is mild, patients may simply be monitored at regular intervals with heart scans to check their heart function. But in other cases, patients will probably need surgery to replace or repair the valve. Medications called nitrates or diuretics may also be required to reduce symptoms such as shortness of breath. Other medications may be required to treat an irregular or abnormally fast heart beat.
If patients have severe mitral regurgitation but are unsuitable for surgery, or are continuing to have problems following surgery, they may be offered medications called angiotensin-converting enzyme (ACE) inhibitors or beta blockers to help manage the condition.
Mitral valve prolapse occurs when one or more of the mitral flaps are floppy and do not close tightly, leading to backflow of blood.
Most patients with a mitral valve prolapse do not have symptoms, unless the problem causes severe mitral incompetence. The prolapse is usually discovered by chance during echocardiography (an ultrasound scan of the heart) carried out for another reason. But sometimes the prolapse can cause problems such an irregular heartbeat (arrhythmia) or sudden, noticeable palpitations.
Mitral valve prolapse can be caused by problems with the connective chords that join the mitral valve and the heart muscles. Less frequently it can be caused by damage to the heart muscles themselves as the result of a heart attack.
Sometimes patients are born with the condition and it's more common in people with connective tissue disorders, such as Marfan Syndrome.
If the prolapse is not causing symptoms and the patient is at low risk of developing severe mitral incompetence, they will not require surgery.
Mild symptoms may be controlled with lifestyle changes, such as giving up alcohol, cigarettes and caffeine because these can over stimulate your heart.
Surgical repair or replacement of the valve may be advised if you have severe mitral incompetence causing symptoms, no symptoms but an enlarged lower heart chamber or severe mitral incompetence with irregular or abnormal heart beat or raised blood pressure.