A B C D E F G H I J K L M N O P R S T U V W

MITRAL VALVE DISEASE

What is Mitral Valve Disease ?

The heart consists of two pumps side by side in one organ; they are called the left heart and the right heart. The heart's valves make sure that the blood flows in the right direction and if they are damaged the blood will not flow properly. The two valves in the left heart are the aortic valve and the mitral valve. The mitral valve lies between the receiving chamber (Ieft atrium) and the pumping chamber (left ventricle). It consists of two flaps (cusps) held in position by strands of tissue called chordae. The chordae are connected to papillary muscles which are part of the left ventricle. If the valve is narrowed (mitral stenosis) there is a restriction in blood flow. If it leaks (mitral regurgitation), the extra blood has to be pumped out again. With a mild valve problem there are no symptoms. Later, mitral stenosis and regurgitation cause heart failure, with breathlessness and swelling of the ankles and feet. Mitral stenosis eventually affects the heart rhythm. It changes from its usual regular pattern and becomes irregular and fast. This is called atrial fibrillation. Awareness of this may cause palpitation, sometimes felt as a fluttering feeling in the chest. When it happens the symptoms of heart failure may suddenly get worse.

Why does Mitral Valve Disease occur ?

Mitral stenosis is caused by rheumatic fever which is now rare. Mitral regurgitation can also be caused by rheumatic fever but there are other causes too. Diseases of the left ventricle may affect the valve by damaging the papillary muscles or altering the valve structure. Coronary artery disease (due to hardening of the arteries) may do this by causing a heart attack (or myocardial infarction). Heart muscle disease (cardiomyopathy) can do the same. The cusps and chordae may deteriorate. This is called mitral valve prolapse. This usually occurs alone, but may be part of a rare condition called Marfan’s syndrome where there are also abnormalities of other parts of the body. Infection on an abnormal mitral valve leads to a disease called infective endocarditis, and can occur even if the valve abnormality is minor. This usually causes a worsening of any previously leaking valve.

Treatment Involved for Mitral Valve Disease

DIAGNOSIS The diagnosis is usually made at a medical examination, but tests such as chest x-rays and electrocardiograms (ECGs) are helpful. A test, called echocardiography, uses high frequency sound (ultrasound) to confirm the diagnosis and to judge how severe it is. The ultrasound comes from a microphone-like instrument, called a transducer, placed on the chest. The sound is reflected off the heart, back to the transducer, where it is converted into electrical impulses which are displayed as a TV picture. A similar method (Doppler) measures the blood flowing through the valve. It is a good way of measuring valve narrowing or leaking. If there is doubt about the severity, a cardiac catheterization is needed. This involves threading small tubes, called catheters, into the heart from blood vessels in the arm or groin. It is usually needed before an operation, to assess the valve and also the coronary arteries. TREATMENT A mild valve abnormality needs no treatment. The symptoms of heart failure (breathlessness and ankle swelling) need medication called diuretics and, for mitral regurgitation, ACE inhibitors. These get rid of excess fluid that the kidneys retain and you pass more urine. If this treatment is not enough or if the heart is getting worse, valve surgery may be needed. A narrowed valve can sometimes be opened up and a leaking valve repaired, but frequently the valve must be replaced. If the heart rhythm changes to atrial fibrillation, treatment is needed to slow the heart. Usually, the drug digoxin is used. With atrial fibrillation, blood dots may form in the left atrium and travel to other parts of the body. They can cause damage such as strokes. The clotting risk must then be reduced with a blood-thinning medicine called warfarin. This treatment is called anticoagulation and it must be started either before, or immediately after the heart rhythm changes. Anticoagulation may be needed for the rest of your life.

During Treatment for Mitral Valve Disease

Regular check-ups are important to make sure that the valve defect and its effect on the heart's pumping does not become dangerous. Should breathlessness occur or get worse, seek advice from your doctor. Treatment may need to be started or increased. It is especially important to seek help if you develop rapid palpitation. This may cause a sudden increase in breathlessness even at rest. If germs get into the bloodstream there is a risk of getting infection on an abnormal mitral valve. This is called infective endocarditis and it can happen even if the valve defect is minor. Germs get into the blood through the gums after dental treatment or with other operations or investigations which use instruments passed inside the body. Prevention, by taking antibiotics, is better than cure. They are given, usually by mouth, an hour before dentistry or an operation. You should carry a card with all the details. Show it to any doctor or dentist treating you.

If Mitral Valve Disease is Left Untreated

If valve surgery is left too late it may not provide the expected improvement. Regular checks are essential to ensure that your heart condition is not getting worse. If the heart rhythm is allowed to change without the right treatment there is a risk of blood clots causing strokes or other serious damage.

Effects on Family of Mitral Valve Disease

You should be able to lead a relatively normal life, although you may have to take less exercise. This should not affect your family or friends unduly.