Abnormalities of the heart valves, which may impair blood flow through the heart
- Age, gender, genetics, and lifestyle as risk factors depend on the cause
There are four valves in the heart that ensure that blood flows in one direction by opening to let blood through and then closing tightly when the heart muscle contracts. If a heart valve is damaged, blood flow through it may be restricted or blood may leak backwards because a valve fails to close completely. As a result, the heart then has to work harder in order to pump blood around the body. Disorders of the heart valves often do not cause symptoms, but sometimes they result in tiredness and shortness of breath on exertion. Since the efficiency of the heart is impaired, a severe heart valve disorder may result in chronic heart failure or an arrhythmia, in which the heart beats abnormally. Damaged valves are also more susceptible to infection (see Infective endocarditis).
Some heart valve disorders are present at birth. Heart valves may also be damaged later in life by changes due to aging, infection of the heart lining, or a heart attack (see Myocardial infarction). Rheumatic fever was once a major cause of heart valve damage but is now rare in developed countries such as the UK.
What are the types?
The cusps (flaps) inside a heart valve may not open fully, making the opening too narrow (see Mitral stenosis, and Aortic stenosis). Alternatively, a valve may not form a tight seal when closed, allowing blood to leak back through it (see Mitral incompetence, and Aortic incompetence). In some cases, both stenosis and incompetence occur in the same valve. Mitral valve prolapse is a common, but usually harmless, cause of incompetence; the mitral valve bulges backwards when it is closed and allows slight leakage of blood.
What might be done?
Valve disorders may be diagnosed in a routine examination or after symptoms have developed. Your doctor listens for sounds, called heart murmurs, that are made by turbulent blood flow through abnormal valves. You may have an ECG to check the electrical activity of the heart. Chest X-rays may also be taken, and the imaging technique echocardiography may be used to view the interior of the heart and its blood flow.
If treatment is needed, you may be given drugs to control the heartbeat or relieve the symptoms. In severe valve disorders, surgery may be needed to repair or replace the valve (see Heart valve replacement). An abnormal or replacement heart valve is more susceptible to infection (see Infective endocarditis) than a normal valve. Your doctor will advise you to maintain good oral hygiene to reduce the risk of infection. You will also be told how to recognize symptoms of infective endocarditis so that treatment can be given promptly if it does develop.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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