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Heart Valve Disease
The heart valves primary function is to ensure that blood flows in
one direction through the heart and cardiovascular system. Any form of
heart valve disease interferes with blood flow to and from the heart.
Valvular disorders that are acquired can be a result of acute
conditions, such as infective endocarditis, or chronic conditions such
as rheumatic heart disease. Rheumatic heart disease is the most common
cause of heart valve disease.
Acute myocardial infarction (heart attack) can also damage heart valves,
causing tearing, ischemia (tissue death), or damage to the papillary
muscle that affects valve leaflet function. The heart valves may also be
affected by congenital heart defects and many times symptoms are not
apparent until adulthood. As a person gets older their heart structure
and function can change increasing the risk for valvular disease.
There are two major types of heart valve disease: stenosis and
regurgitation. Stenosis occurs when the valve leaflets cannot completely
open or close because they are fused together and the valve opening
narrows and becomes rigid. Calcium deposits as well as scarring of the
valves from endocarditis or heart attack can cause stenosis. Stenotic
valves impede the forward flow of blood, decreasing cardiac output
because of impaired ventricular filling or ejection and stroke volume.
Backflow also occurs because the valves do not completely close.
Regurgitation is a condition where the regurgitant valves are unable to
close completely. These types of valve are also referred to as
insufficient or incompetent valves. This allows a backflow of blood, or
regurgitation, back through the valve the blood just passed through.
Regurgitation can result from a deformity or erosion of valve cusps
caused by vegetative lesions of bacterial endocarditis, by the scarring
or tearing from a heart attack, or by cardiac dilation. As the heart
enlarges, the valve annulus, which is the supporting ring of the valve,
is stretched and the valve edges no longer meet to allow complete
closure.
Smooth blood flow through the heart is disrupted by heart valve
disorders. As the flow becomes turbulent a murmur is created which is a
characteristic symptom of valve disease. This is usually the first sign
that there is indeed a problem with the heart and vascular system.
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