Definition Mitral Valve Stenosis
Mitral valve stenosis is a narrowing of the heart valve that separates the left atrium from the left ventricle. The narrowing of this valve impairs the blood flow between the left atrium and the left ventricle. The normal opening area of the mitral valve is approximately 4-6 cm2.
If this area is reduced by half or more, this is called mitral valve stenosis. Consequently, the filling of the left ventricle is disturbed during the filling phase of the heart action. Since the left ventricle does not fill up sufficiently with blood, the amount of blood ejected into the body’s circulatory system is reduced and an undersupply of vital tissues may occur.
In addition to the reduced ejection into the body’s circulation, the pressure difference between the left atrium and left ventricle increases. The pressure in the left atrium rises and expands like a water balloon (so-called dilatation). The expansion/expansion (dilatation) of the left atrium can also cause blood to back up via the pulmonary vessels into the lungs (pulmonary hypertension).
This means that the right heart has to work more because it also has to pump against the blood backlog in front of the left atrium. If the right heart is stressed over a longer period of time, this can lead to so-called right heart failure. As a consequence of the dilatation of the atrium, some patients suffer from cardiac arrhythmia, especially the so-called atrial fibrillation. Mitral valve insufficiency is a weakness in the closure of the mitral valve. This means that with each pumping action, an additional volume (regurgitaion volume) is pumped into the atrium, which can also cause the left atrium to overstretch, causing symptoms similar to those of mitral valve stenosis.
Frequency of mitral valve stenosis
Mitral valve stenosis is one of the most common acquired heart defects and affects women more frequently than men. Mitral valve stenosis accounts for about 20% of all heart valve defects. The incidence (frequency) of mitral valve stenosis decreased due to the therapy with penicillin, as penicillin was found to be a successful agent against Gram positive pathogens such as streptococci.
3-4% of Europeans suffer from heart valve disease. In patients with mitral valve stenosis, the 5-year survival rate is approximately 45-80%. About half of the patients with mitral valve stenosis and about 20 – 30% with mitral valve insufficiency develop cardiac arrhythmias.
