Is the mitral valve a crescent-shaped valve
Different types of heart valve defects
The disease of a heart valve leads either to a narrowing (stenosis) or a leak (insufficiency). If a diseased (calcified) heart valve can neither open nor close properly, one speaks of a combined heart valve defect.
Normal functioning of the mitral valve
It is the inlet valve for the blood flowing from the left atrium (atrium) into the left ventricle. It has an anterior and posterior valve leaflet, its shape resembles a bishop's cap (miter). The valve leaflets open in diastole towards the ventricle and close when the ventricle contracts (systole), so that no more blood can flow back into the left atrium. Tendon threads between papillary muscles in the left ventricle and the valve leaflets, like the struts of an umbrella, prevent the valve leaflets from penetrating into the left atrium.
If the mitral valve leaks, there is mitral valve regurgitation (also known as mitral regurgitation for short).
Mitral valve stenosis
In mitral valve stenosis (abbreviated as: mitral stenosis), the diastolic opening of the valve leaflets is more or less severely restricted. In severe mitral stenosis, the blood from the left atrium backs up into the pulmonary veins. Overcrowding of blood in the lungs causes shortness of breath, the main symptom of mitral stenosis. The left atrium expands as a result of the blood backlog and the increase in pressure, and pulmonary hypertension gradually develops.
Normal functioning of the aortic valve
It is the outlet valve of the left ventricle. It is located between the outflow path of the left ventricle and the beginning of the large body artery (aorta). The aortic valve is designed as a pocket valve with three crescent-shaped pockets. During the ejection phase (systole) of the left ventricle, the pockets are normally pressed against the aortic wall by the blood flowing out. During the relaxation phase (diastole) of the heart, the pockets are filled by the blood flowing back into the aorta. This closes the valve and prevents blood from flowing back into the left ventricle.
Aortic valve insufficiency means a leak in the aortic valve. At the beginning of the relaxation phase (diastole) of the heart, the blood flows in the artery back towards the aortic valve - there it is no longer sufficiently held up because the valve no longer closes tightly.
Aortic valve stenosis (short: aortic stenosis) is a narrowing of the aortic valve. While a healthy aortic valve when open (during systole) has an opening area of 3 - 4 cm2, the opening area is less than 0.75 - 1.0 cm2 in the case of a higher-grade aortic valve stenosis. As a result, the pressure gradient across the aortic valve - that is, the pressure difference between the peak pressure in the left ventricle and the peak pressure in the ascending aorta - can increase from 0 mm Hg with a normal valve to over 100 mm Hg with severe aortic valve stenosis.
Normal functioning of the tricuspid valve
The tricuspid valve is located between the right atrium and the right ventricle. The venous, deoxygenated blood flows from the right atrium through the tricuspid valve into the right ventricle. The valve has three valve leaflets.
Tricuspid valve stenosis
Due to a narrowing of the tricuspid valve, the filling of the right ventricle is disturbed during diastole (relaxation and filling phase of the heart).
Due to a leak in the tricuspid valve, blood flows back from the right ventricle into the right atrium and vena cava during the ejection phase (systole). Doctors distinguish between two forms: acute tricuspid regurgitation (for example as a result of a pulmonary embolism) and chronic insufficiency (for example due to primary pulmonary hypertension).
Normal functioning of the pulmonary valve
The pulmonary valve is located between the right ventricle and pulmonary circulation and - like the aortic valve - has three crescent-shaped valve pockets. During diastole, they prevent the blood from flowing back into the right ventricle.
Pulmonary valve stenosis
A narrowing of the pulmonary valve usually only occurs as a congenital heart valve defect. In addition to valve stenosis, there are also constrictions below (subvalvular) and above (supravalvular) the pulmonary valve.
Pulmonary valve regurgitation
Due to insufficient closure of the pulmonary valve (i.e. the heart valve in the expulsion path of the right ventricle), blood flows back from the pulmonary artery into the right ventricle during diastole. Pulmonary valve insufficiency is also a rare heart defect.
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