What is the mitral valve?
It is called the mitral valve because it resembles a mitre, a kind of ceremonial hat that is typically worn by traditional high ranking religious officials. It is called the bicuspid valve because the valve consists of two flaps known as leaflets or cusps.
It is called the left atrioventricular valve because of its central position in relation to the heart’s ventricles and atria. The tricuspid valve, another of the four heart valves, is also an atrioventricular valve.
What does the mitral valve look like?
The average size of a mitral valve in humans is five square centimeters. The two leaflets (the posterior leaflet and more prominent anterior leaflet) of the valve protect its opening – which is bordered by a tissued ring called the mitral annulus – and give the valve its ‘mitral’ shape.
Attached to each leaflet of the bicuspid valve is a series of stiff, cord-like tendons of varying thickness (the chordae tendinae) that attach to anterior and posterior papillary muscles in the left ventricle wall. These “heart strings” cause the leaflets to coapt or meet neatly and tightly when the valve closes during left ventricular contraction, preventing prolapse, regurgitation, and malfunction.
What is the mitral valve’s function? How does it work?
The mitral bicuspid valve has a vital role in the heart. It regulates blood flowing between the left atrium (the top left chamber) and the ventricle (the bottom left chamber).
In normal function, oxygenated blood enters from the pulmonary veins and accumulates in the atrium. As it fills up, the two mitral flaps are pushed open, blood passes through to a relaxed left ventricle, and then the left atrium contracts, pushing more blood into the ventricle. Next, the left ventricle contracts, the mitral valve shuts tightly, and blood pushes through the aortic valve into the aorta.
What happens when the mitral valve doesn’t function properly?
If the mitral valve or its structures are damaged, defective, or abnormal in some way, the valve can malfunction, causing various symptoms and complications.
The abnormality may be due to a congenital defect or a disease, or it may occur as a result of natural aging degeneration. Mitral regurgitation, mitral valve prolapse, and mitral stenosis are three common types of heart valve disease that affect the bicuspid. Mitral atresia occurs less often.
People with diseased valves can usually be treated successfully. However, the prognosis depends largely on the cause and severity of the problem and the patient’s specific circumstances.