Mitral valve is the valve between the left atrium and the left ventricle. The left atrium is the upper chamber on the left side of the heart. Left ventricle is the lower chamber on the left side of the heart.
What’s the function of mitral valve in a normal heart?
This valve regulates the flow from the left atrium to the left ventricle.
Diseases affecting mitral valve
There are two different types of mitral valve diseases.
Mitral Stenosis – Restricted opening or narrowing of mitral valve leading to pooling of blood in the left atrium. This is referred in medical jargon as MS.
Mitral Regurgitation – Leaky mitral orifice leading to back leak of blood from left ventricle to left atrium. This is referred in medical jargon as MR.
Disease processes that affect the mitral valve:
Mitral valve can be affected by three major disease processes:
Rheumatic mitral valve disease – infective disease that affects young children’s joints in the early phases with predominantly becomes a heart involvement at a later age.
Degeneration of the mitral valve – disease that affects elderly hearts due to wear and tear of the structures of heart.
Myxomatous changes in mitral valve – also known as mitral valve prolapse or MVP, in this disease there is an inherent structural problem of mitral valve leading to abnormal thickening, restricted or excessive movement.
Consequences of these disease processes:
These three different types of mitral valve involvement can lead to different consequences.
Rheumatic mitral valve disease usually presents with mitral stenosis but at times it can present with mitral regurgitation also.
Degenerative mitral valve disease usually presents with mitral regurgitation but in certain percentage of people can present with mitral valve narrowing or mitral stenosis.
Rheumatic Mitral Valve Disease
In rheumatic mitral valve disease there is an infection of the joints. Rheumatic means joints disease. So there is an infection of the joints that will go and afflict the heart because of immune phenomenon. So whenever there is a infective disease that can affect the joints and the heart, that problem is called a rheumatic heart disease. This can be either stenosis or a leaky valve or regurgitation. Usually this rheumatic problems present at a much younger age usually between 20’s to 40’s or at times between 18 to 40 years of age this rheumatic mitral valve disease happens.
Degenerative Mitral Valve Disease
Contrary to rheumatic mitral valve disease, degenerative mitral valve disease is a disease of the ageing. In this disease with wear and tear of heart structures there would be progressive calcium deposition. This process of calcium deposition is called calcification. Calcification means that is like these structures in the heart they become more like a rock because of accumulation of calcium. So whenever there is an accumulation of the calcium that can extend from the base and progress into the valve and causing a limitation of the movement of the valve. So usually when there is limitation of the movement of the valve there will not be adequate closure of both the leaflets. When there is an inadequate contact between the leaflets that will cause a leaky valve. So degenerative mitral stenosis disease usually presents with the regurgitation and very rarely with a stenosis.
Mitral Valve Prolapse (MVP or Barlow Disease)
In a mitral valve prolapse or a myxomatous mitral valve problem the valve leaflets which are normally thin get thickened to more than 4mm or 5mm in thickness. So whenever the valve gets thickened it leads to a gap between the leaflets causing a leaky mitral valve or mitral regurgitation. MVP presents with mitral regurgitation and not mitral stenosis.