Types Of Mitral Valve Disease
There are 3 types of mitral valve disease: mitral stenosis (MS), mitral regurgitation (MR) and mitral valve prolapse (MVP). Mitral stenosis and mitral regurgitation occur most commonly due to rheumatic valvular heart disease, whereas MVP has a familial incidence. All three mitral diseases give rise to shortness of breath as a symptom. Mitral stenosis causes abdominal and leg swelling due to right heart failure. Mitral regurgitation cause shortness of breath on exertion and at rest due to left heart failure and eventually cause congestive cardiac failure. The commonest symptoms in mitral valve prolapse are atypical chest pain under the breast or on the left side of the sternum.
There are mainly three types of mitral valve disease
- Mitral stenosis (MS)
- Mitral regurgitation (MR)
- Mitral valve prolapse (MVP)
Mitral stenosis (MS) is the narrowing of the mitral valve lumen. This leads less blood flow from the left atrium to left ventricle. There are many causes for mitral stenosis such as:
- Rheumatic valvular heart disease – this is the most common cause, mitral valve is affected in 90% of rheumatic valvular heart disease. However, the incidence of rheumatic of rheumatic fever is gradually decreasing now. This is more common in females.
- Congenital mitral stenosis
- Mitral stenosis occurring in elderly people due to calcification and fibrosis of the valve.
In an healthy individual the mitral valve orifice is about 5cm2, when the valve orifice is reduced to 2cm2 its moderately stenosed, 1cm2 it’s severely stenosed. With the mitral stenosis the left atrial pressure increases and cause left atrial dilatation and hypertrophy. This increases the pulmonary vessels pressure and cause pulmonary edema pulmonary hypertension. That causes right heart failure (RHF).
Initially there won’t be any symptoms, with the development of pulmonary venous hypertension and recurrent bronchitis shortness of breath and a productive cough with blood tinge occur. With the development of RHF lower limb and abdominal swelling occur.
Mitral regurgitation (MR) is the leak for blood through the mitral valve to the left atrium. There are many causes for MR such as:
- Rheumatic valvular heart disease – 50% of mitral regurgitation is due to this
- Aortic valve disease
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Ischemic heart disease
- Hypertensive heart disease
- Infective endocarditis
Mitral regurgitation cause some amount if blood to regurgitate back to the left atrium. This dilates the left atrium due to increase volume. With time it increases the pressure in the left atrium then in the pulmonary veins which leads to pulmonary edema and pulmonary hypertension. Since a proportion of blood is regurgitated the cardiac output reduces in each cycle which leads to left ventricle enlargement to increase the cardiac output.
The symptoms occur very late in the disease, any patients stay without any symptoms with mitral regurgitation. With the development of pulmonary edema, pulmonary hypertension and left hear failure shortness of breath occur on exertion and on rest. Fatigue and lethargy occurs due to reduced cardiac output. Palpitations can also be felt. At the late stage right heart failure also develops which gives rise to abdominal and leg swelling. With time congestive heart failure (left and right heart failure) occurs.
Mitral Valve Prolapse
This is also known as Barlow’s syndrome or floppy mitral valves. This can be due to enlarged mitral valve leaflets, an enlarged mitral valve annulus or dysfunction of the papillary muscle contraction. Commonly seen in young females with a family history and known to have a familial incidence.
The exact cause of mitral valve prolapse (MVP) is unknown but it is associated with Marfan’s syndrome, thyrotoxicosis, atrial septal defect, rheumatic heart disease and ischemic heart disease. During the ventricular contraction one of the mitral valve leaflets prolapse into the left atrium. This cause abnormal ventricular contraction and mitral valve regurgitation.
Atypical chest pain is the commonest symptom; the pain is either just below the breast or on the left side of the sternum, its stabbing, aching pain. Palpitations can be felt due to abnormal ventricular contractions.
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