Mitral Stenosis: Definition

MS is where mitral valve narrowing restricts the flow of blood from the left atrium into the ventricle impairing left ventricular filling. Symptoms may not occur until the valve area is reduced to 1-1.5cm2 (normal 4-6cm2).

Anatomy of the mitral valve

Once the valve area is <1cm2, the patient almost always has significant heart failure and very poor survival rates without surgery [8].

The causes of mitral stenosis are shown in Table 1.

Table 1
Table 1: Causes of mitral stenosis
Acquired Other rare causes are:
  • Rheumatic heart disease (commonest cause worldwide)
  • Infective endocarditis
  • Calcification of the mitral annulus
  • SLE
  • Carcinoid syndrome
  • Left atrial myxoma can cause left atrial obstruction and mimic MS
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