The mitral valve consists of a large anterior leaflet and a smaller posterior leaflet. It allows the passage of blood from the left atrium to the left ventricle.

Mitral stenosis is a condition that leads to progressive thickening and restriction of the mitral leaflets that make it more difficult for blood to flow into the left ventricle. The two most common causes of mitral stenosis are rheumatic heart disease (long-term consequence of childhood rheumatic fever), and mitral annular calcification (usually seen in older patients, advanced kidney disease – particularly if on dialysis).

As the condition worsens, the pressure in the left atrium becomes higher to ‘force’ the blood into the left ventricle. Eventually, this puts strain on the blood vessels in the lung circulation and right-side of the heart.

Exertional breathlessness is the most common symptom

Later in the course of disease patients may develop arrhythmias (atrial fibrillation) which significantly increase the risk of stroke.

• Invasive treatment for mitral stenosis is required when it becomes severe (either at rest or with exercise).
• Depending on the appearance of the mitral valve and age of the patient, some people may be offered a balloon valvuloplasty.
• Many patients will require a valve replacement, particularly is there is a lot of ‘calcium’ in the leaflets / supporting structures