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, and prevents ‘backwards’ flow during ventricular contraction, so that blood is only permitted to flow into the aorta.

Mitral regurgitation is where blood travels ‘backwards’ from the left ventricle to the left atrium during ventricular contraction – this reduces the amount of blood pumped into the aorta.

As this condition worsens, the left atrium becomes larger to accommodate the ‘extra’ blood and this in turn places increased strain on the vessels in the lung (causing breathlessness).

If severe and untreated, this can lead to heart failure.

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 regurgitation is generally required when it becomes severe and associated with symptoms or heart muscle impairment (even in the absence of symptoms).
• Depending on the appearance of the mitral valve, it may be possible to repair the leaflets, or a valve replacement (tissue or mechanical) may be required in more complex abnormalities