Mitral valve prolapse (also known as “click murmur syndrome” and “Barlow’s syndrome”) is the most common heart valve abnormality, affecting five to ten percent of the world population.

Your mitral valve is located between the left atrium and the left ventricle of the heart and has 2 leaflets as well as some attachments to your left ventricle. When the ventricles contract, the mitral valve leaflets close snugly and prevent the backflow of blood from the left ventricle into the left atrium. When the ventricles relax, the valves open to allow oxygenated blood from the lungs to fill the left ventricle.

In patients with mitral valve prolapse, the mitral valve has started to “leak”. When the left ventricle contracts the valve leaflets prolapse (flop backwards) into the left atrium. This usually allows for some leakage of blood back through the valve opening (mitral regurgitation):