Causes

The mitral valve controls the flow of blood between the upper and lower chambers of the left side of the heart. When your heart is working properly, the mitral valve closes completely when the heart pumps and prevents blood from flowing back into the upper left chamber (left atrium).

But in some people with mitral valve prolapse, one or both of the mitral valve leaflets have extra tissue or stretch more than normal, which causes them to bulge like a parachute into the left atrium each time the heart contracts.

The bulging may keep the valve from closing tightly. In some cases, blood may leak backward through the valve (mitral valve regurgitation).

This may not cause problems if only a small amount of blood leaks back into the left atrium. More severe mitral valve regurgitation can cause symptoms such as shortness of breath, fatigue or lightheadedness.

Another name for mitral valve prolapse is click-murmur syndrome. When a doctor listens to your heart using a stethoscope, he or she may hear a clicking sound as the valve's leaflets billow back, followed by a whooshing sound (murmur) resulting from blood flowing back into the atrium.

Other names to describe mitral valve prolapse include:

• Barlow's syndrome
• Floppy valve syndrome
• Billowing mitral valve syndrome
• Myxomatous mitral valve disease