Mitral Valve Prolapse

The mitral valve lies between the left atrium and left ventricle. It, like the other heart valves, prevents blood from flowing backward. When the blood pushes forward against it, the valve opens; when blood tries to push backwards, the valve closes to prevent wrong-way flow. Prolapse occurs when the mitral valve does not close completely when the left ventricle contracts. This usually causes a characteristic sound (a click and/or a murmur). It is usually a harmless, symptomless condition. But it may rarely cause symptoms such as chest pain, fatigue, dizziness, difficulty breathing, or palpitations, and it can lead to endocarditis or tachycardia.