The mitral valve is the valve that allows oxygenated blood into the left ventricle from the left atrium.
Valves direct the flow of blood through the heart's chambers.
Blood returning to and leaving from the heart flows in and out of these valves. When closed, the mitral valve prevents a backflow of blood, and when open, permits the blood to move forward to its next destination. When a valve fails to close properly, as is the case in a common disorder called mitral valve prolapse, there is a regurgitation or backflow of blood. The majority of individuals with this condition do not have symptoms. When symptoms do occur, they include palpitations, fatigue, chest pain, and dizziness.