Mitral Valve

The mitral valve (bicuspid valve) is the heart valve that separates the left atrium from the left ventricle. The mitral valve is also known as the left atrioventricular valve. The mitral apparatus is made up of three elements:A ring;A veil consisting of two valves;A sub-valvular apparatus, consisting of cords and pillars.During diastole, in the open position, the mitral valve has a funnel-shaped appearance, with a diameter of 32 mm at the ring and 26 mm at the apex of the valves. The normal mitral surface area in adults is 4 to 6 cm2. The mitral valve has two very distinct roles:It ensures permeability and continence between the left atrium and the left ventricle during the various movements of the cardiac revolution (systole and diastole);It plays an active part in left ventricular contraction through the action of the muscular pillars and cords. The mitral valve acts as a non-return valve between the left atrium and the left ventricle, imposing a one-way flow of blood. In the left heart, during a cardiac revolution, blood can flow normally from the left atrium to the left ventricle, then from the left ventricle to the aorta. During ventricular diastole (passive filling) and atrial systole (active filling), the valve must open sufficiently to allow blood to flow from the left atrium to the left ventricle;During ventricular systole, the valve must close correctly to prevent blood from flowing retrogradely from the ventricle to the atrium. The blood contained in the left ventricle must be expelled to the aorta through the aortic valve.