mitral valve mitral valve the mitral valve (/ˈmaɪtrəl/), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. it has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. the heart valves are all one-way valves allowing blood flow in just one direction. the mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles. mitral valveanterior (frontal) view of the opened heart. white arrows indicate normal blood flow. (mitral valve labeled at center right.)base of ventricles exposed by removal of the atria. (bicuspid (mitral) valve visible at bottom left. tricuspid valve visible at bottom right.)detailsidentifierslatinvalva atrioventricularis sinistra,valva mitralis,valvula bicuspidalismeshd008943ta98a12.1.04.003ta23987fma7235anatomical terminology in normal conditions, blood flows through an open mitral valve during diastole with contraction of the left atrium, and the mitral valve closes during systole with contraction of the left ventricle. the valve opens and closes because of pressure differences, opening when there is greater pressure in the left atrium than ventricle and closing when there is greater pressure in the left ventricle than atrium. in abnormal conditions, blood may flow backward through the valve (mitral regurgitation) or the mitral valve may be narrowed (mitral stenosis). rheumatic heart disease often affects the mitral valve; the valve may also prolapse with age and be affected by infective endocarditis. the mitral valve is named after the mitre of a bishop, which resembles its flaps. structure operative view of the mitral valve with a chordal rupture "fail" of the anterior leaflet 3d medical animation still shot of mitral valve prolapse