Normal mitral valve cross section on echocardiography
RV: Right ventricle; IVS: Interventricular septum; LVPW: Left ventricular posterior wall
This parasternal short axis echocardiogram is a cross section of the left ventricle at the mitral valve level. Both anterior mitral leaflet (AML) and posterior mitral leaflet (PML) are seen well. Three scallops posterior leaflet are called P1, P2 and P3. Correspondingly anterior mitral leaflet is divided into three virtual regions: A1, A2 and A3. Scallops are best visualised by three dimensional transesophageal echocardiography. Read Carpentier nomenclature of mitral leaflet scallops.
The leaflets of normal mitral valve are thin, pliable, non calcified and open well in diastole, with valve area of 4-6 square centimeters. Opening of a normal mitral valve may be reduced in low cardiac output states, even without significant mitral stenosis. In mitral stenosis, the valve leaflets will be grossly thickened with anterior leaflet doming in diastole and posterior leaflet moving paradoxically due to commissural fusion.