TY - JOUR T1 - The extents of mitral leaflet opening and closure are determined by left ventricular systolic function JF - Heart JO - Heart SP - 126 LP - 128 DO - 10.1136/hrt.2003.014373 VL - 90 IS - 2 AU - S Kaul Y1 - 2004/02/01 UR - http://heart.bmj.com/content/90/2/126.abstract N2 - The extent of opening of the mitral leaflets in diastole and their degree of closure during systole are mediated either indirectly or directly through the force of left ventricular systole. Therefore measures of incomplete opening or incomplete closure both reflect left ventricular systolic function In order to appreciate the spatiotemporal relation between the mitral leaflets and mitral annular plane during the cardiac cycle, one has to begin with the “neutral” position of the mitral leaflets in relation to the mitral annular plane. This can be defined as the position of the mitral leaflets when there is no pressure difference between the left atrium and left ventricle. If the annulus were a Euclidean plane, the neutral position of the leaflets would be in the plane of the annulus (fig 1A). Because the mitral annulus is saddle shaped1 the neutral position of the mitral leaflets is not in the Euclidean plane but is caudal to it (fig 1B). This position results from the tension on the leaflets by the saddle shaped annulus which affords them a spring-like quality so that a greater force is required to move them cephalad towards the mitral annular plane than to move them caudally further into the left ventricular (LV) cavity (fig 1B). Figure 1 Effect of the shape of the mitral annulus on the neutral position of the mitral leaflets. If the annulus is in the Euclidean plane, the leaflet coaptation plane will remain within that same plane (A). When the annulus is saddle shaped, the leaflet coaptation plane will move caudally (B). A greater force is required to move the leaflets cephalad towards the mitral annular plane (large arrow) than to move them caudally further into the left ventricular cavity (small arrow). AML, anterior mitral leaflet; Ao, aorta; LA, left atrium; LV, … ER -