Figure 2

Models of symmetric and asymmetric phenotypes of CIMR. Figure 2 depicts two types of CIMR phenotypes, asymmetric (panels A and B) and symmetric (panels C and D), based on the model established in Figure 1, with arrows indicating the forces which have changed in magnitude. An inferoposterior myocardial infarction (black area in panels A and B) causes local outpouching of the LV myocardium in a posterior direction, which displaces the posteromedial PM and increases tethering forces exerted on the leaflets. In addition, there is less LV closing force (green arrows) and decreased basal clockwise rotation force (blue arrow). Due to posterior > anterior leaflet tethering and pseudoprolapse, there is posteriorly directed eccentric MR (green shaded area). Global LV dilatation and spherical remodelling (indicated by black areas of panels C and D) displaces both PMs with posterior, lateral, and apical vectors exerted on the mitral leaflets (orange arrows). Aggregate LV closing force is reduced (green arrow). The enlarged mitral annulus contributes to higher passive tethering force on the leaflets (red arrows) and less mitral annular contraction (red arrows). The net result is apical displacement of the mitral leaflets and their coaptation zone, with central MR.