Representative measurements of tenting height, tenting angles, and tenting area. Panel A shows the measurement of tenting height, tenting area, and tenting angles in a mid-systolic parasternal long axis TTE image. The mitral annulus line is drawn and the distance from the annulus line to the coaptation point (red hatched line) represents tenting height. The posterior and anterior leaflets’ silhouettes are traced from the annular line to the coaptation zone to delineate an area (yellow shading) that represents the tenting area. Tethering angles are measured as the angle that the mitral leaflets create with the mitral annulus line. Panel B shows measurement of apical displacement the anterolateral PM in the apical four chamber view (green line), and Panel C shows measurement of apical displacement the posteromedial PM in the apical three chamber view (pink line). Panel D shows a representative parasternal short-axis mid-ventricular level view in early systole with PM bodies in cross-section. A reference grid of a mid-septal perpendicular chord (white line) spanning the septal insertions of right ventricle myocardium and another line orthogonal to and originating from the center of the first line (hatched white line) was created. The mid-septal perpendicular chord allows posterior displacements of both PMs to be measured (blue lines), as well as to measure lateral displacements of both PMs (yellow lines). Intra-PM distance is shown by the red line. These distances are all elevated in CIMR compared to normal controls. Though there is significant overlap in the distances among symmetric and asymmetric CIMR phenotypes, relative displacements of the posteromedial PM are increased in asymmetric CIMR as compared to the anterolateral PM (see Table 5).