English: Animation illustrating the myocardial sheets motion proposed by LeGrice et al. 2. On the cross-section of LV, myocardial sheets with the width of 4 myocytes separated by cleavage planes of loose connective tissue could be identified. When myocardial cells contract, the myocardial sheets slide on each other causing shear strain. The myocardial sheets approached the LV endocardium obliquely from the apical direction, becoming nearly parallel to the endocardial surface in LVPW while, in the IVS, the sheets approached the LV endocardium rather vertically from the opposite direction. This difference in sheets orientation at end-diastole would cause difference in systolic radial strain between IVS and LVPW. Myocardial sheets slide relative to each other and change orientation from end diastole to end systole, and this sliding (shearing) motion pushes the endocardium towards the LV cavity, which is more prominent in LVPW than IVS. As a result, both radial normal strain and shear strain are significantly larger in LVPW than in IVS.