Comparison between early shortening of posterior basal loop free wall (top) and ascending (epicardial) LV free wall. Note the widening of crystals (upward trajectory) in LV free wall, while their ongoing shortening and downward trajectory continues in LV epicardial muscle, shown by distance between dotted and hatched lines. This widening event transpires during the phase of deceleration of LV pressure associated with the isovolumetric period.