Figure 1.

A – Schematic representation of longitudinal, radial and circumferential strain. Basal and apical rotation are also depicted, from which twisting and untwisting are calculated. Echocardiographic apical and short axis imaging planes are represented in gray. B – While the imaging plane is maintained in a fixed position, the heart is moving through the plane during the cardiac cycle, due to contraction, relaxation, translational, rocking or swinging motion, or even dyssynchrony (LS – longitudinal strain, RS – radial strain, CS – circumferential strain, CBR – clockwise basal rotation, CCAR – counter clockwise apical rotation)