Figure 1.

Myocardial deformation contains three strain components: circumferential, radial and longitudinal of the left ventricle; longitudinal (a), radial and circumferential (b). The direction of the deformation in diastole is shown as a dashed line and in systole shown as a solid line. The myocardial fibres shorten and lengthen in the three spatial directions: longitudinal, radial and circumferential. The strain can be calculated as the difference between myocardial fibre length (radial, circumferential and longitudinal) at end-diastole and at end-systole divided by the length at end-diastole, and expressed as a percentage (%).¹²