Echocardiographic assessment of left ventricular systolic function: from ejection fraction to torsion

Assessment of left ventricular (LV) systolic function is the cornerstone of the echocardiographic examination. There are many echocardiographic parameters that can be used for clinical and research purposes, each one with its pros and cons. The LV ejection fraction is the most used one due to its feasibility and predictability, but it also has many limits, related to both the imaging technique used for calculation and to the definition itself. LV longitudinal function is expression of subendocardial fibers contraction. Because the subendocardium is often involved early in many pathological processes, its analysis has been a fertile field for the development of sensitive parameters. Longitudinal function can be evaluated in many ways, such as M-mode echocardiography, tissue Doppler imaging, and speckle tracking echocardiography. This latter is a relatively new tool to assess LV function through measurement of myocardial strain, with a high temporal and spatial resolution and a better inter- and intra-observer reproducibility compared to Doppler strain. It is angle independent, not affected by translation cardiac movements, and can assess simultaneously the entire myocardium along all the three-dimensional geometrical (longitudinal, circumferential, and radial) axes. Speckle tracking echocardiography also allows the analysis of LV torsion. The aim of this paper was to review the main echocardiographic parameters of LV systolic function and to describe its pros and cons.