Toward diagnostic criteria for left ventricular systolic dysfunction from myocardial deformation

Today, echocardiography is regarded as the clinical gold standard for evaluation of left ventricular (LV) dysfunction. Although a number of quantitative metrics are commonly used in conjunction with specific criteria to diagnose and prognosticate the disease state, part of the assessment of LV function is still qualitative and performed visually. Subjectively derived indices such as the wall motion score index are subject to significant inter-observer variability. Ultrasound-based measures of myocardial deformation (strain) have been available for several years, even in commercially distributed packages, and have the potential to offer a quantitative, objective, and more operator-independent assessment of LV function. However, despite growing evidence on the clinical utility of deformation imaging, a consensus on the meaning, interpretation, and normal ranges of myocardial strain is still lacking, thus preventing routine use of such estimates in clinical practice. In this article, we outline the current status of myocardial strain estimation and address the existing hurdles that must be overcome in order to incorporate this powerful technique into standard clinical assessment of LV function.