Speckle-Tracking analysis of left ventricular systolic function in the intensive care unit

Speckle-tracking analysis is a new available tool in order to assess left ventricular function in cardiology. Its novelty relies on the technological ability to track natural acoustic markers (known as speckle) within the myocardium during the cardiac cycle. This technology allows the evaluation of myocardium strain during systole and diastole. To date, global longitudinal strain (GLS) has been extensively studied in cardiology. It is now well established that GLS is more sensitive than left ventricular ejection fraction with 2D echocardiography in detecting systolic function impairment. It is also superior to left ventricular ejection fraction in the prediction of major cardio-vascular events. In the intensive care unit (ICU) setting, data are scarce. In experimental model and human studies in septic shock, speckle-tracking analysis suggests that GSL is impaired along with preserved left ventricular ejection fraction. Recent data also suggest that GLS impairment could predict in-ICU mortality in septic shock. In severe subarachnoid haemorrhage patients, speckle-tracking analysis could be more sensitive in detecting stress cardiomyopathy. However, there are many gaps to fill in the critically ill patient. For instance, the influence of mechanical ventilation on GLS is not fully elucidated, and there are, to date, too few data to exactly assess potential GLS alterations on the patient's outcome. Nonetheless, this new tool provides objective and sensitive data with acceptable intra and inter-observer variability and may be of primary interest in the evaluation of left-ventricular systolic function in the ICU.