Additionally, recently, speckle-tracking echocardiography (STE) is a cardiac ultrasound examination method used to assess LV deformation over time by following speckles, which are referred to as ultrasound echoes.5) STE is divided into two-dimensional (2D) and three-dimensional (3D) STE. 2D STE is limited to the 2D plane movement of speckles and ignores the characteristics of 3D cardiac wall motion. So, more recently, 3D STE is rapidly advancing as an important technique for accurately and comprehensively evaluating myocardial function by overcoming the limitations of 2D STE and analyzing the wall motion of the 3D left ventricle.

Recently, the global longitudinal strain (GLS) measured by STE represents a change in length between systole and diastole, serving as a surrogate measure of LV contractility. Furthermore, GLS is not influenced by angles and is less dependent on loading conditions (changes in preload or afterload). Furthermore, GLS has been demonstrated to be more sensitive in detecting subclinical cardiac dysfunction compared to LVEF.6) Generally, it has been reported that GLS impairment is more commonly observed in intensive care unit patients who have experienced septic shock compared to those without septic shock. Therefore, 3D and 2D strain images can be valuable additional imaging parameters as useful clinical tools for monitoring the progression of myocardial deformation.7)8)

However, assessing GLS may be limited in critically ill patients at bedside due to the need for good image resolution, endocardial visualization, and a high frame rate.

Despite these limitations, it is known that abnormal LV strain occurring during sepsis (whether too high or too low) is associated with significant cardiovascular events in patients with pre-existing cardiac conditions.9)

Furthermore, in septic shock patients, diastolic function may be impaired. However, the assessment of this parameter should be performed in conjunction with the evaluation of LV filling pressures, as diastolic function can vary depending on the loading conditions. In addition, atrial fibrillation or tachycardia caused by sepsis can worsen diastolic dysfunction, and this can impose limitations on the use of diastolic function as a diagnostic measure.

Additionally, previous studies have reported that right ventricular dysfunction may coexist in 50% of patients with severe sepsis and septic shock.10) According to the American Society of Echocardiography criteria, right ventricular dysfunction can be defined based on the following criteria: tricuspid annular systolic excursion (TAPSE) <16 mm, tricuspid annular lateral systolic velocity (TDI Str’ wave) <15 cm/s, and right ventricular FAC <35%. Due to the shape of the right ventricle, there are challenges in geometric assessment, and the evaluation of the right ventricle using TAPSE or S wave is limited to longitudinal assessment. Currently, STE may be a promising tool for detecting right ventricular dysfunction, but the associations between right ventricular strain and TAPSE or other parameters used to assess right ventricular function are moderate. Additional research is necessary to determine whether right ventricular dysfunction is a result of abnormal loading conditions or an inherent issue with myocardial function in the future.10)

Despite these limitations, some previous studies have shown that isolated right ventricular dysfunction may be associated with worse survival rates.10)

In summary, the 3D STE and 2D echocardiography for LV and right ventricular assessment are standard tests for patients with SCM, and these tests can assist in predicting the patient’s prognosis.