Eyes can’t see what the mind doesn’t know Assessment of left ventricular systolic function is a core application within critical care echocardiography. This review synthesizes current methodologies and clinical applications of echocardiography in evaluating left ventricular function, emphasizing parameters such as measurements of cardiac dimensions, linear measurements such as E-point septal separation (EPSS), and ejection fraction (EF). It also discusses the calculation of cardiac output, assessment of regional wall motion abnormalities, and myocardial strain. This chapter provides vital information on how the clinician can use this highly useful image set, as their fifth pillar of examination within more advanced hemodynamic management.