Diagnostic Value of Fractional Shortening and E-Point Septal Separation in Predicting Left Ventricular Longitudinal Strain in Dyspneic Emergency Patients

<i>Background and Objectives:</i> Dyspnea is a common chief complaint in the emergency department. While global longitudinal strain and biplane ejection fraction are reliable markers of left ventricular systolic function, their assessment requires advanced echocardiographic tools and expertise. Simple point-of-care ultrasound parameters, such as E-point septal separation and fractional shortening may serve as practical alternatives for rapid bedside evaluation. <i>Materials and Methods:</i> EPSS and FS were measured by emergency physicians using POCUS, while reference EF and GLS were obtained by cardiologists via transthoracic echocardiography. Correlation analyses, receiver operating characteristic curves, and agreement statistics were used to evaluate the diagnostic accuracy of EPSS and FS for predicting reduced EF (<50%) and GLS (<16%). <i>Results:</i> Reduced EF was present in 54.0% and reduced GLS in 55.6% of patients. EPSS showed strong negative correlations with EF (ρ = -0.834) and GLS (ρ = -0.782), while FS correlated positively with EF (ρ = 0.773) and GLS (ρ = 0.714), all <i>p</i> < 0.001. ROC analysis demonstrated excellent diagnostic accuracy of EPSS (AUC = 0.922 for EF; 0.949 for GLS) and good accuracy of FS (AUC = 0.874 for EF; 0.865 for GLS). Optimal cut-off values were EPSS ≥ 7.0 mm and FS ≤ 25%. Agreement with reference TTE was good for EPSS (κ = 0.676 for EF; κ = 0.738 for GLS) and moderate for FS (κ ≈ 0.56). <i>Conclusions:</i> Both EPSS and FS measured by POCUS provide reliable estimates of left ventricular systolic function in dyspneic ED patients, with EPSS demonstrating superior diagnostic performance.