Introduction: Assessing cardiac function is crucial for managing acute dyspnea. In this study we aimed to evaluate displacement of the aortic root (DAR) as a method for calculating ejection fraction (EF) in patients with undifferentiated dyspnea presenting to the emergency department (ED). The primary objective was to compare EF values obtained through DAR with the modified Simpson method, which is considered the criterion reference, within an Indian academic ED.

Methods: We conducted a prospective, cross-sectional study spanning two years (December 2019–December 2021). The study enrolled 110 consecutive ED patients ≥18 years of age, presenting with undifferentiated dyspnea and normal sinus rhythm. Ultrasound-trained investigators measured DAR using M-mode ultrasonography. Experienced echocardiographers, blinded to DAR, determined EF using the modified Simpson method. Statistical analyses included the Shapiro-Wilk test, McNemar test, and the receiver operating characteristic curve.

Results: The mean DAR measurement was 0.781 centimeters, with an average calculated EF of 54.4%. The EF calculated using DAR did not differ significantly from EF calculated using the modified Simpson method. Comparative analysis revealed DAR’s superior sensitivity (86.21%) compared to mitral annular plane systolic excursion (48.28%) and end-point septal separation (45.45%). The DAR method exhibited high accuracy (area under the curve = 0.958) with a cut-off value 0.706 (sensitivity 88.7%, specificity 93.1%).

Conclusion: Evaluating displacement of the aortic root to calculate ejection fraction in undifferentiated dyspnea demonstrated high accuracy, sensitivity, and agreement with the modified Simpson method, which is considered the criterion reference. Its simplicity and non-invasiveness makes it a valuable initial screening tool in emergency settings, with the potential to reshape cardiac assessment approaches and optimize patient care pathways in the ED.