Objective To explore the echocardiographic features of critically ill patients with infection, and to evaluate the predictive value of echocardiographic parameters for 28-day mortality and myocardial injury.

Methods Using a single-center prospective cohort design, 120 critically ill patients with infection admitted to the Intensive Care Unit, Jinshan Hospital of Fudan University from January 2024 to January 2025 were enrolled consecutively. According to the severity of infection, patients were divided into the sepsis group (n＝75) and the non-sepsis group (n＝45). Cox proportional hazards models and modified Poisson regression were used to analyze risk factors of 28-day all-cause mortality and myocardial injury. Kaplan-Meier survival curve and log-rank test were used to assess prognosis differences among patients with different ultrasound parameters. ROC curve and area under the curve (AUC) were applied to evaluate the predictive performance of ultrasound parameters, and restricted cubic spline (RCS) model was used to explore nonlinear relationships.

Results The E/e′ ratio was significantly higher in the sepsis group than in the non-sepsis group (P＜0.001), while left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were lower in the sepsis group (P＜0.05). The Cox proportional hazards model found no association between ultrasound parameters and 28-day all-cause mortality. Modified Poisson regression showed that, after adjusting for confounding factors, elevated E/e′ was an independent risk factor of myocardial injury (RR＝1.12, 95% CI 1.07–1.17, P＜0.001). Survival analysis demonstrated that patients with E/e′ ＞10.9 had lower 28-day survival rates (P＝0.02), and the AUC for E/e′ predicting myocardial injury was 0.835. RCS analysis suggested a nonlinear relationship between E/e′ and myocardial injury risk (P＜0.001).

Conclusions E/e′, LVEF, and LVFS have no significant predictive value for 28-day mortality risk in critically ill patients with infections. Elevated E/e′ is an independent risk factor of myocardial injury in such patients, with a nonlinear relationship.