Left atrial strain by two-dimensional and three-dimensional echocardiography are independent predictors of improved ejection fraction and outcomes in heart failure patients with reduced ejection fraction: a prospective cohort study

Left atrial (LA) dysfunction is associated with adverse outcomes in heart failure, but the comparative prognostic value of LASr (Left Atrial Strain reservoir) measured by two-dimensional (2DE) and three-dimensional echocardiography (3DE) for predicting left ventricular ejection fraction (LVEF) recovery remains uncertain. This prospective single-center cohort included 126 consecutive patients hospitalized with newly diagnosed heart failure with reduced ejection fraction (HFrEF). Baseline 2DE- and 3DE-derived LASr were assessed. LVEF was reassessed after 6 months, and patients were classified as having heart failure with improved ejection fraction (HFimpEF) or persistent HFrEF. Sequential multivariable logistic regression and likelihood-ratio tests evaluated independent and incremental predictive value. Long-term outcomes were assessed during follow-up. At 6 months, 36 patients (28.6%) had HFimpEF. After adjustment for age, sex, log-transformed NT-proBNP, baseline LVEF, LV end-systolic volume index, LV global longitudinal strain, LA volume index, and systolic pulmonary artery pressure, both LASr by 2DE (OR per 1% increase, 1.25; 95% CI, 1.08–1.45; p = 0.004) and LASr by 3DE (OR, 1.30; 95% CI, 1.11–1.53; p = 0.001) were independently associated with HFimpEF when evaluated separately. Adding LASr by 3DE to a model containing LASr by 2DE significantly improved model fit (ΔLR χ²=5.33; p = 0.021), whereas adding LASr by 2DE to a model containing LASr by 3DE did not. When both were included, only LASr by 3DE remained independently associated with HFimpEF. In survival analysis, Kaplan–Meier curves demonstrated that baseline LASr by 2DE < 16.5% and LASr by 3DE < 15.5% (below median) were significantly associated with lower cumulative survival (Log-rank p = 0.019 and p = 0.004, respectively). Both LASr by 2DE and 3DE predicted LVEF recovery, but LASr by 3DE provided incremental prognostic value beyond 2DE and may improve risk stratification in newly diagnosed HFrEF.