Back to basics: can a standard 12-lead ECG predict acute pulmonary edema in HFrEF? the superiority of ST-segment depression over LVEF and QRS duration

Background

Acute pulmonary edema (APE) is a life-threatening manifestation of heart failure (HF). While electrocardiographic (ECG) abnormalities are prevalent in HF patients, specific ECG markers that predict the development of APE in patients with reduced ejection fraction (HFrEF) remain under-investigated.

Purpose

We aimed to evaluate the relationship between admission ECG parameters, clinical characteristics, and the presence of APE in a cohort of HFrEF patients.

Methods

We conducted a retrospective analysis of 605 patients with HFrEF presenting to the emergency department. The study population was stratified into two groups: those presenting with APE (n=167) and those without APE (n=438). Baseline demographics, comorbidities, laboratory data (including NT-proBNP), echocardiographic parameters, and surface ECG findings (ST-segment changes, bundle branch blocks, left ventricular hypertrophy, and QRS duration) were compared. Multivariable logistic regression analysis was performed to identify independent predictors of APE, adjusting for age, sex, LVEF, diabetes mellitus, and hypertension.

Results

Patients presenting with APE were significantly older (71.7±10.5 vs. 67.6±12.0 years, p<0.001) and had a higher prevalence of diabetes mellitus (53.3 vs. 42.0%, p=0.013) compared to those without APE. NT-proBNP levels were markedly higher in the APE group (median 6959 vs. 2726 pg/mL, p<0.001), and renal function was significantly worse (p=0.002). Notably, there was no significant difference in Left Ventricular Ejection Fraction (LVEF) between the APE and non-APE groups (24.2 vs. 25.3, p=0.115).

Regarding ECG parameters, ST-segment depression was observed significantly more frequently in the APE group (15.0 vs. 6.9, p=0.002). Conversely, structural and conduction abnormalities, including Left Bundle Branch Block (LBBB), Right Bundle Branch Block (RBBB), Left Ventricular Hypertrophy (LVH), and QRS duration, did not differ significantly between the groups.

In multivariable logistic regression analysis, ST-segment depression emerged as a robust independent predictor of APE (Adjusted OR: 2.225; 95% CI: 1.251–3.957; p=0.007), alongside diabetes mellitus (OR: 1.631, p=0.011) and age (OR: 1.035, p<0.001). LVEF was not an independent predictor of APE.

Conclusion

In patients with HFrEF, admission ST-segment depression is a strong, independent predictor of acute pulmonary edema, increasing the risk more than two-fold. In contrast, neither baseline LVEF nor chronic conduction abnormalities (such as LBBB or prolonged QRS) discriminated between patients with and without edema. These findings suggest that ST depression likely reflects acute hemodynamic strain or subendocardial ischemia, which acts as a precipitant for pulmonary edema regardless of the baseline systolic function.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.