B-typeQuery natriuretic peptides, particularly N-Terminal pro B-type natriuretic peptide (NT-proBNP), have been identified as potential biomarkers in heart failure (HF) prognosis. However, their predictive value for poor outcomes across varying ejection fraction (EF) categories remains under-explored. This study aims to evaluate the predictive value of NT-proBNP for poor outcomes in HF patients stratified by ejection fraction (HFpEF, HFmrEF, HFrEF) and assess the prognostic role of right ventricular global longitudinal strain (RV GLS) in conjunction with NT-proBNP across these subgroups. A prospective cohort study was conducted at the Cardiovascular Department, Faculty of Medicine, Zagazig University, Egypt, between June 2022 and June 2023. A total of 100 HF patients were classified into three EF groups: Group A (heart failure with preserved ejection fraction (HFpEF), LVEF ≥ 50%), Group B (heart failure with mid-range ejection fraction (HFmrEF), LVEF 41–49%), and Group C (heart failure with reduced ejection fraction (HFrEF), LVEF ≤ 40%). NT-proBNP was measured in all participants. NT-proBNP levels were significantly higher in Group C (HFrEF) compared to Group B (HFmrEF) and Group A (HFpEF) (p1 = 0.008, p2 = 0.046). The optimal NT-proBNP cutoff for predicting poor outcomes was found to be 849 pg/mL, with sensitivity of 71.87% and specificity of 51.47%. NT-proBNP is a reliable biomarker for predicting poor outcomes in HF patients, with an optimal cutoff of 849 pg/mL. It may serve as a valuable tool in risk stratification, particularly for those with reduced ejection fraction.