Background and Objectives: Heart failure (HF) is a complex clinical syndrome with a high prevalence and significant morbidity. Classification of HF into preserved (HFpEF), mildly reduced (HFmrEF), and reduced ejection fraction (HFrEF) groups helps improve patient stratification and treatment. This study aimed to compare clinical, laboratory, echocardiographic, and electrocardiographic characteristics between different HF ejection fraction groups in a single-center patient cohort. Materials and Methods: A retrospective analysis of 1144 patients hospitalized with HF between 2022 and 2023 was performed. Patients were divided into three groups based on left ventricular ejection fraction. Results: HFrEF patients were predominantly male and younger, while HFpEF and HFmrEF groups had a higher proportion of older females. Atrial fibrillation and arterial hypertension were more common in HFpEF, while HFrEF patients showed more significant ventricular and atrial remodeling, lower tricuspid annular plane systolic excursion (TAPSE) values, and higher N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. No significant difference in in-hospital outcomes was found between HF groups. Conclusions: HF subtypes demonstrate distinct clinical and structural profiles, supporting the need for phenotype-based diagnostic and therapeutic approaches.