New-Onset Acute Heart Failure With Reduced Ejection Fraction Associated With Severe Microcytic Anemia.

Severe microcytic anemia may serve as a potentially reversible precipitating factor in heart failure with reduced ejection fraction (HFrEF). This case highlights the diagnostic complexity and hemodynamic consequences of severe, microcytic anemia with undetermined etiology in a patient presenting with newly diagnosed heart failure. A 60-year-old Hispanic woman presented with new-onset acute dyspnea, chest pain, and bilateral edema. Investigations revealed severe microcytic anemia (hemoglobin 4.5 g/dL, MCV 60.8 fL) and an ejection fraction of 33%. Iron studies (iron 40 μg/dL, ferritin 14 ng/mL, total iron binding capacity 541 μg/dL, transferrin saturation 7%) were consistent with presumed iron deficiency anemia. Imaging and fecal occult blood testing did not identify a source of bleeding or malignancy, and endoscopic imaging was not completed due to financial constraints. The patient received packed red blood cells and intravenous iron to stabilize the acute condition. This case highlights the importance of considering severe anemia as a possible precipitating factor in new-onset heart failure, as well as the need for comprehensive evaluation to identify potentially reversible triggers.