Acute heart failure (AHF) may arise from systolic or diastolic dysfunction, rhythm disorder or preload and afterload mismatch from various aetiologies. The strongest sign is presence of a S3 or gallop rhythm on auscultation. Other clinical signs depend on the aetiology of AHF and its correlation with the history helps guide further investigation and treatment. The investigation is performed by electrocardiogram, and imaging techniques such as chest X-ray, computed tomography (CT), and echocardiography. For optimal management of AHF, full blood count, clotting, urea and electrolytes, blood glucose, cardiac enzymes, inflammatory markers and arterial blood gas analysis are recommended. The other investigations for AHF include coronary angiography, endomyocardial biopsy, and CT angiogram. The invasive monitoring of AHF is performed by arterial line, central venous lines, pulmonary artery flotation catheter and echocardiography. The management of AHF includes ventilatory support, the use of inotropes and renal replacement therapy.