BNP stands for B-type natriuretic peptide, also known as brain natriuretic peptide, which belongs to the peptide hormone class. It is an active hormone synthesized and secreted by the body and can be detected in tissues such as heart and brain, with more expression in the ventricles. When cardiac myocytes are stimulated, the precursor of BNP is cleaved into inactive linear polypeptide (NT-proBNP) and active cyclic polypeptide (BNP) by the action of enzymes. When cardiac insufficiency occurs, the myocardium dilates and rapidly synthesizes active BNP for release into the blood, which helps regulate cardiac function and is more specific in reflecting changes in ventricular function. Therefore, in clinical practice, this index is often tested to clarify the presence of heart failure and guide the diagnosis.