Atrial natriuretic peptide (ANP), released by the heart muscle and induces sodium excretion by the kidneys. It is released in response to atrial and ventricular stretch. Another peptide known as brain type natriuretic peptide (BNP) is also released from the heart during heart failure. BNP levels in blood can be estimated and is fast becoming a popular test for heart failure in the emergency room. This is useful in differentiating respiratory from cardiac causes of breathlessnes in the severely ill individual. High BNP levels indicate poorer results.
