B-type natriuretic peptide (BNP) is a neurohormone produced mainly by ventricular myocytes in response to increased left ventricular end-diastolic pressure. Patients with acute decompensated heart failure often have elevated plasma BNP. However, recent clinical observations have demonstrated that in patients with advanced heart failure, the plasma level of BNP is lower than those with acute heart failure. We hypothesized that a lower circulating BNP level in patients with chronic and advanced heart failure is due to the exhaustion of the biosynthesis mechanisms and is associated with a poor outcome in these patients.