High amino-terminal natriuretic peptide precursors are often indicative of heart failure. In patients with acute respiratory distress, appropriate tests are often needed to determine whether cardiac or pulmonary factors are responsible for the respiratory distress, and high amino-terminal natriuretic peptide precursors are often indicative of cardiac factors causing respiratory distress. Amino-terminal natriuretic peptide precursors are cardiac hormones secreted by the ventricles and have potent natriuretic, diuretic, vasodilator, and antagonistic effects on the renin-angiotensin-aldosterone system. In humans, it can have a compensatory function for cardiac insufficiency by counteracting the water and sodium retention caused by endothelin and angiotensin II. The amino-terminal natriuretic peptide precursor is significantly elevated in patients when heart failure is present, and is one of the diagnostic indicators of heart failure.