Atrial natriuretic peptide in congestive heart failure after acute myocardial infarction.

The concentration of atrial natriuretic peptide, a newly discovered hormone produced in the atrial wall, was measured in 55 patients during the first 72 h after acute myocardial infarction. 37 patients became clinically congested, while 18 patients avoided this complication. 13 patients (9 congested and 4 uncongested) experienced tachycardia, known to raise the concentration of atrial natriuretic peptide both with and without congestive heart failure. In the remaining 42 patients, the congested group had a significantly higher plasma atrial natriuretic peptide concentration than the uncongested group (p < 0.05) on all 3 days. In the congested group the concentration of atrial natriuretic peptide did not normalize after initiation of treatment. We conclude that the concentration of atrial natriuretic peptide is increased in all patients with acute myocardial infarction and that the level of atrial natriuretic peptide declines during the first 24 h in all patients and normalizes in the uncongested patients while the level of atrial natriuretic peptide is still elevated (at least for 72 h) in the congested patients.