Atrial natriuretic peptide response is blunted in patients with acute myocardial infarction and mild left ventricular dysfunction.

Neurohumoral parameters in 45 asymptomatic patients with acute myocardial infarction were measured. In patients with mild left ventricular dysfunction (ejection fraction < or = 45% and/or left ventricular end-diastolic pressure > or = 15 mm Hg), atrial natriuretic peptide levels differed significantly from those in patients with normal left ventricular function (127 +/- 74 pg/ml vs. 79 +/- 71 pg/ml; p < 0.001). After stimulus an increase in atrial natriuretic peptide levels (79 +/- 71 to 118 +/- 86 pg/ml; p < 0.001) was found only in patients with normal hemodynamic parameters. These data show that in patients with left ventricular dysfunction, the atrial natriuretic system is activated; however, atrial natriuretic peptide response to stimulus is present only in patients with normal hemodynamics.