Serial changes in atrial natriuretic peptide and endothelin-1 concentrations. Their relationships to the cardiac performance of patients hospitalized for acute myocardial infarction.

AIM

The study was designed to assess temporal changes in atrial natriuretic peptide (ANP) and endothelin-1 (ET) concentrations in patients hospitalized for acute myocardial infarction (AMI) and their relationships to cardiac performance determined by radionuclide ventriculography.

PATIENTS AND METHODS

20 patients with first AMI were studied. Blood samples were drawn within the first 4-18 h, after 18-24 h, and on days 2, 3 and 6. Plasma concentrations of ANP and ET were measured in blood samples taken simultaneously. Radionuclide ventriculography was performed on the day of discharge to determine left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume index, end-systolic volume index and left-ventricular stroke volume index.

RESULTS

Median concentrations of ET decreased from 2.15 pmol/l on admission to 1.45 pmol/l at discharge (32%, p < 0.001). Median ANP rose from 29 to 79 pg/ml (172%, p < 0.001). The increment in ANP and the decrease in ET concentrations from admission to discharge was inversely correlated (r = -0.81, p < 0.005). ANP was inversely correlated to LVEF (r = -0.82, p < 0.001) and to the end-systolic volume index at discharge (r = -0.73, p < 0.003).

CONCLUSION

Dynamic and inverse fluctuations in ET and ANP occur within the 1st week of AMI. The magnitude of endocrine activation in the ANP-ET system seems to reflect an impairment in the left-ventricular systolic performance.