Correlation between serial changes in left-sided heart chambers and atrial natriuretic peptide and N-terminal pro atrial natriuretic peptide after a first myocardial infarction. An echocardiographic study.

Dilatation of the left ventricle predicts morbidity and mortality after acute myocardial infarction. We compared serial echocardiographic examinations of the left atrium and ventricle with measurements of plasma atrial natriuretic peptide (ANP) and plasma N-terminal pro atrial natriuretic peptide (NT-proANP) in 22 patients during the first 6 months following a first myocardial infarction. ANP, but not NT-proANP, was found to be significantly correlated to the diastolic/systolic size of the left atrium (r = 0.58/0.60) and the systolic size of the left ventricle (r = 0.43) in the acute phase 2-4 days after infarction. At 10-12 days after the infarction, we found a significant correlation between all sizes of the left-sided chambers and ANP, whereas NT-proANP only correlated with the left atrial sizes. Three months after the infarction, all sizes of the left-sided chambers correlated with both ANP and NT-proANP, with the exception of a non-significant correlation between NT-proANP and the left atrial diastolic size. After 6 months only the area of the diastolic and systolic left atrium correlated with plasma ANP and only the systolic size of the left atrium correlated with NT-proANP. The percentage change in the size of the left atrium, but not the left ventricle, correlated significantly with the percentage change in both ANP (r = 0.57) and NT-proANP (r = 0.70). We conclude that the distension of the left atrium rather than the dilatation of the left ventricle is related to the concentration of ANP and NT-proANP after an acute myocardial infarction.