Urinary Excretion of Catecholamines and their Main Metabolites after Myocardial Infarction; Relationship to the Clinical Syndrome

Abstract

Serial measurements of the urinary excretion of noradrenaline (NA), adrenaline (A), normetanephrine + meta‐nephrine (NMN) and vanillylmandelic acid (VMA) have been made in 18 patients with acute myocardial infarction and in 2 patients with severe and recurrent episodes of angina pectoris. The urinary excretion of these 4 compounds was significantly elevated in the patients with myocardial infarction whereas it was within the normal range in the 2 patients with angina pectoris. — NA+A / NMN+VMA ratio was calculated in the 18 patients with myocardial infarction. This ratio was significantly higher in the patients (during the first 4 days after the onset of the infarction) than in the controls. This may indicate that the rate of enzymatic inactivation of NA and A is relatively decreased after myocardial infarction.— The excretion of catecholamines and metabolites was found to be higher in patients with hypotension (systolic blood pressure < 90 mm Hg) and heart failure, than in patients without these complications. Frequent and. severe ventricular arrhythmias were observed in the 6 patients with the highest urinary excretion of catecholamines and metabolites. Among the 12 patients who had a less marked increase in excretion of these compounds, 2 had episodes of ventricular arrhythmias, 5 had supraventricular arrhythmia and 5 had no complications. — Our results suggest that in most cases of myocardial infarction, the marked release of catecholamines is accompanied by a decreased rate of inactivation of these amines. This must lead to high levels of circulating catecholamines which could be related to the development of arrhythmias.