Urinary excretion of free norepinephrine and free epinephrine in patients with acute myocardial infarction in relation to its clinical course

Serial estimations of urinary excretion of free norepinephrine and epinephrine were made in 19 patients with recent myocardial infarction of varying clinical courses. An increase in urinary excretion of catecholamines during the acute phase was noted, more distinct in cases characterized by severe clinical course. In patients with myocardial infarction complicated by shock, circulatory insufficiency, and transient fall in blood pressure the urinary excretion of free norepinephrine was more significantly elevated than that of epinephrine. The urinary excretion of free epinephrine was more enhanced in patients with myocardial infarction complicated by disturbances in cardiac rhythm. The results suggest a relationship between the clinical course of myocardial infarction and the activity of the sympathoadrenal system.