Plasma catecholamines in acute myocardial infarction.

Plasma catecholamine levels were determined in 26 cases of uncomplicated myocardial infarction within 24 hours of onset of acute chest pain. Blood samples were collected at time of entry and at 4-hour intervals during the 48 hours following admission. Average values of plasma catecholamines within 1 hour of onset of pain were 0.87 ng./ml +/- 0.21 and remained elevated during the first 24 hours period. A gradual fall in catecholamine values was observed during the second 24-hour period. Catecholamines were higher in patients with sinus tachycardia and lower in patients with sinus bradycardia, and were higher in patients with anterior or anterolateral infarction. Catecholamine values were significantly higher when determined while patients presented ventricular ectopic beats or ventricular tachycardia. Sinus tachycardia, ventricular arrhythmias, and elevated plasma catecholamine values may be considered indicators of pain, anxiety, and/or left ventricular dysfunction without necessarily being causally related between themselves.