Hemodynamic Changes in Patients with Acute Myocardial Infarction

T HE hemodynamic changes in patients with acute myocardial infarction have been the subject of several investigations. In most seriously ill patients the usual circulatory abnormality is a low cardiac output with peripheral vasoconstriction.1-9 Some cases with a high cardiac output have been reported, however, and recently Malmcrona and Varnauskas'0 have shown a correlation between high cardiac output and a rise of the patient's temperature. The concept of low cardiac output and a state of peripheral vasoconstriction is mainly based on studies of groups of patients on whom single hemodynamic measurements have been made during the first few days following acute myocardial infarction. The purpose of this paper is to report serial measurements and clinical observations made on patients during each of the first 3 days following acute myocardial infarction, at about 1 week later and, when possible, before the patient left hospital. The results suggest that the hemodynamic state can be influenced to an important extent by factors not directly related to the myocardial contractile defect, and that these factors are not always apparent from the clinical examination.