Hemodynamic studies of patients with myocardial infarction

Cardiac output, venous and arterial pressure, total peripheral resistance and blood volume were measured in patients with acute myocardial infarction, with and without shock, and on recovery, and in patients without heart disease. Cardiac output falls to below normal after myocardial infarction, and rises significantly, though not always to normal, on recovery. Cardiac output was very low when myocardial infarction was complicated by shock. Fall of cardiac output to very low levels following myocardial infarction does not necessarily lead to development of shock. Venous pressure tended to be elevated in patients in shock as a result of myocardial infarction. Cardiac output was subnormal in patients with arteriosclerosis but without clinical heart disease: this was not attributable to reduced body oxygen consumption.