The authors studied the influence of intravenously administered nitroglycerin on the general and local contractile function of the left ventricle with the aid of ultrasound examination of the heart and measurement of the end diastolic pressure in the left pulmonary artery by balloon Swan-Hanz catheters. A group of 56 patients with transmural myocardial infarction was examined: 33 during the acute period of disease received nitroglycerin, 23 patients constituted the control group. Intravenous administration of nitroglycerin shows decrease in the end diastolic and end systolic volumes, mean arterial pressure, in the end diastolic pressure of the pulmonary artery and increase in the cardiac output. The control group did not show such statistically significant changes. Only 33 patients with myocardial infarction of lower localization myocardial movements in the affected area were observed. No such thing was seen in the control group. In the treated group significant decrease in the end systolic and end diastolic pressures were recorded and also increase in the output fraction and so remained up to the 7th day of the disease as compared to the control group.