Cardiovascular effects of dopamine after experimental coronary occlusion in the dog.

Hemodynamic effects of dopamine were studied on 30 open-chest dogs with experimental myocardial infarction. These dogs were divided into 3 groups. Three different doses of intravenous dopamine, 5, 10, and 20 mug/Kg/min, were administered for 30 min. Heart rate and myocardial contractility were increased dose-dependently. Total peripheral vascular resistance was reduced with 5 or 10 mug/Kg/min of dopamine. With 20 mug/Kg/min of dopamine, it became the lowest 5 min after the initiation of infusion but increased above the control value 20 min after the start of administration. Renal vascular resistance was decreased with 5 mug/Kg/min of dopamine but increased with 20 mug/Kg/min. These results suggested that this drug would be useful for treatment of shock state.