Direct Cardiac Effects of Dopamine

Abstract

The cardiac effects of dopaminie, an epinephrine precursor, were studied in 20 dog heart-lung preparations. In 8 uncontrolled rate preparations. dopamine, 0.5 to 1 mg., increased the heart rate an average of 18 pet cent. In controlled rate preparations. dopamine, 100 to 500 µg ., consistently increased ventricular contractile force, cardiac output and blood pressure; there was a consistent decrease of right and left atrial pressure. Comparable hemodynamic effects were produced by 1 to 5 µg . of levarterenol, except that the effects of dopamine tended to be of longer duration and were less likely to be followed by cardiac depression. It is concluded that doparnine has significant positive inotropic and chronotropic effects in the dog heart-lung preparation.