Hemodynamic comparison of intravenous amrinone and dobutamine in patients with chronic congestive heart failure.

Amrinone, a new inotropic agent, has been shown to be beneficial in patients with congestive heart failure. However, its hemodynamic effects have not been compared with those those of currently useful catecholamines. In this study, the effects of intravenously administered dobutamine and amrinone were compared in eight patients with severe chronic congestive heart failure. Dobutamine was infused with a maximal increase in cardiac index was reached for undesirable effects were produced. This dose was then continued for 8 hours. After a return of hemodynamic values to baseline level, amrinone was infused at a rate of 40 microgram/kg per min for 1 hour and then 10 microgram/kg per min for 24 hours. Both drugs significantly improved cardiac index while simultaneously decreasing systemic vascular resistance and right atrial and pulmonary wedge pressures (p less than 0.05). Initially no differences could be found between the drugs. However, with prolonged infusion amrinone produced a sustained improvement whereas dobutamine had a decreased effectiveness. Thus, amrinone is comparable in effect with the optimal dose of dobutamine and would appear to be an extremely promising drug in the acute treatment of severe congestive heart failure.