Comparative haemodynamic and metabolic effects of vasodilator and inotropic agents in experimental myocardial infarction.

Following coronary embolisation and onset of left ventricular failure 27 awake dogs were randomly assigned to infusion of saline (controls), nitroprusside, or dobutamine (a new inotropic agent). Nitroprusside and dobutamine both increased cardiac output and lowered left ventricular filling pressure while raising coronary sinus flow. Dobutamine, however, increased myocardial oxygen consumption whereas nitroprusside reduced it. Therefore vasidilators may be more beneficial than inotropic agents in acute myocardial infarction.