What is the primary reason for using dobutamine or dopamine in a heart failure patient?

Short-term support in acute decompensated heart failure

Dobutamine and dopamine are used in acute decompensated heart failure to increase the contractility and vasodilation in order to provide short term support for the patient. Dobutamine is a beta-one agonist, which will stimulate the heart to increase contractility and inotropic activity--this is its primary reason for use. Dopamine has dose-dependent effects at different receptors. Between 3-10 mcg/kg/min, dopamine is a beta-one agonist that increases heart rate and contractility, thus increasing cardiac output. Thus, these agents are used to increase cardiac output, not for acutely treating hypertension, although blood pressure would be lowered by their use, due to the increased cardiac output requiring less vasoconstriction to maintain blood pressure.