Dobutamine is a beta adrenergic agonist with a greater effect on beta 1 receptors than than beta 2. Beta 1 receptors are mainly found in the heart and work by increasing chronotropy (contractility) and inotropy (heart rate). Due to this effect, it makes sense that this drug is commonly used in the case of heart failure, cardiogenic shock, and stress testing.
DoButa = DoBeta
If you look further into dobutamine’s receptor signaling, you’ll see that when beta 1 and beta 2 receptors are stimulated they start the G-stimulatory cascade (Gs protein class). Gs receptors activate adenylyl cyclase which turns ATP into cAMP. The cAMP in turn activates protein kinase A causing an increase in calcium within heart cells. This calcium is what causes the effects you see in contractility, while the stimulation of Na/K inward funny channels aid in increasing the heart rate.
G-protein class: α1 α2 β1 β2 = Q I S S, respectively