Which type of medication is typically a beta-adrenergic agonist used to increase heart contractility?

Dobutamine is a beta-adrenergic agonist primarily used to increase heart contractility, particularly in patients with heart failure or low cardiac output. It primarily stimulates beta-1 adrenergic receptors in the heart, leading to an increase in myocardial contractility, heart rate, and cardiac output. This makes it effective in acute settings, such as during cardiac decompensation, as it enhances the force of the heart's contractions without significantly increasing systemic vascular resistance, which can be crucial in managing critically ill patients.

In this context, dopamine is a catecholamine that can have different effects depending on the dose; at low doses, it primarily stimulates dopaminergic receptors, and at moderate to high doses, it can stimulate beta-1 receptors but is not primarily used for increasing contractility. Digoxin, while it does increase contractility through a different mechanism (by inhibiting the Na+/K+ ATPase pump), is not classified as a beta-adrenergic agonist. Carvedilol is a non-selective beta blocker that is used primarily for hypertension and heart failure management but works by decreasing heart rate and myocardial oxygen demand rather than increasing contractility.