• Increase heart rate (chronotropic effect).
• Increase contractility (positive inotropic effect).
• Increase the speed of conduction through the AV node.

These effects are achieved through the activation of ß receptors. There are at least two types of ß receptors, ß1 and ß2.

In normal hearts, the population of ß1 receptors is usually larger than that of the ß2 receptors.

In some pathological conditions, e.g. heart failure, there is a relative increase in the population of ß2 receptors.