What effect do anticholinergic agents have on heart rate?

Anticholinergic agents, such as atropine, primarily work by blocking the action of acetylcholine at muscarinic receptors in the parasympathetic nervous system. The parasympathetic nervous system is responsible for the "rest and digest" functions of the body, including the regulation of heart rate through the vagus nerve. When acetylcholine binds to its receptors, it typically exerts a slowing effect on the heart rate by decreasing the rate of depolarization of the sinoatrial (SA) node.

By blocking these receptors, anticholinergic agents inhibit the parasympathetic influence on the heart. This results in an unopposed effect of sympathetic stimulation, which can lead to an increase in heart rate. Therefore, the use of anticholinergic agents can effectively elevate heart rate, particularly in situations where an increased heart rate is desirable, such as in bradycardia.

The other options presented do not adequately describe the actions of anticholinergic agents on heart rate. While some may suggest potential stabilization or arrhythmias, these effects are not the primary function of anticholinergic drugs regarding heart rate modulation.