What effect does atropine have on the heart rate?

Atropine is an anticholinergic medication that works primarily by blocking the action of the neurotransmitter acetylcholine on muscarinic receptors in the body, including those in the heart. By inhibiting the parasympathetic nervous system, which typically exerts a slowing effect on heart rate through the release of acetylcholine, atropine leads to an increase in heart rate.

Specifically, by preventing the normal inhibitory effect of the vagus nerve on the sinoatrial (SA) node and atrioventricular (AV) node, atropine facilitates a more rapid heart rate as well as enhances AV conduction. This mechanism is particularly useful in clinical settings to address bradycardia or to increase heart rate during certain types of cardiac emergencies. The overall effect of atropine on heart rate and conduction reflects its ability to counteract the parasympathetic influences that typically reduce heart rate. Therefore, the conclusion that atropine causes an increase in heart rate and enhances conduction through the AV node aligns accurately with its pharmacological actions.