Final answer:
Beta blockers cause bradycardia without AV blocks by blocking the beta-1 receptors in the heart, which normally increase heart rate. Overprescription of beta blockers can lead to bradycardia and heart stoppage.
Step-by-step explanation:
Beta blockers cause bradycardia without AV blocks by blocking the beta-1 receptors in the heart. These receptors are responsible for binding to the neurotransmitter norepinephrine (NE), which normally increases heart rate. By blocking these receptors, beta blockers slow down the heart rate.
For example, some beta blockers like metoprolol specifically block the beta-1 receptor. By doing so, they reduce the stimulation of the heart and lower the heart rate. This can be an effective treatment for hypertension.
However, overprescription or excessive use of beta blockers may lead to bradycardia, which is a slow heart rate, and in extreme cases, it can even lead to the stoppage of the heart.