Final answer:
A patient with heart failure starting on metoprolol (Lopressor) will be monitored for a reduced heart rate, decreased myocardial automaticity, and delayed AV node conduction, as these are typical effects of beta blockers. Metoprolol will not increase heart rate or myocardial contractility.
Step-by-step explanation:
A patient with heart failure starting the beta blocker metoprolol (Lopressor) will be monitored for several expected cardiovascular effects. Metoprolol is a type of medication known as a beta blocker which is used to treat conditions such as hypertension and heart failure. It works by binding to beta-1 receptors in the heart, subsequently blocking the action of neurotransmitters like norepinephrine (NE) that would normally increase heart rate and myocardial contractility.
Regarding the effects of metoprolol, it would specifically cause:
- Reduced heart rate - By blocking beta-1 receptors, metoprolol decreases heart rate (a negative chronotropic effect).
- Decreased myocardial automaticity - The drug reduces the heart's propensity to initiate its own contractions outside of the normal rhythm, leading to more regulated cardiac cycles.
- Delayed AV node conduction - Metoprolol can slow the conduction speed through the AV node, leading to decreased heart rate and allowing more time for the ventricles to fill with blood before contraction (a negative dromotropic effect).
Metoprolol would not be expected to increase heart rate or myocardial contractility as such effects are contrary to its action. Overprescription of beta blockers, however, can lead to dangerously low heart rates (bradycardia) and in severe cases, stoppage of the heart.