Final answer:
To reduce cardiac contractions, β-blockers such as metoprolol and propranolol, and calcium channel blockers are used. β-blockers work by blocking β-1 receptors to slow HR and decrease contraction force, while calcium channel blockers limit calcium ion flow. Potassium channel blockers also treat irregular heart rhythms by affecting ion movement.
Step-by-step explanation:
To reduce the rate and strength of cardiac contractions, a class of medications known as β-blockers is commonly used. β-blockers, such as metoprolol and propranolol, function by blocking β-1 receptors on the heart, which slows down the heart rate (HR) and reduces the force of the heart's contractions. These drugs are essential for treating conditions like hypertension, angina pectoris, and serving as a post-myocardial infarction therapy.
Another group of agents that can reduce cardiac contractility are calcium channel blockers, which include drugs from the dihydropyridine, phenylalkylamine, and benzothiazepine classes. These substances decrease the strength of contraction by limiting the flow of calcium ions into the heart muscle cells, which is essential for muscle contraction.
Beyond these, potassium channel blockers like procainamide and amiodarone are used to treat cardiac dysrhythmias by altering the movement of potassium ions through voltage-gated potassium channels, affecting the action potentials that regulate heartbeats.