Difficulty: Medium
Average Score: 70%
Simulated
A nurse is caring for a client admitted to the intensive care unit for a cardiac dysrhythmia. The nurse understands the prescribed calcium channel blocker has which of the following mechanisms of action?
Correct answer
C
Rationale
Correct Answer: C - Reduces the contractility and conductivity of the heart
Rationale: Calcium channel blockers work by blocking calcium from entering the cells of the heart and blood vessels. By doing so, they reduce the contractility (strength of contractions) and conductivity (speed of electrical impulses) of the heart. This results in a decreased workload for the heart and helps to lower blood pressure. Choice A is incorrect because calcium channel blockers actually decrease heart rate and contractility. Choice B is incorrect as calcium channel blockers do not directly increase oxygen delivery. Choice D is incorrect because calcium channel blockers do not act on beta cells or regulate cardiac rhythm in that manner.
Rationale: Calcium channel blockers work by blocking calcium from entering the cells of the heart and blood vessels. By doing so, they reduce the contractility (strength of contractions) and conductivity (speed of electrical impulses) of the heart. This results in a decreased workload for the heart and helps to lower blood pressure. Choice A is incorrect because calcium channel blockers actually decrease heart rate and contractility. Choice B is incorrect as calcium channel blockers do not directly increase oxygen delivery. Choice D is incorrect because calcium channel blockers do not act on beta cells or regulate cardiac rhythm in that manner.