Assertion: Beta-blockers should not be given routinely to every patient with myocardial infarction. Reason: Beta-blockers decrease heart rate and cardiac workload.

Appeared in: NORCET-11 Mains

Explanation

Both the assertion and the reason are independently true statements.
The assertion is correct because beta-blockers are contraindicated in MI patients with conditions like cardiogenic shock, severe bradycardia, or heart block.
The reason is correct because the mechanism of beta-blockers is to decrease heart rate and myocardial contractility, thus reducing cardiac workload.
However, the reason does not fully explain the assertion. It states the drug's general action but fails to specify why this action is dangerous for certain patients, which is the point of the assertion.

Close distractor alert - Option A: The reason does not adequately explain the assertion. The reason states the beneficial mechanism of action, but the assertion is about the exceptions and contraindications. A complete explanation would need to link the mechanism to the specific risks in certain patient populations.
Option C: The reason provided is a true statement. The fundamental action of beta-blockers is to decrease heart rate and cardiac workload.
Option D: The assertion is a true statement. It is a standard clinical principle that not all MI patients are candidates for beta-blocker therapy.

Clinical Relevance

Nursing practice connection: Knowing Pharmacology of Beta-Blockers in Myocardial Infarction helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must perform a thorough assessment before administering beta-blockers to an MI patient, specifically checking heart rate, blood pressure, and for signs of heart failure (e.g., lung crackles).
Administering a beta-blocker to a patient with contraindications can lead to severe hypotension, cardiogenic shock, or complete heart block, which are life-threatening emergencies.
What if? If the patient's heart rate was 55 bpm and blood pressure was 92/60 mmHg, the nurse should withhold the beta-blocker and notify the physician. These borderline values indicate a high risk for hemodynamic instability if the drug's effects take hold.

How to Approach the Question

First, evaluate the Assertion statement for its factual accuracy. Is it true that beta-blockers are not given to every MI patient? Yes, contraindications exist.
Second, evaluate the Reason statement for its factual accuracy. Is it true that beta-blockers decrease heart rate and workload? Yes, this is their mechanism.
Third, analyze the relationship. Does the Reason logically and completely explain the Assertion? The reason explains how the drug works, but the assertion is about when it shouldn't be used. The reason doesn't mention the negative consequences in specific groups.
Since both statements are true but the explanatory link is incomplete, select the option that reflects this.
This type of question tests your ability to distinguish between a drug's mechanism of action and the clinical reasoning for its contraindications.

Concept Tested & Keywords

Concept Tested: Pharmacology of Beta-Blockers in Myocardial Infarction
Stem keywords: Beta-blockers, myocardial infarction, assertion, reason
Lead-in keywords: Both the assertion and reason are true, reason correctly explains

Q6SfUcRl9i3DnQVRBfLUlb

E6 Pharmacology Nursing Lilley 11e Part 2 p. 57-59

E6 Pharmacology Katzung 16e p. 257-259

Practise the full NORCET-11 Mains

Attempt every question from this paper in a timed mock, then review the full solution for each one.