Pharmacology Myocardial Infarction Meds #3

Question

Which is the most accurate response by the registered nurse when the nursing student inquires why beta blockers are administered during a myocardial infarction?

Answers

  1. "Beta blockers help dilate coronary blood vessels, thereby increasing cardiac output."
    • Rationale:

      This answer is not correct because vasodilators, such as nitroglycerin performs this action of dilating coronary blood vessels. This action increases cardiac output and is why nitroglycerin is also administered during a myocardial infarction.

  2. "Beta blockers relax smooth muscle, thereby decreasing workload of the heart."
    • Rationale:

      This answer is not correct because calcium channel blockers perform this action of relaxing smooth muscle. This action decreases the workload of the heart and is why this medication is also administered to a client with a myocardial infarction.

  3. "Beta blockers decrease fluid in the circulatory system, thereby decreasing preload."
    • Rationale:

      This answer is not correct because diuretics, such as furosemide, performs this action of decreasing fluid in the circulatory system, thereby decreasing preload. This medication is often administered to reduce the incidence or effects of heart failure, which can occur when a client experiences a myocardial infarction.

  4. "Beta blockers decrease catecholamines, thereby decreasing oxygen demands."
    • Rationale:

      This answer is correct because beta blockers decrease catecholamines, thereby decreasing oxygen demand. When a client is experiencing a myocardial infarction, the coronary blood vessels have experienced complete loss of blood and oxygenation to the myocardial muscle being supplied by that vessel. Decreasing the catecholamines reduces the heart rate and blood pressure, which decreases the workload and oxygen demand to the heart.

Overview

Beta blockers are utilized as treatment during a myocardial infarction due to its ability to decrease catecholamines. This decreases oxygen demand, which is the goal of treatment of beta blockers.

Explanation

Learning Outcomes

Beta blockers are effectively used during a myocardial infarction due to its ability to block or decrease the effects of the body’s natural catecholamines. Catecholamines increase the blood pressure and heart rate, which causes the heart to work harder and need more oxygen. When beta blockers block or decrease this natural action, there is less oxygen demand. This reduces the workload on the heart and helps produce better outcomes for the client.

Test Taking Tip

When answers look very similar, stop and look at what makes each answer different.

Video Rationale