An adult male patient is admitted to the hospital with congestive heart failure. Medical management of heart failure focuses on improving myocardial contractility. This can be achieved by administering?

1. A

   Tab. Digoxin (Lanoxin) 0.25 mg per orally daily

2. B

   Frusemide (Lasix) 40 mg po every morning

3. C

   2 liter O2 by via nasal cannula

4. D

   Nitroglycerin (Nitrol) 1 inch topically every 4 hours

Appeared in: NORCET 5 Prelims - Sept 2023 (Shift-1)

Explanation

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• Digoxin is classified as a cardiac glycoside and a positive inotropic agent, meaning it directly increases the force and strength of the heart's contractions.
• This action improves the heart's efficiency as a pump, increasing cardiac output and alleviating symptoms of heart failure.
• The primary goal of improving myocardial contractility is to make the weakened heart muscle pump more effectively, which is the specific mechanism of action for Digoxin.

Why Other Options Were Wrong

• Option B: Frusemide is a loop diuretic. Its primary action is to reduce fluid volume (preload) by promoting urination, not to increase the force of heart contractions.
• Option C: Oxygen therapy is used to correct hypoxemia (low blood oxygen). It does not have any direct effect on the heart's contractile strength.
• Option D: Nitroglycerin is a vasodilator. It reduces the heart's workload by decreasing preload and afterload but does not increase myocardial contractility.

Related Visual

• Visual 1: Diagram: Mechanism of action of Digoxin on a cardiac myocyte, illustrating the inhibition of the Na+/K+ pump and the resulting increase in intracellular calcium.
• Visual 2: Flowchart: Differentiating the primary effects of major heart failure drug classes: Inotropes (Digoxin), Diuretics (Frusemide), Vasodilators (Nitroglycerin), and Beta-blockers.

Clinical Relevance

• Nursing practice connection: Use the key finding related to Pharmacological management of heart failure: improving myocardial contractility to guide bedside assessment, documentation, and the next nursing action.
• A critical nursing safety measure before administering Digoxin is to assess the apical pulse for one full minute. The medication is typically held and the provider notified if the heart rate is less than 60 bpm for an adult.
• Nurses must educate patients on the signs of Digoxin toxicity (nausea, vision changes, confusion, bradycardia) and the importance of regular follow-up and blood tests.
• What if? If the patient presented with acute shortness of breath and crackles in the lungs (signs of pulmonary edema), the priority medication would be intravenous Frusemide to rapidly remove fluid, even though Digoxin might also be part of the long-term plan.

How to Approach the Question

• First, identify the key phrase in the question: 'improve myocardial contractility'. This is the central therapeutic goal you need to address.
• Next, recall the primary mechanism of action for each medication listed in the options.
• Analyze each option: Digoxin is an inotrope (increases contractility), Frusemide is a diuretic (reduces fluid), Oxygen treats hypoxia, and Nitroglycerin is a vasodilator (reduces workload).
• Match the drug's mechanism to the therapeutic goal. Only Digoxin directly increases myocardial contractility.
• Therefore, select Digoxin as the correct answer that achieves the specific goal stated in the question.

Concept Tested & Keywords

• Concept Tested: Pharmacological management of heart failure: improving myocardial contractility
• Stem keywords: congestive heart failure, myocardial contractility
• Lead-in keywords: improving, achieved by administering
• Clinical cues: Diagnosis: congestive heart failure

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