Clinical Scenario:
A 65-year-old man with a history of hypertension and diabetes presents with sudden-onset, crushing substernal chest pain radiating to his left arm. He is diaphoretic and pale. His blood pressure is 150/90 mmHg, and his heart rate is 110 bpm. An ECG shows ST-segment elevations in leads II, III, and aVF.

Question:
What is the most appropriate initial medication to administer in this patient, and why?

Options:

• A) Nitroglycerin

• B) Aspirin

• C) Atropine

• D) Clopidogrel

• E) Morphine

  

Correct Answer:
B) Aspirin

🧠 Key Insight: Aspirin is the primary antiplatelet agent, essential for reducing mortality by addressing the underlying thrombotic process in acute MI

🧠 Underlying Cause: Coronary Artery Atherosclerosis
⬇️
Plaque Rupture in Coronary Artery (Right Coronary Artery - RCA)

⬇️
🧠 Platelet Aggregation and Clot Formation

Effect: Thrombus formation blocks blood flow
⬇️
Coronary Artery Occlusion (↓ Blood flow in RCA)
⬇️

🧠 ↓ Oxygen Delivery to Myocardium (Inferior Wall)
⬇️
↓ ATP Production
⬇️
Switch to Anaerobic Metabolism
⬇️
Lactic Acid Accumulation (Tissue Ischemia)
⬇️
Myocardial Cell Death and Necrosis (Myocardial Infarction)
⬇️
🧠 Clinical Manifestations Due to Ischemia and Necrosis
⬇️

• Chest Pain: Severe, crushing, substernal pain radiating to left arm

• Diaphoresis: Sympathetic nervous system activation

• Pallor: Reduced oxygenation

• ↑ Blood Pressure (150/90 mmHg) and ↑ Heart Rate (110 bpm): Stress response

  ECG Findings

  ST-Segment Elevation in Leads II, III, and aVF
  ⬇️
  🧠 Indicates Inferior Wall MI (RCA occlusion)

  

  Source Image:LearnTheHeart.com

  Correct Answer: B) Aspirin
  ⬇️
  🧠 Mechanism: Inhibits platelet aggregation by blocking COX-1 → ↓ Thromboxane A2 production
  ⬇️
  Reduces clot progression and limits myocardial damage
  ⬇️
  Result: Decreases mortality in acute MI

Explanation of Other Options

A) Nitroglycerin

• Mechanism: Vasodilator, reduces preload, and relieves angina

• Limitation: Does not directly reduce thrombus formation or mortality in acute MI

C) Atropine

• Mechanism: Increases heart rate by blocking vagal tone

• Limitation: Not indicated without bradycardia; doesn’t address ischemia or thrombus

D) Clopidogrel

• Mechanism: Antiplatelet agent (P2Y12 inhibitor), adjunctive therapy

• Limitation: Often added later after aspirin but not used alone as initial treatment

E) Morphine

• Mechanism: Pain relief and vasodilation

• Limitation: Symptomatic relief only; does not prevent further clot formation

Flashcards

Stay Hungry, Stay Curious!

Your Brother In This Struggle

Dr. Shoaib Ahmad