Question

Which of the following pathophysiological events differentiates myocardial infarction from stable angina?

• A. Transient myocardial ischemia
• B. Reversible myocardial injury
• C. Irreversible myocardial necrosis
• D. Increased myocardial oxygen demand

Hint:

Both stable angina and myocardial infarction (MI) result from reduced blood supply to the heart, but the key distinction is whether the heart muscle is permanently damaged.

Answer 1

The Correct Option is C

Step 1: Understand what the question is asking.
Both myocardial infarction (MI) and stable angina involve reduced blood supply to the heart, but one key pathophysiological difference separates them. The question asks what that difference is.

Step 2: What happens in stable angina?
In stable angina, a fixed plaque partially blocks a coronary artery. With exertion, oxygen demand rises but supply cannot keep up. This causes transient (temporary) ischemia. The moment the patient rests, blood flow recovers and no cells die. Options 1 and 2 describe stable angina correctly but do NOT differentiate MI from it.

Step 3: What happens in myocardial infarction?
In MI, a plaque ruptures and a clot completely blocks the artery. The heart muscle supplied by that artery is cut off from oxygen entirely. If not treated rapidly, the cells die permanently. This is called irreversible myocardial necrosis.

Step 4: Rule out Option 4.
Increased myocardial oxygen demand (Option 4) can trigger angina but is not the defining feature of MI itself. MI is defined by the irreversible cell death that follows.

Step 5: Confirm the correct answer.
The one event that distinguishes MI from stable angina is the permanent, irreversible death (necrosis) of heart muscle cells.

Answer: Option (3) — Irreversible myocardial necrosis