Myocardial infarction is defined as?

• A. Heart attack due to plaque rupture with thrombus formation
• B. Aortic aneurysm
• C. Aortic dissection
• D. Hypoglycemia

Answer: (A)

Myocardial infarction is the death of heart muscle caused by prolonged lack of blood flow from a blocked coronary artery. The typical mechanism is rupture of a vulnerable atherosclerotic plaque in a coronary artery, which then triggers thrombus (clot) formation and partial or complete occlusion of the vessel. Without oxygen-rich blood, the affected myocardium becomes ischemic and ultimately necrotic, which is why it’s often called a heart attack.

This explains why the other conditions aren’t MI: an aortic aneurysm is a dilation of the aorta, not a blockage of a coronary artery; an aortic dissection involves a tear in the aortic wall layers; hypoglycemia is low blood glucose and does not describe myocardial injury from ischemia.