Thrombo-embolism refers to clots inside which location that can cause a myocardial infarction?

• A. In the pulmonary arteries
• B. Inside a coronary artery causing MI
• C. In systemic arteries
• D. In the venous heart tissue

Answer: (B)

Thrombo-embolism refers to a clot blocking a vessel. For a myocardial infarction, the critical blockage is inside a coronary artery. When a thrombus forms there or an embolus becomes lodged in a coronary artery, blood flow to part of the heart muscle is cut off, leading to ischemia and tissue death that defines an MI. A clot in the pulmonary arteries causes a pulmonary embolism, not an MI. Clots in venous tissue don’t directly cause a myocardial infarction, and while systemic arteries can be involved in other problems, the heart attack results specifically from an occlusion in the coronary arteries.