Which event is most directly responsible for a heart attack?

Which event is most directly responsible for a heart attack?

• A. Occlusion of a coronary artery
• B. Contraction of arterial walls
• C. Increased myocardial oxygen supply
• D. Infection of heart valves

Answer: (A)

The event most directly responsible is a blockage in a coronary artery. When a coronary artery becomes occluded, blood flow to a region of the heart muscle is suddenly cut off. That interruption deprives the tissue of oxygen (ischemia), and if blood flow isn’t restored quickly, the affected heart muscle can die, producing a myocardial infarction (heart attack). This occlusion is usually due to a thrombus forming on a ruptured atherosclerotic plaque. Other options don’t cause a heart attack directly: normal arterial contraction doesn’t block flow, increasing oxygen delivery would relieve risk rather than cause it, and infection of heart valves (infective endocarditis) is a valve problem with different consequences, not the immediate cause of a myocardial infarction.

The event most directly responsible is a blockage in a coronary artery. When a coronary artery becomes occluded, blood flow to a region of the heart muscle is suddenly cut off. That interruption deprives the tissue of oxygen (ischemia), and if blood flow isn’t restored quickly, the affected heart muscle can die, producing a myocardial infarction (heart attack). This occlusion is usually due to a thrombus forming on a ruptured atherosclerotic plaque. Other options don’t cause a heart attack directly: normal arterial contraction doesn’t block flow, increasing oxygen delivery would relieve risk rather than cause it, and infection of heart valves (infective endocarditis) is a valve problem with different consequences, not the immediate cause of a myocardial infarction.