Which statement best describes the mechanism of angina pectoris?

Which statement best describes the mechanism of angina pectoris?

• A. myocardial oxygen supply exceeds the demand.
• B. one or more coronary arteries suddenly spasm.
• C. myocardial oxygen demand exceeds supply.
• D. a coronary artery is totally occluded by plaque.

Answer: (C)

Angina pectoris occurs when the heart’s demand for oxygen outstrips what the coronary arteries can deliver. During activity or stress, the heart needs more oxygen, but with atherosclerotic narrowing the blood flow can’t increase adequately, leading to transient myocardial ischemia and chest pain. If oxygen supply were greater than demand, there would be no ischemia or pain. Coronary artery spasm can cause transient ischemia and angina, but it’s a specific cause rather than the general mechanism. A totally occluded plaque typically leads to a myocardial infarction, not the usual angina pattern. So the best description is that myocardial oxygen demand exceeds supply.

Angina pectoris occurs when the heart’s demand for oxygen outstrips what the coronary arteries can deliver. During activity or stress, the heart needs more oxygen, but with atherosclerotic narrowing the blood flow can’t increase adequately, leading to transient myocardial ischemia and chest pain. If oxygen supply were greater than demand, there would be no ischemia or pain. Coronary artery spasm can cause transient ischemia and angina, but it’s a specific cause rather than the general mechanism. A totally occluded plaque typically leads to a myocardial infarction, not the usual angina pattern. So the best description is that myocardial oxygen demand exceeds supply.