What is the main mechanism behind angina pectoris according to the source?

What is the main mechanism behind angina pectoris according to the source?

• A. Thrombosis in an atherosclerotic artery
• B. Bacterial infection of coronary arteries
• C. Low blood pressure
• D. Dehydration

Answer: (C)

Angina pectoris comes from the heart not getting enough oxygen to meet its needs, a mismatch between supply and demand. The source highlights the driving factor as reduced coronary perfusion pressure. When systemic blood pressure drops, the pressure gradient pushing blood into the coronary vessels falls, especially during diastole when the coronaries are normally perfused. In someone with already narrowed (atherosclerotic) arteries, this reduction in driving pressure can markedly limit oxygen-rich blood reaching the heart muscle. As the heart’s workload increases—during exercise or stress—oxygen demand rises while supply remains constrained, leading to chest pain. So, low blood pressure is described as the main mechanism because it directly lowers the coronary blood flow available to the myocardium, triggering ischemia and anginal symptoms in susceptible individuals.

Angina pectoris comes from the heart not getting enough oxygen to meet its needs, a mismatch between supply and demand. The source highlights the driving factor as reduced coronary perfusion pressure. When systemic blood pressure drops, the pressure gradient pushing blood into the coronary vessels falls, especially during diastole when the coronaries are normally perfused. In someone with already narrowed (atherosclerotic) arteries, this reduction in driving pressure can markedly limit oxygen-rich blood reaching the heart muscle. As the heart’s workload increases—during exercise or stress—oxygen demand rises while supply remains constrained, leading to chest pain. So, low blood pressure is described as the main mechanism because it directly lowers the coronary blood flow available to the myocardium, triggering ischemia and anginal symptoms in susceptible individuals.