What is the primary action of nitroglycerin in the treatment of angina?

The primary action of nitroglycerin in the treatment of angina is to dilate blood vessels. Nitroglycerin is a nitrate that works by relaxing the smooth muscles of blood vessels, leading to vasodilation. This effect decreases the workload on the heart as well as the oxygen demand by reducing the resistance against which the heart must pump during contraction.

By dilating both the arteries and veins, nitroglycerin enhances blood flow to the heart muscle itself. This increased blood flow can alleviate angina symptoms, which is primarily caused by an imbalance between oxygen supply and demand in the heart. Therefore, the primary role of nitroglycerin in angina management is effectively linked to its ability to dilate blood vessels, improving oxygen delivery and reducing myocardial ischemia.