Which mechanism describes how nitroglycerin relieves cardiac-related chest pain?

Nitroglycerin is a medication primarily used to relieve angina, or cardiac-related chest pain, by acting as a potent vasodilator. The mechanism by which it alleviates this pain primarily involves vasodilation, which leads to an increase in blood flow to the heart muscle itself—referred to as the myocardial oxygen supply.

When administered, nitroglycerin relaxes the smooth muscle of blood vessels, particularly veins, which decreases the amount of blood returning to the heart (preload). This reduction in preload results in diminished myocardial oxygen demand because the heart does not have to work as hard to pump blood. Furthermore, by dilating coronary arteries, nitroglycerin can help improve blood flow to areas of the heart that may be ischemic or receiving inadequate oxygen, thus enhancing myocardial oxygen supply.

Overall, by alleviating both the preload and improving blood flow, nitroglycerin effectively reduces cardiac workload while increasing the supply of oxygen to the heart muscle, thereby relieving the chest pain associated with angina. This combined effect makes it a critical medication in the management of acute coronary syndromes and chronic angina.