What is the primary action of nitroglycerin in treating cardiac conditions?

The primary action of nitroglycerin in treating cardiac conditions is its ability to dilate coronary arteries. This vasodilatory effect helps to increase blood flow to the heart muscle, improving oxygen delivery, especially in cases of angina or acute coronary syndrome. By relaxing the smooth muscle in the walls of blood vessels, nitroglycerin effectively decreases the workload on the heart while alleviating chest pain.

This mechanism is particularly beneficial during episodes of ischemia when the heart requires increased blood flow due to reduced oxygen supply. The dilation of coronary arteries can also lead to a reduction in myocardial oxygen demand, providing relief from the symptoms associated with cardiac conditions.