AEMCA Practice Exam

What is the effect of nitroglycerin on the cardiovascular system?

1. It increases cardiac output

2. It causes vasodilation

3. It decreases heart rate

4. It constricts blood vessels

The correct answer is: It causes vasodilation

The effect of nitroglycerin on the cardiovascular system is primarily that it causes vasodilation. Nitroglycerin works by relaxing the smooth muscles within blood vessels, particularly the veins, which leads to their dilation. This vasodilation reduces the amount of blood returning to the heart (preload) and subsequently decreases the heart's oxygen demand. It is especially beneficial in conditions such as angina, where reducing the workload on the heart can alleviate chest pain. The mechanism through which nitroglycerin exerts its effects is primarily related to its conversion to nitric oxide in the body, which is a potent vasodilator. By widening blood vessels, it can improve blood flow and alleviate symptoms associated with ischemia in the heart muscle. Given this understanding, while nitroglycerin does not directly increase cardiac output or decrease heart rate, its primary action is to promote vasodilation. Therefore, the correct choice effectively captures the primary and significant impact that nitroglycerin has on the cardiovascular system.