AEMCA Practice Exam

How does nitroglycerin benefit patients with angina?

1. Increases heart rate

2. Reduces oxygen demand by vasodilating vessels

3. Decreases blood pressure significantly

4. Stops heart rhythm irregularities

The correct answer is: Reduces oxygen demand by vasodilating vessels

Nitroglycerin benefits patients with angina primarily by reducing oxygen demand through the process of vasodilation. When nitroglycerin is administered, it acts as a vasodilator, which means it relaxes and expands blood vessels. This dilation decreases systemic vascular resistance and lowers the pressure against which the heart must pump, effectively reducing the workload on the heart and, as a result, the oxygen demand. Additionally, by expanding the coronary arteries, nitroglycerin increases blood flow to the heart muscle itself, which can relieve the pain associated with angina that typically results from insufficient blood flow and thus insufficient oxygen supply to the heart. This mechanism is crucial for patients experiencing angina, as it directly addresses the core issue of oxygen supply versus demand. The other options do not adequately capture the primary therapeutic effect of nitroglycerin in managing angina.