What is the primary hemodynamic effect of nitrates used for angina?

What is the primary hemodynamic effect of nitrates used for angina?

• A. Decreased afterload
• B. Increased heart rate
• C. Decreased preload
• D. Increased contractility

Answer: (C)

Nitrates used for angina primarily cause venodilation, which reduces venous return to the heart. This lowers right and left ventricular end-diastolic volume and pressure (preload), decreasing wall tension and myocardial oxygen demand. While nitrates can cause some arterial dilation and a drop in blood pressure at higher doses (which can reduce afterload), the hallmark effect with angina relief is the decrease in preload. They do not increase contractility; any reflex heart rate increase would be a secondary response to lower BP, not a direct effect.

Nitrates used for angina primarily cause venodilation, which reduces venous return to the heart. This lowers right and left ventricular end-diastolic volume and pressure (preload), decreasing wall tension and myocardial oxygen demand. While nitrates can cause some arterial dilation and a drop in blood pressure at higher doses (which can reduce afterload), the hallmark effect with angina relief is the decrease in preload. They do not increase contractility; any reflex heart rate increase would be a secondary response to lower BP, not a direct effect.