What is the effect of reducing afterload on stroke volume in a healthy heart?

• A. Increases stroke volume
• B. Decreases stroke volume
• C. No effect on stroke volume
• D. Increases heart rate

Answer: (A)

Reducing afterload lowers the resistance the left ventricle must overcome to eject blood. When this resistance drops, the ventricle can empty more effectively during systole, so end-systolic volume decreases while end-diastolic volume stays about the same (assuming venous return isn’t vastly altered). Since stroke volume equals EDV minus ESV, a smaller ESV leads to a larger stroke volume. In a healthy heart, contractility and venous return are typically adequate, so the main effect of reduced afterload is an increase in stroke volume. The other options don’t fit because decreasing afterload does not directly lower stroke volume, and it doesn’t inherently raise heart rate.