Increased afterload tends to affect stroke volume in which way?

Increased afterload tends to affect stroke volume in which way?

• A. Increase
• B. Decrease
• C. No change
• D. Immediate increase then decrease

Answer: (B)

Afterload is the pressure the ventricle must generate to eject blood into the aorta. When afterload rises, the ventricle faces a higher resistance to outflow. If contractility and preload aren’t increased to meet that demand, less blood is pushed out with each beat, so the stroke volume falls. On a pressure–volume view, higher afterload raises the end-systolic pressure and volume, narrowing the amount ejected during systole. The heart can partially compensate by increasing contractility, but the typical immediate effect of increased afterload is a decreased stroke volume.

Afterload is the pressure the ventricle must generate to eject blood into the aorta. When afterload rises, the ventricle faces a higher resistance to outflow. If contractility and preload aren’t increased to meet that demand, less blood is pushed out with each beat, so the stroke volume falls. On a pressure–volume view, higher afterload raises the end-systolic pressure and volume, narrowing the amount ejected during systole. The heart can partially compensate by increasing contractility, but the typical immediate effect of increased afterload is a decreased stroke volume.