Final answer:
Increasing afterload makes the heart work harder to pump blood into the arteries which may lead to a decrease in stroke volume.
Step-by-step explanation:
Increasing afterload makes the heart work harder to pump blood into the arteries which may lead to a decrease in stroke volume. Afterload refers to the tension that the ventricles must develop to pump blood effectively against the resistance in the vascular system. Any condition that increases resistance requires a greater afterload to force open the semilunar valves and pump the blood. Damage to the valves, such as stenosis, which makes them harder to open will also increase afterload. Any decrease in resistance decreases the afterload.