If stroke volume increases, what happens to afterload?

If stroke volume increases, what happens to afterload?

• A. Afterload decreases
• B. Afterload increases
• C. Afterload remains the same
• D. Afterload fluctuates with heart rate

Answer: (A)

Afterload is the pressure the left ventricle must overcome to eject blood. When afterload decreases, the ventricle faces less resistance to outflow, so it can eject more blood with each beat, increasing stroke volume. Therefore, an increase in stroke volume implies that afterload has decreased. If afterload were higher, stroke volume would tend to drop; if afterload stayed the same, changes in stroke volume would depend on preload or contractility, not a direct change in afterload.

Afterload is the pressure the left ventricle must overcome to eject blood. When afterload decreases, the ventricle faces less resistance to outflow, so it can eject more blood with each beat, increasing stroke volume. Therefore, an increase in stroke volume implies that afterload has decreased. If afterload were higher, stroke volume would tend to drop; if afterload stayed the same, changes in stroke volume would depend on preload or contractility, not a direct change in afterload.