An increase in afterload on the left ventricle typically causes which change on the PV loop?

• A. End-systolic pressure increases and stroke volume decreases.
• B. End-systolic pressure decreases and stroke volume increases.
• C. End-diastolic pressure increases with no change in stroke volume.
• D. End-diastolic volume decreases.

Answer: (A)

Increasing afterload means the left ventricle has to push blood against a higher pressure in the aorta. To do that, the ventricle must generate a higher end-systolic pressure, and because it ejects less blood against that greater resistance, the stroke volume falls. On a pressure-volume loop, the end-systolic corner shifts to higher pressure and higher volume (end-systolic volume increases), while the overall stroke volume (the width of the loop) decreases if preload is unchanged. The end-diastolic conditions stay mainly the same, so end-diastolic pressure/volume aren’t the primary changes. That’s why the correct description is that end-systolic pressure increases and stroke volume decreases.