Cardiovascular Dynamics Lab Practice Test

When we look at the right heart, afterload is the pressure in the pulmonary circulation that the right ventricle must overcome to eject blood. A decrease in pressure in the right beaker mirrors a decrease in afterload because the ventricle faces less resistance to outflow. With less pressure opposing ejection, the right ventricle can push blood into the pulmonary arteries more easily, which is exactly what reduced afterload implies.

Decreasing preload would reflect lower filling pressure and ventricular stretch before contraction, not the pressure the ventricle has to overcome to eject blood. Increasing afterload would raise the resistance the ventricle must overcome, which is the opposite of the scenario. Increasing preload would raise filling pressures, not the outflow pressure.