Which describes the pressure in the filled ventricle at the end of diastole?

• A. Afterload
• B. Preload
• C. Systemic resistance
• D. Ejection fraction

Answer: (B)

This question is about preload—the pressure inside a ventricle at the end of diastole when the chamber is filled and ready to contract. Preload reflects how much the ventricle has been stretched by the volume it received from venous return. The more filled the ventricle is, the higher the end-diastolic pressure, up to the point where the myocardium can stretch optimally (the Frank-Starling relationship), which helps determine the subsequent stroke volume.

If you think about the other terms, they describe different phases or aspects: afterload is the pressure the ventricle must overcome to eject blood (essentially arterial/systemic pressure against which the ventricle works), systemic resistance is part of that vascular load but not the ventricular filling pressure itself, and ejection fraction is a ratio of how much blood is pumped out relative to how much was filled, not a description of filling pressure.

So the pressure in the filled ventricle at the end of diastole is preload.