Which of these conditions is characterized by an elevated stroke volume?

Aortic regurgitation is a condition where the aortic valve does not close properly, allowing blood to flow back into the left ventricle during diastole. This backflow increases the volume of blood in the left ventricle, leading to a higher stroke volume. The left ventricle compensates for the increased volume over time by dilating and accommodating the extra blood, which ultimately results in an elevated stroke volume.

This condition often leads to an increase in cardiac output initially, as the heart attempts to maintain adequate perfusion despite the volume overload. However, if the regurgitation is severe and left untreated, it can ultimately lead to left ventricular dysfunction and heart failure.

In contrast, heart failure typically presents with a reduced stroke volume due to impaired cardiac function. Hypertension may affect stroke volume indirectly through afterload but does not inherently characterize an elevated stroke volume. Hypovolemia, defined by a decrease in blood volume, would also lead to a reduced stroke volume as there is less blood available to fill the heart's chambers. Thus, aortic regurgitation stands out as the condition where stroke volume is elevated due to the unique hemodynamic changes associated with this valvular heart disease.