Why would an increase in stroke volume lead to a drop resting heart rate?

An increase in stroke volume would not lead to a drop in resting heart rate. In fact, it would likely cause the resting heart rate to increase.

Stroke volume is the amount of blood that the heart pumps out with each beat. If stroke volume increases, then the heart is pumping out more blood with each beat. This means that the heart has to work harder, which will cause the heart rate to increase.

There are a few exceptions to this rule. For example, if a person is taking beta blockers, their heart rate may not increase even if their stroke volume increases. Beta blockers are a type of medication that slows down the heart rate.