If stroke volume is reduced, what is the compensatory mechanism to maintain the cardiac output?

If stroke volume is reduced, what is the compensatory mechanism to maintain the cardiac output?

Cardiac output is a product of stroke volume and heart rate. So if stroke volume decreases, there is a compensatory increase in heart rate so that the product (cardiac output) remains the same. This is achieved by activation of the sympathetic nervous system which stimulates the sino-atrial node to fire more rapidly.