<prompt> True about stroke volume isDecreases by increase in hea rateDetermined by pre-diastolic volumeDetermined by afterloadIs equal to cardiac output  <response>: Stroke volume is an impoant determinant of cardiac output, which is the product of stroke volume and hea rate and is also used to calculate ejection fraction, which is stroke volume divided by end-diastolic volume. So to maintain cardiac output it decreases if hea rate increases and vice versa. 