<P> In cardiovascular physiology, stroke volume (SV) is the volume of blood pumped from the left ventricle per beat . Stroke volume is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called end - systolic volume) from the volume of blood just prior to the beat (called end - diastolic volume). The term stroke volume can apply to each of the two ventricles of the heart, although it usually refers to the left ventricle . The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70 - kg man . </P> <P> Stroke volume is an important determinant of cardiac output, which is the product of stroke volume and heart rate, and is also used to calculate ejection fraction, which is stroke volume divided by end - diastolic volume . Because stroke volume increase in certain conditions and disease states, stroke volume itself correlates with cardiac function . </P> <Table> Example values in healthy 70 - kg man <Tr> <Th_colspan="3"> Ventricular volumes <Ul> <Li> view </Li> <Li> talk </Li> <Li> </Li> </Ul> </Th> </Tr> <Tr> <Th> Measure </Th> <Th> Right ventricle </Th> <Th> Left ventricle </Th> </Tr> <Tr> <Td> End - diastolic volume </Td> <Td> 144 mL (± 23mL) </Td> <Td> 142 mL (± 21 mL) </Td> </Tr> <Tr> <Td> End - diastolic volume / body surface area (mL / m) </Td> <Td> 78 mL / m (± 11 mL / m) </Td> <Td> 78 mL / m (± 8.8 mL / m) </Td> </Tr> <Tr> <Td> End - systolic volume </Td> <Td> 50 mL (± 14 mL) </Td> <Td> 47 mL (± 10 mL) </Td> </Tr> <Tr> <Td> End - systolic volume / body surface area (mL / m) </Td> <Td> 27 mL / m (± 7 mL / m) </Td> <Td> 26 mL / m (± 5.1 mL / m) </Td> </Tr> <Tr> <Td> Stroke volume </Td> <Td> 94 mL (± 15 mL) </Td> <Td> 95 mL (± 14 mL) </Td> </Tr> <Tr> <Td> Stroke volume / body surface area (mL / m) </Td> <Td> 51 mL / m (± 7 mL / m) </Td> <Td> 52 mL / m (± 6.2 mL / m) </Td> </Tr> <Tr> <Td> Ejection fraction </Td> <Td> 66% (± 6%) </Td> <Td> 67% (± 4.6%) </Td> </Tr> <Tr> <Td> Heart rate </Td> <Td> 60--100 bpm </Td> <Td> 60--100 bpm </Td> </Tr> <Tr> <Td> Cardiac output </Td> <Td> 4.0--8.0 L / minute </Td> <Td> 4.0--8.0 L / minute </Td> </Tr> </Table>

What factor will not directly affect stroke volume