What Is Fraction & Stroke Volume?

Exercising increases ejection fraction and stroke volume. Heart failure has low ejection fraction and stroke volume.

Ejection fraction and stroke volume are related to cardiovascular physiology. The estimation of ejection fraction and stroke volume is a fundamental measurement in evaluating cardiac function as well as assessing and monitoring patients with heart disease.

Ejection Fraction

Ejection fraction is the fraction of blood ejected by either ventricle compared to its end-diastolic volume, which is the volume of blood in a ventricle at the end of filling. Healthy individuals have ejection fractions of more than 60 percent. In those with severe heart failure, ejection fraction may be less than 20 percent due to the heart's inability to eject blood.

Stroke Volume

Stroke volume is the amount of blood ejected from the left ventricle during each heart beat. It represents the difference between end-diastolic volume and end-systolic volume, the amount of blood remaining in the ventricles after a heart contraction. In heart failure, stroke volume decreases and end-diastolic volume increases resulting in a diminished ejection of blood.

Diagnostic Testing

Ejection fraction is usually tested through an echocardiogram, which uses ultrasound waves to take pictures of your heart through the use of echoes. The echocardiogram allows doctors to view evidence of reduced fractional shortening or reduced contractility. This diagnostic testing, introduced in 1952, allows doctors to see what is happening specifically to a patient' heart.

References

• Ped-onc Resource Center: Late Effects: Heart-damage, Diagnostic Tests
• Cardiovascular Physiology Concept: Ventricular Ejection Fraction
• Sports Fitness Advisor: The Cardiovascular System and Exercise
• Heartsite: Echocardiogram