Calculate the ejection fraction of a female patient with a stroke ...

[D2AR0N]

Calculate the ejection fraction of a female patient with a stroke volume of 40 mL and an end-diastolic volume of 125 mL.
 
  a. 0.32
  b. 3.1
  c. 85
  d. 165

Question 2

What is the most determining factor for preload?
 
  a. Contractility
  b. Venous return
  c. Ejection fraction
  d. Vascular resistance

[ecox1012]

Answer to Question 1

ANS: A
Ejection fraction is calculated using the ratio of stroke volume to the ventricular end-diastolic volume. In this case the ejection fraction is 40 mL/125 mL = 0.32.

Answer to Question 2

ANS: B
Preload, the filling pressure of the ventricle at the end of ventricular diastole is dependent on the level of venous return and in addition the compliance of the ventricles. Contractility is the force that the ventricle generates during each cardiac cycle and is estimated using the ejection fraction. Vascular resistance is a measurement used to determine the afterload of a ventricle, or the force the heart needs to overcome to eject the blood from the ventricles.