Ejection fraction (EF) is a measure of the amount of blood that the left ventricle of the heart pumps out with each contraction, and it is used to assess the overall function of the left ventricle.

It is defined as the percentage of blood in the left ventricular end-diastolic volume (the volume of blood in the left ventricle at the end of the relaxation phase) that is expelled during systole (the contraction phase of the heart).

It is typically calculated by performing an echocardiogram, which is an ultrasound of the heart, and measuring the left ventricular end-diastolic volume and end-systolic volume (the volume of blood in the left ventricle at the end of systole). The EF is then calculated by dividing the end-systolic volume by the end-diastolic volume and multiplying by 100.

A normal ejection fraction is typically considered to be between 55-70%. An ejection fraction below 55% is considered to be decreased, indicating reduced function of the left ventricle.

Causes of abnormal ejection fraction include:

  • Coronary artery disease
  • Hypertensive heart disease
  • Cardiomyopathy
  • Valvular heart disease
  • Pulmonary hypertension
  • Myocarditis
  • Pulmonary embolism
  • Pericardial disease

Reference:

  1. Ejection Fraction. American College of Cardiology. https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2021/01/14/ejection-fraction
  2. Ejection Fraction. MedlinePlus. https://medlineplus.gov/ency/article/007198.htm
  3. Ejection Fraction. Mayo Clinic. https://www.mayoclinic.org/tests-procedures/echocardiogram/about/pac-20393501