The normal range for cardiac ejection fraction is 50% or more. The cardiac ejection fraction is the amount of blood output per contraction of the heart, as a percentage of the volume of the ventricles at end-diastole. Ejection fraction can be checked by cardiac ultrasound and is one of the most important indications of the type of heart failure. The formula is EF=(EDV-ES)×100%/EDV, where EF is the ejection fraction; EDV is the ventricular end-diastolic volume; and ES is the ventricular end-systolic volume. Ventricular contraction can not be all the blood of the ventricle into the artery, normal adult resting state, the ventricular diastolic volume: the left ventricle is about 125mL, the right ventricle is about 137mL, the amount of beat out of 60-80mL, that is, the ejection of blood when the ventricle has a certain amount of residual blood, the beat out of the ventricular diastolic volume of the percentage is called the ejection fraction. The ejection fraction is related to the contractility of the myocardium. The stronger the contractility of the myocardium, the greater the output per beat and the greater the ejection fraction. Normally, the left ventricular ejection fraction is ≥50%; the right ventricular ejection fraction is ≥40%. If it is less than this value, it is cardiac insufficiency. If the ejection fraction is abnormal, seek medical attention and follow the doctor’s instructions.