EF in the echocardiogram report form is the abbreviation for ejection fraction, which, in the absence of special circumstances, refers to the left ventricular ejection fraction. The formula for calculating EF is EF equals left ventricular end-diastolic volume minus left ventricular end-systolic volume, divided by left ventricular end-diastolic volume multiplied by 100%. EF is currently the most commonly used reference for assessing left ventricular systolic function in clinical practice. In 2016, the Ultrasound Branch of the Chinese Medical Association organized a study of normal echocardiographic values in a healthy Han Chinese population in dozens of hospitals in China, and concluded that normal EF values in Han Chinese are around 60% for both men and women. Increased EF values are generally seen in fever, anemia, bradycardia, etc. Decreased EF values are generally seen in reduced cardiac systolic function, heart failure, etc.