The normal value of left ventricular function on cardiac ultrasound is above 50%. There are currently three types of definitions of heart failure. The first condition is heart failure with preserved ejection fraction, which means that the ejection fraction is above 50%; the second condition is heart failure with intermediate ejection fraction, where the ejection fraction of the heart is between 40% and 50%; and the third condition is called heart failure with declining ejection fraction, where the ejection fraction is below 40%. The assessment of left ventricular function by cardiac ultrasound may be affected by some factors, such as valve disease, when the valve is not closed, there may be a false increase in ejection fraction. Therefore, a normal ejection fraction or a reduced ejection fraction by cardiac ultrasound needs to be combined with clinically relevant symptoms and signs to make a comprehensive judgment, so as to assess the patient’s normal heart function status.