The functions of the heart, mainly refers to the ability of the heart to pump blood, push blood flow, provide pressure for blood flow, and responsible for the recovery of blood, which is usually referred to as the ejection fraction in medical terms, in addition to the secretory function of the heart. 1. Pumping: Under normal conditions, the heart ejects blood from the left ventricle into the aorta through the constant contraction and diastole of the heart muscle and pushes the blood to provide nutrients and oxygen to the vital organs of the body, such as the brain, kidneys, lungs, and liver, and recycles carbon dioxide and metabolic wastes, which are then eliminated from the body through the lungs, liver, and kidneys. 2. Ejection fraction: usually measured by cardiac ultrasound, the ratio of the amount of blood ejected from the ventricles to the end-diastolic volume of the ventricles, so as to determine the cardiac function, the normal value is between 50% and 75%, lower than 50% is considered to be the existence of cardiac insufficiency, which usually requires further examination to clarify the cause of the disease, and symptomatic treatment. 3. Secretory function: it refers to the secretion of atrial peptide by the heart muscle, which has the functions of sodium excretion and diuresis, vasodilatation, lowering of blood pressure and bronchodilatation. The heart is one of the important parts of human organs, if the heart function is impaired in life, must go to the hospital in time for examination and treatment.