Cardiac function refers to the ability of the heart to provide satisfactory blood circulation to the body through diastolic activity to sustain life, and is usually classified into four grades. Grade 1: Occasional symptoms of shortness of breath, able to engage in physical activities. Grade 2: Can engage in light physical activities and normal work, but easily get short of breath after exertion. Grade 3: Can’t engage in physical activities, can still take care of himself, but will get shortness of breath after a little activity. Grade 4: Severe heart failure, unable to live a normal life, can only rest in bed. The first 2 levels can be improved by resting and taking a small amount of cardiotonic and diuretic drugs; the last 2 levels should be seen by a hospital for strict comprehensive treatment.