A low ejection fraction is defined as an ejection fraction that is lower than the normal percentage. Patients who present with cardiac insufficiency often have a reduced ejection fraction. The chance of sudden death from malignant arrhythmias increases significantly when the ejection fraction drops below 35 percent. So how do we prevent these diseases that lead to low ejection fraction? 1, prevention of predisposing factors: Once diagnosed, patients are often highly nervous, anxiety, depression, serious concern, frequent medical care, urgent requirements for drug control arrhythmia, and completely ignore the causes, the prevention and treatment of predisposing factors, often resulting in noise, the cart before the horse, common predisposing factors: smoking, alcoholism, overwork, tension, excitement, overeating, indigestion, fever, excessive salt intake, low potassium, magnesium, etc., patients Can be combined with the actual situation of the previous onset, summarize the experience, avoid possible triggers, easier, safer and more effective than the simple use of drugs. 2, stable emotions: maintain a calm and stable emotions, mental relaxation, not overly nervous, mental factors, especially nervous emotions easily induced arrhythmia, so the patient should be treated with a calm mind, avoid too happy, too sad, too angry, do not care about trivial matters, in case of their own relief, do not watch tense and exciting TV, ball games, etc. 3, reasonable medication: low ejection fraction treatment emphasizes the individualization of medication, and some patients are often willing to receive the advice of patients and change their own medication, change the amount, which is dangerous, patients must take the medication according to the doctor’s requirements, and pay attention to observe the reaction after the medication, some anti-arrhythmic drugs can sometimes lead to arrhythmia, so, should be used as little as possible, to achieve a reasonable combination of drugs. 4.Regular physical examination: Regularly review electrocardiogram, electrolytes, liver function, nail function, etc., because anti-arrhythmic drugs can affect electrolytes and organ function, after the use of drugs should be regular follow-up and observation of the effect of drugs and adjustment of drug dose. Actively treat diseases that cause abnormal enlargement of the heart and ventricular hypofunction, such as hypertension and valvular disease, in terms of low ejection fraction.