Chronic ischemic cardiomyopathy (ICM) belongs to a special type or advanced stage of coronary heart disease, which refers to long-term myocardial ischemia caused by coronary atherosclerosis, resulting in diffuse myocardial fibrosis and producing a clinical syndrome similar to primary dilated cardiomyopathy. In 1995, WHO/ISFC defined ischemic cardiomyopathy as dilated cardiomyopathy with impaired systolic function, which is caused by long-term myocardial ischemia and is therefore closely related to coronary heart disease. What are the causes of chronic ischemic heart disease? Infection is a common cause, respiratory tract infection is the first, especially lung infection, which may be related to the reduced ability to clear respiratory secretions after pulmonary stasis. Fever, hypermetabolism and sinus tachycardia increase the hemodynamic load on the heart. Acute rheumatic fever recurrence, infective endocarditis, various allergic inflammatory diseases and myocardial inflammation due to infectious diseases can directly impair myocardial function and aggravate pre-existing cardiac diseases. 2, arrhythmias Rapid arrhythmias such as the most common atrial fibrillation reduce the volume of cardiac output. Tachycardia increases myocardial oxygen consumption and induces and aggravates myocardial ischemia. Severe bradycardia decreases cardiac output. Arrhythmias also lead to loss of atrial assist pumping and impairment of ventricular filling function. 3, pulmonary embolism Heart failure patients who are bedridden for a long time are prone to thrombosis and pulmonary embolism, which aggravates right heart failure due to increased hemodynamic load of the right ventricle. 4, excessive exertion physical activity, emotional excitement and climate change, excessive diet or excessive salt intake. 5.Pregnancy and childbirth can increase the heart load and increase myocardial oxygen consumption and induce heart failure, especially when maternal bleeding or infection is more likely to induce heart failure. 6, anemia and bleeding Chronic anemia increases blood displacement, increases heart load and reduces oxygen uptake of hemoglobin, causing myocardial hypoxia and even necrosis, resulting in anemic heart disease. Large amount of bleeding reduces blood volume, decreases the amount of blood returned to the heart and cardiac excretion, and decreases myocardial blood supply and reflex heart rate, increases myocardial oxygen consumption, which leads to myocardial ischemia and hypoxia. 7. Others Mainly include excessive or too fast blood transfusion. Electrolyte disorders and acid-base balance disorders, such as acidosis is a common cause of heart failure, electrolyte disorders induced heart failure is most common in hypokalemia, hypomagnesemia and hypocalcemia. Digitalis overdose, diuretic overdose, cardiac depressants and anti-arrhythmic drugs and glucocorticoids cause water and sodium retention, etc.