Myocardial infarction is a pathological process in which a coronary artery is persistently ischemic and the myocardium it controls undergoes irreversible necrosis. The basic cause of myocardial infarction in the elderly is coronary atherosclerosis. Common causes include excessive fatigue, high mental stress, cold stimulation, major surgery, high-fat or overeating, smoking, carbon monoxide poisoning, etc. Elderly myocardial infarction has the following clinical characteristics: ① Clinical symptoms are often atypical; ② Many people have other diseases (hypertension, diabetes, cerebrovascular disease, respiratory tract, gastrointestinal tract and urinary tract infections, etc.) before the onset of the disease; ③ The onset is regular during the day and night, and most of the attacks occur between 6 and 12 in the morning, which may be related to changes in catecholamine levels in the body; ④ Relationship with weather and climate change.