The causes of myocardial infarction are related to insufficient myocardial oxygen supply, increased myocardial oxygen consumption, and decreased blood perfusion in the heart. 1. Insufficient oxygen supply to the myocardium: low blood pressure, shock, bradyarrhythmia, respiratory failure, etc., will lead to insufficient oxygen supply to the myocardium, causing tissue necrosis at the site of hypoxia, resulting in myocardial infarction. 2. Increased myocardial oxygen consumption: severe hypertension, sustained tachyarrhythmia will lead to increased myocardial oxygen consumption, resulting in myocardial damage and causing myocardial infarction. 3. Decreased blood perfusion in the heart: coronary atherosclerosis, coronary microcirculation dysfunction, coronary embolism, etc., can lead to insufficient blood supply to the myocardium, causing myocardial infarction. When myocardial infarction occurs, it is recommended to go to the hospital for timely treatment.