Myocardial infarction can be diagnosed through physical examination, electrocardiography, myocardial injury marker examination and other examination methods. 1. Physical examination: including cardiac auscultation, cardiac percussion, etc. The heart rate of myocardial infarction patients is mostly increased, accompanied by various arrhythmias and other symptoms. The results of physical examination are not very specific, so it is only used as an auxiliary means of examination. 2. Electrocardiogram (ECG): ECG should be performed on patients suspected of having myocardial infarction. If the first ECG fails to make a clear diagnosis, the ECG should be reviewed several times to understand the changes in the condition. Electrocardiogram can remind patients whether there is myocardial ischemia or not, and the dynamic changes of electrocardiogram can also reflect the trend of cardiac ischemia and the extent of myocardial infarction. 3. Myocardial injury marker examination: myoglobin, troponin and creatine kinase isoenzyme are more specific and sensitive markers for diagnosing myocardial infarction. Myocardial infarction will cause necrosis of myocardial cells, which will increase the above indexes, and therefore it can play a role in confirming the diagnosis. When there is pain or stuffiness in the precordial area, you should consult a doctor in time, and a professional doctor will make a clear diagnosis through various tests.