The characteristics of the ECG in acute infarction include: 1. Hyperacute phase: i.e., myocardial ischemia, T wave elevation will appear first, and then ST segment arch-back elevation will appear after several 10 minutes. If it continues to develop, it will fuse with the QRS wave to form a tombstone shape, also known as “red flag” in medicine; 2. Acute phase: If the myocardium is further necrotic, necrotic Q wave will be formed, Q wave > 0.04 seconds, amplitude > 1/4 necrotic Q wave, divided into anterior interval wall infarction, anterior wall infarction, anterior lateral wall infarction, high lateral wall infarction, right ventricular infarction, posterior wall infarction. In addition, there are atypical infarcts, such as isotonic Q waves and myocardial infarction combined with bundle branch block.