Myocardial ischemia may manifest as chest tightness and chest pain. If ischemia is aggravated, arrhythmia and cardiac insufficiency may occur. Myocardial ischemia can manifest chest tightness and chest pain, which is characterized by a feeling of tightness and pressure-like pain in the chest, and often occurs during a certain degree of exercise or physical labor. The pain often spreads to the inner left arm, shoulder or back. When myocardial ischemia worsens, symptoms related to arrhythmia such as chest tightness, palpitations (rapid heartbeat, often accompanied by panic), generalized weakness, dizziness, fainting, and other symptoms, and symptoms related to heart failure such as shortness of breath, dyspnea, cyanosis, and irritability, may also occur. Some patients may also experience frequent gastrointestinal symptoms such as nausea, vomiting, and epigastric pain. Large myocardial infarction may cause shock symptoms such as lowered blood pressure and rapid pulse. It is recommended to go to the hospital in time when the above symptoms occur.