Acute heart attack is one of the most serious emergencies in cardiology, and it is important to recognize early warning symptoms of heart attack. Most patients have new onset of angina symptoms or frequent episodes or worsening of existing angina symptoms within a week before the onset of the attack, or within 3-4 weeks before the onset of the attack. Some patients have symptoms such as weakness, chest discomfort, palpitations during activity, shortness of breath, and other symptoms several days before the onset. A small number of patients may not have any symptoms before the onset of myocardial infarction, which requires understanding the symptoms of heart attack and seeking medical attention as early as possible. Be alert to the occurrence of a heart attack if the following conditions occur in daily life: chest pain at night or at rest: when you have dull pain or pressure-like pain or burning pain in the precordial area without any reason in the resting state or at night while sleeping, or a sore and swollen feeling in the jaw, or with sore and swollen pain in the left upper limb, be highly alert to a heart attack. Continuous nocturnal attacks need to be seen in the cardiology department of the hospital as soon as possible. Aggravation of angina symptoms: Patients with existing angina present with aggravation of angina symptoms, manifested as chest pain with light physical activity, increased number of chest pains and prolonged duration of chest pain, medically known as exertional worsening angina, should be on high alert for infarction attack. New onset of angina symptoms: people who have never had chest pain symptoms and have recently experienced activity-related dullness or pressure-like pain or burning pain in the precordial region, or jaw soreness and swelling, or with soreness and swelling of the left upper limb, and still experience episodes of chest pain when the intensity of activity gradually decreases, especially people who have the habit of morning exercise and experience the above-mentioned chest pain symptoms during morning exercise, should be on high alert for an attack of heart attack. Pain in other parts related to angina: If there is pain in other parts related to activities, such as epigastric pain, toothache, jaw pain, left upper limb pain, shoulder and back pain, all need to be alert. In summary, if the degree, duration, and triggering factors of chest pain are different from previous episodes, you should be highly alert to the occurrence of heart attack.