When a cold wave comes and the temperature changes suddenly, the sympathetic nerves in the body suddenly become excited, causing a faster heartbeat, peripheral vasoconstriction and higher blood pressure, which all lead to an increase in myocardial oxygen consumption. Under the stimulation of cold wind, the coronary arteries contract and spasm. Cold can induce platelet aggregation to form thrombus, which leads to myocardial infarction. I. How to prevent myocardial infarction? First of all, patients with combined coronary artery disease, angina pectoris and the elderly should pay attention, go to the hospital for early medical examination and adjust the use of drugs. If frequent episodes of angina pectoris are likely to be the precursor of a “volcanic eruption”, it is recommended to seek medical attention in time to avoid myocardial infarction and other malignant events. Secondly, you should try to improve the body’s ability to adapt to sudden changes in the weather, physical exercise and appropriate outdoor exercise is a good way. These methods can promote blood circulation, enhance immunity and improve the body’s ability to resist sudden changes in weather factors. But pay attention to the choice of exercise time, cardiovascular disease attacks have a “morning peak phenomenon”, especially the cold air in the morning is more likely to induce cardiovascular disease. It is recommended that the temperature is relatively high 10-16:00 for exercise is the most appropriate. The following symptoms should be alerted: 1, unexplained fatigue, chest tightness or sudden angina attacks frequently, the degree of aggravation, prolongation and recent arrhythmias; 2, sudden nighttime panic, shortness of breath, can not lie down, constantly coughing out foamy blood sputum; 3, sudden unconsciousness, fall to the ground, incontinence; 4, hypertensive patients with unstable blood pressure, sometimes high and sometimes low, fluctuations. If the above symptoms appear, you should call “120” to send to the hospital for rescue. Before the arrival of medical personnel, the patient should immediately lie down on the ground, stabilize the patient’s emotions. And quickly do the following treatment: give the patient population containing nitroglycerin or quick-acting heart pills, if the family has oxygen bags, should immediately give oxygen, do not drive the patient to the hospital.