Acute myocardial infarction is a sudden and life-threatening disease. In addition to the patient's coronary atherosclerotic stenosis, due to some triggers, the coronary atherosclerotic plaque ruptures. The platelets accumulate on the surface of the ruptured plaque, forming a blood clot (thrombus), suddenly blocking the lumen of the coronary artery, resulting in ischemic necrosis of the myocardium. Acute myocardial infarction can be induced when myocardial oxygen demand increases dramatically or coronary artery spasm. Improper disposal of acute myocardial infarction can be life threatening.

Common causes of myocardial infarction are physical exertion, emotional agitation, overeating, cold stimulation, constipation, smoking, heavy drinking, etc. Some patients with acute myocardial infarction have prodromal symptoms 1-2 days or 1-2 weeks before the onset. The most common symptoms are the exacerbation of the original angina, prolonged onset time, worsen effect of taking nitroglycerin, or long time of angina with no history. However, there are also many patients who do not have any signs before the onset, which is unexpected.

Symptoms of myocardial infarction include:

1. Sudden onset of severe and persistent retrosternal or precordial crushing pain.

2. A small number of patients shows no pain. More than half of the elderly have no chest pain, but only chest tightness.

3. Some patients have pain located in the epigastric region. It might be misdiagnosed as an acute abdomen such as gastric perforation and acute pancreatitis.

4. A small number of patients show neck, jaw, pharynx and tooth pain.

5. Mental disorders may appear, which can be seen in shock patients or patients with "cerebral heart syndrome".

6. Indescribable feeling of impending death and discomfort.

7. Gastrointestinal symptoms, manifested as nausea, vomiting, bloating, etc.

8. About 75%-95% of patients have arrhythmia, which mostly occurs within 24 hours. Anterior myocardial infarction is prone to rapid ventricular arrhythmias, and inferior myocardial infarction is prone to slowed heart rate and atrioventricular block.

9. Heart failure, mainly acute left heart failure, manifested as dyspnea, cough, cyanosis, irritability and other symptoms, is easy to occur in the first few hours of the onset, and can also occur a few days after the onset.

10. Hypotension, or shock.

On-site first aid methods for acute myocardial infarction are as follows:

The first is early identification. The typical symptom of myocardial infarction is angina in the middle or center left of the sternum, with a dying, oppressive feeling that can last 5 to 15 minutes or more. Other patients may be accompanied by symptoms such as sweating and nausea. In general, ordinary angina does not take more than 5-10 minutes. When the chest pain lasts for 20 minutes and does not relieve, it is highly suspected that it is a myocardial infarction. In addition, sometimes myocardial infarction is also manifested as atypical symptoms, such as stomach pain, toothache, and sore throat, which are very easy to ignore. When the above symptoms occur, the patient and his family should be extra vigilant. It is best to send the patient to the hospital immediately. The patient should never endure the paint.

The second is to rest quietly. If the above symptoms occur, the patient should immediately stop any heavy physical activity, rest in place, and calm the excitement in time to reduce myocardial oxygen demand. It is not recommended to walk around, especially do not walk to the side of the road to wait for an ambulance. Because it will increase the burden on the heart, which may directly lead to sudden death.

The third is to call 120. According to the survey, nearly 1/4 of patients do not call the emergency number at the first time, but call their families to come and call 120 after arrival, thus delaying the rescue time. Statistics show that nearly half of myocardial infarction patients went to the hospital on their own, thinking that it was faster. Less than 26% of people arrived at the hospital by calling an ambulance. But in fact, many patients died on their way to the hospital due to improper handling.

The fourth is general treatment. The patient should lie flat or semi-recumbent, and stay quiet to reduce irritation. It is necessary to keep warm in winter. If the patient has symptoms of hypoxia, such as dyspnea, cyanosis of the lips, etc., oxygen can be given, and it should be noted that oxygen intake should be moderate. Excessive oxygen intake is harmful. If the patient has a history of coronary heart disease and there may be acute myocardial infarction, nitroglycerin, aspirin and other drugs can be taken under the guidance of professionals. If there is no history or the patient's condition is not clear, it is best not to give the patient medicine casually.

The fifth is to prevent sudden death. After myocardial infarction, one of the most serious arrhythmias is ventricular fibrillation. Ventricular fibrillation appears when the heart is in a state of trembling that cannot pump blood, which is similar to cardiac arrest. If not treated immediately, sudden death may occur. At this point, the patient should be immediately placed in a supine position. Others should call the patient. If the patient is not conscious and does not breathe within 5-10 seconds or there is only has death-like breathing, effective chest compressions and rescue breaths should be performed immediately on the spot. An automated external defibrillator (AED) can be used follow instruction where possible, until the professional arrives at the scene.

The sixth is to save the heart muscle. The core of saving the heart muscle is to cooperate with doctors and do a good job in doctor-patient communication. The emergency capacity of hospitals varies greatly, so be sure to follow the arrangements of the emergency doctor and send them to a hospital capable of treating acute myocardial infarction. If the patient is diagnosed with myocardial infarction, special treatment such as thrombolysis and catheter should be carried out immediately. Family members must trust and cooperate with the doctor, sign quickly, and carry out special treatment for the patient as soon as possible to avoid wasting precious rescue opportunities.