Fatal arrhythmias are arrhythmias that can cause life-threatening or sudden death, and are characterized by frequent multi-source premature ventricular beats, ventricular tachycardia, R on T (or R riding T) phenomenon, ventricular fibrillation, complete atrioventricular block, slow fast The most common causes of bradycardia are: ventricular tachycardia, ventricular tachycardia, R on T, ventricular fibrillation, complete AV block, bradycardia and severe bradycardia. In everyday life, some seemingly healthy people suddenly feel ill or have palpitations, and then die instantly. Most of these patients die from fatal arrhythmias. Sudden death can occur at home, at work, while walking, or at any point in the medical process. Middle-aged men are more likely to die in recreational settings or during sexual intercourse. Because of the unpredictability, unpreparedness, and lack of emergency care, the onset of the arrhythmia is often too late to save the patient and he dies. What factors can cause fatal arrhythmias? Coronary heart disease is the most common cause of fatal arrhythmias. Fatal arrhythmias can easily occur due to myocardial ischemia and hypoxia, decreased contractility, decreased cardiac output, electrophysiological instability of the myocardium, and damage to the cardiac conduction system as a result of atheromatous plaques, emboli, and spasms in the coronary arteries. In addition, it can occur due to structural changes in the heart, such as ventricular wall rupture, severe metabolic acidosis, electrolyte disturbances (severe hyperkalemia, hypokalemia, or hyponatremia), hypothermia (<29°C), and digoxin toxicity. What are the manifestations of patients with fatal arrhythmias? Patients may experience mild panic, shortness of breath, chest tightness or precordial discomfort, precordial pain, sweating, weakness, and dizziness. These symptoms may occur suddenly or unconsciously, and some patients may not feel anything at all. If the fatal arrhythmia is secondary to a disease, the disease is often the main manifestation. Patients with idiopathic arrhythmias may also have no specific manifestations. Patients with obesity, diabetes, hypertension, hyperlipidemia, coronary artery disease, old myocardial infarction, valvular heart disease, cardiomyopathy, cardiac insufficiency or heart failure, use of drugs toxic to the heart, patients with vomiting and diarrhea, cerebrovascular disease, history of syncope and convulsions, men over the age of 40 or menopausal women with these symptoms should seek medical advice. An electrocardiogram or ambulatory electrocardiogram and echocardiogram should be performed by a physician. Repeated ECGs are needed to detect these arrhythmias as early as possible. Fatal arrhythmias can occur in healthy people, but are more common in people with coronary artery disease and the other groups mentioned above. There is no effective way to accurately predict fatal arrhythmias and therefore no effective prevention. If a fatal arrhythmia is detected during an ambulatory electrocardiogram, prophylactic drug therapy (e.g., amiodarone or sotalol) should be administered. In patients with ischemic heart disease who have recurrent malignant ventricular arrhythmias, a buried cardioverter-defibrillator may be considered to prevent sudden cardiac death.