Causes of cardiac arrest include massive myocardial infarction, malignant arrhythmias, and severe disorders of the electrical mechanism. Massive myocardial infarction leads to a significant decrease in the contractility of the heart, and in some patients the onset of cardiac arrest can occur rapidly, manifesting as sudden death. In some patients, cardiac arrest is caused by malignant arrhythmias, such as ventricular fibrillation and ventricular tachycardia, and severe electrolyte disturbances can also lead to cardiac arrest, such as severe hypokalemia. Cardiac arrest requires rapid assessment of the condition, continuous cardiopulmonary resuscitation, immediate electrical defibrillation to restore sinus rhythm in patients with malignant arrhythmias, electrolyte supplementation in patients with electrolyte disturbances, and immediate vascularization and emergency PCI in patients with acute myocardial infarction. Cardiac arrest is a clinical emergency, after the onset of resuscitation, and find the primary cause of the disease, in the local rescue at the same time, to immediately contact the 120 emergency physician.