Contraindications to electrical defibrillation are as follows: 1. Arrhythmias caused by digitalis intoxication, such as premature ventricular contractions and atrioventricular block cannot be treated with electrical defibrillation, but ventricular fibrillation caused by digitalis intoxication can be treated with defibrillation; 2. Sluggish cardiac arrhythmias, including sick sinus node syndrome, atrial fibrillation, atrial flutter, atrial tachycardia accompanied by a high degree or complete atrioventricular block, and patients with severe hypokalemia cannot be treated with defibrillation. Sudden cardiac arrest is very common, the common cause of sudden cardiac arrest is coronary heart disease, such as poisoning, cerebrovascular accidents can also lead to sudden cardiac arrest, especially arrhythmia caused by sudden cardiac arrest is the most common. Arrhythmias are most commonly caused by ventricular fibrillation. If ventricular arrest occurs, electrical defibrillation is required, which should not be performed blindly. The type of arrhythmia cannot be specified, and the need for defibrillation therapy needs to be determined under the guidance of medical personnel.