The principle of defibrillators is to remove arrhythmia by applying an electric current to the heart to restore the heart to a normal rhythm. Defibrillators, also known as electrical resuscitators, were initially invented using industrial alternating current (AC), which is more dangerous, and with the development of modern technology, direct current is mainly used to defibrillate the heart. Defibrillators are mostly used for the treatment of supraventricular or ventricular tachyarrhythmias, in which all heart muscle cells are depolarized at the same time by an electrical shock of a certain energy, and then repolarized at the same time by the physiological effect of the current’s disappearance. Since the sinus node possesses the highest autoregulation in the heart, the sinus node can regain dominance over the contraction beat rhythm of the heart. It is important to note that not all arrhythmias can be treated with a defibrillator and the decision to use one should be made by a physician.