去颤，是指对于危及生命的心律不整（cardiac dysrhythmias）、心室颤动（ventricular fibrillation）、无脉性心室频脉（pulseless ventricular tachycardia）一种常见的治疗手段，具体方法为使用去颤电击器给予心脏治疗剂量的电能。这么做能使极大部分的心肌去极化，终止心律不整，并使窦房结中的节律点能重建窦性节律。

去颤电击器又分为体外型、静脉置入型、植入型，依不同需要使用。

Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. Defibrillation consists of delivering a therapeutic dose of electrical current to the heart with a device called a defibrillator. This depolarizes a critical mass of the heart muscle, terminates the dysrhythmia and allows normal sinus rhythm to be reestablished by the body's natural pacemaker, in the sinoatrial node of the heart.