What is the role of electric shock when resuscitating a patient? What are the circumstances under which electric shocks are used?

The shock device is called a defibrillator, which is used to correct ventricular fibrillation in order to return the patient to sinus rhythm. If the patient's heart has stopped beating, the shock will not restore the heartbeat. Simply put, the shock is to defibrillate the patient's original abnormal heart rhythm back to normal.