As a medical professional with expertise in emergency medicine, I can provide guidance on the use of a defibrillator in the context of asystole. In a situation where a patient is experiencing asystole, which is an electrical standstill of the heart with no organized electrical activity, the use of a defibrillator is typically not indicated. Defibrillators are designed to deliver a high-energy shock to the heart to restore a normal rhythm in cases of ventricular fibrillation (VF) or pulseless ventricular tachycardia (VTach), not for asystole. The initial approach to asystole should focus on providing high-quality cardiopulmonary resuscitation (CPR) and rapidly addressing any potential reversible causes. Advanced life support (ALS) protocols may include the administration of epinephrine, atropine, or other medications, and the consideration of electrical pacing in specific situations. read more >>

In most popular medical dramas, when a patient has a cardiac arrest and "flatlines" the doctors many times use a defibrillator to "shock the heart back into rhythm'. I know that actually, the proper protocol is CPR and epinephrine (if possible), and that you should shock rhythms such as ventricular fibrillation.read more >>