Editing Automated external defibrillator (section)

=== Conditions that the device treats ===
An automated external [[defibrillator]] is used in cases of life-threatening cardiac [[Heart arrhythmia|arrhythmia]]s which lead to sudden [[cardiac arrest]], which is not the same as a heart attack. The rhythms that the device will treat are usually limited to:

# Pulseless [[Ventricular tachycardia]] (shortened to VT or V-Tach)<ref name=AHA1/>
# [[Ventricular fibrillation]] (shortened to VF or V-Fib)

In each of these two types of shockable [[cardiac arrhythmia]], the heart is electrically active, but in a dysfunctional pattern that does not allow it to pump and circulate blood. In ventricular tachycardia, the heart beats too fast to effectively pump blood. Ultimately, ventricular tachycardia leads to ventricular fibrillation. In ventricular fibrillation, the electrical activity of the heart becomes chaotic, preventing the [[ventricle (heart)|ventricle]] from effectively pumping blood. The fibrillation in the heart decreases over time, and will eventually reach [[asystole]].

AEDs, like all defibrillators, are not designed to shock asystole ('flat line' patterns) as this will not have a positive clinical outcome. The asystolic patient only has a chance of survival if, through a combination of CPR and [[cardiac stimulant]] drugs, one of the shockable rhythms can be established, which makes it imperative for CPR to be carried out prior to the arrival of a defibrillator.