Is AEDs used for atrial fibrillation or ventricular fibrilation?

Automated External Defibrillators (AEDs) are primarily used for ventricular fibrillation, a life-threatening heart rhythm that requires immediate defibrillation to restore a normal heartbeat. They are not effective for atrial fibrillation, which is a less critical condition that typically does not lead to sudden cardiac arrest. AEDs analyze the heart's rhythm and deliver a shock only when necessary, specifically targeting conditions like ventricular fibrillation.