An automated external defibrillator (AED) is a portable electronic device that automatically diagnoses life-threatening cardiac arrhythmias of ventricular fibrillation and ventricular tachycardia in a patient, and is able to treat them through defibrillation, the application of electrical therapy which stops arrhythmia, allowing the heart to reestablish an effective rhythm. The device itself provides simple audio and visual commands, making it easy for use by most people in the event of a cardiac emergency. For more information on how to use an AED, please the following website. www.heart.org/cpr