The Automated External Defibrillator (AED) is a portable electronic device that automatically diagnoses the potentially 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 the arrhythmia, allowing the heart to re-establish an effective rhythm to prevent the host from dying. The defibrillator is used in cases of life threatening cardiac arrhythmias which lead to cardiac arrest.