More recently, the appearance of an equipment box with the symbol of a red heart and the letters AED are in hallways of schools and office buildings. Do we know what the letters AED stand for? It is an automated external defibrillator An automated external defibrillator is a device that can be attached to your chest. It senses your heart's rhythm during cardiac arrest and, in some cases, delivers an electric shock to get your heart beating again.It is estimated that on average it takes eight to 10 minutes for first responders (9-1-1) to reach a victim so it is essential for the public to be trained and certified in performing CPR and using an AED until advanced help arrives. As secretariat for the Accredited Standards Committee for Safety Signs and Colors, ANSI Z535, and the International Standards Organizations Technical Advisory Group for ISO TC 145, NEMA facilitates work to develop standardization of safety symbols such as the red heart with a jagged white lightning bolt on the AED equipment. NEMAs finger remains on the pulse and were not missing a beat .