An automated external defibrillator is a computerized medical device that can check a person’s heart as well as shock it back to a normal rhythm. It can help save the life of someone who has suffered sudden cardiac arrest, the abrupt loss of heart function. The AED uses voice prompts, lights and text messages to tell the rescuer the steps to take. AEDs are very accurate and easy to use. With a few hours of training, anyone can learn to operate an AED safely.