A defibrillator is a device that gives a high energy shock (known as defibrillation) to the heart, through the chest wall, to someone that is in cardiac arrest. The aim being is to restore normal heartbeat and this is done by delivering precisely calibrated and timed electrical shocks. Top brands include Philips and Lifepak, Freelance Surgical are happy to help with a professionally refurbished unit, when in stock.