In Italy, people who die from cardiac arrest sudden (A.C.I.) are more than 200 per day, over 70 thousand per year. In 80% of the cases, the cardiac arrest hits in extra-hospital environments (in the houses private, in public offices, in streets and squares, at work, inside of sports facilities) without giving warning signs. For every minute that passes, the chances of surviving are lowered by 10%. If we consider that for the rescue arrivals the waiting time is more than 8-10 minutes, it is important that those present on the area, after having alerted the rescue, will be the first to practice cardiopulmonary resuscitation and have available the defibrillator.