Heartwize, aims to tackle the important public health problem of out-of-hospital cardiac arrest. Every year in the UK, over 60,000 people have a cardiac arrest in which the heart stops pumping due to a sudden failure of the electrical activation. The brain and other vital organs are deprived of oxygen and without immediate resuscitation, death will ensue. Over half of the cardiac arrests that occur out of hospital are witnessed, with about 80% occurring in the home rather than in a public place. A prompt and effective bystander response can be the difference between life and death yet most people lack the knowledge or confidence to intervene as a result of which less than one in ten of those affected survive. The aim of Heartwize is to improve outcomes after cardiac arrest by raising community awareness and providing training in basic resuscitation skills in schools, businesses and the wider community.