More than 300 adolescents and young adults die suddenly and unexpectedly each year in the UK. Most of these deaths are caused by inherited forms of heart disease and are potentially preventable. Mass screening programmes are unlikely to be cost-effective, but targeted cardiac evaluation of ‘at risk’ cohorts – those with symptoms and a family history of inherited cardiac disease or premature sudden death – should identify the majority of individuals at risk. Identification of disease-causing genes is feasible and genetic evaluation facilitates definition of ‘at risk’ relatives. The majority of affected individuals will not die suddenly. Importantly, it is possible to stratify risk and implement effective treatments with drugs or devices, such as the implantable cardioverter defibrillator, a specialised pacemaker which recognises and terminates potentially lethal arrhythmias.