Sudden cardiac arrest (SCA) causes ~20% of all deaths in Europe. SCA is lethal within minutes if left untreated and survival rates are presently only 5-20%. Therefore, there is a large medical need to improve SCA prevention and treatment. Designing effective individualized prevention and treatment strategies requires knowledge on genetic and environmental risk factors. So far, these efforts have been hampered by the lack of sufficiently large study cohorts of SCA patients with detailed information. Obtaining SCA patient samples is challenging as the condition happens suddenly and unexpectedly. In this project, leading European scientific teams which have created large relevant population cohorts, mostly dedicated to SCA research, join forces to fully exploit available data towards improving SCA management. This will be done by: - Building an unique and growing database of >100.000 (DNA) samples including >20.000 SCA patient samples, by combining existing European databases and infrastructures. - Identifying risk factors (inherited, acquired, environmental) and first-response treatment strategies that may explain the differences in SCA occurrence and survival between European countries - Collaborating with professional networks, such as the European Heart Rhythm Association, and European Resuscitation Council, to translate the outcomes into changes in clinical practice and influencing European health policies on SCA management.