Sudden cardiac death (SCD) is a major cause of adult mortality, accounting for about 350 000 deaths in Europe annually. SCDs in patients without structural heart disease are caused by ventricular arrhythmias generated from areas with abnormal electrical properties (‘substrate’) present within the heart. Paradoxically, despite the existence of efficient preventive therapies, most patients at risk cannot be identified pre-emptively to avoid sudden death. The major problems are 1) our incomplete mechanistic understanding in the role of electrical substrates in arrhythmia induction, 2) the information derived from the current benchmark noninvasive data is insufficient. Real-time, noninvasive imaging of cardiac electrical activity can be obtained through electrocardiographic imaging (ECGI) that could be used to gain insight into the mechanisms of sudden cardiac death. My aim is to develop a novel non-invasive electrical mapping tool, which will allow detection of key electrical signatures related directly to the substrates responsible for lethal arrhythmias, in order to understand the mechanisms underlying SCD in patients with structurally normal hearts. The unique approach proposed to achieve this objective will consist of: (1) defining the key electrical signatures specific to arrhythmogenic substrates using animal models designed to reflect previously identified clinical phenotypes and human donor hearts from SCD survivors; (2) developing and validating ECGI and post-processing techniques to identify these critical signatures using both experimental and clinical data; (3) Apply the noninvasive tools developed in a clinical setting to identify the mechanisms underlying arrhythmogenic risk in SCD survivors This project will constitute a new paradigm in clinical cardiac investigations and could allow a major breakthrough in the prevention of arrhythmic deaths in the world.