 However, most people who die from sudden cardiac death are not found to be at high risk by our current risk markers and 40 of the people who have ICDs do not have therapy within the first 4 years after implant. We need new and better ways of identifying people who are at high risk of sudden cardiac death so that we can prevent their deaths with ICDs. Our understanding of the electrical signals in the heart has increased considerably in recent years; in no small part this is due to our Principal Investigator Professor Andre Ngs basic science work. This study aims to take the understanding of action potential duration APD restitution gained through our work and other studies in humans and in computer simulations and translate it into a fresh way of assessing risk of sudden cardiac death. 