TNNI3 and Myocardial necrosis: In order to validate the model, we sought to achieve the key criteria set out in the fourth universal definition, where MI is defined as myocardial necrosis in the context of myocardial ischaemia resulting in an elevation of a cardiac biomarker, such as cTnI (Daubert & Jeremias, 2010), with at least one value above the 99th percentile upper reference limit.