Fifth Universal Definition of Myocardial Infarction (2026)

“The main update is that the previous numerical classification of MI has been replaced. The Fifth UDMI has been devised to align with the usual pathway for evaluation of patients with suspected MI, while also considering underlying pathophysiology and incorporating more objective diagnostic criteria to enable more consistent application in practice, research and clinical trials.”

“Clinicians often do not use the previous numerical terminology – e.g. type 2 or type 4c – in patient discussions as it is rather complex. With the new approach, we can now talk with patients about the cause of their MI so that they can understand their condition and recognise why the next steps, such as further tests and treatments, are needed.”

“The previous universal definition used a numerical system to categorise the different types of MI but this was not always easy to apply in clinical practice, leading to inconsistences in diagnosis and treatment. The ESC, ACC, AHA and WHF have worked together to devise an updated and simplified classification system for MI, which aims to address these limitations.”