Top Things to Know: Fifth Universal Definition of Myocardial Infarction (2026)
Updated: August 28, 2026
Prepared by Prashant Nedungadi, PhD, National Vice President- Clinical Guidelines
- The Fifth Universal Definition of Myocardial Infarction (UDMI) developed jointly by ESC/ACC/AHA/WHF provides an updated, evidence-based definition and classification of myocardial infarction (MI) to support consistent diagnosis in both clinical practice and research.
- The consensus document introduces a simplified clinical classification that categorizes MI as primary, secondary, or procedure-related based on underlying pathophysiology, aligned with clinical evaluation of patients and supported by objective diagnostic criteria.
- The criteria for acute and chronic myocardial injury are refined and the underlying mechanisms discussed in the consensus document. Sex-specific 99th percentile upper reference limits for cardiac troponin define myocardial injury.
- MI is now classified into one of three clinical types:
- Primary MI: spontaneous presentation due to a primary acute coronary pathology
- Secondary MI: resulting from myocardial oxygen supply–demand imbalance due to another acute condition, and
- Procedure-related MI: occurring as a complication of a percutaneous or surgical cardiac procedure.
- The definition of MINOCA is updated to ‘myocardial injury with non-obstructive coronary arteries’ in recognition that this is a working rather than final diagnosis.
- Accelerated diagnostic pathways using high-sensitivity cardiac troponin assays are introduced and guidance is provided for the areas of practice in which the interpretation of cardiac troponin is challenging.
- The diagnosis of MI following sudden death is discussed and new, objective criteria are provided for silent or unrecognized MI.
- New guidance is provided for the diagnosis of MI in low-resource settings.
- International Classification of Disease 11th Revision (ICD-11) codes for use in hospital episode statistics and public health monitoring are proposed that align with the updated classification of MI to encourage implementation and further research.
- Adoption of the classification in practice and research will ensure the diagnosis of MI is meaningful for patients and clinicians with clear implications for care across healthcare settings.