The Fifth Universal Definition of Myocardial Infarction changes some familiar language around MI and puts new emphasis on how we interpret troponin, myocardial injury and imaging. For emergency clinicians, these changes affect both how we describe what is happening and how confidently we can make the diagnosis.
Iain Beardsell introduces Rick Body, Professor of Emergency Medicine at the University of Manchester, who works through what has changed and what it means in practice.
In this podcast:
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Why the familiar type 1–5 classification has been replaced by primary, secondary and procedure-related myocardial infarction.
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How conditions including plaque rupture, spontaneous coronary artery dissection, coronary vasospasm and embolism now fit within primary MI.
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Why the definition now supports sex-specific 99th percentile high-sensitivity troponin thresholds, and what this may mean for commonly used assays.
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How coronary or cardiac imaging has become more important when moving from a likely MI diagnosis towards confirmation and defining the underlying mechanism.
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Why a raised troponin is not synonymous with myocardial infarction, and how acute myocardial injury may result from inflammation, haemodynamic stress, physiological stress, catecholamine excess, toxicity or trauma.
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The challenge of diagnosing chronic myocardial injury in the emergency department when the definition describes assessment in a stable clinical setting.
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Why interpreting a troponin delta remains nuanced: absolute versus relative change, time from symptom onset and the interval between samples all matter.
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Where occlusive myocardial infarction (OMI) now sits: the terminology has not replaced STEMI/NSTEMI, but recognised occlusion patterns including de Winter T waves, Wellens syndrome, Sgarbossa criteria and posterior MI are explicitly discussed.
About Rick Body
Rick Body is Professor of Emergency Medicine at the University of Manchester and an honorary consultant at Manchester Foundation Trust. He is also Editor-in-Chief of the Emergency Medicine Journal and chairs the NICE Interventional Procedures Advisory Committee.
Timestamps
00:00 – Introduction and why the new definition matters
02:00 – Primary, secondary and procedure-related MI
04:00 – Sex-specific troponin thresholds
05:00 – Imaging and confirmation of myocardial infarction
06:00 – Acute myocardial injury and its causes
09:00 – Chronic myocardial injury in the ED
11:00 – Absolute versus relative troponin deltas
15:00 – OMI, STEMI and NSTEMI terminology
Links and resources
Read the accompanying St Emlyn’s article
Read the Fifth Universal Definition of Myocardial Infarction
View the IFCC high-sensitivity cardiac troponin assay reference tables
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