Ep 297 - The 5th Universal Definition of MI - what emergency clinicians need to know

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:

Why the familiar type 1–5 classification has been replaced by primary, secondary and procedure-related myocardial infarction.

How conditions including plaque rupture, spontaneous coronary artery dissection, coronary vasospasm and embolism now fit within primary MI.

Why the definition now supports sex-specific 99th percentile high-sensitivity troponin thresholds, and what this may mean for commonly used assays.

How coronary or cardiac imaging has become more important when moving from a likely MI diagnosis towards confirmation and defining the underlying mechanism.

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.

The challenge of diagnosing chronic myocardial injury in the emergency department when the definition describes assessment in a stable clinical setting.

Why interpreting a troponin delta remains nuanced: absolute versus relative change, time from symptom onset and the interval between samples all matter.

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