30/08/2026
The 5th Universal Definition of MI is out. Thankfully, no more type 1, 2, 4a, 4b, 5 MI. Simpler and more clinically relevant.
Here is my summary on the document:
1. Primary MI. Wider than the old type 1. Atherothrombosis, SCAD, embolism, vasospasm. Stent thrombosis, restenosis, or graft failure past 30 days is now primary, not procedural.
2. Secondary MI. Supply-demand mismatch from another illness. Much stricter now. Demand ischemia plus a troponin bump is not enough. You need obstructive CAD or a new wall motion abnormality.
3. Procedure-related MI. Any cardiac procedure, within 30 days instead of 48 hours. However, we need an angiographic evidence or a new RWMA. Both if it happens during the case itself or the procedure was for an acute MI. Troponin supports the diagnosis but doesnโt make it (>5x URL at 6h for PCI, >35x at 24h for surgery).
4. Type 3 MI is gone. If someone dies, classify by the clinical setting or post-mortem findings.
5. Troponin cutoffs are sex-specific. For high sensitivity troponin, the female upper limit is about half the male.
6. MINOCA is now myocardial injury, not infarction. Non-obstructive means under 50% stenosis. Itโs a working diagnosis, since most of these patients turn out to have myocarditis or Takotsubo cardiomyopathy.
7. Silent MI has criteria now. Pathological Q waves arenโt enough. Confirm with imaging, ideally CMR with LGE, new RWMA
8. Shouldnโt say typical and atypical pain; rather chest discomfort. Rather, say โchest discomfort.โ
9. A whole section on structural. Bottom line, troponin rise after TAVR by itself is no longer an MI. You need the angio finding or new RWMA.
