Expansion
ECG first, then troponin, then the diagnosis follows
Expansion
| ECG | Troponin | Pathology | |
|---|---|---|---|
| Unstable angina | Normal or ischaemic | Normal | Plaque rupture, partial occlusion |
| NSTEMI | Normal or ischaemic, no ST elevation | Raised | Partial or intermittent occlusion |
| STEMI | ST elevation or new LBBB | Raised | Complete occlusion |
“The ECG decides the pathway, the troponin decides the label.” A STEMI is diagnosed and treated on the ECG alone; waiting for troponin wastes myocardium.
STEMI criteria: 1 mm in two contiguous limb leads, 2 mm in two contiguous chest leads (1.5 mm in women), or new left bundle branch block with a compatible history.
Immediate management, remembered as MONA-B but given in a sensible order:
- Aspirin 300 mg plus a second antiplatelet
- Analgesia, morphine with an antiemetic
- Nitrate, if not hypotensive
- Oxygen only if saturations are below 94 per cent; routine oxygen is harmful
- Anticoagulation
Reperfusion in STEMI: primary PCI within 120 minutes of first medical contact, otherwise thrombolysis. In NSTEMI, risk stratify with the GRACE score and angiograph within 72 hours, or immediately if unstable.