The fork
Chest pain plus an ECG within 10 minutes of arrival. The ECG splits the pathway:
- ST elevation in two contiguous leads (or new LBBB with a convincing clinical picture) → STEMI, reperfusion now
- No ST elevation → serial troponin decides between NSTEMI (troponin rises) and unstable angina (troponin normal)
Note that unstable angina and NSTEMI are managed almost identically; the label matters mostly for prognosis and documentation.
STEMI: reperfusion and the clock
- Primary PCI if it can be delivered within 90 minutes of first medical contact at a PCI centre, or 120 minutes if transfer is required
- Fibrinolysis if PCI is not achievable in that window, ideally within 30 minutes of arrival. Transfer for angiography afterwards regardless of apparent success
- Absolute contraindications to lysis worth memorising: any prior intracranial haemorrhage, ischaemic stroke within 3 months, known cerebral vascular malformation or malignant intracranial neoplasm, suspected aortic dissection, active bleeding, significant closed head injury within 3 months
Immediate treatment for both pathways
- Aspirin 160–325 mg chewed — the intervention with the clearest mortality benefit
- Second antiplatelet: ticagrelor or prasugrel preferred over clopidogrel for PCI
- Anticoagulation: unfractionated heparin, LMWH or fondaparinux
- Nitrates for ongoing pain, avoided in right ventricular infarction, hypotension, or after a phosphodiesterase-5 inhibitor within 24–48 hours
- Beta-blocker within 24 hours unless there is heart failure, low output, heart block or shock
- High-intensity statin for everyone
- Oxygen only if saturations are below 90% — routine oxygen in the normoxic is harmful
- Morphine for pain not relieved by nitrates, accepting that it slows antiplatelet absorption
Risk stratification without ST elevation
TIMI or GRACE scores drive timing. Early invasive angiography (within 24 hours) for high-risk features: ongoing ischaemia, dynamic ST change, rising troponin, haemodynamic or electrical instability, heart failure.
Complications by timing
| Timing | Complication |
|---|---|
| Minutes to hours | Ventricular fibrillation, complete heart block (inferior) |
| 1–3 days | Pericarditis, arrhythmia, heart failure |
| 3–7 days | Papillary muscle rupture (acute mitral regurgitation, flash pulmonary oedema), ventricular septal rupture (new harsh murmur, shock), free wall rupture (tamponade, PEA arrest) |
| Weeks | Ventricular aneurysm, mural thrombus, Dressler's syndrome |
Secondary prevention on discharge
Aspirin indefinitely, second antiplatelet for 12 months, high-intensity statin, ACE inhibitor (especially with reduced ejection fraction, diabetes or anterior infarct), beta-blocker, and cardiac rehabilitation — which is a genuine mortality intervention and a frequent correct answer. Address smoking, and assess driving and return-to-work restrictions.