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ACS & STEMI
Time is myocardium — the ECG decides the next 90 minutes. Get a 12-lead ECG within 10 minutes, recognise STEMI and the STEMI equivalents, activate the reperfusion pathway, and risk-stratify everyone else with high-sensitivity troponin. Built for revision, not live patient decisions.
Settle them, and check the basics
ECG within 10 minutesRed flags — what each should make you think
Repeat the ECG. A first ECG is normal in a good proportion of MIs, and changes evolve over minutes. Repeat it every 15–30 minutes while the pain continues, and compare it with old ECGs. And never thrombolyse or anticoagulate before you've thought about aortic dissection.
Immediate actions
- ECG12-lead within 10 min
- AspAspirin 300 mg
- 💊Pain relief
- O₂Oxygen only if needed
- ☎STEMI → call the PPCI centre
- IVIV access, bloods
Understand the patient & read the ECG
STEMI or not?STEMI criteria
- New ST elevation at the J point in two contiguous leads: ≥1 mm in limb leads; in V2–V3 ≥2 mm in men over 40, ≥2.5 mm under 40, ≥1.5 mm in women; ≥1 mm in other chest leads
- Posterior MI — horizontal ST depression V1–V3 with tall R waves; confirm with ST elevation in V7–V9
- New LBBB or paced rhythm with ongoing ischaemic symptoms — discuss with the cath lab (Sgarbossa criteria help)
- De Winter — upsloping ST depression with tall T waves in the chest leads (LAD occlusion)
Territories: inferior II, III, aVF (RCA usually; check right-sided V4R for RV infarct — avoid nitrates and give fluid if hypotensive); anterior V1–V4 (LAD); lateral I, aVL, V5–V6 (circumflex).
Reperfusion (NICE NG185)
- STEMI within 12 h of onset → primary PCI if it can be delivered within 120 minutes of when fibrinolysis could have been given
- If PCI can't be delivered in time → fibrinolysis (no contraindications), then transfer for angiography
- Presenting after 12 h with ongoing ischaemia or shock → still consider PCI
- Second antiplatelet and anticoagulation per the PPCI centre protocol
Work A–E — assess and act as you go
The diagnoses you must not miss
tap to open eachWhat points toward it, what would rule it in, and how to manage it.
Ischaemic pain with ST elevation, or a STEMI equivalent (posterior, de Winter, new LBBB with symptoms, hyperacute T waves).
ECG — don't wait for troponin.
Aspirin, analgesia, call the PPCI centre, transfer with defibrillator pads on.
Ischaemic pain with ST depression, T inversion or a normal ECG.
High-sensitivity troponin pathway (local 0/1 h or 0/3 h protocol); a rise and/or fall above the 99th centile.
Aspirin, antithrombin (e.g. fondaparinux unless high bleeding risk or immediate angiography), calculate GRACE. Angiography within 72 h if 6-month mortality risk above 3%; immediately if unstable, ongoing pain or arrhythmia.
Hypotension, cold peripheries, confusion, oliguria, pulmonary oedema after MI.
Clinical, lactate, bedside echo.
Emergency PCI, senior cardiology and ITU, inotropes/mechanical support under specialist care.
Sudden deterioration, new pansystolic murmur (papillary muscle rupture or VSD), or tamponade (free wall rupture).
Urgent echo.
Cardiothoracic surgery; senior cardiology now.
Sudden tearing pain radiating to the back, pulse or BP difference between arms, neuro signs, new aortic regurgitation; inferior STEMI if the dissection involves the RCA.
CT aortogram.
No thrombolysis, no anticoagulation. BP and HR control, cardiothoracic surgery.
Investigate — what to order, when, and what it tells you
test with a question in mindECG
High-sensitivity troponin
Other bloods
Imaging
How the plan comes together
disposition · handovercardiology
NSTEMI/unstable angina: cardiology ward, GRACE-guided angiography, secondary prevention (dual antiplatelets, high-intensity statin, ACEi, beta-blocker, cardiac rehab).
cath lab / CCU
STEMI or equivalent, ongoing pain, haemodynamic or electrical instability.
Hand over: time of onset, ECG time, drugs given and times, door-to-balloon plan.
Look hard at the ECG, repeat it, and compare it with old ones. Know the equivalents (posterior MI, de Winter, Wellens), and don't let a normal first troponin reassure you when the story is classic. Nicely done getting here.
Clerking template
copy or downloadACS & STEMI — documentation structure
A structure and prompt list to help you document and think systematically. It is not a completeness check and cannot guarantee nothing is missed — use your trust's own proforma, your seniors, and your clinical judgement.
Test yourself
active recallCover the answer, say it out loud, then reveal. Retrieval beats re-reading.
0 / 12 knownFrequently asked questions
quick answersWhat are the red flags for acute coronary syndrome (ACS) and STEMI?
- ST elevation in contiguous leads — think STEMI — activate PPCI
- ST depression V1–V3, tall R — think posterior MI
- New LBBB/paced + ongoing pain — think occlusion MI — discuss with cath lab
- Deep or biphasic T in V2–V3, pain-free — think Wellens — critical LAD
- Hypotension, cold, wet — think cardiogenic shock
- Tearing pain to the back, unequal arm BP — think aortic dissection — no anticoagulation
- New harsh murmur after MI — think papillary muscle or septal rupture
What is the initial management of acute coronary syndrome (ACS) and STEMI?
- 12-lead within 10 min — repeat if pain persists; add V7–V9 and right-sided leads if posterior or RV MI suspected
- Aspirin 300 mg — unless genuinely allergic or dissection suspected
- Pain relief — GTN (if BP allows); IV morphine titrated with an antiemetic
- Oxygen only if needed — if SpO₂ below 94% (88–92% if at risk of hypercapnia)
- STEMI → call the PPCI centre — don't wait for troponin
- IV access, bloods — troponin, FBC, U&E, glucose, lipids, clotting
Always alongside senior support and your local guideline.
What diagnoses must you not miss in acute coronary syndrome (ACS) and STEMI?
- STEMI / occlusion MI — activate PPCI
- NSTEMI / unstable angina — troponin rise · no ST elevation
- Cardiogenic shock — cold · wet · hypotensive
- Mechanical complications — new murmur days after MI
- Aortic dissection (mimic) — don't lyse
Open each one in the must-not-miss section for what points toward it, how to rule it in, and how to manage it.
What investigations should a junior doctor order for acute coronary syndrome (ACS) and STEMI?
- ECG — V7–V9 (posterior), V4R (RV).
- High-sensitivity troponin — Myocardial injury; interpret with symptoms and ECG (sepsis, PE, AKI, myocarditis also raise it).
- Other bloods — FBC, U&E, glucose, HbA1c, lipids, clotting, LFT.
- Imaging — Pulmonary oedema, widened mediastinum.
Admit or discharge: how is the plan decided for acute coronary syndrome (ACS) and STEMI?
- Cardiology — NSTEMI/unstable angina: cardiology ward, GRACE-guided angiography, secondary prevention (dual antiplatelets, high-intensity statin, ACEi, beta-blocker, cardiac rehab).
- Cath lab / ccu — STEMI or equivalent, ongoing pain, haemodynamic or electrical instability.
Is there a clerking template for acute coronary syndrome (ACS) and STEMI?
Yes — there is a free clerking template for acute coronary syndrome (ACS) and STEMI on this page, structured as presenting complaint, red flags asked, history, examination (A–E), investigations, differentials, plan and escalation. You can copy it or download it as a Word document. Jump to the template.
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