Bloods to order immediately: Troponin (hs-TnI/TnT), D-dimer (if PE suspected), FBC, U&E, LFTs, clotting, glucose, CRP. Request CXR and request echo if tamponade/dissection suspected.
All items target completion within 10 minutes of arrival
STEMI Criteria: ST-elevation ≥1mm in ≥2 contiguous limb leads, OR ≥2mm in ≥2 contiguous chest leads, OR new Left Bundle Branch Block (LBBB)
Target: door-to-balloon (PPCI) <90 minutes. Activate cath lab immediately.
| Territory | Leads | Artery |
|---|---|---|
| Anterior | V1–V4 | LAD |
| Inferior | II, III, aVF | RCA (usually) |
| Lateral | I, aVL, V5–V6 | LCx / diagonal |
| Posterior | V7–V9 (ST dep V1–V3) | RCA / LCx |
| Right ventricular | V3R–V4R | RCA proximal |
NSTEMI: Elevated hs-troponin + ischaemic symptoms, WITHOUT ST-elevation. May show ST-depression, T-wave changes, or normal ECG.
Draw at presentation (0h) and 3 hours. Delta change >20% = acute MI. If initial result very low and no delta rise — rule out.
Validated with specific assays. Rule-in at 1h if absolute rise > assay-specific delta. Rule-out if 0h very low AND 1h rise minimal.
Elevated troponin alone does NOT diagnose MI — interpret with clinical context, ECG, and symptoms.
GRACE score stratifies NSTEMI patients into low, intermediate, and high risk — drives timing of angiography.
| Killip Class | Clinical Features | 30-day Mortality |
|---|---|---|
| Class I | No signs of heart failure | ~6% |
| Class II | Mild–moderate HF: basal crackles, S3, raised JVP | ~17% |
| Class III | Severe HF: frank pulmonary oedema, bilateral crackles >50% | ~38% |
| Class IV | Cardiogenic shock: hypotension + peripheral hypoperfusion | ~67% |
In low-probability patients (Wells 0–1), if ALL 8 PERC criteria are negative, D-dimer can be safely omitted.
If ALL 8 PERC criteria absent in low-probability patient: PE excluded without D-dimer. Post-test probability <2%.
D-dimer is highly sensitive, low specificity. A negative result in low-to-moderate probability patients excludes PE. A positive result does NOT diagnose PE — CTPA required for confirmation.
D-dimer is elevated by: age, pregnancy, malignancy, post-op, infection, inflammation, DIC, renal failure, recent trauma. Age-adjusted threshold: age × 10 mcg/L (in patients >50).
Haemodynamic instability (SBP <90 or drop >40 mmHg >15 min, not explained by arrhythmia or hypovolaemia)
Haemodynamically stable BUT evidence of RV dysfunction (echo/CTPA/biomarkers: elevated troponin or BNP)
Haemodynamically stable, no RV dysfunction, low biomarkers (PESI score low)
Nursing alert — thrombolysis (alteplase 100mg): Maintain 2 large-bore IVs. No IM injections, arterial lines, unnecessary venepuncture during and 24h post-thrombolysis. Monitor for bleeding (gum ooze, haematuria, reduced GCS). Reverse with FFP / cryoprecipitate if major bleed.
Surgical emergency. Type A (involves ascending aorta) — emergency surgery. Type B (descending only) — medical management first.
Beck's Triad: Hypotension + Muffled heart sounds + Raised JVP. Medical emergency — pericardiocentesis required.
Distinguish from STEMI — pericarditis ST elevation is diffuse, concave up, with PR depression. No reciprocal changes. Troponin mildly elevated in myopericarditis.
DO NOT wait for CXR if tension PTX suspected. Needle decompression immediately: 2nd intercostal space, midclavicular line, then chest drain.
Delta rise >20% between 0h and 3h troponin strongly suggests acute MI. Alert clinician without delay — do not wait for all results before escalating.
Escalate immediately if: New ST elevation, VT/VF on monitor, SBP <90 mmHg, SpO₂ falling <94%, new altered consciousness, severe pain unresponsive to GTN
Use SBAR framework for on-call escalation. Document all calls with time, clinician name, information given, and response received. If advice inadequate — escalate to senior.
| Leads | Criteria for ST-Elevation | Territory | Special Notes |
|---|---|---|---|
| Limb leads (I, II, III, aVL, aVF) | ≥1mm elevation in ≥2 contiguous leads | Inferior / lateral / high lateral | Check reciprocal depression |
| Chest leads (V1–V6) | ≥2mm elevation in ≥2 contiguous leads | Anterior / septal / lateral | V2–V3 highest sensitivity |
| New LBBB | Treat as STEMI equivalent | Presumed anterior | Sgarbossa criteria for LBBB MI |
| Posterior (V7–V9) | ≥0.5mm in V7–V9 | Posterior wall | ST depression V1–V3 = posterior mirror |
| Right ventricle (V3R–V4R) | ≥1mm in V3R/V4R | RV infarct | Occurs with inferior STEMI — avoid nitrates |
RV infarct (inferior STEMI + V4R elevation): Highly nitrate-sensitive — GTN can cause catastrophic hypotension. Fluid resuscitation is the treatment. Always do right-sided leads in inferior STEMI.
| Pain Character | Top Diagnoses | Key Differentiator |
|---|---|---|
| Crushing / pressure | ACS (STEMI/NSTEMI), aortic stenosis | ECG, troponin, radiation |
| Tearing / ripping | Aortic dissection | Maximum at onset, BP difference |
| Sharp / pleuritic | PE, pericarditis, PTX, pleuritis | Wells score, D-dimer, ECG, CXR |
| Burning | GORD, oesophageal spasm, ACS atypical | Relation to food, antacids, GTN trap |
| Reproducible on palpation | Costochondritis, Tietze, rib fracture, MSK | No cardiac risk factors, normal ECG/troponin |
| Positional (worse flat) | Pericarditis, GORD, aortic dissection | Pericardial friction rub, PR depression |
Gulf populations have disproportionately high rates of ACS at a younger age (<50). Key risk drivers: type 2 diabetes mellitus (epidemic-level prevalence), hypertension, obesity, dyslipidaemia, and heavy shisha and cigarette smoking. Acute MI in patients aged 30–45 is not uncommon in GCC emergency departments.
All GCC licensing exams test ACS/chest pain assessment. SCFHS and DHA commonly test STEMI criteria, Wells score, and Killip classification.
Pain descriptors may differ — some patients describe ACS as "tightness" or "heavy feeling." Many patients may not present until pain is severe due to cultural stoicism or healthcare system unfamiliarity (expatriate workers). Provide discharge instructions in Arabic and English. Involve family in cardiac education where culturally appropriate.