Acute Coronary Syndrome

Cardiology

Spectrum of unstable angina, NSTEMI and STEMI from acute coronary plaque rupture or erosion.

Causes

  • Atherosclerotic plaque rupture
  • Coronary spasm
  • Embolism
  • Spontaneous dissection

Risk factors

  • Age, male, FHx
  • Smoking
  • Hypertension
  • Diabetes
  • Dyslipidaemia
  • Obesity
  • CKD

Clinical features

  • Central crushing chest pain >20 min
  • Radiation to arm/jaw
  • Diaphoresis, nausea
  • Dyspnoea (esp diabetics, elderly)

Examination

  • Pallor, sweating, anxious
  • S4 / new murmur
  • Pulmonary crackles if LV failure
  • Cool peripheries if shock

Investigations

  • 12-lead ECG within 10 min
  • High-sensitivity troponin 0 + 3 h
  • CXR, glucose, U&E, lipids
  • Echo for wall motion / EF

Diagnosis

  • STEMI: ST elevation or new LBBB + symptoms
  • NSTEMI: troponin rise + symptoms / ECG changes
  • UA: symptoms ± ECG changes, no troponin rise

Management

  • MONA-B: morphine, O₂ if SpO₂ <94, nitrate, aspirin 300, β-blocker if no CI
  • DAPT (ticagrelor/clopidogrel)
  • Anticoagulation (fondaparinux/LMWH)
  • STEMI: PPCI <90 min or fibrinolysis ≤12 h
  • NSTEMI: invasive angiography 24–72 h (risk-based)
  • Statin, ACEi, β-blocker on discharge

Complications

  • Arrhythmia (VF, AV block)
  • Cardiogenic shock
  • Mechanical: VSD, papillary muscle rupture
  • Pericarditis (Dressler)

Prevention

  • Lifestyle: smoking cessation, exercise, diet
  • BP, lipid, glucose control
  • Antiplatelet + statin in established disease

Follow-up

  • Cardiac rehab
  • 12-lead, lipids, HbA1c at 6 weeks
  • Echo at 6 weeks if LV impairment

Clinical pearls

  • Atypical presentation in elderly, diabetics, women
  • Posterior MI: tall R + ST↓ V1–V3 → reciprocal V7–V9
  • Right-sided leads for inferior MI (V4R)

References

  • ESC ACS 2023
  • AHA/ACC 2025

Educational — verify locally.

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