Acute Coronary Syndrome

Last Updated on by frcemuser

Acute Coronary Syndrome

  • ST-segment-elevation myocardial infarction (STEMI)
    • ST-segment elevation or new left bundle branch block (LBBB) present on ECG
  • Non-ST-segment-elevation acute coronary syndromes
    • Non-ST-segment-elevation myocardial infarction (NSTEMI)
      • Other ECG changes (e.g. ST-segment depression, T-wave inversion) or normal ECG with troponin release present
    • Unstable angina (UA)
      • Other ECG changes or normal ECG with troponin consistently negative


  • Ischaemic ECG findings:
    • Regional ST-segment elevation (2 mm ST-elevation in two contiguous chest leads or 1 mm ST-elevation in two contiguous limb leads)
    • New left bundle branch block (LBBB)
    • Regional ST-segment depression (> 0.5 mm) or deep T wave inversion (> 2 mm deep)
    • Pathological Q waves
  • Serum troponin (I or T)
    • Perform high-sensitivity troponin tests with the first sample taken at initial assessment and a second sample taken 3 hours after onset of symptoms

Localisation of Lesion in STEMI

Affected myocardial area Leads with ST-segment elevation Occluded coronary artery
Septal V1 – V2 LAD
Anterior V3 – V4 LAD
Lateral V5 – V6, I, aVL LCX
Anteroseptal V1 – V4 LAD
Anterolateral V3 – V6, I, aVL (R: II, III, aVF) LAD or LCX
Inferior II, III, aVF (R: I, aVL) RCA
Posterior R: V1 – V3 (P: V7 – V9) RCA or LCX
  • Posterior MI
    • Tall dominant R waves
    • ST depression (horizontal)
    • Unright T waves V1-V3
    • posterior ECG can be obtained by placing posterior leads V7, V8, and V9 below the patients left scapula along the same horizontal plane as V6- Posterior ECG shows – ST-elevation v7-v9
  • Inferior MI
    • complete set of right-sided leads is obtained by placing leads V1-6 in a mirror-image position on the right side of the chest
    • The most useful lead is V4R, which is obtained by placing the V4 electrode in the 5th right intercostal space in the mid-clavicular line

Immediate Management of ACS

  • Immediate management Of suspected ACS
  • GTN (sublingual or buccal)
  • pain relief – intravenous opioids such as morphine titrated to effect
  • Single loading dose 300m: aspirin (unless allergic to it)
  • Supplemental oxygen (as per BTS oxygen guidelines

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