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Acute coronary syndrome

Prevalence
Clinical features
Differential diagnosis
Investigations
Therapy
Prevention
Prognosis
Investigations
  • blood count b
  • urea, electrolytes and creatinine d
  • glucose d
  • serial cardiac enzymes, ideally CK-MB b  
    Less helpful alternatives include
    • troponin T a b c or troponin I c
    • myoglobin c 
    • serial creatine kinase (CK) b c, aspartate transaminase (AST) a, lactate dehydrogenase (LDH) a  taken over at least 24 hours a 
  • a 12-lead ECG a b  - read it carefully! a
    • Look for features suggestive of cardiac ischaemia
      • any ST elevation, particularly if in 2 or more leads or not known to be old a b  
      • any ST depression, particularly if not known to be old b
      • any Q waves, particularly if in 2 leads or more or not known to be old a b
      • any T wave inversion particularly if not known to be old b
      • any conduction defect, particularly if not known to be old b
    • followed by serial ECGs, looking for b  
      • acute injury: ST elevation in ≥ 1 mm in 2 contiguous limb leads, or ≥ 2 mm in 2 contiguous precordial leads,
      • acute ischaemia: ST depression ≥1 mm in 2 contiguous leads or symmetrical T wave inversion of >≥3 mm in 2 contiguous leads,
      • in patients with BBB: ST depression or elevation ≥ 1 mm towards deflection of main QRS deflection in 2 contiguous leads, or ≥ 7 mm away from QRS deflection and > 50% amplitude of T wave in 2 contiguous leads
  • chest x-ray d
Arrange stress testing on discharge or as an outpatient using any of
  • exercise ECG a
    • Look for a  
      • horizontal or down sloping ST slope and 1 mm or more of depression in any lead b
      • angina during test
    • Use the following clinical prediction rule, to rank your patient for risk of dying. a  

      Sum the following:

      • duration of exercise in minutes
      • minus (5 x maximal net ST-segment deviation during or after exercise, mm)
      • minus (4 x treadmill angina index)

      Treadmill angina index

      Angina during stress test score
      no angina during exercise 0
      non-limiting angina 1
      stopped due to angina 2

      Exercise ECG score

      Total score risk of dying
      <-10 high
      -10 to 4 moderate
      5 or more low

       

  • exercise echocardiography a
  • scintigraphy a b
    • Look for a reversible perfusion defect b
  • exercise SPECT (single-photon emission computed tomography) a
  • electron-beam CT a
  • coronary MR angiography a
Refer for angiography with a view to revascularisation if d
  • prolonged angina with an ischaemic ECG d
  • abnormal stress testing
  • moderate to severe angina after hospital discharge despite maximal anti-ischaemic therapy
Perform angiography followed by revascularisation as soon as possible. b

 

 

Expiry date: June 2003
Levels of Evidence used in grading these guides

Authors   CM   Ball , N   Shenker
Reviewer   I K   Jang
CAT Writers   N   Shenker , CJ   Wotton , CM   Ball , RS   Phillips