Wednesday, 12 July 2017

ECG of the Week - 10th July 2017 - Interpretation

The following ECG is from a 52 yr old who presented to a remote medical center, 360km from the nearest tertiary hospital, with chest pain for 1 hour.


  
Click to enlarge
Rate:
  • 66 bpm
Rhythm:
  • Regular
  • Ectopic atrial rhythm
    • Inverted P waves in inferior leads
Axis:
  • Normal
Intervals:
  • PR - Normal
  • QRS - Normal 
Additional:
  • Marked ST elevation leads II (5mm), III (6mm), aVF (6mm)
  • ST Depression leads I, aVR, aVL, V1-6
  • T wave inversion leads aVR, aVL, V1-2
  • Biphasic T wave leads V3-5
Interpretation:
  • Inferior STEMI
    • Likely posterior extension
Given the remote location this patient was thrombolysed and subsequently transferred for further tertiary management. I don't have the results of his subsequent angiogram or echo unfortunately.

What are the contraindications to thrombolysis ?

If you work in a metropolitan or tertiary center you probably send all your STEMI's for urgent angiography but it remote and rural centers thrombolysis must be considered.
The following list is taken from the Australian Resuscitation Council Guideline 14.3 'Acute Coronary Syndromes: Reperfusion Strategy'.

Contraindications to thrombolysis in STEMI
ARC Guideline 14.3
Click to enlarge

What agents can you use and how are they given ?
  • Streptokinase 1.5 million units iv over 60 minutes
  • Alteplase initial iv bolus plus variable dose infusion over 90 minutes
  • Reteplase 10 units iv over 2 minutes followed 30 minutes later by a further 10 units iv over 2 minutes
  • Tenecteplase 30-50mg iv bolus depending on patient's weight

What are the complications of thrombolysis for STEMI ?
  • Haemorrhage ~10%
  • Intracranial haemorrhage ~0.8%
  • Allergic reaction / anaphylaxis
  • Hypotension
  • Myocardial rupture if thrombolysis given greater than 12 hrs onset ischaemia
  • Re-perfusion arrhythmias
  • Re-occlusion / Re-infarction
  • Bone pain with streptokinase
References / Further Reading
Life in the Fast Lane
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.