Wednesday, 2 April 2014

ECG of the Week - 31st March 2014 - Interpretation

The following is a rhythm strip from a 77yr old male. He has a history of hypertension and hypercholesterolaemia. He complained of chest pain during this ECG recording.
Check out the comments from our original post here.



Click to enlarge

Lead II Rhythm Strip - Total time 20 seconds


Rate:

  • ~95 bpm
Rhythm:

  • Regular
  • Sinus
    • Lots of baseline artifact
Axis:

  • Unable to assess
Intervals:

  • PR - Normal (~200ms)
  • QRS - Normal (100ms)
  • QT - 360ms (QTc Bazette 450-460 ms)
Segments:
  • ST elevation <1mm
Additional:
  • Initiation of PVT / VF 3 seconds prior to end of rhythm strip
    • Short-long cycle initiation secondary to PVC
Interpretation:
  • PMVT/VF with QTc Prolongation
What happened ?


Pre-hospital the patient underwent successful DC cardioversion. On arrival to the Emergency Department the patient has ongoing chest pain and a further 3 episodes of PVT/VF which responded to DC cardioversion.
ECGs whilst in the Emergency Department did not show definitive ST segment changes but 
the patient's medications included amlodipine which was ceased on admission.

Coronary angiogram showed:
  • RCA - Dominant -  30% proximal lesion
  • LMCA - Normal
  • LAD - 60% proximal
  • LCx - distal 80% - stented
Echo
  • Antero-apical hypokinesis
  • Preserved LV function
Following stent insertion an AICD was inserted given episode of QT prolongation and recurrent tachyarrhythmia.
In the setting of QT prolongation refractory VT/VF can be difficult to treat and urgent cardiology input in advised, in these settings amiodarone can further prolong the QT and should be avoided. Underlying causes need to be corrected including ceasing drugs known to prolong QT, correcting electrolyte abnormalities, and treating ischaemia.

References / Further Reading

National Guidelines
  • Australian Resuscitation Council - Managing Acute Dysrhythmias - here
Life in the Fast Lane

List of QT Prolonging Drugs



Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.