Friday, 22 January 2016

ECG of the Week - 18th January 2015 - Interpretation

This week's ECG is another ECG from our patient from last week. He is an 88yr old male who had an episode of VT on a background of ischaemic cardiomyopathy. Following successful cardioversion he underwent an ICD insertion. His CXR and ECG are shown below.



Click to enlarge
Rate:
  • 60
Rhythm:
  • Regular
  • Retrograde P waves visible in mid-portion of ST segment
    • Inverted P leads II, III, aVF
Axis:
  • RAD
Intervals:
  • QRS - Prolonged (130ms)
  • QT - 420ms
Segments:

  • Discordant ST segment changes

Additional:

  • Prominent T waves especially leads V2-4 in comparison to QRS magnitude
  • Notching in S wave leads V1-2

Interpretation:

  • V-Paced Rhythm
  • Retrograde P waves
  • Prominent T waves should raise possibility of hyperkalaemia or acute ischaemia but in this case represent patient's 'normal' paced ECG - likely secondary to associated scarring from ischaemic cardiomyopathy


Click to enlarge

What about the CXR ?

I don't normally cover x-rays on this blog but this one has a few interesting points relating to implantable devices. There is a disconnected old RV pacing lead which ends in overlying the right hemithorax- labelled in green below. There is a new left ICD over the left mid chest with the lead also implanted in the right ventricle. The distal portion of the new lead is the shock coil. This ICD also has an atrial sensing function, the sensors are the two dense square blocks situated in the right atrium.

Click to enlarge

This patient has a Biotronik Lumax ICD which has the ability to provide atrial sensing via a single lead. This allows differentiation between SVT, AF and VT without having to implant an atrial lead. The advantage of a single lead insertion is that it is a quicker procedure and is associated with less complications.

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.