Wednesday, 14 November 2012

ECG of the Week - 12th November 2012 - Interpretation

Another ECG from our patient from last week.

Following last week's ECG, what happened next ?

Patient was sedated & underwent DC cardioversion
Post cardioversion ECG is below
 



 
 
Click to enlarge

I'd like to welcome some new members to our blogging team, Dr Shakeeb Razak and Dr Arieh Keren, both Cardiology Speciailsts.
They have kindly agreed to provide their thoughts, and interpretations on our cases.

Rate:
  • 60
Rhythm:
  • Regular
  • Nil p waves visible

Axis:
  • Extreme Axis Deviation
Intervals:
  • PR - Nil p waves visible
  • QRS - Prolonged (180-200 ms)
  • QT - 400ms (QTc Bazette ~ 400 ms)
Segments:
 
  • ST Elevation Leads II, III, aVF, V4-6
  • ST Depression I, aVL
 
Additional:
 
  • Pacing Spikes seen Leads II, V2, V3
  • LBBB Morphology

Interpretation:
 
  • Atrial Fibrillation
  • RV Pacing - LBBB Morphology & Low to high activation in inferior leads
 
  • ST Segment Changes
    • ? Inferolateral Infarction
    • ? T Wave / Cardiac Memory Post VT
 
Why do the pacing spikes vary in amplitude ?

  • Varying pacing spike amplitudes seem to be a phenomenon of the limitations of the ECG recording systems picking up and recording the bipolar pacing spikes rather than the pacemakers / bipolar pacing leads themselves

The patient was noted to have a raised troponin of >5 [Normal <0.05].
During the admission the patient underwent PPM change to Dual Chamber ICD.

For more information of ST segment changes and acute myocardial infarction in the presence of LBBB or paced rhythm the Sgarbossa or modified Sgarbossa criteria can be used. For information on Sgarbossa criteria see links below.

References / Further Reading
 
Life in the Fast Lane
 
  • Paced Rhythms here
  • Sgarbossa Criteria here
Academic Life in Emergency Medicine

  • Sgarbossa Criteria here
Dr Smith's ECG Blog


Papers

  • Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule. Ann Emerg Med. 2012 Aug 31 EPub. PMID: 22939607

  • Sgarbossa EB, Pinski SL, Barbagelata A, Underwood DA, Gates KB, Topol EJ, Califf RM, Wagner GS. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators. N Engl J Med. 1996 Feb 22;334(8):481-7. PMID: 8559200
 
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.