Wednesday, 16 November 2016

ECG of the Week - 14th November 2016 - Interpretation

The following ECG's are from an 84yr old male who presented following an episode of syncope in which he sustained a head injury. 
The initial ECG was taken on presentation to the Emergency Department and the second ECG was performed several hours later. The patient was asymptomatic on both occasions with a normal blood pressure. 

Click to enlarge
Initial ECG on presentation
Key features:
  • Bradycardia - mean ventricular rate 54 bpm
  • Marked sinus arrhythmia
    • ~2 sec pause between 1st and 2nd complex
  • Inferior axis
  • 1st Degree AV block - varying magnitude 220-280 ms
  • Right bundle branch block
  • Discordant ST / T wave changes
    • ST Elevation leads aVR, aVL
    • ST Depression leads II, III, aVF, V6 with T wave inversion

Click to enlarge
ECG several hours later
Key features:

  • Bradycardia - mean ventricular rate 36 bpm
  • Marked sinus arrhythmia
  • Morphology of axis, QRS, ST segments and T waves same as prior ECG

  • Sinus Node Dysfunction
    • Marked sinus bradycardia
    • History of collapse / syncope
 The following AFP article has a nice general overview of sinus node dysfunction / sick sinus syndrome:

What happened ?

The patient remained asymptomatic during episodes of bradycardia. There were no correctable electrolyte abnormalities or culprit medications to account for bradycardia.<35 a="" an="" and="" bpm="" bradycardia="" cardiac="" chamber="" diagnosis="" dual="" during="" dysfunction="" font="" given="" his="" history="" hospitalization.="" insertion.="" made="" marked="" node="" noted="" of="" on="" pacemaker="" patient="" sinus="" syncope="" telemetry="" the="" underwent="" uneventful="" was="">
A diagnosis of sinus node dysfunction was made and a dual chamber pacemaker was inserted. The patient made an uneventful post-procedural recovery and was discharged home following a brief in-patient stay.

References / Further Reading
Life in the Fast Lane
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.

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