ECG of the Week - 6th February 2017 - Interpretation

These ECG are from a 59yr old male who presented to the Emergency Department following 2 episodes of syncope. He had a long history of infrequent unexplained syncope over the prior 15 years. His only past medical history is diet controlled T2DM and he was taking no regular medications.

Patients initial ECG on presentation

NOTE this is a non-diagnostic ECG recording as it was generated retrospectively from the rhythm telemetry unit

Click to enlarge

Key features: 

• Sinus rhythm rate ~90 bpm
• Left axis deviation
• RBBB Morphology
• Prominent T waves and ST elevation in leads II, III, aVF, V2-5 with high voltage complexes
• This ECG was generated using the monitor (non-diagnostic) algorithm. The filter applied in this mode is 0.5 to 40 Hz which can over- or under-estimate low frequency portions of the ECG including the ST segment.
• The diagnostic algorithm filter performs at 0.05 to 150 Hz.
• For a somewhat complicated overview of ECG filtering check out:
• ECG Filters MEDTEQ
• Borderline 1st degree AV block

Impression:

• Bifascicular Block
• Borderline PR prolongation
• Requires cardiology referral for monitoring and consideration of PPM insertion given history of syncope
• ST / T wave changes without chest pain or electrolyte abnormality - related to ECG filtering algorithm

The patient complained of palpitations

Due to rate and rhythm change a rhythm strip was automatically generated

Click to enlarge

Key features:

• Atrial rate 136 bpm
• Ventricular rate 27 bpm
• AV Dissociation 
• Broad Complex QRS

Impression:

• Complete heart block
• Ventricular escape rhythm

 

Subsequent 12-lead ECG
Click to enlarge

Interpretation:

• Compared with rhythm strip above
• Complete heart block
• AV Dissociate with ventricular escape rhythm, rate 24 bpm
• Slowing of atrial rate now ~115 bpm

What happened ?

The patient was treated with atropine followed by isoprenaline infusion. The next day he underwent an uneventful dual chamber PPM insertion. A subsequent echo showed was normal with an ejection fraction of 64%.
On review of his medical records prior ECG's had shown alternating left and right bundle branch blocks confirming progressive conducting system disease. 

References / Further Reading

Life in the Fast Lane

• Complete heart block
• Right bundle branch block
• Anterior / Posterior left fascicular block
• Trifascicular block

Textbook

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