ECG Case 108

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.

ECG on presentation
ECG Case 108a LITFL Top 100 EKG

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

Describe and interpret this ECG


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:
  • Borderline 1st degree AV block


  • 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

ECG with palpitations

The patient complained of palpitations. Due to rate and rhythm change a rhythm strip was automatically generated

ECG Case 108b LITFL Top 100 EKG


Key features:

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


  • Complete heart block
  • Ventricular escape rhythm
ECG Case 108c LITFL Top 100 EKG


  • 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 next?

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. 

Further reading:

TOP 150 ECG Series

Emergency Medicine Specialist MBChB FRCEM FACEM. Medical Education, Cardiology and Web Based Resources | @jjlarkin78 | LinkedIn |


  1. Dear G’ time
    The 2nd ECG shows atrial to ventricular complexes 4 to 1 in a regular fashion which it can be seen in atrial tachycardia while in complete Av block not ? Best regards
    Dr. Mortadha Saadedden Phd

  2. The second ECG shows 4:1 conduction block— ventr rate is around 25 and constant PR interval ( arnd 0.4 s)— s this should be a case of Type 2 Mobitz block and not 3 rd degree AV block

  3. Do you know if in this case, did the atropine help the patient? If they are in CHB would atropine work? Or is it being paired with isoprenaline create a more desired effect?

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.