ECG of the Week 9th March 2022 – Interpretation

You are reviewing a 49 year old man who presented with chest pain and an unremarkable ECG. His observations remain within normal limits and your management plan was to repeat a troponin and ECG and discharge home with a stress test as follow up. His repeat ECG is below.


  • Rate: Ventricular rate = 48 Atrial rate = 72
  • Rhythm: Sinus rhythm with AV block
  • Axis: Normal
  • Morphology: Nil of note
  • Intervals: PR QRS QTc all within normal limits in conducting beats
  • Summary: Mobitz Type 2 with a 2:1 block. The narrow QRS indicates the failed conduction lies within the Bundle of His itself.

Other Details from history:

  • Details re cause (history of Ischaemic chest pain, auto-Immune or Inflammatory of Infiltrative disease, drug history etc – see LITFL article linked below)
  • Risk of progression to complete heart block

Further Reading – Textbook:

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

Further Reading – Online:

AV Block: 2nd degree, Mobitz II (Hay block)