ECG of the Week - 31st July 2017 - Interpretation

The following ECG is from a 66 yr old male for presented to the Emergency Department complaining of dizziness and pre-syncope without chest pain. He has a history of ischaemic heart disease.

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Rate:

• Mean atrial rate 100 bpm
• Mean ventricular rate 35 bpm

Rhythm:

• Regular atrial and ventricular activity
• AV dissociation
• Atrial rate greater than ventricular rate

Axis:

• Right axis deviation

Intervals:

• QRS - Prolonged (140ms)

Additional:

• Subtle ST elevation leads aVR and aVL
• Subtle ST depression leads II, aVF, V2-4
• Distortion of QRS complexes due to superimposed P waves 

Interpretation:

• Complete heart block

The majority of complete heart block we see is idiopathic in origin but consideration needs to be made as to potential underlying and more importantly reversible causes including:

• ACS
• Drug toxicity
• Hypothermia
• Inflammatory - myocarditis
• Infiltrative disease - sarcoid etc.

What happened ?

There were no identifiable reversible causes and the patient was admitted for an uneventful PPM insertion/

References / Further Reading

Life in the Fast Lane

• Complete heart block 

Textbook

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