ECG of the Week - 1st May 2017 - Interpretation

The following ECG is from a 27yr old female who presented with a 1 hour history of palpitations. She has a 12 yr history of intermittent palpitations which have not been captured during investigation.

Click to enlarge

 Rate:

• 162 bpm

Rhythm:

• Regular

Axis:

• Normal

Intervals:

• QRS - Narrow

Segments:

• ST Depression leads II, III, aVF, V4-6
• ST Elevation lead aVR

Additional:

• Variable notching before QRS complexes
• Best seen leads V3-5

Interpretation:

• Regular narrow complex non-sinus tachycardia

DDx include:

• Atrial tachycardia with 2:1 block
• Atrial flutter with 2:1 block - not typical baseline appearance
• AVNRT
• AVRT

What happened ?

Following vagal manoeuvres the patient reverted to sinus rhythm, ECG below:

Post cardioversion

The post reversion ECG does not show features of pre-excitation with a normal pr interval and normal QRS morphology, same as ECG during tachydysrhythmia. Note the ST segment changes have also resolved and likely reflect demand changes due to high heart rate rather than primary ischaemic pathology.


References / Further Reading

Life in the Fast Lane

• SVT Overview

Textbook

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