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This post is an answer to the ECG Case 321

• Rate: 162 bpm
• Rhythm: regular
• Axis: normal
• Intervals: QRS – Narrow
• Segments:
  • ST Depression in 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.

Differential dignoses include:

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

What happened next ?

Following vagal manoeuvres the patient reverted to sinus rhythm.

This 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 ischemic pathology.

READ MORE: ECG Interpretation: All you need to know