78 yr old male presents with a 2 day history of lethargy and dizziness. He has a history of ischaemic heart disease, type 2 diabetes, hypertension, and chronic renal failure. His medications include calcium-channel blocker, beta-blocker, and ACE-inhibitor.

He is conscious with systolic BP of 70.

Describe and interpret this ECG

ECG ANSWER and INTERPRETATION

Rate:

Rhythm:

  • Regularly irregular 
    • Complexes occurring in paired group
  • Flat baseline without atrial activity

Axis:

  • 1st Complex in pair
  • 2nd Complex in pair

Intervals:

  • 1st Complex in pair
    • QRS – Normal (80ms)
    • QT – 520ms
  • 2nd Complex in pair
    • QRS – Normal in limb leads, Prolonged V1-3 (80-120ms)
    • QT – 440ms

Segments:

  • 1st Complex in pair
    • ST Depression leads II, aVF
  • 2nd Complex in pair
    • Minimal ST elevation lead aVR

Additional:

  • 1st Complex in pair
    • T wave inversion II, III, aVF
    • Biphasic T lead V3
  • 2nd Complex in pair
    • RsR’ Morphology V1-3
    • Inverted notching terminal portion QRS II, III, aVF also positive notching aVL
      • ? Retrograde P waves ? Secondary to conduction delay

Interpretation:

  • Escape bigeminy
    • In setting of sinus arrest / sinus exit block
  • Non-specific ST / T wave changes

Differential of causes:

  • Ischaemia
  • Electrolyte disturbance
  • Acid-base disturbance
  • Cardiotoxic drugs
  • Sinus node dysfunction
  • Hypothermia
    • Multifactorial combination of above

WHAT HAPPENED NEXT?

Bloods showed:

  • Acute on chronic renal failure
  • Metabolic acidosis – pH 7.0 Bicarb 7.0
  • K 6.0

Treated with isoprenaline, sodium bicarb, cessation of cardiotoxic medication, and dialysis.

Following acute episode found to have sinus pauses on telemetry necessitating pacemaker insertion.

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