ECG of the Week - 20th November 2017 - Interpretation

The following rhythm strip is from a patient who presented with an episode of syncope. Their baseline ECG showed 1st degree AV block with no other abnormal features.

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Rate:

• Initial ventricular rate ~50 bpm
• Mean atrial rate ~54 bpm

Rhythm:

• Initial regular sinus rhythm rate ~50 bpm
• Then slowing of atrial rate (5th complex) to ~40 bpm
• Followed by ~3.8s of ventricular standstill
• Single ventricular complex
• Followed by further pause of >9 seconds
• Persisting P waves throughout

Intervals:

• PR - Prolonged (~240ms)
• QRS - Normal (100ms)

Additional:

• Irregular baseline lead II

Interpretation:

• Intermittent ventricular standstill

What happened ?

The patient recovered spontaneously from this recorded event and was admitted for PPM insertion. No identifiable or reversible cause was found.

Cause of ventricular standstill include:

• Myocardial ischaemia or infarction
• Atrioventricular nodal disease including degenerative and infiltrative
• Medications including amiodarone, beta blockers, calcium channel blockers and digoxin
• Electrolyte imbalance
• Acidosis
• States of increased vagal tone
• Hypoxia
• Hypothermia

References / Further Reading

Textbook

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