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ECG library

Long QT in an adolescent with syncope

core15 years old· adolescent

A 15-year-old who collapsed during a swimming race, with a brief jerking episode witnessed by the coach. A cousin died suddenly at 19.

25 mm/s · 10 mm/mV · synthetic tracing
100%
IIIIIIaVRaVLaVFV1V2V3V4V5V6
II (rhythm)
Calipers:2000 ms50.0 small boxes30 bpm if R-RDrag the orange markers. One small box = 40 ms.

Key findings

  • QTc above 500 ms
  • Exertional syncope with a 'seizure'
  • Sudden death in a young relative

Learning points

  • Measure the QT yourself and correct it: a machine QTc on a teenager with sinus arrhythmia is often wrong in both directions.
  • Exertional or startle syncope, swimming, a witnessed 'seizure' with quick recovery, and a family history of early sudden death are red flags that turn a faint into a cardiology referral.
  • Beta blockade, avoiding QT-prolonging drugs, and screening the family are the plan the cardiologist makes; the ward's job is to recognise the pattern and not send her home with a diagnosis of epilepsy.

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