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Long QT syndrome — RACP Paediatrics MCQ

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HardCardiologyLong QT syndromeRACP Paediatrics

A 12-year-old collapses while swimming and recovers spontaneously. There is a family history of sudden unexplained death in a teenage cousin. Examination is normal. What is the most likely diagnosis?

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Correct answer: A — Congenital long QT syndrome

Syncope during swimming with a family history of sudden death is a red flag for congenital long QT syndrome, especially LQT1. Vasovagal syncope is usually associated with prodrome and upright triggers, not exertional aquatic collapse. The pearl is that exertional syncope should be considered cardiac until proven otherwise and needs ECG and specialist assessment.

Reference: RCH Clinical Practice Guidelines: Syncope; Therapeutic Guidelines (eTG)