Short QT Syndrome — RACP Adult Medicine MCQ

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HardCardiologyShort QT SyndromeRACP Adult Medicine

A 35-year-old woman with no previous medical history presents with an incidental finding of a shortened QT interval (QTc 310 ms) on a pre-employment ECG. She has a family history of sudden cardiac death. What condition does this suggest?

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Correct answer: C — Short QT syndrome

Short QT syndrome (SQTS) is a rare inherited channelopathy characterised by a QTc <340 ms (some criteria use <360 ms with symptoms or family history), predisposing to atrial and ventricular fibrillation and sudden cardiac death. Causes of acquired short QT include hypercalcaemia, hyperkalaemia, acidosis, and digoxin effect. Genetic SQTS involves gain-of-function mutations in potassium channels (KCNH2, KCNQ1, KCNJ2). ICD implantation is recommended for survivors of cardiac arrest or those with a strong family history. Quinidine may be used as adjunctive therapy.

Reference: eTG – 2025 – Cardiovascular; ESC – 2022 – Ventricular Arrhythmia Guidelines