Long QT syndrome causing an apparently typical first seizure

Long QT syndrome is an uncommon cardiac condition characterised by QT prolongation with a risk of syncope and sudden death from torsades de pointes ventricular arrhythmias. Seizures and seizure-like episodes can occur, and there may be a delay in recognising them as the underlying cause. A 37-year-old man who presented with a seemingly uncomplicated single seizure was later found to have long QT syndrome. His initial ECG showed a prolonged QTc (QT interval corrected for heart rate) of 507 ms (normal 350-450), while subsequent 'interictal' ECGs were reportedly normal. We highlight the importance of considering long QT syndrome in first seizure (first fit) clinics by documenting the QTc interval and taking an appropriate family history.