The rarity of<unk>  makes calculating prognosis accurately difficult. The risk of sudden cardiac death has been estimated at 0.8% per year, leading to a cumulative risk of sudden cardiac death of 41% by the age of 40. A previous history of cardiac arrest predicts a higher likelihood of further dangerous arrhythmias. Some have suggested that those with the<unk> est QT intervals may have a higher risk of arrhythmias, but this view has not been supported by all. The findings from invasive electrophysiological studies do not predict an individual with<unk> 's risk of cardiac arrest.
Short QT syndrome
Long QT syndrome
Opitz G/BBB syndrome
Brugada syndrome
Familial atrial fibrillation
Aicardi–Goutières syndrome
Phidippides cardiomyopathy
Pacak–Zhuang syndrome