Rett syndrome is a severe neurodevelopmental disorder of unknown aetiology.
A prolonged QT interval has been described previously in patients with Ret
t syndrome. To investigate QT prolongation and the presence of cardiac tach
yarrhythmias in Rett syndrome electrocardiography and 24 hour Holter monito
ring were performed prospectively in a cohort of 34 girls with Rett syndrom
e. The corrected QT value was prolonged in nine patients. Compared with a g
roup of healthy controls of a similar age range, the patients with Rett syn
drome had significantly longer corrected QT values. Clinical severity was n
ot a predictor for prolonged QT intervals in the Rett syndrome cohort. The
prolonged QT syndrome is a serious and potentially lethal cardiac disorder
and should be considered in all girls with Rett syndrome.