Cardiac syncope from occult transposition masquerading as convulsive epilepsy.

A four-year-old boy on Valproate therapy for a presumed diagnosis of epilepsy presented with a recurrence of tonic spasms. A history of precipitation of these episodes with exercise prompted a search for an underlying cardiac disorder. The child was ultimately diagnosed to have corrected transposition of great arteries with 2:1 atrioventricular block. This case illustrates that cardiac syncope due to underlying congenital heart disease can masquerade as epilepsy in children.