Epilepsy misdiagnosed as long QT syndrome: it can go both ways.

Cardiogenic seizures are common and could be the sentinel event heralding the presence of congenital long QT syndrome (LQTS). Distinguishing a cardiogenic seizure from a neurogenic one is of the utmost importance. Herein, we present the case of a 12-year-old boy with recurrent episodes of syncope and seizures. Despite absence of QT prolongation on electrocardiogram, absence of documented arrhythmias, a negative LQTS genetic test, and recurrent episodes while on nadolol beta-blocker therapy, he was diagnosed with LQTS and implanted with an implantable cardioverter defibrillator (ICD). When syncope and seizure occurred with normal sinus rhythm documented on the ICD, he was referred to neurology, and an electroencephalogram was positive for numerous bursts of bilaterally synchronous generalized discharges. He was started on antiepileptic treatment after which his seizures resolved. His LQTS diagnosis was removed, beta-blocker therapy discontinued, and his ICD was explanted. He has been seizure-free for over 2 years.