[Novel mutation in long QT syndrome in a patient with prior diagnosis of epilepsy].

Congenital long QT syndrome (LQTS) can present as syncope or seizures, secondary to polymorphic ventricular tachycardia, mimicking a primary seizure disorder. In patients treated with an implantable cardioverter-defibrillator (ICD), the recurrence of arrhythmias with subsequent frequent therapeutic shocks may cause adverse reactions, which can be psychogenic. We report the case of a 22-year-old woman with syncope and seizures who was diagnosed in childhood as epileptic and in whom LQTS was diagnosed only in adulthood. Beta-blocker therapy failed and an ICD was implanted. However, as arrhythmias persisted, left cardiac sympathetic denervation was performed. After surgery, three-month follow-up showed a significant reduction in arrhythmias. The genetic study identified a heterozygous mutation, c.1817 C>T p.S606F, on the KCNH2 gene that has not previously been reported in the literature. We also report the rare occurrence of an electrical storm in the course of H1N1 infection. This case illustrates the difficulties in the diagnosis and treatment of LQTS. The possibility of a common genetic basis for arrhythmic diseases and epilepsy is discussed.