No abstract

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.

No abstract

Type 1 long QT syndrome is the most common long QT syndrome genetic subtype. Exercise and emotional stress can precipitate sudden cardiac events in patients with type 1 long QT syndrome; however, the precise mechanism remains elusive. We report the case of a teenage girl with type 1 long QT syndrome secondary to a rare frameshift mutation (p. L191fs+90X) in the KCNQ1-encoded Kv7.1 potassium channel. During emotional distress, her continuous QTc recordings precipitously increased, peaking within minutes to 669 ms and then returning to baseline (520 ms) as she calmed without concomitant increase in heart rate. This is the first described case documenting transient, marked accentuation of the QTc interval in a long QT syndrome patient during emotional distress. Such events may be triggered by transient accentuation of the intrinsic perturbation in cardiac repolarisation and increase the risk of degeneration to a ventricular arrhythmia. This case illustrates the need improved understanding of the complex interaction between emotion and cardiac stability in patients with long QT syndrome.