Abstracts

Rationale: Long QT syndrome (LQTS) is a disorder resulting in ventricular tachyarrhythmia and sudden death. The mortality rates is estimated to 77% without treatment and 7% under treatment. It is less recognized that LQTS may initial present as syncope with convulsions and be interpreted as epilepsy. We report a LQTS case with sudden onset of ventricular tachyarrhythmia: Torsade de Pointes (TdP), presenting as epileptic seizure during inpatient video-EEG monitoring.Methods: Case report: An 18-year-old woman had a one-year history of episodic spells. The spells were characterized by sudden onset loss of consciousness with arms stiffening, fingers curling, foaming from the mouth, and body arching back. Afterward she felt generalized weakness without significant confusion. The spells occurred 2-3 times per-month. An MRI of the brain was normal and an EEG reportedly abnormal due to “a 2 second burst of high amplitude, sharp and slow wave discharges in the range of 3 Hertz.” She was treated with zonisamide 400mg daily and levetiracetam 1500mg bid, still had 2-3 spells per month prior the visit at our institution. She was healthy previously. There is no family history of seizures. A paternal aunt had sudden death at age 21-year-old with unknown etiology. Results: A 4 days inpatient continuous video EEG was performed. On day number 4, she developed a typical spell. The spell occurred upon awaking from sleep. The EKG suddenly converted to a polymorphic ventricular tachycardia consistent with TdP. It lasted 2 minutes and 10 seconds, then became more idioventicular before reverted back to sinus rhythm. The Video recording showed that 9 seconds after developed TdP she developed her typical spell identical as described before. EEG demonstrated normal waking EEG acutely changed to high amplitude 1.5 to 3 Hz delta activities 22 seconds after she developed TdP. It lasted 1 minute 37 seconds, then turned to diffuse background suppression and 1.5 to 2 Hz delta slowing. The EEG was back to alpha rhythm 15 seconds after the EKG reverted back to sinus rhythm. The rest of the 4 days of EEG was normal. Cardiology was consulted. An EKG demonstrated normal sinus rhythm with prolonged QT (corrected QT interval 0.50 seconds). A beta blocker was started and a cardioverter-defibrillator and atrial pacing were implanted subsequently. Antiepileptic medications were discontinued. Follow up for 4 months, no further events were noted clinically, nor via device interrogation.Conclusions: Our case demonstrated how LQTS related syncope can cause convulsion and be interpreted as epilepsy with delays in both diagnosis and treatment. Our case also showed that acute cerebral hypoxia can cause high amplitude rhythmic or semi-rhythmic delta activities in EEG which may mimic a generalized spike wave discharges. Since there is very high mortality without treatment and specific and effective therapy is available, LQTS should be considered in differential diagnosis whenever there are atypical epileptic seizure features or if there is no response to antiepileptic medications.