Long QT syndrome mimicking refractory epilepsy: case report and
literature review
Abstract
Epileptic seizures can be difficult to distinguish from other etiologies
that cause cerebral hypoxia, especially cardiac diseases. Long QT
syndrome (LQTS), especially LQTS type 2 (LQT2), frequently masquerades
as seizures because of the transient hypoxia caused by ventricular
arrhythmia. Early and correct diagnosis of LQTS effectively prevents
inappropriate treatment with anti-epileptic drugs (AEDs) and sudden
death. We report a case of congenital LQT2 with potassium voltage-gated
channel subfamily H member 2 gene (KCNH2) mutation misdiagnosed as
refractory epilepsy and treated with various AEDs for 22 years. The
possibility of cardiac arrhythmia was suspected after the
electrocardiograph (ECG) monitor in emergency room showed paroxysmal
ventricular tachycardia during attacks. Atypical seizure like attacks
with prodromal uncomfortable chest sensation and palpitation, triggered
by auditory stimulation, and typical ventricular tachycardia monitored
by ECG raised suspicion for LQT2, which was confirmed by exome
sequencing. Although the patient rejected implantation of an implantable
cardioverter defibrillator, β-blocker was given and the syncope only
attacked 1-2 per year when there was an incentive. Our case illustrates
how long LQTS can masquerade convincingly as epilepsy and be treated
wrongly with AEDs, putting the patient at high risk of sudden death.
Careful ECG evaluation is recommend for both patients with first seizure
and those with refractory epilepsy.