Overt long QT syndrome in children presenting with seizure disorders in Pakistan

The long QT syndrome (LQTS) is a repolarization defect of heart involving potassium linked channels and it usually manifests clinically as seizures, syncope, or sudden cardiac death syndrome in children secondary to its characteristic ventricular tachy-arrhythmia like torsades de pointes. The reason behind epilepsy or seizures like activity in this disease is the sequelae of prolonged cerebral hypoperfusion secondary to the cardiac dysrhythmia. The aim of study is to look for clinical spectrum and risk factors associated with LQTS among children presenting with epilepsy, which can predict the early diagnosis of LQTS.

For this observational study, 422 patients having epilepsy presenting for the first time in a 3-year period were enrolled. Demographical profile, LQTS measures, and various factors under observation were recorded.

Among the 422 enrolled children (M: F 1.8:1) with age ranging from 4 to 87 months (median 23 months), 8 (1.9%) children who presented with epilepsy had LQTS. Among those, mean QTc on electrocardiogram was 454 ± 31 msec and mean Schwartz score >3. Half of the patients with LQTS had deafness (P = 0.002) and 37.5% had a positive family history (P = 0.0045). Nearly a third (37.5%) presented with syncope and 87.5% patients with LQTS had no postictal drowsiness or sleep (P ≤ 0.004).

LQTS is underestimated in children presenting with epilepsy and LQTS should be considered as an alternate diagnosis in children with recurrent seizures or syncopal attacks. The brief period of seizures with no postictal drowsiness, syncope, and strong family history are the features which may help in segregating LQTS from epilepsy.