Corrected QT interval in patients with epilepsy attending Kenyatta National Hospital and the Kenya association for the welfare of people with epilepsy clinics in Nairobi
Background: Patients with epilepsy have a mortality rate two to three times that of the general population. Sudden unexpected death in epilepsy (SUDEP)is a major cause in studies of mortality in epilepsy. SUDEP is defined as a non accidental death in a patient with epilepsy with or without evidence of a seizure having occurred and excluding status epilepticus, where autopsy reveals no anatomical or toxicological cause. The effects of seizures and anti-epileptic drugs on cardiac conduction are known to cause SUDEP. The duration of the QT interval (prolonged or shortened) has been implicated in its pathogenesis. Objectives: To compare the QT interval in patients with epilepsy with non-epileptic age (to the nearest one year) and sex matched controls. Study design: Comparative cross-sectional study Methods: Standard 12-lead ECGs were recorded from 146 patients with epilepsy (62 not on treatment, 84 on anti-epileptic drugs) and 146 age and sex matched controls from Kenyatta National Hospital and the Kenya Association for the Welfare of people with Epilepsy (KAWE)clinics in Nairobi. The mean QT interval corrected for heart rate (QTc)for the patients with epilepsy and controls were compared. The relationship between mean QTc and seizure frequency, type and number of anti-epileptic drugs was analyzed. Results: The mean QTc for patients with epilepsy (405.7 ±31ms) was significantly shorter than in the control group (414.9±29.6 ms), p<0.0001l.Untreated patients with epilepsy had a significantly shorter mean QTc of 405.6±33ms compared to the matched controls (415.4±27.8ms), p=0.0005. Similarly, patients on anti-epileptic drugs'1lso had a significantly shorter QTc compared to the matched controls (405.9±29.6ms vs. 414.6±31ms, p=0.0003).