Short QTc in epilepsy patients without cardiac symptoms
Teh HS, Tan HJ, Loo CY, and Raymond AA (2007) Short QTc in epilepsy patients without cardiac symptoms. Med J Malaysia 62:2 104–8.
Abstract: Epilepsy patients have a higher mortality rate than the general population. Sudden unexpected death in epilepsy (SUDEP) is a major cause of mortality for these patients. The possibility of cardiac involvement in the pathogenesis of SUDEP has been suggested by many previous studies. This study compared the QT interval in epilepsy patients and normal controls, and identified the factors that affected the QT interval. Standard 12-lead ECGs were recorded from 70 consecutive epilepsy patients from the neurology clinic of HUKM and 70 age, race and gender matched controls. The mean QT interval corrected for heart rate (QTc) was calculated and compared. The mean QTc among the epilepsy patients was 0.401 +/- 0.027s. It was significantly shorter than the QTc (0.420 +/- 0.027s) in the control group (p<0.0005). Thirty five epilepsy patients (50%) and 17 matched controls (24.3%) had a mean QTc shorter than 0.40s (p=0.001). Among the epilepsy patients, the mean QTc did not significantly differ between patients in the duration (F=0.836, p=0.438) of the epilepsy, frequency (F=0.273, p=0.845) and types of seizures (p=0.633). There was no significant difference in the mean QTc between the epilepsy patients on different number of antiepileptic agents (F=0.444, p=0.643). Patients with cryptogenic epilepsy had a mean QTc of 0.392 +/- 0.029s, which was significantly shorter than patients with symptomatic epilepsy (QTc = 0.410 +/- 0.027s, p = 0.015). The mean QTc of the same subjects showed no significant interobserver difference (p=0.661). This study, for the first time, demonstrates that epilepsy patients have a significantly shorter QTc than controls, particularly in the subgroup of patients with cryptogenic epilepsy.
Keywords: QT interval, Shortened, Epilepsy, SUDEP, Cryptogenic
- Study of 70 epileptic paitents and 70 matched controls. The QT interval was significantly shorter in the epilepsy patients at baseline (Cf. Brotherstone et al. for measurements showing longer QT during seizures.) However there was no link between duration or severity of disease and QTc interval among patients. A helpful control is the comparison of QTc values for the same EKG recording as calculated by different observers; no difference was found. Although phenytoin may reduce QT interval (Stramba-Badiale), treatment with increased numbers of AEDs did not correlate with shorter QT interval. For further discussion of QT intervals see annotation at Aurlien et al.