title: Heart rate variability in children with refractory generalized epilepsy.
abstract: OBJECTIVE
  Repetitive seizures can alter the regulation of cardiac activity by the autonomic nervous system (ANS), and ANS dysregulation is thought to be associated with higher morbidity and mortality in epileptic patients, especially from sudden unexpected death. Few studies of interictal dysregulation of cardiac activity in children with epilepsy have been performed. In this study we characterize heart rate variability (HRV) in children with refractory generalized epilepsy.
  
  
  METHODS
  Fifteen male and 15 female children, average age = 10.9+/-0.6 years, all with refractory generalized epilepsy were enrolled into the study group. A control group consisted of 15 males and 15 females with average age = 10.6+/-0.6 years. A lead I ECG was recorded for 5 min in the interictal period during daylight hours from each subject while awake. Frequency-domain analysis of HRV was performed using a non-parametric method of fast Fourier transformation. Changes of HRV were categorized into high frequency power (HF; 0.15-0.45 Hz), which represented vagal regulation, and low frequency power (LF; 0.04-0.15 Hz). LF/(HF+LF) expressed in normalized units (LF%) was considered to mirror sympathetic regulation.
  
  
  RESULTS
  There were significant reductions in RR, LF, and HF in the study group when compared to controls. There was no significant difference in LF% between the two groups.
  
  
  CONCLUSIONS
  We postulate that the lower HRV in our patients results from parasympathetic or vagal reduction. This suggests that decreased HRV in epileptic children occurs by a different mechanism than in adults with epilepsy.
authors.affiliation: Department of Neurosurgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
authors.forename: Tomor
authors.initials: T
authors.lastname: Harnod
authors.forename: Cheryl C H
authors.initials: CC
authors.lastname: Yang
authors.forename: Yue-Loong
authors.initials: YL
authors.lastname: Hsin
authors.forename: Kun-Ruey
authors.initials: KR
authors.lastname: Shieh
authors.forename: Pen-Jung
authors.initials: PJ
authors.lastname: Wang
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
mesh_terms: D000293:Adolescent; D002648:Child; D003627:Data Interpretation, Statistical; D004351:Drug Resistance; D004562:Electrocardiography; D004829:Epilepsy, Generalized / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012727:Sex Characteristics