title: Heart rate variability during interictal epileptiform discharges.
abstract: BACKGROUND
  Seizures may produce a variety of autonomic alterations. These alterations may occur due to evoked autonomic reflexes or as a direct cortical effect on autonomic control. In animal studies, lock step phenomena of interictal discharges to autonomic output have been repeatedly documented. However, the association of interictal discharges and autonomic output is not as well established in humans.
  
  
  METHODS
  RR intervals timely locked to interictal epileptiform discharge (RR(n)) were compared to RR intervals immediately following (RR(n+1)) interictal discharges in 40 patients with focal onset epilepsy and low baseline heart beat variability.
  
  
  RESULTS
  In 20 patients with 200 left sided interictal epileptiform discharges, RR(n) shortened in 100 and prolonged in 31 when compared to RR(n+1) intervals. While in 20 patients with 200 right sided interictal epileptiform discharges RR(n) intervals shortened in 17 and prolonged in 116 (Chi square P<0.001). No consistent differences in RR(n) intervals variability between frontal versus temporal localization of the interictal discharges from the same side was found.
  
  
  CONCLUSIONS
  Interictal discharges, may influence autonomic control over the cardiac cycle and agree with animal studies. Further study of the relationship of interictal discharges to autonomic output is needed to delineate the potential lateralized influences over autonomic nervous system.
authors.affiliation: Department of Neurology, University of North Carolina, Chapel Hill, NC 27599-7025, USA. mmzid@med.unc.edu
authors.forename: Megdad M
authors.initials: MM
authors.lastname: Zaatreh
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Quint
authors.forename: Michael B
authors.initials: MB
authors.lastname: Tennison
authors.forename: O'Neill
authors.initials: O
authors.lastname: D'Cruz
authors.forename: Bradley B
authors.initials: BB
authors.lastname: Vaughn
mesh_terms: D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged