title: Effects of stroke localization on cardiac autonomic balance and sudden death.
abstract: OBJECTIVE
  Stroke has been shown to alter autonomic function. The purpose of this study was to show the differential effects of stroke localization on autonomic function parameters assessed by heart rate variability (HRV).
  
  
  METHODS
  To determine the differential effect of ischemic stroke localization on autonomic cardiac innervation, we evaluated 62 patients with ischemic stroke and 62 age- and sex-matched controls. The localization of the infarct was determined by CT and MRI. Power spectrum analysis of HRV was performed. Myocardial necrosis was ruled out by echocardiography and creatine kinase myocardial isoenzymes measurements.
  
  
  RESULTS
  All stroke patients had significantly decreased low frequency, high frequency, and standard deviation of all relative risk intervals values (P<0.001). However, patients with right-middle cerebral artery (R-MCA) and insula lesions had significantly lower power spectrum analysis values compared with all other localizations (P<0.001). In addition, 5 patients with R-MCA insular lesions died suddenly compared with 2 patients with left-middle cerebral artery insular lesions during hospitalization. Both sympathetic- and parasympathetic-controlled HRV were decreased in patients with ischemic stroke. The most pronounced decrease was found in the territory of R-MCA insular cortex, which suggests that cardiac autonomic tone may be regulated by insula and that these patients are more prone to cardiac complications such as arrhythmias and sudden death due to autonomic imbalance.
  
  
  CONCLUSIONS
  We conclude that stroke in the region of insula (especially the right) leads to decreased HRV and to increased incidence of sudden death.
authors.affiliation: Department of Cardiology, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: S L
authors.initials: SL
authors.lastname: Tokgözoglu
authors.forename: M K
authors.initials: MK
authors.lastname: Batur
authors.forename: M A
authors.initials: MA
authors.lastname: Topçuoglu
authors.forename: O
authors.initials: O
authors.lastname: Saribas
authors.forename: S
authors.initials: S
authors.lastname: Kes
authors.forename: A
authors.initials: A
authors.lastname: Oto
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D015374:Biosensing Techniques; D002545:Brain Ischemia / Q000150:complications; D016022:Case-Control Studies; D002561:Cerebrovascular Disorders / Q000150:complications / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012306:Risk