title: [Heart rate variability in children with beta-thalassemia major].
abstract: OBJECTIVE
  To study the diagnostic value of heart rate variability (HRV) in heart dysfunction in children with beta-thalassemia major (β-TM)by examining the changes of HRV in β-TM children.
  
  
  METHODS
  A 24 hours Holter monitoring electrocardiogram (Holter) was performed in 21 children with β-TM and 15 healthy children (control group). The time domain and frequency domain indexes of HRV in the two groups were compared. The correlation between serum ferritin levels and HRV was evaluated.
  
  
  RESULTS
  The time domain indexes SDNN, rMSSD and PNN50 and the frequency domain indexes very low frequency (VLF), low frequency (LF) and high frequency (HF) in the β-TM group were significantly lower than in the control group (P<0.05). There was no correlation between serum ferritin level and HRV in children with β-TM.
  
  
  CONCLUSIONS
  The autonomic nerve dysfunction exists in children with β-TM. HRV analysis is useful in the prediction of early cardiac dysfunction in children with β-TM.
authors.affiliation: Department of Pediatrics, Shenzhen Second People's Hospital, Shenzhen, Guangdong 518035, China.
authors.forename: Qi-Ling
authors.initials: QL
authors.lastname: Ma
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Fu
authors.forename: Guang-Fu
authors.initials: GF
authors.lastname: Chen
authors.forename: Zhen-Yan
authors.initials: ZY
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D005293:Ferritins / Q000097:blood; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D017086:beta-Thalassemia / Q000097:blood / Q000503:physiopathology*
chemical_list: D005293:Ferritins