title: An evaluation of heart rate variability and its modifying factors in children with type 1 diabetes.
abstract: OBJECTIVE
  To evaluate heart rate variability by Holter monitoring in type 1 diabetic children compared with a healthy control group and determine the factors modifying heart rate variability.
  
  
  METHODS
  This was designed as a prospective study comparing 28 patients, diagnosed with type 1 diabetes and under follow-up, with 27 healthy control group subjects.
  
  
  RESULTS
  The patients were aged 9.9 ± 4.2 years in the diabetic group, including 13 (46.5%) girls and 15 (53.5%) boys. The healthy control group comprised 20 (74%) girls and seven boys (26%) with an average age of 8.6 ± 3.7 years. The search for factors modifying heart rate variability yielded the following correlations: for the time-dependent variables, negative between age and both average and maximal heart rate (r = -0.263 and -0.460, respectively), negative between haemoglobin A1c and percentage of differences between adjacent RR intervals >50 ms, positive between diabetes duration and square root of the mean of the sum of squares of differences between adjacent NN intervals. The average heart rate and percentage of differences between adjacent RR intervals >50 ms was significantly higher in the girls than the boys in all groups. With regard to the frequency-dependent factors affecting heart rate variability, correlations were found between haemoglobin A1c level and both total power and very low frequency (r = -0.751 and -0.644) and between very low frequency and diabetes duration.
  
  
  CONCLUSIONS
  A reduction in heart rate variability parameters was observed in type 1 diabetes mellitus patients who had a long disease duration or were poorly controlled, as compared with healthy controls.
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Senem
authors.initials: S
authors.lastname: Özgür
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Özben
authors.initials: Ö
authors.lastname: Ceylan
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Şenocak
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Utku A
authors.initials: UA
authors.lastname: Örün
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Vehbi
authors.initials: V
authors.lastname: Doğan
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Yılmaz
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Mahmut
authors.initials: M
authors.lastname: Keskin
authors.affiliation: 2Department of Pediatric Endocrinology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Zehra
authors.initials: Z
authors.lastname: Aycan
authors.affiliation: 3Department of Cardiology,Hacettepe University,Ankara,Turkey.
authors.forename: Sercan
authors.initials: S
authors.lastname: Okutucu
authors.affiliation: 1Department of Pediatric Cardiology,Dr. Sami Ulus Children's Hospital,Ankara,Turkey.
authors.forename: Selmin
authors.initials: S
authors.lastname: Karademir
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology*; D058065:Diabetic Cardiomyopathies / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D018618:Echocardiography, Doppler, Color; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human