title: The effect of metabolic syndrome on heart rate turbulence in non-diabetic patients.
abstract: BACKGROUND
  Metabolic syndrome (MetS), which includes a cluster of risk factors, is being increasingly recognized as a new risk factor for cardiovascular disease. Heart rate turbulence (HRT) is a Holter-based non-invasive method for detecting cardiac autonomic imbalance and is an independent, powerful predictor of cardiac arrhythmias and sudden cardiac death in different patient groups. This study evaluated the effect of MetS on HRT in non-diabetic patients.
  
  
  METHODS
  This study included 80 non-diabetic MetS subjects and 50 healthy subjects. All 130 subjects underwent a 24-h ambulatory Holter electrocardiogram recording. Two indices of HRT were analyzed: turbulence onset (TO) and turbulence slope (TS). HRT values were classified into 3 categories for risk stratification: 1) Category 0, TO and TS were normal; 2) Category 1, either TO or TS was abnormal; 3) Category 2, both TO and TS were abnormal.
  
  
  RESULTS
  When we compared MetS rates in the HRT risk stratification groups, there were significant differences for all groups as compared with the controls (Category 0 = MetS 28.8%, n = 15, Control 71.2%, n = 37, p 〈 0.001; Category 1 = MetS 80.8%, n = 42, Control 19.2%, n = 10, p 〈 0.001; Category 2 = MetS 88.5%, n = 23, Control 11.5%, n = 3, p 〈 0.001). In addition, TO and TS abnormalities were correlated with the number of MetS components (r = 0.608, p 〈 0.001; r = -0.388, p 〈 0.001, respectively).
  
  
  CONCLUSIONS
  To our knowledge, this is the first study to establish a relationship between HRT and MetS. These findings suggest that MetS adversely affects HRT scores. In addition, the number of MetS components is related to impaired HRT scores.
authors.affiliation: Department of Cardiology, Abant Izzet Baysal University, Medical Faculty, Bolu, Turkey. cardiology14@gmail.com
authors.forename: Alim
authors.initials: A
authors.lastname: Erdem
authors.forename: Masahiro
authors.initials: M
authors.lastname: Uenishi
authors.forename: Zekeriya
authors.initials: Z
authors.lastname: Küçükdurmaz
authors.forename: Kazuo
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Ritsushi
authors.initials: R
authors.lastname: Kato
authors.forename: Motoki
authors.initials: M
authors.lastname: Hara
authors.forename: Mehmet
authors.initials: M
authors.lastname: Yazici
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000209:etiology; D015716:Electrocardiography, Ambulatory; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D008875:Middle Aged; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors