title: Which is responsible for cardiac autonomic dysfunction in non-diabetic patients with metabolic syndrome: Prediabetes or the syndrome itself?
abstract: OBJECTIVE
  Cardiac autonomic dysfunction (CAD) is associated with both prediabetes and metabolic syndrome (MS). Heart rate variability (HRV) and heart rate turbulence (HRT) are reliable 24-h Holter-ECG findings of cardiac autonomic function. This study aimed to investigate the relation between MS and its components and CAD using HRV and HRT.
  
  
  METHODS
  The study included 80 non-diabetic patients with MS and 70 control subjects. All study population and the patients with MS were further analyzed for each diagnostic component of MS to investigate which criteria impaired HRV and HRT.
  
  
  RESULTS
  HRV and HRT parameters were disturbed in patients in the MS group. While impairment in HRV and HRT was significantly related to the presence of the fasting plasma glucose (FPG) criterion, there were no differences between groups in terms of the other 4 MS criteria. Moreover, FPG level was significantly correlated with SDNN (r=-0.352, p<0.001), SDNN index (r=-0.423, p<0.001), SDANN (r=-0.301, p<0.001), RMSSD (r=-0.237, p<0.001), pNN50 (r=-0.237, p<0.001), turbulence onset (TO) (r=0.365, p<0.001) and turbulence slope (TS) (r=-0.365, p<0.001). Among the MS diagnostic criteria, only FPG level was an independent determinant of all HRV and HRT parameters.
  
  
  CONCLUSIONS
  This study confirms the relation between MS and CAD. Increased FPG alone appears to be responsible for the mentioned findings among the 5 diagnostic criteria. Accordingly, CAD may be the result of prediabetes, not MS in patients with MS.
authors.affiliation: Başkent University, Medical and Research Center of Alanya, Department of Cardiology, Alanya, Antalya, Turkey. Electronic address: serhatbalcioglu@gmail.com.
authors.forename: Akif Serhat
authors.initials: AS
authors.lastname: Balcioğlu
authors.affiliation: Başkent University, Medical and Research Center of Alanya, Department of Cardiology, Alanya, Antalya, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: Akinci
authors.affiliation: Başkent University, Medical and Research Center of Alanya, Department of Cardiology, Alanya, Antalya, Turkey.
authors.forename: Davran
authors.initials: D
authors.lastname: Çiçek
authors.affiliation: Başkent University, Medical and Research Center of Alanya, Department of Cardiology, Alanya, Antalya, Turkey.
authors.forename: Halil Olcay
authors.initials: HO
authors.lastname: Eldem
authors.affiliation: Başkent University, Medical and Research Center of Alanya, Department of Cardiology, Alanya, Antalya, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Çoner
authors.affiliation: Başkent University, Faculty of Medicine, Department of Cardiology, Ankara, Turkey.
authors.forename: Uğur Abbas
authors.initials: UA
authors.lastname: Bal
authors.affiliation: Başkent University, Faculty of Medicine, Department of Cardiology, Ankara, Turkey.
authors.forename: Haldun
authors.initials: H
authors.lastname: Müderrisoğlu
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001786:Blood Glucose / Q000378:metabolism; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006331:Heart Diseases / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000150:complications / Q000503:physiopathology*
chemical_list: D001786:Blood Glucose
keywords: Autonomic function; Glucose; Heart rate variability; Metabolic syndrome