title: Beta 3 subunit of G-protein and its influence on autonomic nervous system in patients with vasovagal syncope.
abstract: OBJECTIVE
  The aim of this prospective study was to investigate the impact of genetic polymorphisms of β3 subunit of G-protein on the occurrence of vasovagal syncope, hemodynamic parameters and heart rate variability during head-up tilt test (HUT).
  
  
  BACKGROUND
  G-proteins play an important role in the intracellular transmission of impulses in cardiovascular autonomic reflexes.
  
  
  METHODS
  In 157 patients with suspected vasovagal syncope HUT was performed. Ninety-one patients (38 men, 53 women, mean age 48 ± 17 years) had positive HUT. Control group consisted of 109 subjects (69 men, 40 women, mean age 37 ± 16 years) with no history of syncope. Results of HUT, hemodynamic parameters and LF, HF, LF/HF, SDNN, RMSSD parameters of heart rate variability were compared in patients with different genotypes. C825T polymorphism of β3 subunit of G-protein was determined in the study subjects.
  
  
  RESULTS
  There was no significant difference in the distribution of genotypes between patients and control group. Also, there was no significant difference in hemodynamic parameters. A statistically significant difference was found between genotypes in LF/HF in the early HUT (mean rank CC: 48.68 vs CT: 35.51 vs TT: 34.14; p = 0.039) and at RMSSD at the time of syncope (mean rank CC: 32.38 vs CT: 42.74 vs TT: 18.50; p = 0.026).
  
  
  CONCLUSIONS
  In this study, the relation of C825T polymorphism of β3 subunit of G-protein to vasovagal syncope was not documented (Tab. 2, Fig. 4, Ref. 37).
authors.forename: L
authors.initials: L
authors.lastname: Evin
authors.forename: P
authors.initials: P
authors.lastname: Mitro
authors.forename: V
authors.initials: V
authors.lastname: Habalova
authors.forename: M
authors.initials: M
authors.lastname: Simurda
authors.forename: E
authors.initials: E
authors.lastname: Muller
authors.forename: P
authors.initials: P
authors.lastname: Murin
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D019462:Syncope, Vasovagal / Q000235:genetics* / Q000503:physiopathology; D018667:Tilt-Table Test
chemical_list: C000595803:GNB3 protein, human; D020962:Heterotrimeric GTP-Binding Proteins
keywords: HUT test; gene polymorphisms; heart rate variability; vasovagal syncope; β3 subunit of G-protein.