Objectives: 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).
Keywords: HUT test; gene polymorphisms; heart rate variability; vasovagal syncope; β3 subunit of G-protein..