Hemodynamic parameters and heart rate variability during a tilt test in relation to gene polymorphism of renin-angiotensin and serotonin system.
OBJECTIVE
The aim of the study was to evaluate the renin-angiotensin system and serotonin transporter gene polymorphisms in relation to hemodynamic parameters and heart rate variability during a head-up tilt test (HUT) in patients with vasovagal syncope.


METHODS
DNA was collected from 191 patients (mean age 44+/-18 years, 61 men, 130 women). The following gene polymorphisms were determined in genomic DNA: angiotensin-converting enzyme insertion/deletion polymorphism (I/D ACE), angiotensinogen gene polymorphism (M 235), angiotensin II receptor type 1 (ATR1) polymorphism (A 11666C), and polymorphism of serotonin transporter gene (5HTTLPR).Heart rate variability during HUT was assessed in 5-minute intervals by low frequency, high frequency, standard deviation of the normal-to-normal (SDNN), and root mean square successive difference parameters.


RESULTS
AA genotype of A 1166C polymorphism was associated with lower minimal systolic blood pressure (SBP) and diastolic blood pressure (DBP) during HUT compared with other genotypes (minimal SBP: AA 59.6+/-21,8, AC 79.9+/-22.7, CC 65.4+/-22.7 mmHg, P=0.007), (minimal DBP: AA 36.4+/-22.7, AC 52.3+/-22.9, CC 45.4+/-19.5 mmHg, P=0.007).AA genotype was also associated with higher SDNN compared to other genotypes in the early phase of HUT (SDNN in 5 minutes of tilt: AA 59.7+/-24.6, AC 50.6+/-20.6, CC 46.0+/-13.2, P=0.01) and at syncope occurrence (SDNN: AA 71.0+/-20.9, AC 58.2+/-17.9, CC 58+/-10, P=0.04)


CONCLUSIONS
AA genotype of A 1166C polymorphism in the ATR1 gene may be associated with hypotension and decline in sympathetic tone during HUT. Its role in genetic predisposition to vasovagal syncope cannot be excluded.
Mitro
Peter
P
Clinic of Internal Medicine III, Medical Faculty, P.J. Safarik University, Kosice, Slovakia. pmitro@lf.upjs.sk
Mudráková
Klaudia
K
Micková
Helena
H
Dudás
Ján
J
Kirsch
Peter
P
Valocik
Gabriel
G
D000328:Adult; D000085962:Angiotensin-Converting Enzyme 2; D000808:Angiotensinogen / Q000235:genetics*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006339:Heart Rate / Q000235:genetics*; D006801:Humans; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics*; D012084:Renin-Angiotensin System / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D019462:Syncope, Vasovagal / Q000503:physiopathology*; D018667:Tilt-Table Test
D044139:Receptor, Angiotensin, Type 2; D050486:Serotonin Plasma Membrane Transport Proteins; D000808:Angiotensinogen; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2