Modern Pediatrics. Ukraine. 4(108): 61-66. doi 10.15574/SP.2020.108.61
Kovalchuk T. A.
I. Horbachevsky Ternopil National Medical University of the Ministry of Health of Ukraine

For citation: Kovalchuk TA. (2020). Features of vitamin B₆ profile in children and adolescents with vasovagal syncope. Modern Pediatrics. Ukraine. 4(108): 61–66. doi 10.15574/SP.2020.108.61
Article received: Jan 05, 2020. Accepted for publication: May 29, 2020.

Recent studies have drawn attention to the deficiency of B-group vitamins and their possible impact on the frequency and severity of clinical manifestations of syncope. Although studies of vitamin В₆ role in the pathogenesis of vasovagal syncope have not yet been conducted, the effect of this vitamin deficiency on the development of autonomic nervous system dysfunction is not in doubt.
Purpose — to study the vitamin В₆ serum level in children and adolescents with vasovagal syncope, to assess the possible relationships between the vitamin В₆ concentration and main clinical and laboratory parameters of the disease.
Materials and methods. The main group consisted of 30 children aged 8–17 years with a diagnosis of vasovagal syncope. The comparison group consisted of 23 healthy children of the same age. The determination of vitamin В₆ and homocysteine in serum was performed by a colorimetric enzyme-linked immunosorbent assay using the Monobind test system. The suboptimal vitamin B₆ level was determined at its concentration 4.94–7.41 μg/l (equivalent to 20–30 nmol/l), vitamin В₆ deficiency was determined at its concentration <4.94 μg/l (equivalent to <20 nmol/l).
Results. In the group of vasovagal syncope vitamin В₆ level was 10.42±0.93 μg/l. It was significantly lower compared to healthy respondents — 16.11±1.15 μg/l (p=0.0003). The prevalence of suboptimal vitamin B6 level was 23.3%, deficiency — 10.0%. Homocysteine level was elevated in respondents with vasovagal syncope (p<0.05). Vitamin В₆ correlated with the average heart rate per 24 hours (r=0.42), the average heart rate during the active period of the day (r=0.45), the maximum heart rate per 24 hours (r=0.41), the mode (r=00.38) and mean value of PQ interval (r=00.48), the mode of QT interval (r=00.40).
Conclusions. There is a significant decrease in serum vitamin В₆ in patients with vasovagal syncope. Low serum vitamin В₆ is associated with a decrease in heart rate, an increase the mode and average value of PQ interval, the mode of QT interval. This results confirm the indirect effect of vitamin B₆ on the development of autonomic dysfunction and the importance of determining vitamin B6 in all children and adolescents with vasovagal syncope.
The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of these Institutes. The informed consent of the patient was obtained for conducting the studies.
No conflict of interest were declared by the author.
Key words: vasovagal syncope, vitamin В₆, children.

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