Вариабельность сердечного ритма у детей 7 лет

Аннотация

The article presents data on heart rate variability (HRV) in 7 years old children. There are presented information of temporal, geometric, spectral analysis of HRV as well as data of variation pulse oximetry. There is given a comparative assessment of indicators depending on the gender and body mass index of children. An analysis of the results of the study showed a strong direct and inverse relationship between some of the indicators of HRV, as well as a difference in the indicators of HRV in 7 years old children, depending on gender and body mass index. Keywords: 7-year-old children, physical development, heart rate variability. Heart rate variability (HRV) is the simplest and informative method of assessing the status of the vegetative nervous system [5]. Also, HRV indicates the adaptive capacity of the body and helps to identify the risk of unexpected death [1]. Most often, HRV is used in cardiology practice in determination of the adequacy of therapy [4]. HRV is based on the determination of cardio intervals in the second standard lead of electrocardiography. [2,3]. HRV assesses the physiological functions of the body through the ratio of the activity of the different part of vegetative nervous system [1], and allows to evaluate the functional capabilities of the body and carry out preventive measures aimed at maintaining the health of the child [6]. For greater reliability, the minimum recording should be at least 5 minutes. Also, orthostatic test, Valsalva test are used for evaluation. To carry out these tests, it is necessary to adhere to the stationarity condition. Studies should be conducted under the same conditions and the length of the first and second records should be the same. Statistical data processing methods are used to analyze heart rate variability. Statistical methods based on the time difference between R-R intervals. These methods include HR (heart rate), RRNN, mean RR interval duration, which evaluates the balance in the 77 British View ISSN 2041-3963 Volume 8 Issue 6 2023 Universal impact factor 8.528 SJIF 2022: 4.629 vegetative nervous system; SDNN is the square root of the cardio interval`s spread, RMSSD and pNN50% are indicators that assess the state of the parasympathetic link of the autonomic nervous system. Geometric methods are the least influenced by artifacts, these include the triangular index and the St. George index, TINN reflect the total HRV. In spectral analysis, the power is estimated depending on the oscillation frequency. The frequency spectrum is usually divided into: high-frequency (0.2-0.4 Hz), low-frequency (0.04-0.15 Hz) and very low-frequency (0.003-0.04 Hz). Power is measured in ms2. Measure the power contribution of the spectrum depending on the frequency range. HF - high-frequency spectrum showing the activity of the parasympathetic system, LF – indicates the activity of the sympathetic system, VLF – reveals the activity of the suprasegmentally centers of the autonomic nervous system [3]. Purpose of the study. Determine the heart rate variability in 7 years old children. Materials and research methods. The study involved 120 children. All children underwent anthropometric measurements. There were selected only children without acute and chronic diseases. The children were divided into 3 groups depending on the body mass index. The first group consisted of 66 children with BAZ (bmi for age) scores from -2 to +1 SDS; the second group included 29 children, with a BAZ range of +1 to +2 SDS. The third group consisted of 25 children with BAZ > +2 SDS. All children underwent ECG examination, cardiointervalography with orthostatic test. The following indicators were used for analyses of HRV: rrHRV, IQR, RRNN, HR, SDNN, RMSSD, pNN50%, TRI, ApEn, SD1, SD2, SD1/SD2, VLF, LF, HF, IC, CV, Mo (the most common interval RR), SI (stress index), RMI (respiratory modulation index), SAI (sympathoadrenal index), SWAI (slow wave arrhythmia index), VPR (vegetative parasympathetic range), ARPI (indicator of the adequacy of regulatory processes), VBI (vegetative balance index). The statistical significance of the obtained measurements was determined by 78 British View ISSN 2041-3963 Volume 8 Issue 6 2023 Universal impact factor 8.528 SJIF 2022: 4.629 Student's t-test (t) with the calculation of the error probability (P). Significance level p 0.7 was taken as a strong correlation. A strong direct correlation was found between: rrHRV - SDNN - RMSSD - pNN50% - TRI - SD1/SD2 - CV - RMI. A strong inverse correlation was found between the indicators: rrHRV and AMo (% of most common intervals RR), SI, SAI, SWAI, ARPI, VPR. HR has a high inverse correlation with pNN50%, RMSSD, SDNN and a high direct correlation with AMo, SI, SWI, ARPI. SI (stress index) and APRI (an indicator of the activity of regulatory p