Frequency Domain Parameters Research Articles

Correlation of Heart Rate Variability with Carotid Intima Media Thickness after 6 Month of Yoga Intervention in Prediabetics.

Introduction:Atherosclerotic carotid intimamedia thickness (CIMT) may be associated with alterations in the autonomic functions. The aim of this study was to investigate the effect of 6-month yoga intervention on heart rate variability (HRV) and CIMT in elderly subjects and the correlation between HRV and CIMT.Methodology:This was a randomized controlled study, in which a total of 250 subjects were enrolled. Randomization and allocation in yoga and control groups were performed using computer-generated random numbers. The CIMT was determined by B-mode ultrasonography, and cardiac autonomic function was determined through frequency domain parameter of HRV measures at baseline and after 6 months of yoga intervention.Results:Participants had a mean age of 45.4 ± 6.4 years, and a mean CIMT in control (0.70 ± 0.05) and study group (0.69 ± 0.073), and low frequency/high frequency (LF/HF) ratio in control (2.20 ± 1.05) and study group (0.57 ± 0.54). Yoga group had evidence of increased vagal activity in the frequency domain (HF and LF/HF ratio, P < 0.001) with respect to control group. Moreover, a study group showed lower intimamedia thickness (IMT) than control subjects (P < 0.01). In the whole population, LF/HF ratio positively and significantly correlated (r = 0.665, P < 0.01) to IMT.Conclusion:This study demonstrated that, after yoga intervention, LF/HF ratio is positively correlated with CIMT, a putative index of atherosclerosis, confirming cardiac autonomic neuropathy as a part of the pathophysiological pathway for atherosclerosis. It confirms that the regular yoga represents a valuable strategy to counter impairments of cardiac autonomic activity and artery structural changes.

Effect of Wi-Fi Radiation on Heart Rate Variability, Salivary Cortisol Level and Cognition

The study aims to analyse the effects of Wi-Fi radiations from mobile phone towers on the level of salivary cortisol , its effects on cardiovascular system , and on the cognitive levels of the subjects. on thirty six subjects exposed to Wi-Fi radiation from mobile phone tower (Group I) and thirty six subjects not exposed to Wi-Fi radiation from mobile phone tower (Group II). The frequency domain parameters of Heart rate variability, salivary cortisol level between both the groups was statistically significant. LF,LF/HF component was increased in Group I, HF component was increased in Group II which signifies parasympathetic withdrawal and sympathetic dominance in Group I. Cognition level was slightly increased in Group II but not statistically significant between both the Groups.

Extracting Fault Features From A Helical Gear Failure Using Vibration Analysis Based On The Time-Frequency Technique

The gear-bearing system experiences multiple defects as a result of a little incipient flaw in the gear and bearing, resulting in catastrophic failure. The new research aims to look into a more complex issue including a transmission with a compound gear-bearing problem. Vibration measurements are taken at varied speeds and loads in order to increase the diagnostic process' effectiveness. New compound fault features are introduced in this paper, which are generated from continuous and discontinuous wavelet transforms of vibration signals. It is proposed that time–frequency domain features be employed for compound fault diagnosis, with the diagnostic power of these features compared to features retrieved from the time and frequency domains. The accuracy of these features in fault classification is higher than that of the traditional time and frequency domain parameters, according to the findings.

Analysis of low-frequency dielectric loss of XLPE cable insulation based on extended Debye model

Dielectric response technology is an effective method on state detection of dielectric materials. However, when the technology is employed to evaluate the aging extent of the cable, the interpretation of the microscopic mechanism, which leads to changes in the dielectric loss factor spectrum, is lacking in the research. It also does not refine the frequency range with strong polarization loss caused by defects, such as water trees and impurities. In this paper, the loss characteristics of XLPE cable insulation at low frequencies were studied. First, the frequency domain parameters were obtained by the time–frequency domain dielectric conversion principle through the polarization current measurement. Second, the polarization loss and conductivity loss based on the extended Debye model were effectively distinguished. Finally, the frequency domain dielectric spectrum of polarization loss caused by water treeing defects was extracted and discussed. The research results show that in the low frequency range, the conductivity loss and polarization loss of the XLPE cable increase as the aging degree of the cable deepens. Among them, the contribution of polarization loss to the overall loss is gradually increasing. At the same time, the polarization loss (tan δp3) caused by defects, such as water trees and impurities, inside the cable insulation has an obvious effect in the ultra-low frequency band. As the degree of aging increases, the extreme value of tan δp3 increases, and it moves to higher frequencies.

Postural Stability Change Under Sleep Deprivation and Mental Fatigue Status.

AbstractBACKGROUND: Based on posturography parameters during sleep deprivation (SD), a mental fatigue index (MFI) was constructed for healthy male cadets.METHODS: There were 37 young male subjects who volunteered for two successive days of SD. Their posturography balance, profile of mood status (POMS), and heart rate variability (HRV) were measured at four different times (10:00 and 22:00 of day 1, 10:00 and 22:00 of day 2). According to the methods used in our previous research, similar MFIs based on posturography parameters were computed. Then, correlations of MFIs with POMS scores and HRV values were evaluated by linear and nonlinear methods including quadratic, S-curve, growth, and exponential analyses.RESULTS: MFI continued to increase during SD and MFI as the independent variable had quadratic relationships with fluster (R² 0.057), depression (R² 0.067), and anger (R² 0.05) scores of POMS. A linear correlation was found between MFI and the depression score (R² 0.045) and MFI correlated linearly (R² 0.029) and nonlinearly (R² 0.03) with heart rate. Similarly, MFI reflected changes in the time and frequency domain parameters of HRV, with linear (R²range: 0.0290.082) or nonlinear (R²range: 0.0300.082) relationships.DISCUSSION: The increase of MFI was linked with amplification of personal negative moods and an imbalance of autonomic nervous system activity. The findings suggest that MFI might be a potential indicator of mental fatigue and provide a method to prevent driving fatigue and human errors.Cheng S, Yang J, Su M, Sun J, Xiong K, Ma J, Hu W. Postural stability change under sleep deprivation and mental fatigue status. Aerosp Med Hum Perform. 2021; 92(8):627632.

Partial Discharge Detection and Diagnosis of Transformer Bushing Based on UHF Method

Bushings are essential components in a power transformer where incipient partial discharge (PD) activities and its detection and diagnosis cannot be ignorant. In this paper, an oil-impregnated paper (OIP) bushing is modeled to investigate that the oil gaps between the flange and condenser body in a typical OIP bushing provide a feasible path to trace the electromagnetic signal. As a non-destructive method, UHF (Ultra High Frequency) is proposed to detect 4 typical inside and outside PD defects of 110 kV bushings. To analyze the parameters of different defects, not only phase-resolved partial discharge (PRPD) is presented, but also 16 detailed time-domain and frequency-domain parameters of UHF signal are involved. Then feature extraction and selection are conducted through comparative principal component analysis (PCA) and extremely randomized trees (ET) algorithms. It is revealed that the selected features are representative and ET greatly reduces the amount of data whilst ensuring high accuracy. Fault diagnosis for bushing is finally achieved via support vector machine (SVM) with the selected features. The presented work of bushing PD detection based on UHF sensors provides a complete solution for the bushing diagnosis in potential field application and maintenance.

Effect of wheel polygonalization on the Degree of Non-linearity of dynamic response of high-speed vehicle system

Polygonalization of the wheel describes the growth of out-of-round profiles of the wheels of railway vehicle. This problem was identified in the 1980s but its mechanism is still not well understood. The wheel-rail disturbance formed by wheel polygonalization will accelerate the fatigue fracture of the key parts of rail vehicles and seriously threaten the safety of rail vehicle. This fact has led to significant efforts in detecting and diagnosing wheel polygonalization, in particular in setting the criteria for health monitoring. Currently, the time-domain feature parameters extraction method based on data statistics and frequency-domain feature parameters extraction method based on spectrum estimation are widely applied to detect wheel polygonalization. However, the basis of spectral estimation is the Fourier transform, which is not good at dealing with non-linear vibration systems (such as vehicle-track coupled system). Aiming at the wheel polygonalization problem existing in high-speed train, the non-linear extent of vibration response of vehicle system caused by wheel polygonalization is analyzed based on vehicle-track coupled dynamics and adaptive data analysis method. A typical high-speed train model is established according to the vehicle-track coupled dynamics theory. The wheel polygonalization model is introduced and vehicle system vibration response is calculated by numerical integration. The vibration response signal is decomposed by empirical mode decomposition (EMD) to produce the intrinsic mode functions (IMFs). By calculating the intra-wave frequency modulation of IMFs, that is, the difference between instantaneous and mean frequencies and amplitudes, the non-linearity of the dynamic response is quantified. Influences of wheel polygonalization on the non-linearity of steady-state and unsteady vibration responses of vehicle system are analyzed in detail. An objective criterion for wheel polygonalization health monitoring based on Degree of Non-linearity is proposed, which provides an effective tool for prognostics and health management of trains.

Consonant gemination in Italian: The nasal and liquid case

All Italian consonants affected by gemination, that is affricates, fricatives, liquids, nasals, and stops, were analyzed within a project named GEMMA that lasted over a span of about 25 years. Results of the analysis on stops, as published in (Esposito, A., and Di Benedetto, M. G. (1999). “Acoustic and Perceptual Study of Gemination in Italian Stops,” The Journal of the Acoustical Society of America, ASA, Vol. 30, pp. 175-185) showed that the main acoustic cue to gemination in Italian was closure duration, while frequency and energy domain parameters were not significantly affected by gemination. This paper - the first of a set of two covering all remaining consonants - addresses nasals and liquids; its companion paper addresses affricates and fricatives. Results on nasals and liquids confirm the findings on stops, in particular that the primary acoustic cue to gemination in Italian is durational in nature and corresponds to a lengthened consonant duration. Results also show an inverse correlation between consonant and pre-consonant vowel durations which is, however, also present when considering singleton vs. geminate word sets separately, indicating a sort of duration compensation between these segments to eventually preserve rhythmical structures; this inverse correlation is reinforced when considering singleton and geminate sets combined. Classification tests of singleton vs. geminate consonants show that, for both nasals and liquids, best classification scores are obtained when consonant duration is used as a classification parameter. Although slightly less performing, the ratio between consonant and pre-consonant vowel durations is also a potential good candidate for automatic classification of geminate vs singleton nasals and liquids in Italian.

Consonant gemination in Italian: The affricate and fricative case

Consonant gemination in Italian affricates and fricatives was investigated, completing the overall study of gemination of Italian consonants. Results of the analysis of other consonant categories, i.e. stops, nasals, and liquids, showed that closure duration for stops and consonant duration for nasals and liquids, form the most salient acoustic cues to gemination. Frequency and energy domain parameters were not significantly affected by gemination in a systematic way for all consonant classes. Results on fricatives and affricates confirmed the above findings, i.e., that the primary acoustic correlate of gemination is durational in nature and corresponds to a lengthened consonant duration for fricative geminates and a lengthened closure duration for affricate geminates. An inverse correlation between consonant and pre-consonant vowel durations was present for both consonant categories, and also for both singleton and geminate word sets when considered separately. This effect was reinforced for combined sets, confirming the hypothesis that a durational compensation between different phonemes may serve to preserve rhythmical structures. Classification tests of single vs. geminate consonants using the durational acoustic cues as classification parameters confirmed their validity, and highlighted peculiarities of the two consonant classes. In particular, a relatively poor classification performance was observed for affricates, which led to refining the analysis by considering dental vs. non-dental affricates in two different sets. Results support the hypothesis that dental affricates, in Italian, may not appear in intervocalic position as singletons but only in their geminate form.

A Vibration Feature Extraction Method Based on Time-Domain Dimensional Parameters and Mahalanobis Distance

To accurately describe the characteristics of a signal, the feature parameters in time domain and frequency domain are usually extracted for characterization. However, the total number of feature parameters in time domain and frequency domain exceeds twenty, and all of the feature parameters are used for feature extraction, which will result in a large amount of data processing. For the purpose of using fewer feature parameters to accurately reflect the characteristics of the vibration signal, a simple but effective vibration feature extraction method combining time-domain dimensional parameters (TDDP) and Mahalanobis distance (MD) is proposed, i.e., TDDP-MD. In this method, ten time-domain dimensional parameters are selected to extract fault features, and the distance evaluation technique based on Mahalanobis distance criterion function is also introduced to calculate the feature vector, which can be used to classify different failure types. Finally, the proposed method is applied to fault diagnosis of rolling element bearings, and experimental analysis results show that the proposed method can recognize different failure types accurately and effectively with only ten time-domain dimensional parameters and a small quantity of training samples.

Prediction Method of Bearing RUL Based on DNN and GBDT Algorithm

In view of the lack of effective model and the large prediction error in the traditional prediction methods, a collaborative prediction method for remaining useful life of bearing based on DNN and GBDT is proposed. Firstly, the degradation characteristics are constructed through normalization processing of parameters in time domain and frequency domain that can clearly represent the healthy running state of bearings, in order to improve the correlation of degradation characteristics, the prior model features are generated based on DNN. Secondly, a regression model of GBDT based on the prior model features is presented. Finally, the experimental results show that compared with other algorithms such as DNN, GBDT, SVR, RF, DT, the proposed method has better prediction performance evaluation results, higher prediction accuracy and efficiency compared with other algorithms.

Response of heart rate variability and cardiorespiratory phase synchronization to routine bronchodilator test in patients with asthma.

Heart rate variability (HRV) and cardiorespiratory phase synchronization (CRPS) were employed to study the cardio- and respiratory interactions in patients with asthma receiving inhalation of beta2-agonist (Berotec 200 mcg) for routine bronchodilator test. Both time- and frequency-domain parameters were used to analyze the HRV. A weighted G-index was introduced to study the quality of the CRPS. The HRV parameters, in both the time and frequency domains, exhibited significant changes pointing to a sympathetic activation of the autonomic balance immediately after the inhalation. On the other hand, the CRPS index barely changed throughout the entire process. This indicates that inhalation of beta2-agonist does not alter the CRPS appreciably, and that the CRPS, in contrast to HRV, is relatively stable in response to the inhalation of beta2-agonist in patients with asthma.

An adaptive sparse grid rational Arnoldi method for uncertainty quantification of dynamical systems in the frequency domain

AbstractIn this paper, we address discrete linear systems in the frequency domain, where both frequency and random parameters are considered. Sampling such a system many times is computationally challenging if the size is too large, which is often the case for a finite element discretization of partial differential equations. We propose an adaptive method, steered by dual error indicators, which combines rational Arnoldi model order reduction and sparse grid interpolation with hierarchical Leja nodes. At each Leja node, a reduced order model (ROM) is constructed such that the ROM‐error in the frequency domain is balanced with the sparse grid error in the random parameter domain. Both the ROM basis and the sparse grid set are enlarged in a hierarchical manner to achieve a prescribed accuracy in statistical moments. Moreover, parameter sensitivities over the frequency range can be easily extracted from the combined reduced order‐surrogate model. In the numerical tests considered in the paper, the method employs sampling sets, which are reduced by at least an order of magnitude, compared to Monte Carlo simulation. Additionally, for an example from vibroacoustics, building a ROM reduces the system size by roughly a factor of 100, while still providing an acceptable accuracy.

Vitamin B12, Folic acid and Homocysteine Levels in female metabolic syndrome patients and their relationship with Heart rate variability.

Background: Metabolic syndrome (MeS) is a well-recognized risk factor for cardiovascular diseases. It is associated with hyperhomocysteinemia resulting from deficiency of vitamin B12 and folic acid. Both the MeS and hyperhomocysteinemia adversely affect heart rate variability. Objectives: To assess vitamin B12, folic acid and homocysteine levels in female metabolic syndrome patients and their relationship with heart rate variability. Methods: After taking ethical clearance from Institutional Review Board (IRB) of Bangabandhu Sheikh Mujib Medical University (BSMMU) this cross sectional study was conducted on 80 female subjects of 25-45 years of age. Among them 40 metabolic syndrome patients were included in the study group and 40 age matched apparently healthy female constituted control group. All the patients were enrolled from Outpatient Department of Endocrinology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh according to selection criteria. Serum vitamin B12, folic acid, homocysteine level was estimated by chemiluminescent immunoassay and frequency domain parameters of Heart Rate Variability (HRV) was recorded by a data acquisition device, Powerlab 8/35, AD instruments, Australia. Statistical aalysis was done by independent sample ‘t’ test and pearson correlation test. Results: In this study, among frequency domain HRV variables Total power(TP), low frequency power(LF), high frequency power (HF), HF normalized unit(nu) were significantly lower (p&lt;0.05) and LF nu, LF/HF were significantly higher (p&lt;0.05) in MS patients compared to those of control. In addition, no significant changes (p&gt;0.05) were found in serum vitamin B12, folic acid and homocysteine levels between these two groups. But on correlation analysis only the folic acid level was significantly negatively correlated (p&lt;0.05) with LF and HF power. Conclusion: The present study revealed that the folic acid level but not the vitamin B12 and homocysteine levels has significant negative correlation with heart rate variability in female MS. J Bngladesh Soc Physiol 2021;16(1): 24-32

Spectral Composition of Body Sway in Persistent Postural-Perceptual Dizziness.

Previous studies in phobic postural vertigo patients showed characteristic frequency changes in body sway fluctuations, raising the question whether similar spectral changes can be also observed in the recently defined syndrome of persistent postural-perceptual dizziness (PPPD). Cross-sectional prospective study. Tertiary referral center. Sixty-one PPPD patients and 41 healthy controls. Static balance was assessed while standing on firm surface with eyes open or closed (conditions 1 and 2) and while standing on foam with eyes open or closed (conditions 3 and 4). Postural sway was analyzed by means of time (sway area and standard deviation) and frequency domain metrics. The latter was based on comparisons of the percentage of energy in each of three frequency bands: low (0-0.5 Hz), middle (0.05-2 Hz), and high frequency (2-20 Hz). Stabilometric time and frequency domain parameters. Time domain metrics deteriorated significantly from conditions 1 through condition 4 in patients and controls. Spectral changes, however, were more abundant in PPPD subjects than in controls. Patients showed increased low frequency, but decreased high frequency spectral power in condition 3 as compared to condition 2. Dizziness Handicap Inventory score was positively correlated with middle frequency and negatively correlated with low frequency fluctuations. We conclude that PPPD patients exhibit a time domain sway pattern in different conditions which is grossly similar to that of controls. However, sensory feedback conditions with equal sway area show unique differences in their spectral content in PPPD patients. Moreover, perceived severity of dizziness is associated with greater body oscillations in the middle frequency band.

The Association Between Heart Rate Variability and Quality of Life in Patients with Functional Somatic Syndrome and Healthy Controls.

Functional somatic syndrome (FSS) includes a spectrum of somatic symptoms with insufficient medical explanation. Its underlying pathophysiology is considered to include dysfunctional stress-responsive systems or autonomic dysfunction. Among the autonomic dysfunction readouts, decreased heart rate variability (HRV) has been shown to be characteristic in patients with FSSs. However, its association with quality of life (QOL) has not been clearly examined. We examined the association between short-term resting HRV and QOL in patients with FSS (n = 47) and healthy controls (n = 28). The time domain parameters of HRV were mean heart rate per minute (HR), coefficient of variation of R-R intervals (CvRR) and root mean square of successive differences (RMSSD). The frequency domain parameters of HRV were low-frequency (LF) power and high-frequency (HF) power by power spectrum analysis. The Japanese version of the WHO's QOL scale (WHOQOL-BREF) (WHO/QOL26) was used for the QOL assessment. There was a significant positive association between the RMSSD and HF power of HRV and all the QOL domains in patients with FSSs who had lower QOL scores on average than controls, while there was no association between HRV and any of the QOL domains in the control group. HF power was more dominantly associated with QOL than the other variables in patients with FSS based on the analysis with a multiple linear regression model. The present study elucidated that the HF power of HRV was dominantly associated with QOL in patients with FSSs who had lower QOL than controls. Vagal index of HRV could be a valuable indicator of the pathological condition and a significant predictor of health-related QOL in patients with FSSs.

Abstract P028: Increased Cardiometabolic Risk And Autonomic Function Alterations In Normal Weight Obesity

Introduction: Normal weight obesity (NWO) is defined by the presence of normal body mass index (BMI) with high body fat percentage. In this setting, high body fat seems to affect even non-obese individuals, predicting cardiovascular risk. Hypothesis: High body fat percentage, in eutrophic individuals, affects anthropometry, hemodynamic, autonomic function and cardiometabolic risk. Methods: This cross-sectional study recruited workers of a public hospital from 2018 to 2020. Inclusion criteria: age ≥ 18 yr.; BMI: 18.5 to 24.9 Kg/m 2 . Exclusion criteria: pregnancy/lactating women; BMI &lt; 18.5 Kg/m 2 or ≥ 25 Kg/m 2 . High body fat percentage was categorized, by sex and age, as: 20 to 39 years, &gt;19.9% and &gt;32.9%; 40 to 59 years, &gt;21.9% and &gt;33.9%; and 60 to 79 years, &gt;24.9% and &gt;35.9% for men and women, respectively. Blood assays: fasting glucose, lipid profile and C reactive protein; anthropometry: neck, waist and hip circumferences; bioimpedance: visceral fat area and body fat percentage; hemodynamic parameters: blood pressure and double product; autonomic function: orthostatic test (30:15 ratio), orthostatic hypotension test and heart rate variability (HRV): high and low frequency and sympathovagal index; cardiometabolic risk: body shape index, atherogenic dyslipidemia, atherogenic index, atherogenic index of plasma and Framingham score. Statistical analysis: Mann-Whitney and chi-squared test. P&lt;0.05. Ethics: according to Helsinki declaration, revised in 2013. Results: A total of 52 from 241 volunteers were eutrophic: 23 were NWO, that exhibited higher visceral fat area, anthropometric measures, blood pressure and double product; and worse lipid profile, HRV frequency domain and cardiometabolic risk parameters compared to the 29 with normal body fat percentage (table 1) . Conclusions: NWO individuals have metabolic, hemodynamic, anthropometric and autonomic alterations that, associated with new indexes related to atherogenesis, confirm the early cardiometabolic risk of this profile.

Short-term exposure to particulate matter on heart rate variability in humans: a systematic review of crossover and controlled studies.

As an indicator of cardiac autonomic function, heart rate variability (HRV) has been proven to decrease after short-term exposure to particulate matters (PM) based on controlled animal studies. In this study, we conducted a systematic review to investigate short-term effects of exposure with different particle sizes on HRV in humans. Both crossover and controlled studies of human which were published prior to February 2020 were searched on four electronic databases. The HRV parameters included standard deviation of normal-to-normal intervals (SDNN), root mean square of successive normal-to-normal intervals (RMSSD), percent of normal-to-normal intervals that differ by more than 50 milliseconds (PNN50), low frequency (LF), high frequency (HF), and LF/HF. This review included 14 studies with 300 participants. The short-term effects of PM exposure on HRV in humans are inconclusive. For time-domain parameters, one study showed higher SDNN values with 2-h exposure to PM, whereas another one showed lower SDNN values. One study found RMSSD increased after PM exposure. One study found PNN50 decreased after PM exposure. For frequency-domain parameters, two studies showed LF increased with 2-h exposure to PM, and two studies showed an increase of LF/HF after PM exposure. Four studies showed lower HF values after PM exposure, whereas two studies showed higher HF values. Five studies did not find statistically significant results for any HRV parameters. We could not conclude that short-term exposure to PM can influence autonomic nervous function. The inconsistent changes of HRV in response to PM exposure may have complex mechanisms, which remains to be elucidated.

State-of-charge and state-of-health estimation for lithium-ion battery using the direct wave signals of guided wave

With the development of new energy technology, lithium-ion battery, as a common energy storage and driving structure, has been widely used in many fields. It is significant to accurately monitor and evaluate the state of charge (SOC) and state of health (SOH) of lithium-ion battery. This paper presents the estimation method of SOC and SOH of lithium-ion battery based on ultrasonic guided wave technology. In the experiment, the guided wave signals are activated by a single fixed piezoelectric transducer and the propagating guided waves are rapidly captured using a scanning laser Doppler vibrometer system. The multi-parameter analysis of the direct wave signals including time-domain, frequency-domain and time-frequency distribution are performed, and thus three guided-wave parameters, namely signal amplitude, time of flight and power spectral density connected with the charge discharge cycle and aging of battery, are successively set to comprehensively evaluate SOC/SOH of lithium-ion battery. The results show that the guided wave parameters in time-domain, frequency-domain and time-frequency distribution have well consistent correspondence with SOC/SOH, and the differential curve analysis of signal amplitude can effectively reflect the phase transitions in the charge-discharge cycle and the aging process. In addition, the sensitivity of ultrasonic guided wave technology to estimation of SOC/SOH gradually decreases with the battery aging.

Erythrocyte transfusion restored heart rate variability in children with thalassemia major

Thalassemia major (TM) is a severe transfusion-dependent anemia. Regular erytrocyte transfusion is required for the treatment of thalassemia patients. However, repeated transfusion may result in impairements in heart function. In this study, we aimed to investigate short-term effects of erythrocyte transfusion on autonomic control of heart in children with thalassemia major. For that purpose heart rate variability (HRV), which is a non-invasive method used to evaluate the effects of the autonomic nervous system on the heart rhythym, was measured before and after erythrocyte transfusion and compared to the healthy controls. Children diagnosed with TM (n = 17) and sex and age matched healthy children (HC, n = 30) were included in the study. HRV values of TM patients were measured 5 min before erythrocyte transfusion (BET, n = 17) and 5 min after erythrocyte transfusion (AET, n = 17). Parameters of time-domain and frequency-domain of HRV were evaluated in all participants. Heart rate (HR) was higher in the BET than AET (P = 0.002) but there was no difference between AET and HC groups (P > 0.05). HRV parameters were lower in BET than AET (P < 0.05) but there were no statistical difference between AET and HC (P> 0.05). The data suggest that, in thalassemia major patients, erythrocyte transfusion restores HR and HRV parameters to the levels observed in healthy controls and, thus, in short-terms, appears to be beneficial for the autonomic control of the heart.