Frequency-domain Analysis Of Heart Rate Variability Research Articles

The effects of irrelevant speech on physiological stress, cognitive performance, and subjective experience – Focus on heart rate variability

Irrelevant speech impairs cognitive performance, especially in tasks requiring verbal short-term memory. Working on these tasks during irrelevant speech can also cause a physiological stress reaction. The aim of this study was to examine heart rate variability (HRV) as a non-invasive and easy-to-use stress measure in an irrelevant speech paradigm. Thirty participants performed cognitive tasks (n-back and serial recall) during two sound conditions: irrelevant speech (50 dB) and quiet (33 dB steady-state noise). The influence of conditions as well as presentation orders of conditions were examined on performance, subjective experience, and physiological stress. Working during irrelevant speech compared to working during quiet reduced performance, namely accuracy, in the serial recall task. It was more annoying, heightened the perceived workload, and lowered acoustic satisfaction. It was related to higher physiological stress by causing faster heart rate and changes in HRV frequency-domain analysis (LF, HF and LF/HF). The order of conditions showed some additional effects. When speech was the first condition, 3-back performance was less accurate, and serial recall response times were longer, heart rate was faster, and successive heart beats had less variability (lower RMSSD) during speech than during quiet. When quiet was the first condition, heart rate was faster and reaction times in 3-back were slower during quiet than during speech. The negative effect of irrelevant speech was clear in experience, performance, and physiological stress. The study shows that HRV can be used as a physiological stress measure in irrelevant speech studies.

Differences in the cardiovascular hemodynamic response between the Valsalva and Reverse Valsalva Maneuvers in healthy subjects.

The Valsalva Maneuver (VM) is the first-line treatment for paroxysmal supraventricular tachycardia, but a recent, novel, and efficient tool to restore sinus rhythm has been described, i.e., the Reverse Valsalva (RV). This study aims to compare changes in cardiovascular hemodynamics and autonomic system activity (ANS) based on heart rate variability (HRV) analysis during both maneuvers. Fifteen healthy participants performed the VM and RV maneuvers three times in a sitting position for durations of 15 s and 10 s, respectively. Blood pressure (BP) and heart rate (HR) were continuously monitored before, during and after the tests. Autonomic system activity was evaluated using frequency-domain analysis of HRV. The decrease in HR from baseline to the lowest values, expressed as a ratio, was similar during both maneuvers (0.81 during the RV vs. 0.79 during the VM, p = 0.27). However, the final lowest HR in response to the RV was higher than that in response to the VM, 70/min vs. 59/min (p <0.001). The activation of the autonomic nervous system during the most bradycardic phase of the RV (phase II) and VM (phase IV) showed that the total power of HRV was less prominent during the RV than during the VM (p <0.012), with similar levels of parasympathetic activation. Our results showed less HR slowdown during the RV than during the VM. The changes in HRV parameters during both procedures in particular phases of the RV and VM suggest that the autonomic nervous system is activated alternately, so these tests can be used complementarily in a clinical setting with different results.

Essential Fatty Acid Associated with Heart Rate Variability in Highly Trained Male Cross-Country Skiers: A Pilot Study

Polyunsaturated fatty acid (PUFA) metabolites play important roles in the modulation of vascular tone, heart rate variability (HRV), and cardiovascular diseases. This study was undertaken to examine the relationship between HRV and the plasma levels of essential acids. Methods: Highly trained cross-country skiers participated in the study (n = 19). Time-domain and frequency-domain HRV analyses were performed. The plasma levels of fatty acids were determined using gas–liquid chromatography. Results: Plasma eicosapentaenoic acid and docosahexaenoic acid were found to be negatively correlated with resting heart rate (HR) (p = 0.026). The plasma levels of alpha-linolenic acid (ALA) were positively associated with the relative value of high-frequency power (rs = 0.465, p = 0.045) and negatively correlated with the sympathovagal balance ratio (rs = −0.493, p = 0.032) and the absolute and relative values of low-frequency power (rs = −0.490, p = 0.028). The plasma levels of arachidonic acid (ARA) were positively associated with the relative value of high-frequency power (rs = 0.59, p = 0.006) and negatively correlated with the sympathovagal balance ratio (rs = −0.54, p = 0.017) and the relative values of low-frequency power (rs = −0.52, p = 0.022). No correlation was found between n6/n3 and HRV parameters except for HR and pNN50. Conclusions: n-3 PUFAs and ARA play an important role in the autonomic regulation of heart rate in highly trained skiers. Athletes with substantial deficiencies in plasma ALA and excess levels of ARA had increased sympathetic and decreased parasympathetic activity.

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly.

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly. This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)). Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV. In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

Fast Pace Sun Salutations (FPSS) Yoga Postures Influence Brain waves Activity in Addition to Heart Rate Variability Pattern: A Pilot Study

ABSTRACT Background: Sun salutation (Surya namaskar) is an ancient yogic exercise, which is a combination of 12 different postures rhythmically. Yoga practitioners perform this procedure in a slow as well as fast pace manner. Aim: We undertook this study to find out the immediate changes in heart rate variability (HRV) and brain waves spectrum after the practice of fast pace sun salutation (FPSS). Settings and Design: This prospective interventional observational study was conducted on 30 male healthy subjects in the 30–45 years age group from September 2021 to December 2021 after approval from the Institutional Ethics Committee. Participants gave their written consent in the prescribed format. Materials and Methods: Fourteen rounds of FPSS were performed in approximately 10 min under the guidance of a yoga expert. Brain Tap Dinamika Machine (Advanced HRV Test System, Moscow, Russia) was used to assess different HRV and brain waves parameters before and after FPSS. Statistical Analysis Used: Statistical analysis was done by Student’s paired t-test using GraphPad online software. Results: All independent variables of time and frequency domain analysis of HRV were found to be increased after the intervention. A significant upsurge in low frequency (LF)% as compared to high frequency (HF)% and very low frequency (VLF)% showed a relative increase in sympathetic activity. In brain waves, delta, theta, and alpha were decreased, whereas activities of beta and gamma waves were found to be increased. Conclusions: Increase in both LF and HF components showed that both sympathetic and parasympathetic components have increased. Brain wave analysis suggested increased mental alertness after FPSS.

THE NEURAL MECHANISM OF PHYSICAL EXERCISE IN PREVENTION AND TREATMENT OF CARDIOVASCULAR DISEASE UNDER DEEP LEARNING

This work was to explore the application of deep learning (DL) in identifying the neural mechanism of cardiovascular disease (CVD) and the role of physical exercise in the prevention and treatment of CVD. 200 cases of outpatient treatment in the hospital from January to December in 2021 were included as the research objects. 100 people with fitness exercise habits were sorted into the experiment group, and the other 100 cases without fitness exercise habit were in the control group. In addition, a DL-based CVD recognition model was constructed. The results showed that the detection effect of the back propagation (BP) algorithm under DL was better, with an average of over 99%. Heart rate variability (HRV) time domain analysis results showed that the Rrmaen, standard deviation of N-N interval (SDNN), and root mean square of the difference (RMSSD) of the experiment group were [Formula: see text][Formula: see text]ms, [Formula: see text][Formula: see text]ms, and [Formula: see text][Formula: see text]ms, respectively. These were observably higher than those of the control group ([Formula: see text]). In the HRV frequency domain analysis, the total frequency (TF) in the experiment group was [Formula: see text][Formula: see text]MS2, which was notably higher than that in the control group ([Formula: see text][Formula: see text]MS2, [Formula: see text]). The scores of anxiety and depression in the experiment group before exercise intervention were [Formula: see text] and [Formula: see text], respectively, which were highly decreased after intervention ([Formula: see text]). The CVD recognition model based on a DL algorithm could effectively identify CVD. Long-term regular exercise can effectively change the regulatory function of cardiovascular autonomic nerves and depression and anxiety states, which had popularization value.

Response Inhibition Partially Mediates the Relationship Between Emotional States and Creative Divergent Thinking

ABSTRACT Why can some people generate outstanding creative ideas despite receiving frustrating feedback? Although previous studies highlighted the effects of emotional states on creativity, the interactions between specific psychophysiological emotional parameters or affective states and response inhibition (RI) on creativity remain elusive. Therefore, with this study, we aimed to investigate whether RI mediates the effects of emotional states on creative thinking, specifically divergent thinking (DT), while participants receive frustrating or encouraging feedback. We induced positive and negative affect and psychophysiological arousal (PA) by manipulating feedback on performing a go/no-go task (GNGT), one of the standardized tasks for measuring RI. In other words, we provided participants with artificial feedback on GNGT to induce either frustration following (a negative emotional state) or a feeling of success (a positive emotional state). After receiving the manipulated feedback, participants performed the alternative uses task (AUT), a classical test for measuring DT. Subjective affective states were assessed using the Positive and Negative Affect Scale — Expanded Form (PANAS-X). During AUT, PA was measured through skin conductance (SC) and heart rate variability (HRV). Our data revealed that RI mediates the effect of negative affect and fatigue and enhanced PA (measured through HRV) on DT. Moreover, positive affect and PA (measured through SC) directly enhanced the three indices of DT (fluency, originality, and flexibility). Concerning the measurement of HRV, the application of time-domain HRV analyses was superior to that of frequency-domain HRV analyses. Notably, gender had strong direct and indirect effects on fluency and flexibility but not originality. In conclusion, our results suggest distinct mechanisms for modulatory effects of specific emotional states and associated psychophysiological on divergent creative thinking.

Persistent Increase of Sympathetic Activity in Post-Acute COVID-19 of Paucisymptomatic Healthcare Workers.

Healthcare workers (HCWs) represent a population with a significant burden of paucisymptomatic COVID-19, as the general population. We evaluated autonomic nervous system activity by means of heart rate variability (HRV) in HCWs during health surveillance visits. Short-term electrocardiogram (ECG) recordings were obtained 30 days (IQR 5.25-55.75) after a negative naso-pharyngeal swab for SARS-CoV-2 in 44 cases and compared with ECGs of 44 controls with similar age and sex distribution. Time and frequency domain HRV were evaluated. HCWs who used drugs, had comorbidities that affected HRV, or were hospitalized with severe COVID-19 were excluded. Frequency domain HRV analysis showed a significantly higher low/high-frequency power ratio (LF/HF) in the case study compared with controls (t = 2.84, p = 0.006). In time domain HRV analysis, mean standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive RR interval differences (RMSSD) were significantly lower for cases compared with controls (t = -2.64, p = 0.01 and t = -3.27, p = 0.002, respectively). In the post-acute phase of infection, SARS-CoV-2 produces an autonomic imbalance mirrored by a reduction in HRV. These results are consistent with epidemiological data that suggest a higher risk of acute cardiovascular complications in the first 30 days after COVID-19 infection.

Influence of Geopathic Stress Zone on Heart Rate variability Parameters

Background and Aim:&nbsp;Geopathic stress (GS)is the effect of detrimental earth radiation and electro-magnetic radiation on the health of human body.&nbsp;The aim of this study is to evaluate the effect of the geopathic stress on heart rate variability(HRV) parameters in healthy human subjects.&nbsp;Methods:&nbsp;The time and frequency &nbsp;domain HRV analyses were performed to assess the changes in sympathovagal &nbsp;balance in group of 60 healthy volunteers with normal electrocardiogram(ECG).Sixty volunteers we-re selected for the study with &nbsp;no history of illness(40 healthy men volunteers, 20 healthy women vo-lunteers). By using the apparatus Rayocomp PS-10(German, Rayonex), Geopathic stress zone were measured. The time and frequency domain HRV analyses were performed befor and after 60 minutes stay of volunteers in Geopathic stress zone. &nbsp;Results:&nbsp;During 60 minutes stay on the GS zone, the time domain parameters such as standard &nbsp;deviation(SD, ms) of all normal sinus RR intervals were significantly decreased. Then frequency domain parameters such as very low frequency (VLF, ms2), low frequency (LF, ms), and the LF/HF ratio were significantly increased. Conclusion:&nbsp;The study indicated&nbsp;&nbsp;that the stay of healthy&nbsp;human&nbsp;in the GS zone may influence heart rate variability and change the sympathovagal&nbsp;balance.

Reliability of Heart Rate Variability during Polysomnographic Sleep

Spectral analysis of heart rate variability (HRV) is often used as a noninvasive index of cardiac sympathetic and/or parasympathetic activity during sleep. During controlled wake recordings, the low frequency (LF) component of HRV can be unreliable within experimental sessions and against other direct sympathetic measurements. In contrast, the high frequency (HF) component of HRV has higher reported reproducibility within controlled wake sessions. It remains unknown if the frequency component of HRV is reliable across sleep cycles within individuals during stable sleep. The purpose of the present study was to determine HRV reliability during stable stage II (N2) sleep, slow wave sleep (SWS) and rapid eye movement (REM) sleep. We hypothesized that both LF and HF components of HRV would be less reliable during REM sleep than during SWS and N2 sleep. Twenty‐seven participants (11 male, 16 female, 26±1 years, 27±1 kg/m2) were enrolled in the present study. Overnight polysomnography (PSG; NATUS, Middleton, WI) and continuous two‐lead electrocardiography (ECG) were recorded during an 8‐hour sleep opportunity. The nocturnal ECG recordings were imported into a custom software (WinCPRS, Absolute Aliens, Finland) for analysis of HRV via fast‐Fourier transformation function. Autonomic cardiac activity was quantified as LF (0.04‐0.15 Hz) and HF (0.15‐0.4 Hz) HRV. Two separate stable periods of sleep (range, 5‐10 min) absent of cortical arousal were selected from each sleep stage for comparison. Raw LF and HF HRV underwent logarithmic transformation due to non‐normal distribution. Statistical analysis included bivariate correlation of HRV across differing sleep stage cycles (α = 0.05). LF HRV was significantly correlated across two independent sleep cycles in N2 (r=0.694, p&lt;0.001, n=26), SWS (r=0.765, p&lt;0.001, n=25), and REM sleep (r=0.699, p&lt;0.001, n=20). Similarly, HF HRV was reliable across two independent sleep cycles in N2 sleep (r=0.839, p&lt;0.001, n=26), SWS (r=0.765, p&lt;0.001, n=25), and REM sleep (r=0.881 p&lt;0.001, n=21). Taken together, both LF and HF HRV measures were reliable across stable N2, SWS, and REM sleep. Our results support the reliability of frequency domain analysis of HRV during key PSG sleep stages within a single night, but further research across nights is warranted.

Association between Levels of Urine Di-(2-ethylhexyl)phthalate Metabolites and Heart Rate Variability in Young Adults.

Phthalate exposure is associated with cardiovascular risk. Among the various phthalates, di-(2-ethylhexyl) phthalate (DEHP) is a deleterious plasticizer in our daily lives. This study investigated the association between DEHP exposure and the alteration of heart rate variability (HRV). During 2017–2019, we recruited 974 young adults to investigate the effects of living environments and dietary habits on cardiometabolic disorders in Taiwan. We quantitatively analyzed urinary metabolites of DHEP. A continuous electrocardiogram was recorded to obtain a 5-min ECG. Time-domain and frequency-domain HRV analyses were performed. Multiple linear regression showed that urinary oxidized DEHP metabolites MEHHP and MEOHP were associated with decreased HRV after controlling for associated cardiovascular risk factors. A higher MEHHP level was associated with a lower triangular interpolation of NN interval histogram (TINN), very low frequency (VLF), and low frequency/high frequency (LF/HF) ratio. A higher MEOHP level was associated with a decreased LF/HF ratio. In addition, trend analysis showed that higher MEHHP and MEOHP quantiles were significantly associated with a decreased LF/HF ratio. DEHP is a potentially harmful and invisible chemical. The urinary DEHP metabolites MEHHP and MEOHP are associated with decreased HRV, indicating an adverse effect on autonomic balance in young adults in Taiwan.

Effect of Laboratory Mental Stressors on Cardiovascular Reactivity in Young Women During Different Phases of Menstrual Cycle: An Observational Study.

Introduction: Excessive cardiovascular reactivity to mental stress may be a risk factor for cardiovascular disease. However, there is inconsistent report in the literature regarding change in cardiac autonomic tone with the phase of the menstrual cycle and how it is affected by mental stress. Therefore, the present study was aimed at determining the cardiovascular reactivity to different laboratory mental stressors during follicular and luteal phase of menstrual cycle using heart rate variability (HRV).Methods: Thirty-three regularly cycling young females (19–35 years of age) were exposed to four cognitive tasks (Stroop test, Mental Rotation test, n-back test, and Mental Arithmetic Stress Test [MAST]) employed as laboratory mental stressors. HRV of the study participants were recorded before, during, and after each cognitive task and the recording was done in both phases of menstrual cycle for each individual.Results: A significant difference was observed in time domain parameters and nonlinear parameters of HRV in pretest versus during-test condition and during-test versus post-test conditions, but not in frequency domain parameters. No phase difference was found in time domain or frequency domain analysis of HRV in baseline or during performance of task. MAST performance (score out of 50) was significantly higher in luteal than follicular phase, while other tests showed no such difference.Conclusion: All four mental stress tasks used in the present study were able to elicit significant decrease in parasympathetic tone during performance of task as compared with baseline values of HRV. The present study did not elicit any phase difference in cardiovascular reactivity.

Heart Rate Variability Analysis on Electrocardiograms, Seismocardiograms and Gyrocardiograms on Healthy Volunteers.

Physiological variation of the interval between consecutive heartbeats is known as the heart rate variability (HRV). HRV analysis is traditionally performed on electrocardiograms (ECG signals) and has become a useful tool in the diagnosis of different clinical and functional conditions. The progress in the sensor technique encouraged the development of alternative methods of analyzing cardiac activity: Seismocardiography and gyrocardiography. In our study we performed HRV analysis on ECG, seismocardiograms (SCG signals) and gyrocardiograms (GCG signals) using the PhysioNet Cardiovascular Toolbox. The heartbeats in ECG were detected using the Pan–Tompkins algorithm and the heartbeats in SCG and GCG signals were detected as peaks within 100 ms from the occurrence of the ECG R waves. The results of time domain, frequency domain and nonlinear HRV analysis on ECG, SCG and GCG signals are similar and this phenomenon is confirmed by very strong linear correlation of HRV indices. The differences between HRV indices obtained on ECG and SCG and on ECG and GCG were statistically insignificant and encourage using SCG or GCG for HRV estimation. Our results of HRV analysis confirm stronger correlation of HRV indices computed on ECG and GCG signals than on ECG and SCG signals because of greater tolerance to inter-subject variability and disturbances.

Association of Severity of Autism Spectrum Disorder with Cardiac Autonomic Indices in Children

Background &amp; Objectives: Autism Spectrum Disorder (ASD) being a complex neuro-developmentaldisorder is found to be associated with Autonomic Nervous System (ANS) dysfunction. The sympathovagalcontinual dynamic excitatory- inhibitory interactions leads to Heart Rate Variability (HRV) which isan index of cardiac autonomic regulation. Aim of the study was to evaluate cardiac autonomic regulation inchildren with ASD at rest using short-term HRV analysis and to correlate it with severity of autism.Methods: A total of 30 subjects were evaluated in the study comprising of 15 ASD children and 15 healthycontrols. A five minutes recording of resting ECG was carried out from which R-R intervals were procuredand HRV indices were analysed. Frequency domain analysis of HRV was carried out and the followingparameters were evaluated: Spectral powers in low frequency (LF) bands, High frequency (HF) bands, totalpower (TP), LF/HF ratio and average heart rate (HR) were evaluated. HRV indices between the groups werecompared using Student’s t test. Severity of autism was correlated with the evaluated HRV indices usingPearson correlation test.Results: Cardiac sympathetic activity as assessed by low frequency power spectrum (‘p’ value 0.034) andtotal power (‘p’ value 0.023) of the HRV spectrum was significantly higher in autistic children comparedto that of normal controls. However, the association between severity of ASDs and HRV indices were notstatistically significant.Conclusion: Study concludes that here was no significant association between HRV indices and severity ofautism.

Cardiac autonomic modulation assessed by heart rate variability in children with asthma.

To assess cardiac autonomic modulation, measured by short-term frequency domain analysis of heart rate variability (HRV), in children with asthma. We conducted an observational study at a tertiary care teaching hospital. The sample consisted of 119 children aged 7 to 15 years with asthma and 56 age-matched healthy controls. Frequency domain HRV measures included low-frequency (LF; 0.04-0.15 Hz), high-frequency (HF; 0.15-0.4 Hz), and LF/HF ratio. The LF and HF components were expressed in both absolute values of power (ms2 ) and in normalized units (nu). Compared with healthy controls, asthmatic children had significantly higher value of HF (nu) (mean ± standard deviation: 45.9 ± 14.6 vs 40.7 ± 13.6; P = .02), and lower values of LF (nu) (54.1 ± 14.6 vs 59.3 ± 13.6; P = .02) and LF/HF ratio (median, interquartile range: 1.12, 0.82-1.88 vs 1.59, 1.02-2.08; P = .03). We did not find significant differences between children with persistent and intermittent asthma, and between children with well-controlled and partially-controlled or uncontrolled asthma, in terms of HRV measures. Children with stable chronic asthma may have a cardiac autonomic imbalance with a possible enhanced parasympathetic modulation, as assessed by short-term frequency domain analysis of HRV. Neither asthma severity nor asthma control was significantly associated with HRV measures, but the study did not have enough power to draw a firm conclusion on this point.

The Effect of Marine n-3 Polyunsaturated Fatty Acids on Heart Rate Variability in Renal Transplant Recipients: A Randomized Controlled Trial.

Resting heart rate (rHR) and heart rate variability (HRV) are non-invasive measurements that predict the risk of sudden cardiac death (SCD). Marine n-3 polyunsaturated fatty acid (PUFA) supplementation may decrease rHR, increase HRV, and reduce the risk of SCD. To date, no studies have investigated the effect of marine n-3 PUFA on HRV in renal transplant recipients. In a randomized controlled trial, 132 renal transplant recipients were randomized to receive either three 1 g capsules of marine n-3 PUFA, each containing 460 mg/g EPA and 380 mg/g DHA, or control (olive oil) for 44 weeks. HRV was calculated in the time and frequency domains during a conventional cardiovascular reflex test (response to standing, deep breathing, and Valsalva maneuver) and during 2 min of resting in the supine position. There was no significant effect of marine n-3 PUFA supplementation on time-domain HRV compared with controls. rHR decreased 3.1 bpm (± 13.1) for patients receiving marine n-3 PUFA compared to 0.8 (± 11.0) in controls (p = 0.28). In the frequency domain HRV analyses, there was a significant change in response to standing in both high and low frequency measures, 2.9 (p = 0.04, 95% CI (1.1;8)) and 2.7 (p = 0.04, 95% CI (1.1;6.5)), respectively. In conclusion, 44 weeks of supplemental marine n-3 PUFAs in renal transplant recipients significantly improved the cardiac autonomic function, assessed by measuring HRV during conventional cardiovascular reflex tests.

Analisa Detak Jantung dengan Metode Heart Rate Variability (HRV) untuk Pengenalan Stres Mental Berbasis Photoplethysmograph (PPG)

Emotions influence individual behavior and there is no emotional experience that has a stronger influence than stress. Prolonged stress has a direct negative influence on physical and emotional conditions. For that reason, it is important to know a person's mental stress state, so that further action can be taken later, so as not to have a serious impact on physical and mental health. In this study, the photoplethysmograph (PPG) approach is used to recognize mental stress conditions based on Heart Rate Variability (HRV) frequency domain analysis. In this study stress was identified by SVM classifier using LF, HF and LF / HF Ratio from HRV frequency domain analysis. The LF results were increased in mild stress conditions, HF increased in conditions of mild stress and medium stress and the LF / HF Ratio slowly increased from mild stress to severe stress. The training data obtained 80 data with 95% mild stress accuracy from 19 data, medium stress accuracy 96% from 49 data and 99% severe stress accuracy with 12 data.

Rh factor and Autonomic Function Test in Normal and Deep Breathing

Background and Aim Studies have revealed a relationship between erythrocytic antigens of the ABO and Rh blood systems and cardiovascular pathology. Reduced heart rate variability (HRV) indicates an increased risk factor for the development of cardiovascular diseases. The present study was aimed to do correlative analysis of Rh blood groups and HRV in normal individuals. Materials and Method This cross sectional study includes 120 healthy medical students (18–22 years) of both sexes, from Kasturba Medical College, Mangalore, The study was approved by institutional ethical committee and study was carried out with written informed consent of students. All the subjects were grouped in to Rh positive blood group and Rh negative blood groups based on the result of standard slide haem agglutination technique. ECG of all the subjects was recorded in lead II for a period of five minutes and HRV was analysed by measuring the R-R intervals using a software “HRV soft 1.1 Version” software package. The HRV was analyzed both by the time domain method and frequency domain analysis during normal breathing. HRV is also analysed by deep breathing test for one minute and analyzed by the time domain method. In the time domain method, RMSSD-the square root of the mean squared differences of successive RR intervals (in milliseconds) SDNN-Standard deviation of RR intervals (in milliseconds), pNN50- percentage of differences between adjacent normal RR intervals exceeding 50 milliseconds were analyzed. In frequency domain method LF nu-Low frequency in normalized units, HF nuHigh frequency in normalized units, LF/HF-Ratio between low frequency and high frequency was measured. Statistical tests included in this study were ANOVA and student's unpaired ttest. P-value was taken as statistically significant at 5 percent confidence level (P<0.05). Results The time domain analysis and the frequency domain analysis of HRV among Rh positive blood group and Rh negative blood group subjects during normal breathing did not show any statistically significant changes. Further, comparison of HRV between Rh positive blood group and Rh negative blood groups during deep breathing using time domain method did not show any statistically significant results. Conclusions The present study, concludes that there were no significant change in the heart rate variability of Rh positive blood group and Rh negative blood groups subjects. Further research is needed including in a larger sample size to confirm these findings and to show the correlation of Rh groups and heart rate variability.

Testing and Analysis of the HRV Signals from Wearable Smart HRV Sensors

The objective of the test procedure is to obtain bio signals from Photoplethysmograph and Electrocardiograph sensors on selected consumer devices and to statistically validate the data for use with a drowsiness estimation method.The method selected for validation uses LF/HF ratio calculated by a set of R-R interval data to estimate drowsiness state of a human. The value LF to HF ratio calculates balance between sympathetic and parasympathetic activity that can be measured from HRV (Heart rate variability) signals. The statistical data collected are processed by using Fast Fourier Transform and HRV frequency domain analysis on a set of test participants.There is a correlation between medical ECG equipment control output and Matlab tool’s HRVAS (Burg) output of data processed from ECG based wearable smart sensor when the LF/HF ratio is calculated in all observed volunteer data. The results for Photoplethysmograph sensors of this test correlate with other tested tools but level of the values is lower, and data from optical biosensor devices which are designed to measure HRV time-domain properties as pulse did not confirm with ECG equipment results for frequency-domain analysis required for use with selected drowsiness estimation method. The result affecting factors are sensor placement, motion artefacts and discrete vendor-specific signal pre-processing of wearable device output data.The following results confirm the use of consumer grade biosensor that produces discretely pre-processed R-R interval data for the frequency based HRV method and application validation against directly processed ECG data from certified medical equipment.

Testing and Analysis of the HRV Signals from Wearable Smart HRV Sensors

The objective of the test procedure is to obtain bio signals from Photoplethysmograph and Electrocardiograph sensors on selected consumer devices and to statistically validate the data for use with a drowsiness estimation method.The method selected for validation uses LF/HF ratio calculated by a set of R-R interval data to estimate drowsiness state of a human. The value LF to HF ratio calculates balance between sympathetic and parasympathetic activity that can be measured from HRV (Heart rate variability) signals. The statistical data collected are processed by using Fast Fourier Transform and HRV frequency domain analysis on a set of test participants.There is a correlation between medical ECG equipment control output and Matlab tool’s HRVAS (Burg) output of data processed from ECG based wearable smart sensor when the LF/HF ratio is calculated in all observed volunteer data. The results for Photoplethysmograph sensors of this test correlate with other tested tools but level of the values is lower, and data from optical biosensor devices which are designed to measure HRV time-domain properties as pulse did not confirm with ECG equipment results for frequency-domain analysis required for use with selected drowsiness estimation method. The result affecting factors are sensor placement, motion artefacts and discrete vendor-specific signal pre-processing of wearable device output data.The following results confirm the use of consumer grade biosensor that produces discretely pre-processed R-R interval data for the frequency based HRV method and application validation against directly processed ECG data from certified medical equipment.