Quran memorisation and heart rate variability:How do they correlate?

BACKGROUND Heart rate variability(HRV)was shown to be affected by performing religious activities.AIM To examine the relationship between the level of Quran(the holy book of Muslims)memorisation and HRV among teenagers.METHODS This experimental study included 16 Tahfiz students and 16 non-Tahfiz students(n=32).The HRV was measured in three tasks:Recalling familiar verses,memorising new verses,and recalling the newly memorised verses of the Quran.HRV analysis was done using these parameters:Standard deviation of N-N(heartbeat peak)interval;low frequency(LF);high frequency(HF)and LF/HF ratio.RESULTS There were significant differences between tasks for all parameters(P<0.05).However,between the groups,only the LF/HF ratio had significant differences,with F=5.04,P<0.05.Pearson correlation showed a moderate positive correlation between the number of pages memorised and the LF/HF ratio(r=0.61,P<0.05).CONCLUSION Quran memorisation increased the HRV and our results suggested that this activity could be developed as an effective sympathovagal modulation training activity.

A comprehensive review of heart rate variability as an indicator in the regulation of the autonomic nervous system by acupuncture:a bibliometric analysis

This study sought to conduct a bibliometric analysis of acupuncture studies focusing on heart rate variability(HRV)and to investigate the correlation between various acupoints and their effects on HRV by utilizing association rule mining and network analysis.A total of 536 publications on the topic of acupuncture studies based on HRV.The disease keyword analysis revealed that HRV-related acupuncture studies were mainly related to pain,inflammation,emotional disorders,gastrointestinal function,and hypertension.A separate analysis was conducted on acupuncture prescriptions,and Neiguan(PC6)and Zusanli(ST36)were the most frequently used acupoints.The core acupoints for HRV regulation were identified as PC6,ST36,Shenmen(HT7),Hegu(LI4),Sanyinjiao(SP6),Jianshi(PC5),Taichong(LR3),Quchi(LI11),Guanyuan(CV4),Baihui(GV20),and Taixi(KI3).Additionally,the research encompassed 46 reports on acupuncture animal experiments conducted on HRV,with ST36 being the most frequently utilized acupoint.The research presented in this study offers valuable insights into the global research trend and hotspots in acupuncture-based HRV studies,as well as identifying frequently used combinations of acupoints.The findings may be helpful for further research in this field and provide valuable information about the potential use of acupuncture for improving HRV in both humans and animals.

Gene polymorphisms associated with sudden decreases in heart rate during extensive peritoneal lavage with distilled water after gastrectomy

BACKGROUND Our previous study found that the telomerase-associated protein 1(TEP1,rs938886 and rs1713449)and homo sapiens RecQ like helicase 5(RECQL5,rs820196)single nucleotide polymorphisms(SNPs)were associated with changes in heart rate(HR)≥30%during peritoneal lavage with distilled water after gastrectomy.This study established a single tube method for detecting these three SNPs using two-dimensional(2D)polymerase chain reaction(PCR),and investigated whether SNP-SNP and SNP-environment interactions increase the risk of high HR variability(HRV).AIM To investigate whether genotypes,genetic patterns,SNP-SNP and SNP-environment interactions were associated with HRV.METHODS 2D PCR was used to establish a single-tube method to detect TEP1 rs938886 and rs1713449 and RECQL5 rs820196,and the results were compared with those of sanger sequencing.After adjusting for confounders such as age,sex,smoking,hypertension,and thyroid dysfunction,a nonconditional logistic regression model was used to assess the associations between the genotypes and the genetic patterns(codominant,dominant,overdominant,recessive,and additive)of the three SNPs and a risk≥15%or≥30%of a sudden drop in HR during postoperative peritoneal lavage in patients with gastric cancer.Gene-gene and geneenvironment interactions were analyzed using generalized multifactor dimensionality reduction.RESULTS The coincidence rate between the 2D PCR and sequencing was 100%.When the HRV cutoff value was 15%,the patients with the RECQL5(rs820196)TC genotype had a higher risk of high HRV than those who had the TT genotype(odds ratio=1.97;95%CI:1.05-3.70;P=0.045).Under the codominant and overdominant models,the TC genotype of RECQL5(rs820196)was associated with a higher risk of HR decrease relative to the TT and TT+CC genotypes(P=0.031 and 0.016,respectively).When the HRV cutoff value was 30%,patients carrying the GC-TC genotypes of rs938886 and rs820196 showed a higher HRV risk when compared with the GG–TT genotype carriers(P=0.01).In the three-factor model of rs938886,rs820196,and rs1713449,patients carrying the GC-TC-CT genotype had a higher risk of HRV compared with the wild-type GG-TT-CC carriers(P=0.01).For rs820196,nonsmokers with the TC genotype had a higher HRV risk compared with nonsmokers carrying the TT genotype(P=0.04).When the HRV cutoff value was 15%,patients carrying the TT-TT and the TC-CT genotypes of rs820196 and rs1713449 showed a higher HRV risk when compared with TT-CC genotype carriers(P=0.04 and 0.01,respectively).Patients carrying the GC-CT-TC genotypes of rs938886,rs1713449,and rs820196 showed a higher HRV risk compared with GG-CC-TT genotype carriers(P=0.02).When the HRV cutoff value was 15%,the best-fitting models for the interactions between the SNPs and the environment were the rs820196-smoking(P=0.022)and rs820196-hypertension(P=0.043)models.Consistent with the results of the previous grouping,for rs820196,the TC genotype nonsmokers had a higher HRV risk compared with nonsmokers carrying the TT genotype(P=0.01).CONCLUSION The polymorphism of the RECQL5 and TEP1 genes were associated with HRV during peritoneal lavage with distilled water after gastrectomy.

Heart Rate Variability as an Indicator of Stress in Students’ Athletes

Introduction: The wellbeing of student’s athletes has a paramount importance, a prolonged period of cognitive and physical performance that characterizes the life of student’s athletes often leads to fatigue, and a psychobiological state that increases the risk of injury and accidents. The use of Heart rate variability (HRV) has become increasingly popular as a non-invasive methodology that provides an indirect insight into the autonomic nervous system. HRV can be utilized as a diagnostic tool in detection of autonomic nervous system impairment and sympatho-vagal imbalance. HRV technology is employed to monitor the internal response of athletes to workload and identify athletes’s psychophysical stress to predict and therefore prevent injuries. Objective: The objective of the investigation is to establish whether the use of Polar H10 sensor heart rate monitors worn by athletes in a sitting position (inclination 60 degrees) during periods characterized by stress can provide a valid and non-invasive method to assess the psychophysiological state during sports competition and school exams. Method and Statistics: In the study, the HRV of 12 basketball students athletes and 4 students non-athletes was analyzed as a control group. The autonomic nervous system activity was assessed based on heart variability parameters (HRV): SDNN, rMSSD, LF, HF, and LF/HF. The measurements were made after establishing the baseline at rest, during the training phase (CT), competition phase (CC) and during the acute phase of stressors due to school exams coinciding with the competitive season (CC + E). Results: Compared to the respective values prior to the stress of the competitions and exams, a significant decrease in HRV indices was found: SDNN (P Conclusions: The analysis and examination of the data on the sample of the student population also showed a statistically significant correlation between decreased cardiac variability and injuries or indisposition to physical exertion.

Modeling Dynamical Noises Corrupted Chaotic System for Heart Rate Variability Analysis

It is difficult to establish the process of chaos in time series from cardiac dynamics. The output from such a system is probably the result of both its internal dynamics, and the input to the system from its surroundings. We present an optimization algorithm to find a time series that is as close as possible to the heart rate series subject to the constraint that it is deterministic with respect to some dynamics. The algorithm is tested by some famous forced dynamical systems, and applied to heart rate data. We find that the deterministic components of heart rate variability are chaotic.

Does heart rate variability correlate with long-term prognosis in myocardial infarction patients treated by early revascularization?

AIMTo assess the prevalence of depressed heart rate variability (HRV) after an acute myocardial infarction (MI), and to evaluate its prognostic significance in the present era of immediate reperfusion.METHODSTime-domain HRV (obtained from 24-h Holter recordings) was assessed in 326 patients (63.5 ± 12.1 years old; 80% males), two weeks after a complicated MI treated by early reperfusion: 208 ST-elevation myocardial infarction (STEMI) patients (in which reperfusion was successfully obtained within 6 h of symptoms in 94% of cases) and 118 non-ST-elevation myocardial infarction (NSTEMI) patients (percutaneous coronary intervention was performed within 24 h and successful in 73% of cases). Follow-up of the patients was performed via telephone interviews a median of 25 mo after the index event (95%CI of the mean 23.3-28.0). Primary end-point was occurrence of all-cause or cardiac death; secondary end-point was occurrence of major clinical events (MCE, defined as mortality or readmission for new MI, new revascularization, episodes of heart failure or stroke). Possible correlations between HRV parameters (mainly the standard deviation of all normal RR intervals, SDNN), clinical features (age, sex, type of MI, history of diabetes, left ventricle ejection fraction), angiographic characteristics (number of coronary arteries with critical stenoses, success and completeness of revascularization) and long-term outcomes were analysed.RESULTSMarkedly depressed HRV parameters were present in a relatively small percentage of patients: SDNN < 70 ms was found in 16% and SDNN < 50 ms in 4% of cases. No significant differences were present between STEMI and NSTEMI cases as regards to their distribution among quartiles of SDNN (χ2 =1.536, P = 0.674). Female sex and history of diabetes maintained a significant correlation with lower values of SDNN at multivariate Cox regression analysis (respectively: P = 0.008 and P = 0.008), while no correlation was found between depressed SDNN and history of previous MI (P = 0.999) or number of diseased coronary arteries (P = 0.428) or unsuccessful percutaneous coronary intervention (PCI) (P = 0.691). Patients with left ventricle ejection fraction (LVEF) < 40% presented more often SDNN values in the lowest quartile (P < 0.001). After > 2 years from infarction, a total of 10 patients (3.1%) were lost to follow-up. Overall incidence of MCE at follow-up was similar between STEMI and NSTEMI (P = 0.141), although all-cause and cardiac mortality were higher among NSTEMI cases (respectively: 14% vs 2%, P = 0.001; and 10% vs 1.5%, P = 0.001). The Kaplan-Meier survival curves for all-cause mortality and for cardiac deaths did not reveal significant differences between patients with SDNN in the lowest quartile and other quartiles of SDNN (respectively: P = 0.137 and P = 0.527). Also the MCE-free survival curves were similar between the group of patients with SDNN in the lowest quartile vs the patients of the other SDNN quartiles (P = 0.540), with no difference for STEMI (P = 0.180) or NSTEMI patients (P = 0.541). By the contrary, events-free survival was worse if patients presented with LVEF < 40% (P = 0.001).CONCLUSIONIn our group of patients with a recent complicated MI, abnormal autonomic parameters have been found with a prevalence that was similar for STEMI and NSTEMI cases, and substantially unchanged in comparison to what reported in the pre-primary-PCI era. Long-term outcomes did not correlate with level of depression of HRV parameters recorded in the subacute phase of the disease, both in STEMI and in NSTEMI patients. These results support lack of prognostic significance of traditional HRV parameters when immediate coronary reperfusion is utilised.

Relationship between Ambient Fine Particles and Ventricular Repolarization Changes and Heart Rate Variability of Elderly People with Heart Disease in Beijing, China

Objective To explore the effects of particulate matters less than 2.5 μm in aerodynamic diameter （PM2.5） on heart repolarization/depolarization and heart rate variability （HRV）. Methods We conducted a panel study for elderly subjects with heart disease in Beijing from 2007 to 2008. PM2.5 was measured at a fixed station for 20 h continuously each day while electrocardiogram （ECG） indexes of 42 subjects were also recorded repeatedly. Meteorological data was obtained from the China Meteorological Data Sharing Service System. A mixed linear regression model was used to estimate the associations between PMz.s and the ECG indexes. The model was adjusted for age, body mass index, sex, day of the week and meteorology. Results Significant adverse effects of PM2.5 on ECG indexes reflecting HRV were observed statistically and the strongest effect of PM2.s on HRV was on lag i day in our study. However, there were no associations between PM2.5 and ECG indexes reflecting heart repolarization/depolarization. Additionally, the effects of PM2.5 on subjects with hypertension were larger than on the subjects without hypertension. Conclusion This study showed ambient PM2.5could affect cardiac autonomic function of the elderly people with heart disease, and subjects with hypertension appeared to be more susceptive to the autonomic dysfunction induced by PM2.5.

Heart rate variability： a new tool to predict complications in adult cardiac surgery

Heart rate variability （HRV） refers to the variations between consecutive heartbeats, which depend on the continuous modulation of the sympathetic and parasympathetic branches of the autonomic nervous system. HRV has been shown to be effective as a predictor of risk after myocardial infarction and an early warning sign of diabetic neuropathy, and in the cardiology setting is now recognized to be a useful tool for risk-stratification after hospital admission and after discharge. Recent evidences suggest that HRV analysis might predict complications even in patients undergoing cardiac surgery, and the present review summarizes the importance of HRV analysis in adult cardiac surgery and the perspectives for HRV use in current clinical practice. Although future larger studies are warranted before HRV can be included into daily clinical practice in adult cardiac surgery, HRV is a novel tool which might detect autonomic instability in the early postoperative phase and during hospital stay, thus predicting or prompt-diagnosing many of the post-operative complications.

Effects of Impaired Glucose Metabolism on Heart Rate Variability and Blood Pessure Variability in Essential Hpertensive Patients

To investigate the effects of impaired glucose metabolism （IGM） on cardiovascular autonomic nervous systems in essential hypertensive （EH） patients by comparing heart rate variability （HRV） and blood pressure variability （BPV） in EH patients with or without type 2 diabetes mellitus （T2DM）. Simultaneous 24-h recordings of ambulatory ECG and blood pressure monitoring were performed in 36 male old patients with simple EH and 33 male old patients with EH combined with T2DM. HRV analysis included time domain parameters such as SDNN, SDANN, SDNNi, rMSSD and pNN50, and total spectral power （TP） of HRV, which mainly consists of VLF, LF and HF component along with LF/HF ratio, was also obtained. The value of ambulatory blood pressure was represented as the mean blood pressure （mean systolic/mSBP, diastolic/mDBP and pulse pressure/mPP） during different periods （24 h/24 h, day time/d and night time/n）. Standard deviation （SD） as well as coefficient of variance （CV） of blood pressure during each above-mentioned period were obtained to reflect the long-term BPV. Our result showed that SDNN, SDNNi, SDANN, rMSSD, PNN50, TP and HF of HRV in cases of EH with T2DM were all significantly lower than those in simple EH subjects （P〈0.05）. No significant differences in VLF or LF was found between the two groups （P〉0.05）, while LF/HF ratio was significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.01）. Moreover, dmSBP, 24 h-mPP and dmPP were all significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.05）, while nmSBP, 24 h-mSBP, 24 h-mDBP, dmDBP, nmDBP or nmPP showed no significant difference between this two groups of patients （P〉0.05）. And dSBPSD, dSBPCV and 24 h-SBPSD were all significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.05）, while the other BPV indexes showed no significant difference between this two groups （P〉0.05）. It is concluded that the cardiovascular autonomic nervous systems in EH patients was further impaired by T2DM, displaying lowering of HRV and enlargement of BPV, which in turn induced abnormal structural and functional changes of cardiovascular systems. Therefore, improving cardiovascular autonomic nervous systems might reduce the occurrence of cardiovascular complications in the EH patients with IGM.

Acu-TENS lowers blood lactate levels and enhances heart rate recovery after exercise

Objective:The primary aim of this study is to investigate the effect of application of transcutaneous electrical nerve stimulation over acupuncture points(Acu-TENS)on postexercise blood lactate level.The secondary aim is to explore the effect of Acu-TENS on heart rate recovery and its association with autonomic nervous system.Methods:Twenty healthy subjects(mean age 26.9
1.3)acting as their own controls,were randomized to receive either Acu-TENS or Placebo-TENS as the first of two intervention protocols,implemented one week apart.During Acu-TENS,subjects received 45 min TENS bilaterally over the acupoints Neiguan(PC6).Subjects receiving Placebo-TENS had identical electrode placement but with no electrical output from the TENS unit despite an active output light.Interventions were followed by a 10-min ergometer exercise at 70%age-predicted maximal heart rate.Oxygen consumption and heart rate(HR)were recorded continuously throughout exercise.Blood lactate and blood pressure were taken at 4 time points:prior to,immediately after,at 15-min after exercise,and when HR had returned to baseline values.Results:The post-exercise blood lactate level in the Acu-TENS group was lower than that of the placebo group by 1.12
0.39 mmol/L(p Z 0.01).The Acu-TENS group also had a faster return of HR to pre-exercise level compared to placebo(9.98
4.54 min,p Z 0.047).Heart rate variability analysis inferred reduced sympathetic modulation during exercise after Acu-TENS.There was no between-group difference in post-exercise oxygen consumption.Conclusion:Acu-TENS lowered post-exercise blood lactate level and enhanced heart rate recovery after moderate exercise.The role of Acu-TENS in exercise performance and energy metabolism warrants further investigation.(ClinicalTrails.gov Identifier:NCT01102634)a 2014 Beijing University of Chinese Medicine.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/3.0/).

Power Spectral Analysis of Heart Rate Variability of Driver Fatigue

This investigation was to evaluate the driving fatigue based on power spectral analysis of heart rate variability (HRV) under vertical vibration. Forty healthy male subjects (29.7±3.5 years) were randomly divided into two groups, Group A (28.8±4.3 years) and Group B (30.6±2.7 years). Group A (experiment group) was required to perform the simulated driving and Group B (control group) kept calm for 90 min. The frequency domain indices of HRV such as low frequency (0.04 0.15 Hz, LF), high frequency (0.150.4 Hz, HF), LF/HF together with the indices of hemodynamics such as blood pressure (BP) and heart rate (HR) of the subjects between both groups were calculated and analyzed after the simulated driving. There were significances of the former indices between both groups (P<0.05). All the data collected after experiment of Group A was observed the remarkable linear correlation (P<0.05) and parameters and errors of their linear regression equation were stated (α=0.05, P<0.001) in this paper, respectively. The present study investigated that sympathetic activity of the subjects enhanced after the simulated driving while parasympathetic activities decreased. The sympathovagal balance was also improved. As autonomic function indictors of HRV reflected fatigue level, quantitative evaluation of driving mental fatigue from physiological reaction could be possible.

Analysis of heart rate variability based on singular value decomposition entropy

Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability （HRV） of heart failure patients and healthy persons using the concept of singular value decomposition entropy （SvdEn） is analyzed. SvdEn is calculated from the time series using normalized singular values. The advantage of this method is its simplicity and fast computation. It enables analysis of very short and non-stationary data sets. The results show that SvdEn of patients with congestive heart failure （CHF） shows a low value （SvdEn： 0.056±0.006, p 〈 0.01） which can be completely separated from healthy subjects. In addition, differences of SvdEn values between day and night are found for the healthy groups. SvdEn decreases with age. The lower the SvdEn values, the higher the risk of heart disease. Moreover, SvdEn is associated with the energy of heart rhythm. The results show that using SvdEn for discriminating HRV in different physiological states for clinical applications is feasible and simple.

Altered heart rate variability and pulse-wave velocity after spinal cord injury

BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients.No study has simultaneously investigated HRV and PWV in the same patients.AIM To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.METHODS In this cross-sectional pilot study,patients with(n = 60) and without SCI(n = 60) were recruited from December 7,2019 to January 21,2020.Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000 P.Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.RESULTS We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals,square root of the mean sum of squared successive risk ratio interval differences,physical stress index,total power,very-low frequency,low frequency,high frequency,and arterial elasticity.CONCLUSION Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without,suggesting that SCI may increase cardiac function loading.

Synchronous measurements of prefrontal activity and pulse rate variability during online video game playing with functional near-infrared spectroscopy

Interactions between the central nervous system(CNS)and autonomic nervous system(ANS)play a crucial role in modulating perception,cognition,and emotion production.Previous studies on CNS–ANS interactions,or heart–brain coupling,have often used heart rate variability(HRV)metrics derived from electrocardiography(ECG)recordings as empirical measurements of sympathetic and parasympathetic activities.Functional near-infrared spectroscopy(fNIRS)is a functional brain imaging modality that is increasingly used in brain and cognition studies.The fNIRS signals contain frequency bands representing both neural activity oscillations and heartbeat rhythms.Therefore,fNIRS data acquired in neuroimaging studies can potentially provide a single-modality approach to measure task-induced responses in the brain and ANS synchronously,allowing analysis of CNS–ANS interactions.In this proof-of-concept study,fNIRS was used to record hemodynamic changes from the foreheads of 20 university students as they each played a round of multiplayer online battle arena(MOBA)game.From the fNIRS recordings,neural and heartbeat frequency bands were extracted to assess prefrontal activities and shortterm pulse rate variability(PRV),an approximation for short-term HRV,respectively.Under the experimental conditions used,fNIRS-derived PRV metrics showed good correlations with ECG-derived HRV golden standards,in terms of absolute measurements and video game playing(VGP)-related changes.It was also observed that,similar to previous studies on physical activity and exercise,the PRV metrics closely related to parasympathetic activities recovered slower than the PRV indicators of sympathetic activities after VGP.It is concluded that it is feasible to use fNIRS to monitor concurrent brain and ANS activations during online VGP,facilitating the understanding of VGP-related heart–brain coupling.

Qi Gong and Heart Rate Variability: A Systematic Review

Qì Gōng is a type of exercise that involves meditation and is used for health. With a background from the martial arts, it is known also as an auto healing exercise with three main elements according to Traditional Chinese Medicine (TCM): body focus (posture and movement), breathing and mind focus (meditative elements). Heart rate variability is a tool that allows us to measure the autonomic system velocity to detect and respond to unexpected stimuli. So our goal was to build a systematic review of Qi Gong and Heart rate variability. PUBMED, EBSCO and Science Direct data bases were searched. Key terms (MeSH) were Heart Rate Variability and Ch’i Kung OR Qi Gong with a 10-year filter. Four independent reviewers analyzed all articles and excluded duplicated articles, articles in Chinese and articles with no adherence to the subject. The end result was 5 studies selected. Our results showed no significant improvements in HRV with the practice of Qì Gōng, probably because of data heterogeneity. We found 5 types of Qì Gōng, 3 different instruments and different time intervals to measure HRV and 2 different age groups in the studies. We can conclude that there is evidence that Qì Gōng can improve HRV but studies that would use the same parameters are needed to further confirm that.

Correlation between heart rate variability and pupillary reflex in healthy adult subjects under the influence of alcohol

This study explored the association between pupil area variation, heart rate variability, and fatigue, caused by alcohol consumption. Sixteen healthy young male volunteers were enrolled in this study for a series of structured physical examinations. Individual drinking volume was strictly assessed in accordance with the normalized experimental design. The motions of the subjects＇ pupils, as well as electrocardiograms were recorded by a computerized recording system, both before and after drinking alcohol. After alcohol intake, the pupil diameter, and both low frequency and standard deviation of all heartbeat interval indices of heart rate variability showed significant variations compared with the baseline. In addition, time- and frequency-domain indices of heart rate variability were negatively associated with pupil area. Thus the current study suggests that fatigue status may be determined by significant changes in pupil area and heart rate variability.

Protective effects of rice bran hydrolysates on heart rate variability,cardiac oxidative stress,and cardiac remodeling in high fat and high fructose diet-fed rats

Objective:To examine the ameliorative effect of rice bran hydrolysates(RBH)on metabolic disorders,cardiac oxidative stress,heart rate variability(HRV),and cardiac structural changes in high fat and high fructose(HFHF)-fed rats.Methods:Male Sprague-Dawley rats were daily fed either standard chow diet with tap water or an HFHF diet with 10%fructose in drinking water over 16 weeks.RBH(500 and 1000 mg/kg/day)was orally administered to the HFHF-diet-fed rats during the last 6 weeks of the study period.At the end of the treatment,metabolic parameters,oxidative stress,HRV,and cardiac structural changes were examined.Results:RBH administration significantly ameliorated metabolic disorders by improving lipid profiles,insulin sensitivity,and hemodynamic parameters.Moreover,RBH restored HRV,as evidenced by decreasing the ratio of low-frequency to highfrequency power of HRV,a marker of autonomic imbalance.Cardiac oxidative stress was also mitigated after RBH supplementation by decreasing cardiac malondialdehyde and protein carbonyl,upregulating eNOS expression,and increasing catalase activity in the heart.Furthermore,RBH mitigated cardiac structural changes by reducing cardiac hypertrophy and myocardial fibrosis in HFHFdiet-fed rats.Conclusions:The present findings suggest that consumption of RBH may exert cardioprotective effects against autonomic imbalances,cardiac oxidative stress,and structural changes in metabolic syndrome.

Modeling of Heart Rate Variability Using Time-Frequency Representations

The heart rate variability signal is highly correlated with the respiration even at high workload exercise.It is also known that this phenomenon still exists during increasing exercise.In the current study,we managed to model this correlation during increasing exercise using the time varying integral pulse frequency modulation(TVIPFM)model that relates the mechanical modulation(MM)to the respiration and the cardiac rhythm.This modulation of the autonomic nervous system(ANS)is able to simultaneously decrease sympathetic and increase parasympathetic activity.The TVIPFM model takes into consideration the effect of the increasing exercise test,where the effect of a time-varying threshold on the heart period is studied.Our motivation is to analyze the heart rate variability(HRV)acquired by time varying integral pulse frequency modulation using time frequency representations.The estimated autonomic nervous system(ANS)modulating signal is filtered throughout the respiration using a time varying filtering,during exercise stress testing.And after summing power of the filtered signal,we compare the power of the filtered modulation of the ANS obtained with different time frequency representations:smoothed pseudo Wigner–Ville representation,spectrogram and their reassignments.After that,we used a student t-test p<0.01 to compare the power of heart rate variability in the frequency band of respiration and elsewhere.

A very high frequency index of heart rate variability for evaluation of left ventricular systolic function and prognosis in chronic heart failure patients using five-minute electrocardiogram

Objective A novel index based on fi-equency-domain analysis of heart rate variability （HRV） was tested on patients with reduced left ventricular systolic function. This index, namely VHFI, was defined as the very high frequency （VHF） component of the power spectrum normalized to represent its relative value in proportion to the total power minus the very low frequency component. Methods Patients （n = 130） were divided into a study group, consisting 66 patients with decreased left ventricular systolic function, and a control group, consisting 64 patients with normal heart structure and function and without severe coronary artery stenosis （〈 50%）. Results VHFI in the study group was significantly higher than that in the control group （19.17 ± 13.35 vs 11.37 ± 10.77, P 〈 0.001）. Cardiac events occurred in 18 patients during follow-up （33.34 i 3.26 months）. Defining the positive test as VHFI =15 and negative test as VHFI 〈15, achieved a sensitivity of 57.58% and a specificity of78.13% for predicting decreased left ventricular systolic function, and achieved a sensitivity of 66.67% and a specificity of 64.29% for predicting cardiac events. Univariate Cox regression analysis showed that positive VHFI test was an independent variable in predictive cardiac events. Conclusions The results suggest that VHFI is a useful tool for quick evaluation of left ventricular systolic function and prediction of prognosis

Cardiovascular age of aviation personnel: based on the principal component analysis of heart rate and blood pressure variability

Objective: To introduce a method to calculate cardiovascular age, a new, accurate and much simpler index for assessing cardiovascular autonomic regulatory function, based on statistical analysis of heart rate and blood pressure variability (HRV and BPV) and baroreflex sensitivity (BRS) data. Methods: Firstly, HRV and BPV of 89 healthy aviation personnel were analyzed by the conventional autoregressive (AR) spectral analysis and their spontaneous BRS was obtained by the sequence method. Secondly, principal component analysis was conducted over original and derived indices of HRV, BPV and BRS data and the relevant principal components, PCi orig and PCi deri (i=1, 2, 3,...) were obtained. Finally, the equation for calculating cardiovascular age was obtained by multiple regression with the chronological age being assigned as the dependent variable and the principal components significantly related to age as the regressors. Results: The first four principal components of original indices accounted for over 90% of total variance of the indices, so did the first three principal components of derived indices. So, these seven principal components could reflect the information of cardiovascular autonomic regulation which was embodied in the 17 indices of HRV, BPV and BRS exactly with a minimal loss of information. Of the seven principal components, PC2 orig , PC4 orig and PC2 deri were negatively correlated with the chronological age ( P <0 05), whereas the PC3 orig was positively correlated with the chronological age ( P <0 01). The cardiovascular age thus calculated from the regression equation was significantly correlated with the chronological age among the 89 aviation personnel ( r =0.73, P <0 01). Conclusion: The cardiovascular age calculated based on a multi variate analysis of HRV, BPV and BRS could be regarded as a comprehensive indicator reflecting the age dependency of autonomic regulation of cardiovascular system in healthy aviation personnel.