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.

Stress prevention by modulation of autonomic nervous system (heart rate variability): A preliminary study using transcranial direct current stimulation

Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive, technique for brain stimulation. Anodal stimulation causes neuronal depolarisation and long-term potentiation, while cathodal stimulation causes hyperpolarisation and long-term depression. Stressors are associated with an increase in sympathetic cardiac control, a decrease in parasympathetic control, or both. Associated with these reactions is a frequently reported increase in Low Frequency (LF) Heart Rate Variability (HRV), a decrease in High Frequency (HF) power, and/or an increase in the LF/HF ratio. Objectives and aims: The present work aims to explore the tDCS potential in the modulation of the Autonomic Nervous System (ANS), through indirect stimulation of Anterior Cingulate Cortex (ACC). Methods: Two subjects, a 39 year old female and a 49 year old male, gave informed consent. Saline soaked synthetic sponges involving two, thick, metalic (stainless steel) rectangles, with an area of 25 cm2 each have been used as electrodes, connected to Iomed Phoresor II Auto device. It has been delivered a 2 mA current, for 20 minutes, over the left Dorsolateral Prefrontal Cortex (DLPFC) (Anode). Spectrum analysis (cStress software) of HRV has been performed before and after tDCS administration. Results: The female/male subject results of LF power, HF power and LF/HF ratio, before tDCS administration, were, respectively: 50.1 nu/60 nu, 46.1 nu/21.7 nu and 1.087/2.771;and, after tDCS administration, respectively: 33.5 nu/52.7 nu, 47.6 nu/ 22.8 nu and 0.704/2.312. Conclusions: tDCS over the left DLPFC (left ACC) increased parasympathetic activity and decreased sympathetic activity, suggesting the importance of tDCS in the management of stress-related disorders.

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.

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.

Assessment of Cardiac Autonomic Function by Using Heart Rate Turbulence in Behcet’s Disease

Behcet’s disease (BD) is a chronic inflammatory disorder that can affect many systems in the body. Cardiac involvement increases the risk of cardiovascular mortality and occurs in 1%-5% of patients with BD. Ventricular arrythmias are believed to be the cause of this increased risk of cardiovascular mortality and it is also thought to be related with cardiac autonomic dysfunction. Heart rate turbulence (HRT) is a new predictor of cardiac autonomic activity. HRT is an independent and powerful predictor of mortality. In this study, we investigated the cardiac autonomic activity which can be determined by HRT in patients with BD. Forty patients with BD (20 men, mean age: 40 ± 9 years, range: 27-55 years) were diagnosed according to the International Study Group Criteria (ISGC) and gender and age matched healthy volunteers (20 men, mean age: 39 ± 8 years, range: 26-56 years) were included in this study. All of the participants (patients and controls) underwent 24 hours Holter electrocardiogram. HRT parameters, turbulence onset (TO) and turbulence slope (TS) were calculated with HRT (View Version 0.60-0.1 of Software Program). There were no significant differences in TO and TS values between patients with BD and control subject (TO-BD: 0.014 ± 0.03, TO-Control: 0.011 ± 0.04;TS-BD: 7.88 ± 4.9, TS-Control: 9.42 ± 6.7 respectively). Although increased cardiovascular mortality rates in BD have been shown in many studies, HRT values—detecting the risk of sudden death—do not seem to be altered in this disease.

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.

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 autonomic nervous system function and acute mountain sickness

Objective: To elucidate the role of the autonomic nervous system (ANS) in acute mountain sickness (AMS) during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level residents rapidly ascended to Tibet plateau (3 675 m altitude) by airplane from Chengdu plain (560 m altitude). ANS function was tested in plain and day 2–4 in Tibet by heart rate variability (HRV), cold pressor test (CPT). AMS was evaluated by clinic symptomatic scores. All subjects were divided into non-AMS group (57, scores≤4) and AMS group (42, scores>4). Results: Compared with non-AMS group, AMS group had higher standard deviation of normal to normal intervals (SDNN), root mean square of delta RR (rMSSD), low-frequency (LF) power, and normalized low-frequency (LFnu) power in plain (P<0.05). After arrival at 3 675 m altitude, AMS group had greater reduction in percentage of delta RR>50 ms(PNN50), rMSSD (P<0.01) and SDNN, LF, total power (TP) (P<0.05). Although no significant differences in the increase of SP and DP during CPT were found between 2 groups in plain, the SP increase during CPT of AMS group was less than non-AMS group (P<0.05) at 3 675 m altitude. AMS symptomatic scores was not only positively correlated with SDNN, rMSSD, LF/HF in plain (P<0.05), but also negatively correlated with HFnu in plain (P<0.05). Conclusion: During the initial high altitude exposure, ANS modulation is generally blunted, but the relatively predominant sympathetic control is enhanced, and this characteristic change of ANS function is positively correlated with the development of AMS.

Assessment of the autonomic nervous system is an appropriate biological marker for the well-being in erectile dysfunction

Aim： To investigate whether the autonomic nervous system （ANS） components are suitable biological markers for representing well-being in patients with erectile dysfunction （ED）. Methods： The present study included 74 male patients who had applied for check-ups in the cardiology outpatient clinic at Kirikkale University （Kirikkale, Turkey） and who had been diagnosed as having hyperlipidemia. Of these patients, 26 had an additional diagnosis of ED and made up the patient group. The remaining 48 patients formed the control group. Well-being was assessed with shortform 36 （SF-36）. The International Index of Erectile Function （IIEF） was used as a measure of libido and erectile function. Quantitative assessment of the ANS was made based on the analysis of heart rate variability by means of 24-h holter monitorization. Results： Comparisons between the ED and control groups showed significant differences only in energy scale of SF-36. The ED group also had significantly higher values of sympathetic activity. Except for the general health score of SF-36, which was found to be correlated with parasympathetic activity only in ED group, there were similar correlation patterns within the groups. Although well-being and sympathetic activity were correlated negatively, parasympathetic activity and well-being were correlated positively. Conclusion： Quantitative assessment of the ANS by heart rate variability analysis might be a suitable marker for well-being of patients with ED.

Effects of functional training on geometric indices of heart rate variability

Background： Geometric methods provide an analysis of autonomic modulation using the geometric properties of the resulting pattern, and represent an interesting tool in the analysis of heart rate variability （HRV）. The aim of this study was to evaluate the impact of functional training on cardiac autonomic modulation in healthy young women using the geometric indices of HRV. Methods： Data were analyzed from 29 women, and were stratified into a functional training group （FTG, n = 13; 23.00 ± 2.51 years; 21.90± 2.82 kg/m2） and a control group （CG, n = 16; 20.56 ± 1.03 years; 22.12±3.86 kg/m2）. The FTG received periodized functional training for 12 weeks. The cardiac autonomic modulation of both groups was evaluated before and after this training, and a qualitative analysis was performed using the Poincar6 plot. Results： There was a significant increase in the difference of the triangular index （RRTri）, SDI, SD2, and RR intervals in the FTG as compared to the CG, and the qualitative analysis from the Poincar6 plot showed an increase in the dispersion of beat-to-beat and long-term RR intervals in the functional group after training. No changes were observed in the triangular interpolation of RR interval histogram （TINN） or SD1/SD2. Conclusion： Functional training had a beneficial impact on autonomic modulation, as characterized by increased parasympathetic activity and overall variability, thus highlighting the clinical usefulness of this type of training.

A Study into Blood Flow, Heart Rate Variability, and Body Surface Temperature While Listening to Music

In this study we examined the relaxing effects of listening to music on a total of 12 women aged from their 20s to their 40s by measuring their blood flow, heart rate variability, and their body surface temperature. As a result, We found that there was a tendency for the volume of blood flow to the fingertips to significantly increase when listening to classical music, but there was a variety of changes in blood flow between each age group for healing music and J-Pop music. When measuring heart rate it was found that the LF/HF value, which is an index for the autonomic nervous system which shows tension and stress, fell significantly when listening to each type of music. Lastly, there was a trend for body surface temperature to rise when listening to classical or healing music, a rise which was particularly significant when listening to healing music. This study shows that a relaxing effect can be expected for all indices when listening to classical music. However, for healing music and J-Pop, personal musical preferences seemed to have an effect and the results were varied.

Changes of autonomic nervous system function in healthy young men during initial phase at acute high-altitude exposure

Objective: To investigate the changes of autonomic nervous system (ANS) function during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level male residents were studied in Chengdu plain and then Tibet plateau. Heart rate variability (HRV), cold pressor test (CPT), resting heart rate (HR) and blood pressure (BP) were measured at baseline (560 m altitude) and in 2 to 4 d after arriving at Tibet plateau (3 675 m altitude) to assess the ANS function. Results: Compared with baseline, on day 2 in Tibet the standard deviation of normal to normal intervals (SDNN), high-frequency (HF) power, total power (TP), root mean square of delta RR (rMSSD), percentage of delta RR>50 ms (PNN50), normalized high-frequency (HFnu) and fractal dimension (FD) decreased significantly (SDNN, HF, TP P<0.01, rMSSD, PNN50, HFnu, FD P<0.05), while the normalized low-frequency (LFnu) and LF/HF increased significantly (P<0.01). During day 3–4 in Tibet, SDNN, rMSSD, HF, TP and HFnu tended to rebound while LFnu and LF/HF decreased towards baseline day by day. In addition, in Tibet the increase in systolic pressure (SP) and diastolic pressure (DP) during CPT decreased significantly (P<0.01, 0.05), but resting HR increased compared with baseline (P<0.01). Conclusion: ANS modulation is generally blunted, and the relatively predominant sympathetic control is enhanced originally, then it reverts to the sea level states gradually during the initial days of acute high-altitude exposure.

Vitamin C ameliorated cardiac autonomic neuropathy in type 2 diabetic rats

BACKGROUND Vitamin C(VC)is a common antioxidant with cell protection potentials.However,its possible protective effect on cardiac autonomic nerves from diabetic induced insults is yet to be explored.AIM To investigate the effects of VC on diabetic cardiac autonomic neuropathy.METHODS Thirty male Wistar rats were equally grouped into control,diabetic and diabetic+VC.Type 2 diabetes was induced with fructose diet and alloxan.VC(1 g/kg)was administered for 4 wk via oral canula.Blood pressure and heart rate were measured non-invasively using tail flick blood pressure monitor.Spectral analysis of heart rate variability(HRV)was used to assess cardiac autonomic neuropathy.Blood was collected from the ocular sinus for biochemical analysis.Urethane(1 g/kg-ip)was used for anaesthesia prior to HRV and cervical dislocation to harvest hearts.Intracardiac autonomic nerve was assessed using tyrosine hydroxylase immunohistochemistry on fixed heart sections.RESULTS Results were analysed using ANOVA atα0.05.Unlike VC and control groups,diabetic rats showed significantly(P<0.0001)reduced HRV,increased heart-rate and blood pressure,initial increase in cardiac tyrosine hydroxylase activities at week-2 and sparse activity at week-4 of diabetes.Furthermore,apolipoprotein B,Oxidative stress and inflammatory markers were significantly(P<0.01)reduced in VC treated rats.CONCLUSION VC possesses cardio-autonomic nerve protective potential and ameliorates the symptoms of cardiac autonomic neuropathy in type 2 diabetes.The possible mechanisms via which VC exert these effects may be via downregulation of oxidative stress,inflammation and apolipoprotein B.

Correlation between mood and heart rate variability indices during daily life

We investigated the correlation between mood and heart rate variability (HRV) indices during daily life. The RR-interval and body acceleration of 40 normal male subjects were recorded using ambulatory device for 48 to 72 hours. Every hour that the subjects were awake they registered their current mood on a Visual Analogue Scale questionnaire. The questionnaire scales eight of the subjects’ current moods. Those are happiness, tension, fatigue, worry, depression, anger, vigor, and confusion. The following four HRV indices were calculated. Those are heart rate, root mean square of successive differences of RR-interval sequence, the normalized high-frequency (0.15 - 0.4 Hz) power of RR-in- terval variability, and mean frequency in the high-frequency band of RR-interval variability. The calculated HRV indices data and the mood data were normalized individually, the data with body acceleration exceeding 30 mG were excluded from the analysis to reduce the effect of exercise, and the differences from the first day (?mood and ?HRV-index) were taken to reduce the effect of circadian rhythm. The most three highly correlated combinations were ?vigor and ?HFnu (R = –0.24, p < 0.0001), ?vigor and ?RMSSD (R = –0.24, p < 0.0001), and ?vigor and ?HR (R = 0.22, p < 0.001). Vigor exhibited the most significant correlations with HRV indices of eight moods.

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.

Changes in Heart Rate Variability and Effects on POMS by Whether or Not Soil Observation Was Performed

Introduction: The effects of performing soil observation on autonomic nerve function (ANS) and the profile of mood states (POMS) particularly for upsurge of sentiment were studied table. Methods: The subjects were divided into two groups: Group A with soil observation, and Group B without it. Soil observation was performed by smelling soil, touching the soil and other ways. Evaluation was made using heart rate change variability, POMS and visual analog scale (VAS). Results: Group A showed an increase in high frequency (HF) and the LF (low frequency)/HF ratio and a decrease in heart rate, leading to activating the functions of the parasympathetic nervous system. VAS values for “not comforted at all” indicated that the scale was lower in Group A than in Group B. In POMS, a factor of “vigor” became lower in Group B than in Group A. Discussion: It was suggested that soil observation was effective in bringing people to a state of physiological and mental relaxation and reducing stress because it raised the degree of being comforted, increased HF, decreased the heart rate and activated the parasympathetic nervous system. Conclusions: By performing soil observation, the heart rate decreased, HF increased and an upsurge sentiment became normalized.

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.

Evaluation with Heart Rate Variability for the Treatment Effect of Aminophylline in Patients with Bradycardia after Cervical Spinal Cord Injury: A Preliminary Study

After cervical spinal cord injury (SCI), the autonomic nervous system (ANS) becomes impaired and then, bradycardia can develop. In view of this, we performed to prescribe aminophylline as pharmacotherapy for bradycardia. The study population consisted of 36 patients with cervical SCI. Bradycardia developed in 20 patients (55.6%), of these patients, 8 showed spontaneous recovery. Twelve patients had persistent bradycardia, therefore, aminophylline was administered at 0.5 mg/kg/hr by intravenous infusion. Their average heart rate increased within 24 hours after the start of infusion. In heart rate variability analysis for 7 preliminarily selected patients, the spectral waveforms of “oligowave type” indicating ANS impairment tended to appear in relatively early phase after injury (i.e., 2 days to 2 weeks after injury), whereas “normal type” was observed in the late phase (i.e., at 4 weeks). “Sympathetic block type” was observed throughout the follow-up period (2 days to 4 weeks). “Sympathetic block type” was also observed in a non-bradycardic patient on day 2. These results underscore the importance of treating ANS impairment with aminophylline while keeping in mind that bradycardia can occur even in post-SCI patients without clinical manifestations.

Nadi Yantra: a robust system design to capture the signals from the radial artery for assessment of the autonomic nervous system non-invasively

Ayurvedic and other alternative medical practi-tioners throughout the world have been using pulse diagnosis to detect disease and the organ at distress by feeling the palpations at three close yet precise positions of the radial artery. This paper presents a robust electro-mechanical system, ‘Nadi Yantra’ which uses piezoelectric based pressure sensors to capture the signals from the radial artery. Morphology of the waveforms obtained from our system concurs with standard physiological arterial signals. Reproducibility and stability of the system has been verified. Signal processing techniques were applied to obtain features such as amplitude, power spectral density, bandpower and spectral centroid to reflect variations in signals from the three channels. Further, wavelet based techniques were used to process the pressure signals and percussion peaks were identified. The interval between the percussion peaks was used to calculate Heart Rate Varibility (HRV), a useful tool for assessing the status of the autonomic nervous system of the human body non-invasively. Time domain indices were calculated from direct measurement of peak-peak (PP) intervals and from differences between the PP intervals. Frequency domain indices such as very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power, LF/HF ratio were also calculated. Thereafter, nonlinear Poincare analysis was carried out. A map of consecutive PP intervals was fitted to an ellipse using least squares method. Results from 7 datasets are depicted in this paper. A novel pressure pulse recording instrument is deve loped for the objective assessment of the ancient sci-ence of pulse diagnosis. The features calculated using multi resolution wavelet analysis show potential in the evaluation of the autonomic nervous system of the human body.