Association between Fetal Heart Rate Monitoring during Labor and Neonatal Acidosis in Full-Term Newborns: A Retrospective Multicenter Cohort Study

Introduction: Fetal heart rate monitoring during labor is used to study fetal well-being and predict neonatal acidosis of newborn. Fetal heart rate monitoring is analyzed by the obstetrical team and categorized according to the FIGO guidelines. An important limitation of this diagnostic tool is an inter- and intra-observer variability, leading to subjective cardiotocography interpretation and classification. Our objective was to study the association between the categories of fetal heart rate analysis (according to FIGO classification) and neonatal acidosis of full-term newborns. Study design: This is a multicenter retrospective cohort study conducted between 2014 and 2018 in the Grand-Est region. We searched and included retrospectively children hospitalized in a pediatric intensive care unit in one of the participating hospitals with an ICD-10 coding type “P91.6” corresponding to “Hypoxic Ischemic Encephalopathy”. Maternal, pregnancy, delivery, and newborn characteristics were collected and compared by univariate logistic regression with multiple imputation. Odds Ratio and 95% confidence intervals (CI) were calculated using the model and presented. Multiple imputation with m = 100 imputations was tested, using Rubin rules to combine the results. Results: 55 patients were included in the study. Fetal heart rate tracings classified in Category 3 as “pathological” according to FIGO guidelines were significantly associated with an increased risk of severe neonatal acidosis. Late decelerations and bradycardia during labor were associated with severe neonatal acidosis. Conclusion: Severe neonatal acidosis may be suspected by interpretation of fetal heart rate during labor. Fetal bradycardia and late decelerations are predictive of the severity of neonatal acidosis. This study emphasizes the need to screen severe neonatal acidosis and allows the identification of populations most at risk. Repeated team training and upgrading of fetal heart rate study would further reduce the incidence of neonatal acidosis.

The Signal Extraction of Fetal Heart Rate Based on Wavelet Transform and BP Neural Network

This paper briefly introduces the collection and recognition of bio-medical sig nals, designs the method to collect FM signals. A detailed discussion on the sys tem hardware, structure and functions is also given. Under LabWindows/CVI,the ha rdware and the driver do compatible, the hardware equipment work properly active ly. The paper adopts multi threading technology for real-time analysis and make s use of latency time of CPU effectively, expedites program reflect speed, impro ve s the program to perform efficiency. One threading is collecting data; the other threading is analyzing data. Using the method, it is broaden to analyze the sig nal in real-time. Wavelet transform to remove the main interference in the FM a nd by adding time-window to recognize with BP network; Finally the results of c ollecting signals and BP networks are discussed.8 pregnant women’s signals of F M were collected successfully by using the sensor. The correct of BP network rec ognition is about 83.3% by using the above measure.

Critical evaluation of American categorization of fetal heart rate (FHR) decelerations and three tier classification—Shortcomings, contradictions, remedies and need for debate

Fetal heart rate (FHR) decelerations are the commonest aberrant feature on cardiotocograph (CTG) thus having a major influence on classification ofFHRpatterns into the three tier system. The unexplained paradox of early decelerations (head compression—an invariable phenomenon in labor) being extremely rare [1] should prompt a debate about scientific validity of current categorization. This paper demonstrates that there appear to be major fallacies in the pathophysiological hypothesis (cord compression—baroreceptor mechanism) underpinning of vast majority of (variable?) decelerations. Rapid decelerations during contractions with nadir matching peak of contractions are consistent with “pure” vagal reflex (head compression) rather than result of fetal blood pressure or oxygenation changes from cord compression. Hence, many American authors have reported that the abrupt FHR decelerations attributed to cord compression are actually due to head compression [2-6]. The paper debates if there are major fundamental fallacies in current categorization of FHR decelerations based concomitantly on rate of descent (reflecting putative aetiology?) and time relationship to contractions. Decelerations with consistently early timing (constituting majority) seem to get classed as “variable” because of rapid descent. A distorted unscientific categorization of FHR decelerations could lead to clinically unhelpful three tier classification system. Hence, the current unphysiological classification needs a fresh debate with consideration of alternative models and re-evaluation of clinical studies to test these. Open debate improves patient care and safety. The clue to benign reflex versus hypoxic nature of decelerations seems to be in the timing rather than the rate of descent. Although the likelihood of fetal hypxemia is related to depth and duration ofFHRdecelerations, the cut-offs are likely to be different for early/late/variable decelerations and it seems to be of paramount importance to get this discrimination right for useful visual or computerized system of CTG interpretation.

Interpretation of British experts’ illustrations of fetal heart rate (FHR) decelerations by Consultant Obstetricians, registrars and midwives: A prospective study—Reasons for major disagreement with experts and implications for clinical practice

Objective: To test the reproducibility of British experts’ (eFM, K2MS, Gibb and Arulkumaran) [1-3] illustrations of fetal heart rate (FHR) decelerations by trained British Obstetricians and midwives. To analyze reasons for any discrepancies by examining factors relating to the participants, British experts’ descriptions and NICE guidelines [4]. Design: Prospective observational study. Setting: National Health Service (NHS) Hospitals. Participants: 38 Obstetric Consultants, 49 registrars and 45 midwives. Methods: Printed questionnaire. Statistical Analysis: Fisher’s Exact test. Results: This largest study of its kind showed almost unbelievably high disconnect between CTG interpretation by experts and participants. 98% - 100% midwives, 80% - 100% Registrars and 74% - 100% Consultants categorized FHR decelerations differently from the five experts’ illustrations/interpretations (p < 0.0001). Remarkably, the three experts’ illustrations of early (supposedly most benign) decelerations were classed as atypical variable by 56% Consultants, 78% Registrars and 99% midwives and the CTGs as pathological by 85% of the participants. Conclusions: The high degree of disagreement with the experts’ illustrations (p < 0.0001) did not appear to be due to participant factors. The immediate reasons seemed to be the conflicting illustrations and heterogeneity of experts’ descriptions. But most importantly, these appeared to stem from non-standardized ambiguous definitions of FHR decelerations and many intrinsic systemic flaws in the current NICE guidelines [4]. The NICE concept of “true uniform” (identical) early and late decelerations seems biologically implausible (a myth) and no examples can be found. Another myth seems to be that early and late decelerations should be gradual. Only very shallow decelerations will look “gradual” on the British CTG. These systemic flaws lead to dysfunctional CTG interpretation increasing intervention as well as impairing diagnosis of fetal hypoxemia. This is because the vast majority of FHR decelerations fall in a single heterogeneous “variable” group with many further classed as “atypical” (pathological) based on disproven and discredited criteria [5-7]. There is increasing evidence in USA that a system with variable decelerations as the majority is clinically unhelpful because of loss of information [5-9]. In the interest of patient care and safety, open debate is necessary regarding a better way forward. Classification of FHR decelerations based primarily and solely on time relationship to contractions appears more scientific and clinically useful.

Video-Based Deception Detection with Non-Contact Heart Rate Monitoring and Multi-Modal Feature Selection

Deception detection plays a crucial role in criminal investigation.Videos contain a wealth of information regarding apparent and physiological changes in individuals,and thus can serve as an effective means of deception detection.In this paper,we investigate video-based deception detection considering both apparent visual features such as eye gaze,head pose and facial action unit(AU),and non-contact heart rate detected by remote photoplethysmography(rPPG)technique.Multiple wrapper-based feature selection methods combined with the K-nearest neighbor(KNN)and support vector machine(SVM)classifiers are employed to screen the most effective features for deception detection.We evaluate the performance of the proposed method on both a self-collected physiological-assisted visual deception detection(PV3D)dataset and a public bag-oflies(BOL)dataset.Experimental results demonstrate that the SVM classifier with symbiotic organisms search(SOS)feature selection yields the best overall performance,with an area under the curve(AUC)of 83.27%and accuracy(ACC)of 83.33%for PV3D,and an AUC of 71.18%and ACC of 70.33%for BOL.This demonstrates the stability and effectiveness of the proposed method in video-based deception detection tasks.

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.

Study on Real-Time Heart Rate Detection Based on Multi-People

Heart rate is an important vital characteristic which indicates physical and mental health status.Typically heart rate measurement instruments require direct contact with the skin which is time-consuming and costly.Therefore,the study of non-contact heart rate measurement methods is of great importance.Based on the principles of photoelectric volumetric tracing,we use a computer device and camera to capture facial images,accurately detect face regions,and to detect multiple facial images using a multi-target tracking algorithm.Then after the regional segmentation of the facial image,the signal acquisition of the region of interest is further resolved.Finally,frequency detection of the collected Photo-plethysmography(PPG)and Electrocardiography(ECG)signals is completed with peak detection,Fourier analysis,and a Waveletfilter.The experimental results show that the subject’s heart rate can be detected quickly and accurately even when monitoring multiple facial targets simultaneously.

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.

Unexplained fetal tachycardia:A case report

BACKGROUND This study aimed to explore the possible etiology and treatment of severe fetal tachycardia in the absence of organic disease and provide a reference for clinical management of severe fetal tachycardia.CASE SUMMARY A 29-year-old pregnant woman,with a gravidity 1 parity 0,presented with a fetal heart rate(FHR)of 243 beats per minute during a routine antenatal examination at 31+2 wk of gestation.Before termination of pregnancy at 38 wk of gestation,the FHR repeatedly showed serious abnormalities,lasting more than 30 min.However,the pregnant woman and the fetus had no clinical symptoms,and repeated examination revealed no organic lesions.The mother and the baby were regularly followed up.CONCLUSION This was a case of severe fetal tachycardia with no organic lesions and management based on clinical experience.

An Effective Machine-Learning Based Feature Extraction/Recognition Model for Fetal Heart Defect Detection from 2D Ultrasonic Imageries

Congenital heart defect,accounting for about 30%of congenital defects,is the most common one.Data shows that congenital heart defects have seriously affected the birth rate of healthy newborns.In Fetal andNeonatal Cardiology,medical imaging technology(2D ultrasonic,MRI)has been proved to be helpful to detect congenital defects of the fetal heart and assists sonographers in prenatal diagnosis.It is a highly complex task to recognize 2D fetal heart ultrasonic standard plane(FHUSP)manually.Compared withmanual identification,automatic identification through artificial intelligence can save a lot of time,ensure the efficiency of diagnosis,and improve the accuracy of diagnosis.In this study,a feature extraction method based on texture features(Local Binary Pattern LBP and Histogram of Oriented Gradient HOG)and combined with Bag of Words(BOW)model is carried out,and then feature fusion is performed.Finally,it adopts Support VectorMachine(SVM)to realize automatic recognition and classification of FHUSP.The data includes 788 standard plane data sets and 448 normal and abnormal plane data sets.Compared with some other methods and the single method model,the classification accuracy of our model has been obviously improved,with the highest accuracy reaching 87.35%.Similarly,we also verify the performance of the model in normal and abnormal planes,and the average accuracy in classifying abnormal and normal planes is 84.92%.The experimental results show that thismethod can effectively classify and predict different FHUSP and can provide certain assistance for sonographers to diagnose fetal congenital heart disease.

Autonomic Function in Individuals with Slow Heart Rate Response following an Exercise Stress Test

Objective: To examine the autonomic function using HRV measures in apparently healthy individuals undergoing exercise stress test (EST) and demonstrating slow HRR response. Methods: HRV was measured with 12 lead ECGs during graded EST and analyzed via a post-processing method. Autonomic function was determined by Power Spectral Analysis of the very low frequency (VLF), low frequency (LF), high frequency (HF), and the ratio of LF/HF. We correlated HRV indices with resting, exercise, and recovery data. Results: No differences were found in anthropometric measurements, peak EST HR, and METS between individuals with slow HRR (below 18 b/min) compared with controls (HRR > 18 b/min). Only the VLF component of the HRV indices was statistically different (p = 0.03) at one-minute post-exercise compared with controls. Additionally, a significant correlation between HRR and resting LF and HF indices was found in the individuals with slow HRR but not in the controls. Conclusion: In apparently healthy individuals with slow HRR post-EST, autonomic function did not demonstrate any differences at any phase of the EST, including at one minute of recovery. However, a significant correlation was found between resting LF and HF powers and HRR in individuals with slow vagal reactivation post-exercise. The clinical and prognostic implications of such observation deserve further investigation.

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.

Valvuloplasty of fetal pulmonary atresia with intact ventricular septum and hypoplastic right heart: Mid-term follow-up results

Objective:This study aimed to analyze and evaluate the results of mid-term follow-up after fetal pulmonary valvuloplasty(FPV)in fetuses with pulmonary atresia with intact ventricular septum(PA/IVS).Methods:From August 31,2018,to May 31,2019,seven fetuses with PA/IVS and hypoplastic right heart were included in this study.All underwent echocardiography by the same specialist and were operated on by the same team.Intervention and echocardiography data were collected,and changes in the associated indices noted during follow-up were analyzed.Results:All seven fetuses successfully underwent FPV.The median gestational age at FPV was 27.54 weeks.The average FPV procedural time was 6 min.Persistent bradycardia requiring treatment occurred in 4/7 procedures.Finally,five pregnancies were successfully delivered,and the other two were aborted.Compared to data before fetal cardiac interventions(FCI),tricuspid valve annulus diameter/mitral valve annulus diameter(TV/MV)and right ventricle diameter/left ventricle diameter(RV/LV)of all fetuses had progressively improved.The maximum tricuspid regurgitation velocity decreased from 4.60 m/s to 3.64 m/s.The average follow-up time was 30.40±2.05 months.During the follow-up period,the diameter of the tricuspid valve ring in five children continued to improve,and the development rate of the tricuspid valve was relatively obvious from 6 months to 1 year after birth.However,the development of the right ventricle after birth was relatively slow.It was discovered that there were individual variations in the development of the right ventricle during follow-up.Conclusion:The findings support the potential for the development of the right ventricle and tricuspid valve in fetuses with PA/IVS who underwent FCI.Development of the right ventricle and tricuspid valve does not occur synchronously during pregnancy.The right ventricle develops rapidly in utero,but the development of tricuspid valve is more apparent after birth than in utero.

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.

An Intelligent Sensor Based System for Real Time Heart Rate Monitoring (HRM)

A method and apparatus for monitoring heart rate of the heart using a wearable system is designed and implemented in this paper. A heart rate receives from heart beat signals and stores the data to a database and after a time period this method can determine an idle heart rate of the monitoring body. This idle heart rate is compared with the stored data and can determine the normal and abnormal heart rate variability. After the certain time period this system can detect the heart rate and also can send a signal to the user in time of abnormalities. Consequent estimations of heart rate variability are contrasted with this.

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.