Evidence for time-dependent autonomic cardiac reinnervation in children subsequent to transplantation of the heart

1996 ◽  
Vol 6 (1) ◽  
pp. 12-19
Author(s):  
Joachim Kreuder ◽  
Heinrich Netz ◽  
Thomas Paul ◽  
Andreas Müller ◽  
Jürgen Bauer ◽  
...  
Keyword(s):  
Heart Rate ◽  
Standard Deviation ◽  
Time Domain ◽  
Recovery Time ◽  
Cardiac Transplantation ◽  
Sinus Node ◽  
Time Dependent ◽  
Rr Intervals ◽  
The Mean ◽  
Frequency Power

AbstractAutonomic denervation has been assumed to persist after orthotopic heart transplantation. Analyzing spontaneous and induced variations of heart rate, the status of autonomic cardiac innervation was investigated in six children 19–37 months after cardiac transplantation. The age at the time of transplantation varied from three weeks to 15.4 years. Heart rate variability was assessed on 24-hour Holter recordings by calculating time-domain indices (standard deviation of all RR intervals; standard deviation of the mean RR intervals from successive five-minute periods; mean of the standard deviations of RR intervals from successive five-minute periods; proportion of adjacent RR intervals > 50 msec different; square root of mean square successive differences in RR intervals) and frequency-domain variables (low frequency power, high frequency power and total spectrum power). Sinus node recovery time, sinoatrial conduction time and post-pacing cycle lengths were examined at different rates of endocardial atrial pacing. After the first year subsequent to transplantation, standard deviation of the mean RR intervals reached the normal range in four patients, whereas the other time-domain variables became normal in two patients. Both patients displayed normal or near-normal power spectrums of heart rate with normal day-to-night variations. For the remaining patients, spectrums of heart rate failed to show the main frequency peaks. Only the patient with normal variability in heart rate exhibited a decrease in corrected sinus node recovery time at higher stimulation rates, shortening of the first recovery cycle below the pre-pacing level, and a rapid decline of the accelerated post-pacing heart rate as described in innervated hearts. These results suggest the evolution of time-dependent efferent autonomic reinnervation after cardiac transplantation in children.

scholarly journals Role of Type and Volume of Recreational Physical Activity on Heart Rate Variability in Men

2020 ◽  
Vol 17 (8) ◽  
pp. 2719 ◽  
Author(s):  
Shaea Alkahtani ◽  
Andrew A. Flatt ◽  
Jawad Kanas ◽  
Abdulaziz Aldyel ◽  
Syed Shahid Habib
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Time Domain ◽  
Active Group ◽  
Control Groups ◽  
Rr Intervals ◽  
The Mean ◽  
And Control ◽  
Arab Men ◽  
Frequency Power

The aim of this study was to investigate the effect of recreational aerobic physical activity (PA) type and volume on heart rate variability (HRV) in Arab men. This was a retrospective, cross-sectional study, and included men (n = 75, age = 37.6 ± 7.1 years, body mass index (BMI) = 26.7 ± 3.1 kg/m2) who were members of a walking group, cycling group, or were inactive controls. Monthly distances from the past three months were obtained from walking and cycling groups, and the volume of PA was classified into three subgroups (high, moderate, low). HRV was measured using a computerized electrocardiographic data acquisition device. R–R interval recordings were performed while participants rested in a motionless supine position. RR intervals were recorded for 15 minutes, and a five-minute segment with minimal ectopic beats and artifacts was selected for HRV analysis. Time-domain parameters included the mean R–R interval, standard deviation of the mean R–R interval (SDNN), and root-mean-squared difference of successive RR intervals (RMSSD). The frequency-domain parameters included high-frequency power (HF), low-frequency power (LF), and LF to HF ratio (LF/HF). Results showed that there were no significant differences between walking, cycling, and control groups for all HRV parameters. Time-domain analyses based on PA volume showed that age-adjusted SDNN for the high-active group was greater than the low-active group (P = 0.03), and RMSSD for the moderate-active group was greater than the control group (P = 0.009). For the frequency domain, LF for the high-active group was greater than the low-active and control groups (P = 0.006), and HF for the moderate-active group was greater than the low-active group (P = 0.04). These data indicate that walking >150 km per month, or cycling >100 km per month at a speed >20 km/h may be necessary to derive cardiac autonomic benefits from PA among Arab men.

Abstract P105: Sleep Disordered Breathing and Cardiac Autonomic Modulation in Adolescents - Penn State Child Cohort (PSCC) Study

Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Edward O Bixler ◽  
Fan He ◽  
Sol Rodriguez-Colon ◽  
Julio Fernandez-Mendoza ◽  
Alexandros Vgontzas ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sleep Disordered Breathing ◽  
Population Based ◽  
Apnea Hypopnea Index ◽  
Autonomic Modulation ◽  
Rr Intervals ◽  
Cardiac Autonomic Modulation ◽  
The Mean ◽  
Frequency Power ◽  
Disordered Breathing

Objectives: To investigate the relationship between sleep disordered breathing (SDB) and cardiac autonomic modulation (CAM) in a population-based sample of adolescents. Methods: We used available data from 400 adolescents who completed the follow up examinations in the population-based PSCC study. 1-night polysomnography was used to assess apnea hypopnea index (AHI). AHI was used to define no-SDB (AHI<1), mild SDB (1≤AHI<5), and moderate SDB (AHI≥5). CAM was assessed by heart rate variability (HRV) analysis of beat-to-beat normal R-R intervals from a 39-hour high resolution Holter ECG. The HRV indices in frequency domain [high frequency power (HF), low frequency power (LF), and LF/HF ratio] and time domain [standard deviation of normal RR intervals (SDNN), and the square root of the mean squared difference of successive normal RR intervals (RMSSD), and heart rate (HR)] were calculated on a 30-minute basis (78 repeated measures). Mixed-effects models were used to assess the SDB and HRV relationship. Results: The mean age was 16.9 yrs (SD=2.19), with 54% male and 77% white. The mean (SD) AHI were 0.52 (0.26), 2.38 (1.03), and 12.27 (14.54) for no-, mild-, and moderate-SDB participants. The age, race, sex, and BMI percentile adjusted mean (SE) HRV indices across three SDB groups are presented in Table 1. In summary, sleep disordered breathing was associated with lower HRV and higher HR in this population-based adolescent sample, with a significant dose-response relationship. Conclusion: moderate SDB in adolescents is already associated with lower HRV, indicative of sympathetic activation and lower parasympathetic modulation, which has been associated with cardiac events in adults.

Heart Rate Variability in Diabetes Patients

2006 ◽  
Vol 34 (3) ◽  
pp. 291-296 ◽  
Author(s):  
H Kudat ◽  
V Akkaya ◽  
AB Sozen ◽  
S Salman ◽  
S Demirel ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Standard Deviation ◽  
Frequency Domain ◽  
Autonomic Neuropathy ◽  
Time Domain ◽  
Cardiovascular Autonomic Neuropathy ◽  
Chronic Complications ◽  
Frequency Power ◽  
Diabetes Patients

Diabetes mellitus can cause cardiovascular autonomic neuropathy and is associated with increased cardiovascular deaths. We investigated cardiovascular autonomic neuropathy in diabetics and healthy controls by analysis of heart rate variability. Thirty-one diabetics and 30 age- and sex-matched controls were included. In the time domain we measured the mean R-R interval (NN), the standard deviation of the R-R interval index (SDNN), the standard deviation of the 5-min R - R interval mean (SDANN), the root mean square of successive R - R interval differences (RMSSD) and the percentage of beats with a consecutive R - R interval difference > 50 ms (pNN50). In the frequency domain we measured high-frequency power (HF), low-frequency power (LF) and the LF/HF ratio. Diabetes patients had lower values for time-domain and frequency-domain parameters than controls. Most heart rate variability parameters were lower in diabetes patients with chronic complications than in those without chronic complications.

Rigorous time-domain analysis of statistically oriented graphene sheet fluctuations

2017 ◽  
Vol 36 (5) ◽  
pp. 1351-1363 ◽  
Author(s):  
Athanasios N. Papadimopoulos ◽  
Stamatios A. Amanatiadis ◽  
Nikolaos V. Kantartzis ◽  
Theodoros T. Zygiridis ◽  
Theodoros D. Tsiboukis
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Finite Difference ◽  
Surface Waves ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Mean Value ◽  
Content Type ◽  
The Mean ◽  
Difference Time

Purpose Important statistical variations are likely to appear in the propagation of surface plasmon polariton waves atop the surface of graphene sheets, degrading the expected performance of real-life THz applications. This paper aims to introduce an efficient numerical algorithm that is able to accurately and rapidly predict the influence of material-based uncertainties for diverse graphene configurations. Design/methodology/approach Initially, the surface conductivity of graphene is described at the far infrared spectrum and the uncertainties of its main parameters, namely, the chemical potential and the relaxation time, on the propagation properties of the surface waves are investigated, unveiling a considerable impact. Furthermore, the demanding two-dimensional material is numerically modeled as a surface boundary through a frequency-dependent finite-difference time-domain scheme, while a robust stochastic realization is accordingly developed. Findings The mean value and standard deviation of the propagating surface waves are extracted through a single-pass simulation in contrast to the laborious Monte Carlo technique, proving the accomplished high efficiency. Moreover, numerical results, including graphene’s surface current density and electric field distribution, indicate the notable precision, stability and convergence of the new graphene-based stochastic time-domain method in terms of the mean value and the order of magnitude of the standard deviation. Originality/value The combined uncertainties of the main parameters in graphene layers are modeled through a high-performance stochastic numerical algorithm, based on the finite-difference time-domain method. The significant accuracy of the numerical results, compared to the cumbersome Monte Carlo analysis, renders the featured technique a flexible computational tool that is able to enhance the design of graphene THz devices due to the uncertainty prediction.

Trends in Heart Rate and Heart Rate Variability during Pregnancy and Three Months Postpartum: Continuous Monitoring in a Free-Living Context (Preprint)

2021 ◽  
Author(s):  
Fatemeh Sarhaddi ◽  
Iman Azimi ◽  
Anna Axelin ◽  
Hannakaisa Niela-Vilen ◽  
Pasi Liljeberg ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Pregnant Women ◽  
Time Domain ◽  
Second Trimester ◽  
Third Trimester ◽  
Non Invasive ◽  
The Third ◽  
Invasive Method ◽  
Frequency Power

BACKGROUND Heart rate variability (HRV) is a non-invasive method reflecting autonomic nervous system (ANS) regulations. Altered HRV is associated with adverse mental or physical health complications. ANS also has a central role in physiological adaption during pregnancy causing normal changes in HRV. OBJECTIVE Assessing trends in heart rate (HR) and HRV parameters as a non-invasive method for remote maternal health monitoring during pregnancy and three months postpartum. METHODS Fifty-eight pregnant women were monitored using an Internet-of-Things (IoT)-based remote monitoring system during pregnancy and 3-months postpartum. Pregnant women were asked to continuously wear Gear sport smartwatch to monitor their HR and HRV. In addition, a cross-platform mobile application was utilized for collecting pregnancy-related information. The trends of HR and HRV parameters were extracted using reliable data. We also analyzed the trends of normalized HRV parameters based on HR to remove the effect of HR changes on HRV trends. Finally, we exploited hierarchical linear mixed models to analyze the trends of HR, HRV, and normalized HRV parameters. RESULTS HR increased significantly during the second trimester (P<.001) and decreased significantly during the third trimester (P<.01). Time-domain HRV parameters, average normal interbeat intervals (AVNN), standard deviation of normal interbeat intervals (SDNN), root mean square of the successive difference of normal interbeat intervals (RMSSD), normalized SDNN (nSDNN), and normalized RMSSD (nRMSSD) decreased significantly during the second trimester (P<.001) then increased significantly during the third trimester (P<.01). Some of the frequency domain parameters, low-frequency power (LF), high-frequency power (HF), and normalized HF (nHF) decreased significantly during the second trimester (P<.01), and HF increased significantly during the third trimester (P<.01). In the postpartum period, nRMSSD decreased (P<.05), and the LF to HF ratio (LF/HF) increased significantly (P<.01). CONCLUSIONS Our study showed that HR increased and HRV parameters decreased as the pregnancy proceeded, and the values returned to normal after the delivery. Moreover, our results show that HR started to decrease while time-domain HRV parameters and HF started to increase during the third trimester. Our results also demonstrate the possibility of continuous HRV monitoring in everyday life settings.

Abstract 4669: Does Long-QT Syndrome Involve the Sinus Node?

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Vladimir Shusterman ◽  
Jan Nemec ◽  
Marie Buncova ◽  
Bruce Winter ◽  
Win-Kuang Shen ◽  
...  
Keyword(s):  
Heart Rate ◽  
Long Qt Syndrome ◽  
High Frequency ◽  
Cardiac Rhythm ◽  
Sinus Node ◽  
List Type ◽  
High Frequency Power ◽  
Long Qt ◽  
Qt Syndrome ◽  
Frequency Power

Background: The hallmark of Long QT Syndrome (LQTS) is a prolongation of the ventricular electrical action potential caused by mutations involving key cardiac ion channels on the surface membrane of ventricular myocytes. Different mutations are associated with specific modes of arrhythmia initiation and distinct changes in cardiac rhythm prior to these events. We hypothesized that some LQTS-causing mutations might involve the sinus node, leading to aberrations in cardiac rhythm. To test this hypothesis, we examined the features of cardiac rhythm in 23 genotyped patients with LQTS and 14 matched controls (C) using Holter ECG data (6hrs). Methods: QRS-complexes were identified using custom software and verified by an experienced ECG reader; series of sinus beats were extracted and gaps in time series were linearly interpolated. The mean, max, and min heart rate (HR), the time (SD, SDNN, SDANN, RMSSD, pNN50) and frequency-domain (Total (TP), Very low (VLF), Low (LF), High (HF) frequency powers, and LF/HF) indices of heart rate variability (HRV) were calculated in each 5-min interval and over the entire recording. The short-long-short irregularity was examined using the novel multiscale rhythmogenetic analysis (MRA), which quantifies changes in the HRV indices during the transition from one time-scale window to another. Results: The maximum heart rate was slower in LQTS than in C (101±13 and 119±19bpm, p=0.001). The high-frequency power (HF) was lower in LQTS than in C (80±76 and 113±58ms 2 , p<0.05). However, the short-term irregularity (quantified by the difference in RMSSD between the 75ms and 2000ms time scales) was 4 times greater in LQTS compared to C (p=0.003). Inclusion or exclusion of two patents who were on β-blockers did not change the results. Conclusions: LQTS is associated with specific changes in cardiac rhythm, including: diminished acceleration capacity, decreased high-frequency power, and enhanced short-long-short irregularity. This suggests that LQTS involves channel modifications in the sinus node, which might contribute to arrhythmogenesis. Rhythm characterization in genetic sub-types of LQTS might improve arrhythmia risk stratification in this heterogeneous patient population.

Comparative DFT study for molecular geometries and spectra of methyl pheophorbides-a: test of M06-2X and two other functionals

2010 ◽  
Vol 14 (07) ◽  
pp. 592-604 ◽  
Author(s):  
Do Sung Huh ◽  
Sang Joon Choe
Keyword(s):  
Density Functional Theory ◽  
Standard Deviation ◽  
Density Functional ◽  
Visible Spectrum ◽  
Mean Value ◽  
Time Dependent ◽  
Dft Methods ◽  
Functional Theory ◽  
Td Dft ◽  
The Mean

The recent interest in the application of density functional theory (DFT) has prompted us to test several functions in molecular geometries of methyl pheophorbides-a (MPa), an important starting material in photodynamic therapy (PDT). In this study, we report on tests for three popular DFT methods: M06-2X, B3LYP, and LSDA. Based on the standard deviation and the mean value, and by using the difference between optimized calculated value and experimental value in geometries, we drew the following conclusions: M06-2X/6-311+G(d,p) attained the smallest standard deviation of difference among the tested DFT methods in terms of bond length, whereas the standard deviation of bond angle in LSDA/6-311+G(d,p) was the smallest. In terms of absolute value, the mean value of LSDA/6-311+G(d,p) calculation was larger than that of M06-2X/6-311+G(d,p). We found that M06-2X/6-311+G(d,p) gave the best performance for MPa in the molecular geometries. The UV-visible spectrum was calculated with time-dependent density-functional theory (TD-DFT). Time-dependent M06-2X/6-311+G(d,p) gave the best performance for MPa in CH2Cl2 solution. In general, TD-DFT calculations in CH2Cl2 solution were more red-shifted compared with those in the solid state.

scholarly journals Over-volted breakdown and recovery of short nitrogen spark gaps

2010 ◽  
Vol 28 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Xinjing Cai ◽  
Xiaobin Zou ◽  
Xinxin Wang ◽  
Liming Wang ◽  
Zhicheng Guan ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Breakdown Voltage ◽  
Gaussian Distribution ◽  
Recovery Time ◽  
Time Dependent ◽  
Experimental Conditions ◽  
Pulse Technique ◽  
Residual Nitrogen ◽  
Spark Gap ◽  
Gap Spacing

AbstractThe characteristic of the over-volted breakdown and the gaseous recovery in short nitrogen gaps was experimentally studied. It was found that the breakdown voltage of the gap changes from shot to shot even with the same experimental conditions and obeys Gaussian distribution. The over-volted factor is reduced with an increasing pressure. With a 2.7-mm gap the over-volted factors are 4.53 for 0.1 MPa pressure and 1.74 for 0.4 MPa. The over-volted breakdown voltage depends individually on the gap spacing d and the gas pressure p, rather than on the product of pd. An empirical formula of the breakdown voltage as a function of p and d was derived. The time-dependent recovery of the breakdown voltage, RVb, was obtained using a two-pulse technique. The second breakdown voltage also obeys Gaussian distribution, but it is normally with a smaller standard deviation especially when the interpulse spacing of Δt is relatively short. As a whole, RVb rises with the increase of Δt. However, an intermediate plateau is always observed and it starts when the second breakdown voltage is a little bit higher than the static breakdown voltage of the gap. The first rising edge of the RVb curve corresponds to the recovery of the electro-neutrality and the density. The intermediate plateau and the following rising edge take the spark gap much longer time to recover. The processes governing these two latter phases are as yet not fully clear. It is attributed to the delayed recombination of the residual nitrogen atoms on the cathode to produce the initial electrons for the second breakdown. An increase in pressure has resulted in an upward shift of the intermediate plateau and a shortening in the recovery time of the gaps. The second spark generally does not follow the path of the first spark.

scholarly journals Short-Term Impact of Traffic-Related Particulate Matter and Noise Exposure on Cardiac Function

2020 ◽  
Vol 17 (4) ◽  
pp. 1220 ◽  
Author(s):  
Jean Marie Buregeya ◽  
Philippe Apparicio ◽  
Jérémy Gelb
Keyword(s):  
Heart Rate ◽  
Particulate Matter ◽  
High Frequency ◽  
Noise Exposure ◽  
Personal Exposure ◽  
High Frequency Power ◽  
Short Term ◽  
Rr Intervals ◽  
Total Noise ◽  
Frequency Power

Exposure to traffic-related air pollution and noise exposure contributes to detrimental effects on cardiac function, but the underlying short-term effects related to their simultaneous personal exposure remain uncertain. The aim is to assess the impact of total inhaled dose of particulate matter and total noise exposure on the variations of electrocardiogram (ECG) parameters between pre-cycling and post-cycling periods. Mid-June 2019, we collected four participants’ personal exposure data related to traffic-related noise and particulate matter (PM2.5 and PM10) as well as ECG parameters. Several Bayesian linear models were built to examine a potential association between air pollutants and noise exposure and ECG parameters: heart rate (HR), standard deviation of the normal-to-normal intervals (SDNN), percentage of successive RR intervals that differ by more than 50 ms (pNN50), root mean square of successive RR interval differences (rMSSD), low-frequency power (LF), high-frequency power (HF), and ratio of low- to high-frequency power (LF/HF). We analyzed in total 255 5-min segments of RR intervals. We observed that per 1 µg increase in cumulative inhaled dose of PM2.5 was associated with 0.48 (95% CI: 0.22; 15.61) increase in variation of the heart rate, while one percent of total noise dose was associated with 0.49 (95% CI: 0.17; 0.83) increase in variation of heart rate between corresponding periods. Personal noise exposure was no longer significant once the PM2.5 was introduced in the whole model, whilst coefficients of the latter that were significant previously remained unchanged. Short-term exposure to traffic-related air and noise pollution did not, however, have an impact on heart rate variability.

scholarly journals Autonomic impairment and oxidative stress: Relationship in PCOS patients

2020 ◽  
Vol 14 (2) ◽  
pp. 82-88
Author(s):  
Musfika Mostafa ◽  
Sultana Ferdousi ◽  
Shamima Sultana ◽  
Ayesha Akhter
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Heart Rate ◽  
Standard Deviation ◽  
Polycystic Ovary ◽  
Digital Data ◽  
Autonomic Nerve ◽  
Cardiovascular Risks ◽  
Rr Intervals ◽  
And Oxidative Stress

Background: Polycystic ovary syndrome (PCOS) is one of the most common, heterogeneous endocrine disorder of reproductive aged women. Association of autonomic impairment and elevated oxidative stress may predispose these patients to increased cardiovascular risks. Objective: To evaluate the relationship between cardiac autonomic nerve function (CANF) and oxidative stress in patients with PCOS. Methods: This cross sectional study was conducted in Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka from September, 2018 to August, 2019. For this study, 30 newly diagnosed PCOS patients aged 20-35 years were recruited and similar age, body mass index (BMI) 30 apparently healthy, regularly menstruating women were enrolled as control. CANF was assessed by analyzing time domain measures of Heart Rate Variability (HRV). HRV data were recorded by a digital data acquisition device, Powerlab 8/35 (AD instruments, Australia). For evaluation of oxidative stress, plasma catalase and plasma Malondialdehyde (MDA) levels were measured. Statistical analysis was done by unpaired “t” test and Pearson’s correlation test as applicable. Results: In this study, resting pulse rate, systolic blood pressure (SBP), diastolic blood pressure (DBP) were significantly higher (p<0.001, p<0.01, p<0.01 respectively) and standard deviation of the RR intervals (SDRR) (p<0.01), mean R-R interval, standard deviation of the difference between successive RR intervals (SDSD), square root of mean squared differences of successive RR intervals (RMSSD), proportion of RR interval with duration >50 ms (pRR50%) were significantly lower (p<0.001) in PCOS than healthy controls. In addition, plasma catalase was significantly lower (p<0.01) and plasma MDA was significantly higher (p<0.001) in PCOS patients compared to controls. On correlation analysis, mean heart rate, SDRR, SDSD, RMSSD and pRR50% showed negative correlation with plasma catalase and plasma MDA (p<0.05) in PCOS patients but these were not significant. Conclusion: The present study reveals that reduced parasympathetic activity in PCOS patients may be related to oxidative stress. J Bangladesh Soc Physiol. 2019, December; 14(2): 82-88

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