Heart Rate
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2022 ◽  
Vol 126 ◽  
pp. 108453
Maria Teresa Faria ◽  
Susana Rodrigues ◽  
Manuel Campelo ◽  
Duarte Dias ◽  
Ricardo Rego ◽  

2021 ◽  
Fairouz Grioui ◽  
Tanja Blascheck

2021 ◽  
Marie Uhlig ◽  
Janis Dominik Reinelt ◽  
Mark Lauckner ◽  
H. Lina Schaare ◽  
Deniz Kumral ◽  

Rapid structural brain plasticity after acute stress has been shown in animals. It is unknown whether such stress-related brain changes also occur in humans, in which they have been found, using structural magnetic resonance imaging (MRI), after motor learning and visual stimulation. We here investigated grey matter volume (GMV) changes after acute stress in humans and tested their relation to psychophysiological stress measures. Sixty-seven healthy men (25.8 +/- 2.7 years) completed a standardized psychosocial laboratory stressor (Trier Social Stress Test) or a control version while blood, saliva, heart rate, and psychometrics were sampled. T1-weighted MP2RAGE images at 3T MRI were acquired 45 min before and 90 min after intervention onset. GMV changes were analysed using voxel-based morphometry. Associations with endocrine, autonomic, and subjective stress measures were tested with linear models. We found significant group-by-time interactions in several brain clusters including anterior/mid-cingulate cortices and bilateral insula: GMV was increased in the stress group relative to the control group, in which several clusters showed a GMV decrease. We found no significant group-by-time interaction for other MRI parameters, including cerebral blood flow, but a significant association of GMV changes with state anxiety and heart rate variability changes. In summary, we show rapid GMV changes following acute psychosocial stress in humans. The results suggest that endogenous circadian brain changes are counteracted by acute stress and generally emphasize the influence of stress on the brain.

2021 ◽  
Vol 3 ◽  
Rongjian Zhao ◽  
Lidong Du ◽  
Zhan Zhao ◽  
Xianxiang Chen ◽  
Jie Sun ◽  

The aim of this work is to present a method for accurately estimating heart and respiration rates under different actual conditions based on a mattress which was integrated with an optical fiber sensor. During the estimation, a ballistocardiogram (BCG) signal, which was obtained from the optical fiber sensor, was used for extracting the heart rate and the respiration rate. However, due to the detrimental effects of the differential detector, self-interference, and variation of installation status of the sensor, the ballistocardiogram (BCG) signal was difficult to detect. In order to resolve the potential concerns of individual differences and body interferences, adaptive regulations and statistical classifications spectrum analysis were used in this paper. Experiments were carried out to quantify heart and respiration rates of healthy volunteers under different breathing and posture conditions. From the experimental results, it could be concluded that (1) the heart rates of 40–150 beats per minute (bpm) and respiration rates of 10–20 breaths per minute (bpm) were measured for individual differences; (2) for the same individuals under four different posture contacts, the mean errors of heart rates were separately 1.60 ± 0.98 bpm, 1.94 ± 0.83 bpm, 1.24 ± 0.59 bpm, and 1.06 ± 0.62 bpm, in contrast, the mean errors of the polar beat device were 1.09 ± 0.96 bpm, 1.44 ± 0.99 bpm, and 1.78 ± 0.94 bpm. Furthermore, the experimental results were validated by conventional counterparts which used skin-contacting electrodes as their measurements. It was reported that the heart rate was 0.26 ± 2.80 bpm in 95% confidence intervals (± 1.96SD) in comparison with Philips sure-signs VM6 medical monitor, and the respiration rate was 0.41 ± 1.49 bpm in 95% confidence intervals (± 1.96SD) in comparison with ECG-derived respiratory (EDR) measurements for respiration rates. It was indicated that the developed system using adaptive regulations and statistical classifications spectrum analysis performed better and could easily be used under complex environments.

2021 ◽  
Vol 12 ◽  
Roberto Martin del Campo Vera ◽  
Edmond Jonckheere

In this paper, a new electromyographic phenomenon, referred to as Bursting Rate Variability (BRV), is reported. Not only does it manifest itself visually as a train of short periods of accrued surface electromyographic (sEMG) activity in the traces, but it has a deeper underpinning because the sEMG bursts are synchronous with wavelet packets in the D8 subband of the Daubechies 3 (db3) wavelet decomposition of the raw signal referred to as “D8 doublets”—which are absent during muscle relaxation. Moreover, the db3 wavelet decomposition reconstructs the entire sEMG bursts with two contiguous relatively high detail coefficients at level 8, suggesting a high incidence of two consecutive neuronal discharges. Most importantly, the timing between successive bursts shows some variability, hence the BRV acronym. Contrary to Heart Rate Variability (HRV), where the R-wave is easily identified, here, time-localization of the burst requires a statistical waveform matching between the “D8 doublet” and the burst in the raw sEMG signal. Furthermore, statistical fitting of the empirical distribution of return times shows a striking difference between control and quadriplegic subjects. Finally, the BRV rate appears to be within 60–88 bursts per minute on average among 9 human subjects, suggesting a possible connection between BRV and HRV.

Respiration ◽  
2021 ◽  
pp. 1-10
Qi Jin ◽  
Xin Li ◽  
Yi Zhang ◽  
Zhihui Zhao ◽  
Qing Zhao ◽  

<b><i>Background:</i></b> Attenuated heart rate recovery at 1 min (HRR1) was demonstrated to correlate with poor prognosis in patients with pulmonary arterial hypertension, whereas its role in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. <b><i>Objectives:</i></b> The aim of this study was to investigate the correlations between HRR1 and functional status, echocardiography, hemodynamics, and prognosis of CTEPH. <b><i>Methods:</i></b> We retrospectively enrolled patients with CTEPH who underwent right heart catheterization and cardiopulmonary exercise test between June 2014 to October 2020 in Fuwai hospital. The primary outcome was clinical worsening. Linear regression was performed to assess the association between HRR1 and established markers of CTEPH severity. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff of HRR1. Cox regression models were used to assess the association between HRR1 and clinical worsening. <b><i>Results:</i></b> A total of 211 patients with CTEPH were included in the study. After adjusting for confounders, HRR1 positively correlated with 6-min walk distance, mixed venous oxygen saturation, and peak oxygen consumption, and negatively correlated with NT-proBNP, pulmonary vascular resistance, and ventilatory equivalent of carbon dioxide. Compared with patients with HRR1 ≥16 beats, patients with HRR1 &#x3c;16 beats had approximately a 3-fold risk of experiencing clinical worsening and the risk escalated with time. <b><i>Conclusion:</i></b> HRR1 could reflect disease severity and was independently associated with prognosis in patients with CTEPH.

Signals ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 852-862
Maria S. Zakynthinaki ◽  
Theodoros N. Kapetanakis ◽  
Anna Lampou ◽  
Melina P. Ioannidou ◽  
Ioannis O. Vardiambasis

Estimating the heart rate (HR) response to exercises of a given intensity without the need of direct measurement is an open problem of great interest. We propose here a model that can estimate the heart rate response to exercise of constant intensity and its subsequent recovery, based on soft computing techniques. Multilayer perceptron artificial neural networks (NN) are implemented and trained using raw HR time series data. Our model’s input and output are the beat-to-beat time intervals and the HR values, respectively. The numerical results are very encouraging, as they indicate a mean relative square error of the estimated HR values of the order of 10−4 and an absolute error as low as 1.19 beats per minute, on average. Our model has also been proven to be superior when compared with existing mathematical models that predict HR values by numerical simulation. Our study concludes that our NN model can efficiently predict the HR response to any constant exercise intensity, a fact that can have many important applications, not only in the area of medicine and cardio-vascular health, but also in the areas of rehabilitation, general fitness, and competitive sport.

2021 ◽  
Vol 8 ◽  
Daisuke Harada ◽  
Hidetsugu Asanoi ◽  
Takahisa Noto ◽  
Junya Takagawa

Background: Influence of right ventricular diastolic function on the hemodynamics of heart failure (HF). We aimed to clarify the hemodynamic features of deep Y descent in the right atrial pressure waveform in patients with HF and preserved left ventricular systolic function.Methods: In total, 114 consecutive inpatients with HF who had preserved left ventricular systolic function (left ventricular ejection fraction ≥ 50%) and right heart catheterization were retrospectively enrolled in this study. The patients were divided into two groups according to right atrial pressure waveform, and those with Y descent deeper than X descent in the right atrial pressure waveform were assigned to the deep Y descent group. We enrolled another seven patients (two men, five women; mean age, 87 ± 6) with HF and preserved ejection fraction, and implanted a pacemaker to validate the results of this study.Results: The patients with deep Y descent had a higher rate of atrial fibrillation, higher right atrial pressure and mean pulmonary arterial pressure, and lower stroke volume and cardiac index than those with normal Y descent (76 vs. 7% p &lt; 0.001, median 8 vs. 5 mmHg p = 0.001, median 24 vs. 21 mmHg p = 0.036, median 33 vs. 43 ml/m2p &lt; 0.001, median 2.2 vs. 2.7 L/m2, p &lt; 0.001). Multiple linear regression revealed a negative correlation between stroke volume index and pulmonary vascular resistance index (wood unit*m2) only in the patients with deep Y descent (estimated regression coefficient: −1.281, p = 0.022). A positive correlation was also observed between cardiac index and heart rate in this group (r = 0.321, p = 0.038). In the other seven patients, increasing the heart rate (from median 60 to 80/min, p = 0.001) significantly reduced the level of BNP (from median 419 to 335 pg/ml, p = 0.005).Conclusions: The hemodynamics of patients with HF with deep Y descent and preserved left ventricular systolic function resembled right ventricular restrictive physiology. Optimizing the heart rate may improve hemodynamics in these patients.

Nonhlanhla Mthembu ◽  
Gavin R. Norton ◽  
Vernice R. Peterson ◽  
Ravi Naran ◽  
Suraj M. Yusuf ◽  

Through both backward (Pb) and forward (Pf) wave effects, a lower heart rate (HR) associates with increased central (PPc), beyond brachial pulse pressure (PP). However, the relative contribution to Pf of aortic flow (Q) versus re-reflection of Pb, has not been determined. Using central pressure, aortic velocity and diameter measurements in the outflow tract (echocardiography), we constructed central pressure waveforms that account for the relative contribution of Q versus re-reflection to Pf. We thus evaluated the mechanisms of HR-PPc relations in a community sample (n=824) and the impact of age thereon. Inverse HR-PPc ( P <0.0001), but not HR-brachial PP ( P =0.064) relations were noted. The slope of HR-PPc relation was increased in older adults ( P <0.005). HR was inversely associated with ventricular filling time, ejection duration, stroke volume, and peak Pf ( P <0.001 to P <0.0001). However, an increased Q and hence pressures generated by the product of aortic characteristic impedance and Q did not account for Pf effects. Age-dependent HR-PPc and Pf relations were both accounted for by enhanced Pb ( P <0.0001) with an increased Pf mediated by increments in wave re-reflection ( P <0.0001). The lack of impact of ejection duration on PPc was explained by an increased time to peak Pb ( P <0.0001). In conclusion, increases in PPc and Pf at a decreased HR are accounted for by an enhanced Pb rather than by a prolonged ejection or filling duration and hence flow (Q). These effects at a young-to-middle age are of little clinical significance, but at an older age, are of clinical importance.

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