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Respiratory Medicine 2023Pulse rate variability (PRV) predicts stroke in patients with sleep disordered breathing (SDB). However, the relationship between PRV and cardiovascular disease (CVD)...
OBJECTIVES
Pulse rate variability (PRV) predicts stroke in patients with sleep disordered breathing (SDB). However, the relationship between PRV and cardiovascular disease (CVD) was unknown in SDB.
METHODS
This was a cross-sectional study. Community residents in Guangdong were investigated. Sleep study were conducted with a type Ⅳ sleep monitoring. PRV parameters was assessed from the pulse waveforms derived from the sleep monitoring.
RESULTS
3747 participants were enrolled. The mean age was 53.9 ± 12.7 years. 1149 (30.7%) were diagnosed as SDB. PRV parameters, except for the averages of pulse-to-pulse intervals (ANN), were higher in participants with SDB than those without. After adjusting for traditional CVD risk factors, deceleration capacity of rate (DC), ANN, and the percentage of pulse-to-pulse interval differences that were more than 50 ms (PNN50) were correlated with CVD risk in participants with SDB (OR were 0.826, 1.002, and 1.285; P were 0.003, 0.009, and 0.010), but not in participants without SDB. There was no interaction effect between DC, ANN, PNN50 and oxygen desaturation index. In hierarchical analysis, DC and ANN were predictors for CVD in SDB patients with age <60 years, male, overweight, diabetes, and normal lipid metabolism. PNN50 was predictor for CVD in the elderly SDB patients without overweight, diabetes or dyslipidemia.
CONCLUSIONS
PRV parameters may be specific predictors for CVD in SDB. PNN50 was a potent biomarker for CVD risk in the elderly with SDB, event without traditional CVD risk factors.
Topics: Humans; Male; Aged; Adult; Middle Aged; Cardiovascular Diseases; Polysomnography; Overweight; Heart Rate; Cross-Sectional Studies; Sleep Apnea Syndromes; Sleep; Diabetes Mellitus
PubMed: 37734671
DOI: 10.1016/j.rmed.2023.107408 -
The Journal of Physiological Sciences :... Oct 2023Heat acclimation/acclimatisation (HA) mitigates heat-related decrements in physical capacity and heat-illness risk and is a widely advocated countermeasure for... (Review)
Review
Heat acclimation/acclimatisation (HA) mitigates heat-related decrements in physical capacity and heat-illness risk and is a widely advocated countermeasure for individuals operating in hot environments. The efficacy of HA is typically quantified by assessing the thermo-physiological responses to a standard heat acclimation state test (i.e. physiological biomarkers), but this can be logistically challenging, time consuming, and expensive. A valid molecular biomarker of HA would enable evaluation of the heat-adapted state through the sampling and assessment of a biological medium. This narrative review examines candidate molecular biomarkers of HA, highlighting the poor sensitivity and specificity of these candidates and identifying the current lack of a single 'standout' biomarker. It concludes by considering the potential of multivariable approaches that provide information about a range of physiological systems, identifying a number of challenges that must be overcome to develop a valid molecular biomarker of the heat-adapted state, and highlighting future research opportunities.
Topics: Humans; Hot Temperature; Acclimatization; Biomarkers; Phenotype; Heart Rate
PubMed: 37848829
DOI: 10.1186/s12576-023-00882-4 -
PloS One 2023Proteinoids are thermal proteins which swell into microspheres in aqueous solution. Ensembles of proteinoids produce electrical spiking activity similar to that of...
Proteinoids are thermal proteins which swell into microspheres in aqueous solution. Ensembles of proteinoids produce electrical spiking activity similar to that of neurons. We introduce a novel method for implementing logical gates in the ensembles of proteinoid microspheres using chronoamperometry. Chronoamperometry is a technique that involves applying a voltage pulse to proteinoid microspheres and measuring their current response. We have observed that proteinoids exhibit distinct current patterns that align with various logical outputs. We identify four types of logical gates: AND, OR, XOR, and NAND. These gates are determined by the current response of proteinoid microspheres. Additionally, we demonstrate that proteinoid microspheres have the ability to modify their current response over time, which is influenced by their previous exposure to voltage. This indicates that they possess a capacity for learning and are capable of adapting to their environment. Our research showcases the ability of proteinoid microspheres to perform logical operations and computations through their inherent electrical properties.
Topics: Microspheres; Heart Rate; Learning; Neurons
PubMed: 37721941
DOI: 10.1371/journal.pone.0289433 -
International Journal of... May 2024Previous studies have shown that the human capacity to gauge one's own physiological state is notoriously flawed. The cause for the mismatch between perceived and...
Previous studies have shown that the human capacity to gauge one's own physiological state is notoriously flawed. The cause for the mismatch between perceived and physiological stress has not yet been properly identified. In this study, we assumed that cardioceptive accuracy (CAc) is positively associated with cardiovascular reactivity, and CAc and expectation about stress might account for the discrepancy between perceived and physiological stress. In a crossover experiment, we assessed cardioceptive accuracy in two ways (mental heartbeat tracking task and perception of heart rate), and induced physiological (handgrip exercise) and mental (N-back task) stress in 64 university students (51 % male, mean age 22.2). We assessed cardiac and electrodermal activity, and expected and perceived stress. We found that indicators of cardioceptive accuracy were not associated with cardiovascular reactivity. However, heart rate perception moderated the association between the change in heart rate and perceived stress in the physical but not in the mental task. Whereas heartbeat tracking accuracy was not associated with perceived stress. Moreover, perceived stress was predicted by the expected stress but not by the change in heart rate and electrodermal activity in the mental stress task. In conclusion, heart rate perception and expectation of stress may shape perceived stress more than actual physiological changes in moderate acute stress.
Topics: Humans; Male; Young Adult; Adult; Female; Heart Rate; Hand Strength; Motivation; Perception; Stress, Psychological; Interoception
PubMed: 38460676
DOI: 10.1016/j.ijpsycho.2024.112326 -
Biological Psychology May 2024Altered heart rate (HR) and heart rate variability (HRV) are common observations in psychiatric disorders. Yet, few studies have examined these cardiac measures in...
Altered heart rate (HR) and heart rate variability (HRV) are common observations in psychiatric disorders. Yet, few studies have examined these cardiac measures in obsessive-compulsive disorder (OCD). The current study aimed to investigate HR and HRV, indexed by the root mean square of successive differences (RMSSD) and further time domain indices, as putative biological characteristics of OCD. Electrocardiogram was recorded during a five-minute resting state. Group differences between patients with OCD (n = 96), healthy participants (n = 112), and unaffected first-degree relatives of patients with OCD (n = 47) were analyzed. As potential moderators of group differences, we examined the influence of age and medication, respectively. As results indicated, patients with OCD showed higher HR and lower HRV compared to healthy participants. These group differences were not moderated by age. Importantly, subgroup analyses showed that only medicated patients displayed lower HRV compared to healthy individuals, while HR alterations were evident in unmedicated patients. Regarding unaffected first-degree relatives, group differences in HRV remained at trend level. Further, an age-moderated group differentiation showed that higher HRV distinguished relatives from healthy individuals in young adulthood, whereas at higher age lower HRV was indicative of relatives. Both the role of familial risk and medication in HRV alterations need further elucidation. Pending future studies, alterations in HR and potentially HRV might serve as useful indices to characterize the pathophysiology of OCD.
Topics: Humans; Obsessive-Compulsive Disorder; Heart Rate; Male; Female; Adult; Electrocardiography; Middle Aged; Family; Young Adult; Adolescent; Age Factors
PubMed: 38531496
DOI: 10.1016/j.biopsycho.2024.108786 -
Open Heart Nov 2023Peak oxygen pulse (Opulse=oxygen consumption/heart rate) is calculated by the product of stroke volume (SV) and oxygen extraction. It has been shown to be reduced in...
BACKGROUND
Peak oxygen pulse (Opulse=oxygen consumption/heart rate) is calculated by the product of stroke volume (SV) and oxygen extraction. It has been shown to be reduced in patients with a Fontan circulation. However, in the Fontan population, it may be a poor marker of SV. We propose that the slope of the O pulse curve may be more reflective of SV during exercise.
METHODS
We analysed cardiopulmonary exercise test data in 22 subjects with a Fontan circulation (cohort A) and examined the association between peak SV during exercise (aortic flow measured on exercise cardiac MRI), and O pulse parameters (absolute O pulse and O pulse slopes up to anaerobic threshold (AT) and peak exercise). In a separate Fontan cohort (cohort B, n=131), associations between clinical characteristics and O pulse kinetics were examined.
RESULTS
In cohort A, peak aortic flow was moderately and significantly associated with Opulseslope (r=0.47, p=0.02). However, neither absolute Opulse nor Opulse was significantly associated with peak aortic flow. In cohort B, Opulseslope and Opulseslope were not significantly associated with clinical parameters, apart from a weak association with forced vital capacity.
CONCLUSION
The slope of the O pulse curve to peak exercise may be more reflective of peak SV in the Fontan population than a single peak O pulse value.
Topics: Humans; Fontan Procedure; Stroke Volume; Heart Rate; Exercise Test; Oxygen
PubMed: 37935560
DOI: 10.1136/openhrt-2023-002324 -
Medicine Nov 2023To explore the feasibility of using micro-bolus pulse injection method to reduce the dilution effect of pipeline on high concentration injection, and to understand low...
To explore the feasibility of using micro-bolus pulse injection method to reduce the dilution effect of pipeline on high concentration injection, and to understand low liquid volume bolus injection based on low injection speed. Using a programmable pulse injection pump, a 25-cm - long pipeline containing water-soluble fluorescent agent was flushed using different volumes of bolus, and the time spent for the complete disappearance of the fluorescent agent was recorded to evaluate the flushing efficiency. The finite element simulation of 2-phase flow was carried out using computational fluid dynamics (CFD) technology, and the difference of shear rate and pressure distribution in the vein of pulse injection and direct injection of bolus under hemostasis was compared and simulated. Micro-bolus pulse flushing has advantages in completing perfusion imaging applications, such as small volume imaging agent injection. Compared with non-pulse injection, the effective flushing volume decreases by 49.7%, the average injection speed decreases by 56%, and the maintenance time of high shear rate is shorter when using micro-bolus pulse injection. The impact of micro-bolus pulse injection on the vein can achieve the same or even lower negative effects as other injection methods after increasing the hemostatic distance to 100 mm. In the case of bolus injection requiring high concentration and small volume, such as for radiopharmaceutical dynamic imaging, the application of micro-bolus pulse injection is an effective way to overcome the dilution phenomenon of the imaging agent in the pipeline. During hemostasis, the micro-bolus pulse injection needs to control a longer hemostasis distance to reduce the potential impact on peripheral veins.
Topics: Humans; Injections; Veins; Computer Simulation; Heart Rate; Hemostasis
PubMed: 37933034
DOI: 10.1097/MD.0000000000035607 -
Estimating age and gender from electrocardiogram signals: A comprehensive review of the past decade.Artificial Intelligence in Medicine Dec 2023Twelve lead electrocardiogram signals capture unique fingerprints about the body's biological processes and electrical activity of heart muscles. Machine learning and... (Review)
Review
Twelve lead electrocardiogram signals capture unique fingerprints about the body's biological processes and electrical activity of heart muscles. Machine learning and deep learning-based models can learn the embedded patterns in the electrocardiogram to estimate complex metrics such as age and gender that depend on multiple aspects of human physiology. ECG estimated age with respect to the chronological age reflects the overall well-being of the cardiovascular system, with significant positive deviations indicating an aged cardiovascular system and a higher likelihood of cardiovascular mortality. Several conventional, machine learning, and deep learning-based methods have been proposed to estimate age from electronic health records, health surveys, and ECG data. This manuscript comprehensively reviews the methodologies proposed for ECG-based age and gender estimation over the last decade. Specifically, the review highlights that elevated ECG age is associated with atherosclerotic cardiovascular disease, abnormal peripheral endothelial dysfunction, and high mortality, among many other cardiovascular disorders. Furthermore, the survey presents overarching observations and insights across methods for age and gender estimation. This paper also presents several essential methodological improvements and clinical applications of ECG-estimated age and gender to encourage further improvements of the state-of-the-art methodologies.
Topics: Humans; Aged; Signal Processing, Computer-Assisted; Electrocardiography; Machine Learning; Heart Rate; Probability
PubMed: 38042607
DOI: 10.1016/j.artmed.2023.102690 -
Sensors (Basel, Switzerland) Sep 2023Cardio-mechanical monitoring techniques, such as Seismocardiography (SCG) and Gyrocardiography (GCG), have received an ever-growing interest in recent years as potential...
Cardio-mechanical monitoring techniques, such as Seismocardiography (SCG) and Gyrocardiography (GCG), have received an ever-growing interest in recent years as potential alternatives to Electrocardiography (ECG) for heart rate monitoring. Wearable SCG and GCG devices based on lightweight accelerometers and gyroscopes are particularly appealing for continuous, long-term monitoring of heart rate and its variability (HRV). Heartbeat detection in cardio-mechanical signals is usually performed with the support of a concurrent ECG lead, which, however, limits their applicability in standalone cardio-mechanical monitoring applications. The complex and variable morphology of SCG and GCG signals makes the ECG-free heartbeat detection task quite challenging; therefore, only a few methods have been proposed. Very recently, a template matching method based on normalized cross-correlation (NCC) has been demonstrated to provide very accurate detection of heartbeats and estimation of inter-beat intervals in SCG and GCG signals of pathological subjects. In this study, the accuracy of HRV indices obtained with this template matching method is evaluated by comparison with ECG. Tests were performed on two public datasets of SCG and GCG signals from healthy and pathological subjects. Linear regression, correlation, and Bland-Altman analyses were carried out to evaluate the agreement of 24 HRV indices obtained from SCG and GCG signals with those obtained from ECG signals, simultaneously acquired from the same subjects. The results of this study show that the NCC-based template matching method allowed estimating HRV indices from SCG and GCG signals of healthy subjects with acceptable accuracy. On healthy subjects, the relative errors on time-domain indices ranged from 0.25% to 15%, on frequency-domain indices ranged from 10% to 20%, and on non-linear indices were within 8%. The estimates obtained on signals from pathological subjects were affected by larger errors. Overall, GCG provided slightly better performances as compared to SCG, both on healthy and pathological subjects. These findings provide, for the first time, clear evidence that monitoring HRV via SCG and GCG sensors without concurrent ECG is feasible with the NCC-based template matching method for heartbeat detection.
Topics: Humans; Heart Rate; Electrocardiography; Heart; Monitoring, Physiologic; Heart Rate Determination
PubMed: 37836942
DOI: 10.3390/s23198114 -
Computational and Mathematical Methods... 2023Using PSG-guided acute selective REM/SWS sleep deprivation in volunteers, this study examined the effects of sleep deprivation on the cardiovascular and autonomic...
OBJECTIVE
Using PSG-guided acute selective REM/SWS sleep deprivation in volunteers, this study examined the effects of sleep deprivation on the cardiovascular and autonomic nervous systems, as well as the relationship between cardiac neuromodulation homeostasis and cardiovascular disease.
METHODS
An experiment was conducted using 30 healthy volunteers (male : female = 1 : 1, aged 26.33 ± 4.5 years) divided into groups for sleep deprivation of SWS and REM sleep, and then, each group was crossed over for normal sleep (2 days) and repeated sleep deprivation (1 day, 3 times). During the study period, PSG and ELECTRO ECG monitoring were conducted, and five-minute frequency domain parameters and blood pressure values were measured before and after sleep deprivation.
RESULTS
Changes in VLF, LFnu, LF/HF, HF, and HFnu after SWS sleep deprivation were statistically significant ( < 0.05), but not LF ( = 0.063). Changes in VLF, LF, HF, LF/HF, LFnu, and HFnu after REM sleep deprivation were not statistically significant ( > 0.05).
CONCLUSIONS
An increase in sympathetic nerve activity results from sleep deprivation and sudden awakening from SWS sleep is associated with a greater risk of cardiovascular disease.
Topics: Humans; Male; Female; Sleep Deprivation; Heart Rate; Cardiovascular Diseases; Polysomnography; Sleep
PubMed: 37469834
DOI: 10.1155/2023/7121295