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Scientific Reports Jul 2023Seismocardiography (SCG) is the noninvasive measurement of local vibrations of the chest wall produced by the mechanical activity of the heart and has shown promise in...
Seismocardiography (SCG) is the noninvasive measurement of local vibrations of the chest wall produced by the mechanical activity of the heart and has shown promise in providing clinical information for certain cardiovascular diseases including heart failure and ischemia. Conventionally, SCG signals are recorded by placing an accelerometer on the chest. In this paper, we propose a novel contactless SCG measurement method to extract them from chest videos recorded by a smartphone. Our pipeline consists of computer vision methods including the Lucas-Kanade template tracking to track an artificial target attached to the chest, and then estimate the SCG signals from the tracked displacements. We evaluated our pipeline on 14 healthy subjects by comparing the vision-based SCG[Formula: see text] estimations with the gold-standard SCG[Formula: see text] measured simultaneously using accelerometers attached to the chest. The similarity between SCG[Formula: see text] and SCG[Formula: see text] was measured in the time and frequency domains using the Pearson correlation coefficient, a similarity index based on dynamic time warping (DTW), and wavelet coherence. The average DTW-based similarity index between the signals was 0.94 and 0.95 in the right-to-left and head-to-foot directions, respectively. Furthermore, SCG[Formula: see text] signals were utilized to estimate the heart rate, and these results were compared to the gold-standard heart rate obtained from ECG signals. The findings indicated a good agreement between the estimated heart rate values and the gold-standard measurements (bias = 0.649 beats/min). In conclusion, this work shows promise in developing a low-cost and widely available method for remote monitoring of cardiovascular activity using smartphone videos.
Topics: Humans; Vibration; Signal Processing, Computer-Assisted; Heart; Thoracic Wall; Heart Rate; Computers; Electrocardiography
PubMed: 37479720
DOI: 10.1038/s41598-023-38607-7 -
Cleveland Clinic Journal of Medicine Jul 2023Postural orthostatic tachycardia syndrome (POTS)-sustained tachycardia upon standing without orthostatic hypotension-can be diagnosed clinically without an extensive... (Review)
Review
Postural orthostatic tachycardia syndrome (POTS)-sustained tachycardia upon standing without orthostatic hypotension-can be diagnosed clinically without an extensive diagnostic evaluation unless certain atypical features suggest an alternative diagnosis. A unifying pathophysiologic mechanism has not been identified, although several have been proposed. Similarities between POTS and various autoimmune disorders suggest an immune mechanism in a subset of patients. However, no causative antibody has been identified, and associated antibodies are rarely clinically relevant. Moreover, immunotherapies are not currently recommended for POTS, although clinical trials are underway to clarify their utility.
Topics: Humans; Postural Orthostatic Tachycardia Syndrome; Autoimmunity; Autoimmune Diseases; Heart Rate
PubMed: 37400156
DOI: 10.3949/ccjm.90a.22093 -
Aging Clinical and Experimental Research Nov 2023Emerging evidence has linked elevated resting heart rate (RHR) with poor cognitive function in older adults, but the mechanisms underlying their association are poorly...
BACKGROUND
Emerging evidence has linked elevated resting heart rate (RHR) with poor cognitive function in older adults, but the mechanisms underlying their association are poorly understood.
METHODS
This population-based cross-sectional study included 4510 dementia-free participants (age ≥ 65 years; 56.9% females; 38.3% no formal education) in the baseline examination of the Multidomain Interventions to Delay Dementia and Disability in Rural China study. Of these, 1,386 had data on serum proinflammatory cytokines and adhesion molecules. RHR was measured using 12-lead electrocardiograph. We used the Mini-Mental State Examination (MMSE) and a neuropsychological test battery to assess cognitive function. Data were analyzed using the general linear and restricted cubic splines models.
RESULTS
People with high RHR were more likely to have cardiometabolic diseases and worse cognitive function (p < 0.05). There was an inverted J-shaped association of RHR with MMSE and attention scores. Having RHR ≥ 80 bpm (vs. 60-69 bpm) was significantly associated with the multivariable-adjusted β coefficients of - 0.58 [95% confidence interval (CI), - 1.00, - 0.16] for MMSE score and - 0.08 (- 0.15, - 0.01) for attention score. In the serum biomarker subsample, RHR was linearly associated with serum interleukin-6 (IL-6) (β coefficient = 0.19; 95%CI 0.14, 0.24), IL-8 (0.08; 0.02, 0.13), IL-10 (0.09; 0.04, 0.15), tumor necrosis factor-α (0.06; 0.01, 0.11), monocyte chemotactic protein-1 (0.09; 0.04, 0.15), intercellular adhesion molecule-1 (0.16; 0.11, 0.22), and vascular cell adhesion molecule-1 (0.11; 0.06, 0.16).
CONCLUSIONS
There is an inverted J-shaped association of RHR with attention and global cognition. Poor cognitive function and high RHR may be linked through systemic low-grade inflammation and endothelial injury.
Topics: Female; Humans; Aged; Male; Heart Rate; Cross-Sectional Studies; Inflammation; Cognition; Electrocardiography; Risk Factors
PubMed: 37898962
DOI: 10.1007/s40520-023-02576-8 -
Scientific Reports Oct 2023Heart rate (HR) is a crucial physiological signal that can be used to monitor health and fitness. Traditional methods for measuring HR require wearable devices, which...
Heart rate (HR) is a crucial physiological signal that can be used to monitor health and fitness. Traditional methods for measuring HR require wearable devices, which can be inconvenient or uncomfortable, especially during sleep and meditation. Noncontact HR detection methods employing microwave radar can be a promising alternative. However, the existing approaches in the literature usually use high-gain antennas and require the sensor to face the user's chest or back, making them difficult to integrate into a portable device and unsuitable for sleep and meditation tracking applications. This study presents a novel approach for noncontact HR detection using a miniaturized Soli radar chip embedded in a portable device (Google Nest Hub). The chip has a [Formula: see text] dimension and can be easily integrated into various devices. The proposed approach utilizes advanced signal processing and machine learning techniques to extract HRs from radar signals. The approach is validated on a sleep dataset (62 users, 498 h) and a meditation dataset (114 users, 1131 min). The approach achieves a mean absolute error (MAE) of 1.69 bpm and a mean absolute percentage error (MAPE) of [Formula: see text] on the sleep dataset. On the meditation dataset, the approach achieves an MAE of 1.05 bpm and a MAPE of [Formula: see text]. The recall rates for the two datasets are [Formula: see text] and [Formula: see text], respectively. This study represents the first application of the noncontact HR detection technology to sleep and meditation tracking, offering a promising alternative to wearable devices for HR monitoring during sleep and meditation.
Topics: Humans; Heart Rate; Meditation; Sleep; Monitoring, Physiologic; Heart Rate Determination
PubMed: 37865634
DOI: 10.1038/s41598-023-44714-2 -
Journal of the American Chemical Society Sep 2023Inspired by naturally occurring regulatory mechanisms that allow complex temporal pulse features with programmable delays, we demonstrate here a strategy to achieve...
Inspired by naturally occurring regulatory mechanisms that allow complex temporal pulse features with programmable delays, we demonstrate here a strategy to achieve temporally programmed pulse output signals in DNA-based strand displacement reactions (SDRs). To achieve this, we rationally designed input strands that, once bound to their target duplex, can be gradually degraded, resulting in a pulse output signal. We also designed blocker strands that suppress strand displacement and determine the time at which the pulse reaction is generated. We show that by controlling the degradation rate of blocker and input strands, we can finely control the delayed pulse output over a range of 10 h. We also prove that it is possible to orthogonally delay two different pulse reactions in the same solution by taking advantage of the specificity of the degradation reactions for the input and blocker strands. Finally, we show here two possible applications of such delayed pulse SDRs: the time-programmed pulse decoration of DNA nanostructures and the sequentially appearing and self-erasing formation of DNA-based patterns.
Topics: DNA; Heart Rate; Nanostructures; Recombination, Genetic
PubMed: 37710955
DOI: 10.1021/jacs.3c06664 -
PloS One 2024Heart rate variability (HRV) is a frequently used indicator of autonomic responses to various stimuli in horses. This study aimed to investigate HRV variables in horses...
Heart rate variability (HRV) is a frequently used indicator of autonomic responses to various stimuli in horses. This study aimed to investigate HRV variables in horses undergoing cold (n = 25) or hot (n = 26) shoeing. Multiple HRV variables were measured and compared between horses undergoing cold and hot shoeing, including the time domain, frequency domain, and nonlinear variables pre-shoeing, during shoeing, and at 30-minute intervals for 120 minutes post-shoeing. The shoeing method interacted with time to change the HRV variables standard deviation of RR intervals (SDNN), root mean square of successive RR interval differences (RMSSD), very-low-frequency band, low-frequency band (LF), the LF to high-frequency band ratio, respiratory rate, total power, standard deviation perpendicular to the line of identity (SD1), and standard deviation along the line of identity (SD2). SDNN, RMSSD, and total power only increased 30 minutes after hot shoeing (all p < 0.05). Triangular interpolation of normal-to-normal intervals (TINN) and the HRV triangular index increased during and up to 120 minutes after hot shoeing (p < 0.05-0.001). TINN increased only during cold shoeing (p < 0.05). LF increased 30 and 60 minutes after hot shoeing (both p < 0.05). SD1 and SD2 also increased 30 minutes after hot shoeing (both p < 0.05). SDNN, TINN, HRV triangular index, LF, total power, and SD2 were higher in hot-shoed than cold-shoed horses throughout the 120 minutes post-shoeing. Differences in HRV were found, indicating increased sympathovagal activity in hot shoed horses compared to cold shoed horses.
Topics: Animals; Horses; Heart Rate; Male; Cold Temperature; Hot Temperature; Female; Respiratory Rate; Shoes
PubMed: 38843254
DOI: 10.1371/journal.pone.0305031 -
CMAJ : Canadian Medical Association... Feb 2024
Topics: Humans; COVID-19; Oximetry; Heart Rate
PubMed: 38346783
DOI: 10.1503/cmaj.230221 -
Applied Psychophysiology and Biofeedback Dec 2023To determine whether heart rate variability biofeedback (HRV-BF) training, compared to a psychoeducation control condition can strengthen the integration of the central... (Randomized Controlled Trial)
Randomized Controlled Trial
To determine whether heart rate variability biofeedback (HRV-BF) training, compared to a psychoeducation control condition can strengthen the integration of the central and autonomic nervous systems as measured by neuropsychological measures in patients with mild traumatic brain injury (mTBI). Participants were recruited from two university hospitals in Taipei, Taiwan. A total of 49 participants with mTBI were recruited for this study. Forty-one participants completed the study, 21 in the psychoeducation group and 20 in the HRV-BF group. Randomized controlled study. The Taiwanese Frontal Assessment Battery, the Semantic Association of Verbal Fluency Test, the Taiwanese version of the Word Sequence Learning Test, the Paced Auditory Serial Addition Test-Revised, and the Trail Making Test were used as performance-based neuropsychological functioning measures. The Checklist of Post-concussion Symptoms, the Taiwanese version of the Dysexecutive Questionnaire, the Beck Anxiety Inventory, the Beck Depression Inventory, and the National Taiwan University Irritability Scale were used as self-report neuropsychological functioning measures. Furthermore, heart rate variability pre- vs. post-training was used to measure autonomic nervous system functioning. Executive, information processing, verbal memory, emotional neuropsychological functioning, and heart rate variability (HRV) were improved significantly in the HRV-BF group at the posttest whereas the psychoeducation group showed no change. HRV biofeedback is a feasible technique following mild TBI that can improve neuropsychological and autonomic nervous system functioning. HRV-BF may be clinically feasible for the rehabilitation of patients with mTBI.
Topics: Humans; Brain Concussion; Heart Rate; Autonomic Nervous System; Cognition; Biofeedback, Psychology
PubMed: 37335413
DOI: 10.1007/s10484-023-09592-4 -
Sensors (Basel, Switzerland) Mar 2024Wearable technology and neuroimaging equipment using photoplethysmography (PPG) have become increasingly popularized in recent years. Several investigations deriving...
Wearable technology and neuroimaging equipment using photoplethysmography (PPG) have become increasingly popularized in recent years. Several investigations deriving pulse rate variability (PRV) from PPG have demonstrated that a slight bias exists compared to concurrent heart rate variability (HRV) estimates. PPG devices commonly sample at ~20-100 Hz, where the minimum sampling frequency to derive valid PRV metrics is unknown. Further, due to different autonomic innervation, it is unknown if PRV metrics are harmonious between the cerebral and peripheral vasculature. Cardiac activity via electrocardiography (ECG) and PPG were obtained concurrently in 54 participants (29 females) in an upright orthostatic position. PPG data were collected at three anatomical locations: left third phalanx, middle cerebral artery, and posterior cerebral artery using a Finapres NOVA device and transcranial Doppler ultrasound. Data were sampled for five minutes at 1000 Hz and downsampled to frequencies ranging from 20 to 500 Hz. HRV (via ECG) and PRV (via PPG) were quantified and compared at 1000 Hz using Bland-Altman plots and coefficient of variation (CoV). A sampling frequency of ~100-200 Hz was required to produce PRV metrics with a bias of less than 2%, while a sampling rate of ~40-50 Hz elicited a bias smaller than 20%. At 1000 Hz, time- and frequency-domain PRV measures were slightly elevated compared to those derived from HRV (mean bias: ~1-8%). In conjunction with previous reports, PRV and HRV were not surrogate biomarkers due to the different nature of the collected waveforms. Nevertheless, PRV estimates displayed greater validity at a lower sampling rate compared to HRV estimates.
Topics: Female; Humans; Heart Rate; Autonomic Nervous System; Benchmarking; Correlation of Data; Electrocardiography
PubMed: 38610260
DOI: 10.3390/s24072048 -
European Stroke Journal Mar 2024Heart rate turbulence (HRT), an ECG-based marker of autonomic cardiac regulation, has shown high prognostic value in patients with established cardiovascular diseases,... (Observational Study)
Observational Study
BACKGROUND
Heart rate turbulence (HRT), an ECG-based marker of autonomic cardiac regulation, has shown high prognostic value in patients with established cardiovascular diseases, while data in patients with acute ischemic stroke are scarce.
PATIENTS AND METHODS
The HRT parameters turbulence onset and turbulence slope were analyzed using Holter-ECG recordings from patients with acute ischemic stroke, consecutively enrolled in the prospective observational HEBRAS study. HRT was categorized as normal (category 0; both parameters normal), abnormal (category 1; one parameter abnormal), or severely abnormal (category 2; both parameters abnormal). Outcomes of interest were functional outcome according to modified Rankin Scale (mRS) score at 3 months, mortality at 1 year, newly detected atrial fibrillation (AF), and evidence of focal myocardial fibrosis on cardiovascular MRI.
RESULTS
HRT was assessed in 335 patients in sinus rhythm (median age 69 years, 37% female, median NIHSS score 2 on admission), including 262 (78%) with normal HRT, 47 (14%) with abnormal and 26 (8%) with severely abnormal HRT. Compared with normal HRT, severely abnormal HRT was associated with increased disability [higher mRS] at 3 months (adjusted odds ratio [aOR]: 2.9, 95% confidence interval [CI]: 1.3-6.6), new AF (aOR: 3.5, 95% CI: 1.1-10.6), MRI-detected myocardial fibrosis (aOR: 5.8, 95% CI: 1.3-25.9), but not with mortality at 1 year after stroke (aOR: 3.0, 95% CI: 0.7-13.9). Abnormal HRT was not associated with the analyzed outcomes.
CONCLUSIONS
Severely abnormal HRT was associated with increased disability and previously unknown cardiac comorbidities. The potential role of HRT in selecting patients for extended AF monitoring and cardiac imaging should be further investigated.
Topics: Aged; Female; Humans; Male; Atrial Fibrillation; Comorbidity; Fibrosis; Heart Rate; Ischemic Stroke; Prospective Studies
PubMed: 37932964
DOI: 10.1177/23969873231211166