Beat Intervals Research Articles

Dual-Path Beat Tracking: Combining Temporal Convolutional Networks and Transformers in Parallel

The Transformer, a deep learning architecture, has shown exceptional adaptability across fields, including music information retrieval (MIR). Transformers excel at capturing global, long-range dependencies in sequences, which is valuable for tracking rhythmic patterns over time. Temporal Convolutional Networks (TCNs), with their dilated convolutions, are effective at processing local, temporal patterns with reduced complexity. Combining these complementary characteristics, global sequence modeling from Transformers and local temporal detail from TCNs enhances beat tracking while reducing the model’s overall complexity. To capture beat intervals of varying lengths and ensure optimal alignment of beat predictions, the model employs a Dynamic Bayesian Network (DBN), followed by Viterbi decoding for effective post-processing. This system is evaluated across diverse public datasets spanning various music genres and styles, achieving performance on par with current state-of-the-art methods yet with fewer trainable parameters. Additionally, we also explore the interpretability of the model using Grad-CAM to visualize the model’s learned features, offering insights into how the TCN-Transformer hybrid captures rhythmic patterns in the data.

Resonance and beat perception of ballroom dancers: An EEG study.

The ability to synchronize the perceptual and motor systems is important for full motor coordination and the core determinant of motor skill performance. Dance-related training has been found to effectively improve sensorimotor synchronization, however, the underlying characteristics behind these improvements still warrant further exploration. This study was conducted to investigate the behavioral and neuroactivity characteristics of ballroom dancers relative to those of non-dancers. Thirty-two dancers (19.8 ± 1.8 years old) and 31 non-dancers (22.6 ± 3.1 years old) were recruited to perform a finger-tapping task in synchrony with audiovisual beat stimuli at two intervals: 400 and 800 ms, while simultaneously recording EEG data. Behavioral and neural activity data were recorded during the task. The dancers employed a predictive strategy when synchronizing with the beat. EEG recordings revealed stronger brain resonance with external rhythmic stimuli, indicating heightened neural resonance compared to non-dancers (p < 0.05). The task was more challenging with an 800-ms beat interval, as observed through both behavioral metrics and corresponding neural signatures in the EEG data, leading to poorer synchronization performance and necessitating a greater allocation of attentional resources (ps < 0.05). When performing the finger-tapping task involving audiovisual beats, the beat interval was the primary factor influencing movement synchronization, neural activity and attentional resource allocation. Although no significant behavioral differences were observed between dancers and non-dancers, dancers have enhanced neural resonance in response to rhythmic stimuli. Further research using more ecologically valid tasks and stimuli may better capture the full extent of dancers' synchronization abilities.

Enhanced Cardiovascular Assessment in Rats Using a Wireless Data Logger

Study objectives and hypothesis: Cardiovascular assessment in animals can be complicated by signal loss of real-time telemetry. We evaluated the benefits of using a wireless data logger to capture 18 hours of blood pressure (BP) and electrocardiogram (ECG) data. This approach eliminates data loss, simplifies analysis and improves results. Methods: One male Sprague Dawley rat was implanted with a PBTA-L implant (Stellar, TSE Systems) using established procedures to collect BP and ECG. All procedures were approved by the AmplifyBio IACUC. Memory and real-time (RT) BP and ECG were recorded at 500Hz for 18+ hours in the acquisition software (Notocord-hem, Instem) on separate days. ECG RR intervals and BP intervals were compared for memory versus RT recordings. Time-based (RMSSD, SDNN, SDANN) and frequency-based (LF, HF) HRV assessment was performed in 5-minute increments. HRV from ECG vs BP were compared for the memory recording. Data and Results: High quality BP and ECG waveforms were recorded to memory and retrieved into the software with no manual intervention or loss of data. The RT recording included 0.48% signal loss. Interval outliers were removed for HRV assessment using thresholds to limit valid RR/beat intervals. This worked well for BP but was less effective for ECG as there were more erroneous intervals due to movement artifact. Time- and frequency-based HRV parameters were compared for memory vs RT recordings for BP and ECG intervals. HRV from BP showed lower variability for RT vs memory (LF↓24.3%, HR↓6.3%, RMSSD↓0.1%, SDNN↓15.4%, SDANN↓6.1%), while HRV from ECG generally produced higher variability for RT vs memory (LF↑111.8%, HF↑175.1%, RMSSD↑93.9%, SDNN↑16.7%, SDANN↓9.5%). These findings can be explained as follows: BP intervals produced less variability with the RT recording because the long intervals caused by signal loss are distinct and consistently removed by threshold criteria. The lost intervals result in lower HRV. ECG intervals produced more variability with the RT recording because the recordings were 1 week apart, and the later RT recording had more movement artifact on the ECG resulting in inaccurate QRS detection. The erroneous intervals were not as effectively removed by thresholds, resulting in higher HRV. We also compared HRV from the BP and ECG signals in the memory recording. The LF and HF powers were 5.4 and 4.5 times as high respectively for the RR (ECG) vs beat (BP) intervals. The time-based HRV parameters for RMSSD and SDNN were higher by 84% and 14%, while SDANN was very similar with ECG results 2% less than BP results. Conclusions: HRV analysis highlights the benefits of using a wireless data logger to record cardiovascular data. Our assessment demonstrated improvements in the effciency and accuracy of HRV analysis. As a secondary outcome, we demonstrated potential benefits of performing HRV analysis on BP vs ECG signals. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Simulation of heart beat interval series - a neurophysiology based model in comparison with a nonlinear network oscillator model

Simulation of heart beat interval series - a neurophysiology based model in comparison with a nonlinear network oscillator model

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41–78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the “signatures” of the ANS and intrinsic mechanisms and also the anesthesia “signature”. In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

Altered Cardiac Autonomic Regulation in Individuals with Myasthenia Gravis-A Systematic Review and Meta-Analysis.

The aim of this systematic review with meta-analysis was to determine differences in cardiovascular autonomic parameters between patients with myasthenia gravis (MG) and healthy controls (HCs). Two reviewers searched four electronic databases, namely PubMed, Web of Science, EMBASE, and SCOPUS, from database inception to 7 July 2023 for studies investigating cardiovascular autonomic parameters in MG vs. HCs. A random-effects meta-analysis was performed to compute Hedges' g ± 95% confidence intervals (CI). Out of a total of 2200 records, 8 observational studies with a sample size of 301 patients with MG and 454 HCs were included in the systematic review. Meta-analysis revealed lower values of expiration/inspiration ratio (g = -0.45, I2 = 74.7), baroreflex sensitivity (g = -0.56, 95%CI -0.80, -0.33; I2 = 0.3), percentage of adjacent NN intervals differing by more than 50 ms (g = -1.2, I2 = 82.8), square root of the mean of squared differences between successive beat intervals (g = -1.94, I2 = 95.1), mean of the standard deviations of all NN intervals (g = -0.83, 95%CI -1.37, -0.28; I2 = 55.5), and high frequency of HRV during tilt (g = -0.75, 95%CI -0.11, -0.39; I2 = 0). MG patients vs. HCs had higher systolic blood pressure (g = 0.39; I2 = 56.1), sympathovagal balance at rest/during tilt (LF/HF-RRIsupine, g = 0.44; I2 = 0; LF/HF-RRItilt, g = 0.86; I2 = 0; LF/HFtilt, g = 0.40; I2 = 0). As a group, MG patients have altered cardiac autonomic function, including decreased parasympathetic function, lower baroreflex sensitivity, and higher sympathovagal balance at rest and during orthostatic challenges.

The mechano-electric feedback mediates the dual effect of stretch in mouse sinoatrial tissue.

The sinoatrial node (SAN) is the primary heart pacemaker. The automaticity of SAN pacemaker cells is regulated by an integrated coupled-clock system. The beat interval (BI) of SAN, and its primary initiation location (inferior vs. superior) are determined by mutual entrainment among pacemaker cells and interaction with extrinsic effectors, including increased venous return which stretches the SAN. We aim to understand the mechanisms that link stretch to changes in BI and to heterogeneity of BI in the SAN. Isolated SAN tissues of C57BL/6 mice were gradually stretched to different degrees [(low (5-10% lengthening), medium (10-20%), and high (20-40%))] using motor controlled with a custom-made Arduino software. Recordings were acquired 30s following each level of step. In 8/15 tissues, stretch led to a positive chronotropic response, while in 7/15 tissues, a negative chronotropic response was observed. In the positive chronotropic response group, BI was shortened in parallel to shortening of the local Ca2+ release (LCR) period, a readout of the degree of clock coupling. In the negative chronotropic response group, in parallel to a prolongation of BI and LCR period, an unsynchronized firing rate was observed among the cells upon application of stretch. Eliminating the mechano-electrical feedback by addition of blebbistatin disabled the stretch-induced chronotropic effect. Reduction of the sarcoplasmic reticulum Ca2+ levels, which mediates the mechano-electrical feedback, by addition of cyclopiazonic acid disabled the dual effect of stretch on SAN function and BI heterogeneity. Thus, the mechano-electric feedback mediates the dual effect of stretch in mouse SAN tissue.

Abstract P2002: Variability In The Relationship Between Heart Rate And Automatic Breathing Rate Throughout The Mouse Lifespan

Background: Autonomic neural surveillance maintains a symphonic relationship between heart and breathing rhythms. We have established how heart beat interval variability changes across mouse lifespan (6 months - 30 months) in the presence and absence of double autonomic blockade (Baltimore Longitudinal Study on Aging in Mice, BLSAM; Geroscience 2022, PMID: 35759167). Objective: To determine how the automatic breathing rate (BR) changes with age in the same BLSAM cohort, and whether the BR and Heart Rate (HR) track each other in the presence and absence of double autonomic blockade across the lifespan of individual mice. Methods: The BLSAM cohort consists of 58 mice in which HR and BR were assessed from the EKG (under light anesthesia) at 3-month intervals, beginning at 6 months of age until the end of life (30 months of age). EKG was recorded in the presence and absence double autonomic blockade (i.p injection of atropine, 0.5mg/kg, and propranolol, 1mg/kg). Data were analyzed via a mixed ANOVA. Results: The BR remained stable until approximately 21 months of age, and then became sharply reduced between 21 and 30 months of age (Fig. A). The pattern of HR change over the adult life span was similar to that of BR (Fig. B). Both HR and BR were significantly (p&lt;0.05) reduced in the presence of double autonomic blockade (arrows in figs). The relative magnitude of BR reduction beyond 21 months of age was substantially greater than the relative reduction in HR over this age range, resulting in a marked increase in HR/BR Ratio (Fig. C), which was also significantly impacted by autonomic function. Conclusion: Thus, beginning at approximately the 70% of maximum mice lifespan, the harmony between heart rhythm and breathing rhythm gradually deteriorates.

Patient-specific iPSC-derived cardiomyocytes reveal variable phenotypic severity of Brugada syndrome

Brugada syndrome (BrS) is a cardiac channelopathy that can result in sudden cardiac death (SCD). SCN5A is the most frequent gene linked to BrS, but the genotype-phenotype correlations are not completely matched. Clinical phenotypes of a particular SCN5A variant may range from asymptomatic to SCD. Here, we used comparison of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) derived from a SCN5A mutation-positive (D356Y) BrS family with severely affected proband, asymptomatic mutation carriers (AMCs) and healthy controls to investigate this variation. 26 iPSC lines were generated from skin fibroblasts using nonintegrated Sendai virus. The generated iPSCs were differentiated into cardiomyocytes using a monolayer-based differentiation protocol. D356Y iPSC-CMs exhibited increased beat interval variability, slower depolarization, cardiac arrhythmias, defects of Na+ channel function and irregular Ca2+ signaling, when compared to controls. Importantly, the phenotype severity observed in AMC iPSC-CMs was milder than that of proband iPSC-CMs, an observation exacerbated by flecainide. Interestingly, the iPSC-CMs of the proband exhibited markedly decreased Ca2+ currents in comparison with control and AMC iPSC-CMs. CRISPR/Cas9-mediated genome editing to correct D356Y in proband iPSC-CMs effectively rescued the arrhythmic phenotype and restored Na+ and Ca2+ currents. Moreover, drug screening using established BrS iPSC-CM models demonstrated that quinidine and sotalol possessed antiarrhythmic effects in an individual-dependent manner. Clinically, venous and oral administration of calcium partially reduced the malignant arrhythmic events of the proband in mid-term follow-up. Patient-specific and genome-edited iPSC-CMs can recapitulate the varying phenotypic severity of BrS. Our findings suggest that preservation of the Ca2+ currents might be a compensatory mechanism to resist arrhythmogenesis in BrS AMCs. National Key R&D Program of China (2017YFA0103700), National Natural Science Foundation of China (81922006, 81870175), Natural Science Foundation of Zhejiang Province (LD21H020001, LR15H020001), National Natural Science Foundation of China (81970269), Key Research and Development Program of Zhejiang Province (2019C03022) and Natural Science Foundation of Zhejiang Province (LY16H020002).

Ca2+-Driven Selectivity of the Effect of the Cardiotonic Steroid Marinobufagenin on Rabbit Sinoatrial Node Function.

The synergy between Na+-K+ pumps, Na+-Ca2+ exchangers, membrane currents and the sarcoplasmic reticulum (SR) generates the coupled-clock system, which governs the spontaneous electrical activity of heart sinoatrial node cells (SANCs). Ca2+ mediates the degree of clock coupling via local Ca2+ release (LCR) from the SR and activation of cAMP/PKA signaling. Marinobufagenin (MBG) is a natural Na+-K+ pump inhibitor whose effect on SANCs has not been measured before. The following two hypotheses were tested to determine if and how MBG mediates between the Na+-K+ pump and spontaneous SAN activity: (i) MBG has a distinct effect on beat interval (BI) due to variable effects on LCR characteristics, and (ii) Ca2+ is an important mediator between MBG and SANC activity. Ca2+ transients were measured by confocal microscopy during application of increasing concentrations of MBG. To further support the hypothesis that Ca2+ mediates between MBG and SANC activity, Ca2+ was chelated by the addition of BAPTA. Dose response tests found that 100 nM MBG led to no change in BI in 6 SANCs (no BI change group), and to BI prolongation in 10 SANCs (BI change group). At the same concentration, the LCR period was prolonged in both groups, but more significantly in the BI change group. BAPTA-AM prolonged the BI in 12 SANCs. In the presence of BAPTA, 100 nM MBG had no effect on SANC BI or on the LCR period. In conclusion, the MBG effects on SANC function are mediated by the coupled clock system, and Ca2+ is an important regulator of these effects.

An IOT framework for detecting cardiac arrhythmias in real-time using deep learning resnet model

An IOT framework for detecting cardiac arrhythmias in real-time using deep learning resnet model

Multi-wavelength SPAD photoplethysmography for cardio-respiratory monitoring

There is a growing interest in photoplethysmography (PPG) for the continuous monitoring of cardio-respiratory signals by portable instrumentation aimed at the early diagnosis of cardiovascular diseases. In this context, it is conceivable that PPG sensors working at different wavelengths simultaneously can optimize the identification of apneas and the quantification of the associated heart-rate changes or other parameters that depend on the PPG shape (e.g., systematic vascular resistance and pressure), when evaluating the severity of breathing disorders during sleep and in general for health monitoring. Therefore, the objective of this work is to present a novel pulse oximeter that provides synchronous data logging related to three light wavelengths (green, red, and infrared) in transmission mode to optimize both heart rate measurements and a reliable and continuous assessment of oxygen saturation. The transmission mode is considered more robust over motion artifacts than reflection mode, but current pulse oximeters cannot employ green light in transmission mode due to the high absorbance of body tissues at this wavelength. For this reason, our device is based on a Single-Photon Avalanche Diode (SPAD) with very short deadtime (less than 1 ns) to have, at the same time, the single photon sensitivity and high-count rate that allows acquiring all the wavelengths of interest on the same site and in transmission mode. Previous studies have shown that SPAD cameras can be used for measuring the heart rate through remote PPG, but oxygen saturation and heart-rate measures through contact SPAD-based PPG sensors have never been addressed so far. The results of the preliminary validation on six healthy volunteers reflect the expected physiological phenomena, providing rms errors in the Inter Beat Interval estimation smaller than 70 ms (with green light) and a maximum error in the oxygen saturation smaller than 1% during the apneas. Our prototype demonstrates the reliability of SPAD-based devices for continuous long-term monitoring of cardio-respiratory variables as an alternative to photodiodes especially when minimal area and optical power are required.

Heart rate variability during social interaction: Effects of valence and emotion regulation

Conceptual models of psychosocial influences on short-term changes (i.e., reactivity) in vagally-mediated heart rate variability (vmHRV) emphasize self-regulatory effort and social threat versus comfort. However, these two general perspectives have been tested separately in nearly all cases, limiting conclusions about the relative importance or possible interactive effects of effortful self-regulation and social stress. The present study compared effects of effort to regulate emotional expression and social stress versus safety on vmHRV reactivity during an interpersonal interaction, in a 2 (self-regulate emotion vs. express emotion freely) × 3 (positive vs. neutral vs. negative interaction valence) × 2 (male vs. female) between-subjects randomized factorial design. A sample of 180 undergraduates (90 women; 69 % White) discussed a current events topic (i.e., human-caused climate change) with a prerecorded partner, presented as a live interaction over a computer. Self-reports of affective responses, self-regulation effort, and appraisals of the partner's behavior, as well as observer ratings of participants' behavior during the interaction, supported the effectiveness of self-regulation and interaction valence manipulations, although the former manipulation may have been somewhat weaker than the latter. Primary analyses of high-frequency heart rate variability (HF-HRV) and root mean square of successive differences (RMSSD) in heart beat intervals recorded at baseline and during the interaction revealed larger decreases in vmHRV during negative than neutral or positive interactions, but no effects of self-regulation instructions. Overall, results indicated more robust effects of social stress on vmHRV reactivity, relative to effects of self-regulatory effort.

Quasinormal modes and echo effect of a cylindrical anti–de Sitter black hole spacetime with a thin shell

This paper investigates the quasinormal mode (QNM) vibrations of a rotating cylindrical black hole (or black string) spacetime that is surrounded by a thin shell rotating synchronously with the black string's axis. The existence of the thin shell leads to a piecewise metric of the black hole spacetime beyond the horizon, which is divided into two stationary spacetime parts by the radius of the thin shell. As a result, the potential function $V(r)$ of the QNM equation is also discontinuous. To solve the QNM equation with the discontinuous potential function, we propose two methods, the matrix method and the generalized Horowitz-Hubeny method. We find that the influence of the thin shell can reduce the QNM frequency of the black string while alleviating their amplitude decay rate. Our suggested method can be easily applied to other QNM calculations of black hole spacetime with discontinuous potential function, thus facilitating investigations into more intricate and realistic black hole spacetimes, such as those with accretion disks. Additionally, the finite difference method is employed to investigate the spacetime too. This analysis discloses a substantial gap in the potential function when the thin shell's mass and charge achieve sufficiently high values, resulting in the outer spacetime nearing gravitational collapse and extreme black hole scenarios. Within this gap, the QNM wave displays oscillations, producing an echo effect. Moreover, it is established that the closeness of the spacetime to the collapse threshold and charge extremality have positive correlation with the beat interval of this echo.

Diagnostic accuracy of smart gadgets/wearable devices in detecting atrial fibrillation in primary prevention: a meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Atrial fibrillation (AF) is the most common sustained arrhythmia and an important risk factor for stroke and heart. Recent technology advances have allowed for heart rhythm monitoring using smart gadgets/wearable devices which can be used for early AF diagnosis. Purpose We performed a systemic review and meta-analysis to assess the accuracy of AF diagnosis by smart gadgets/wearable devices in primary prevention. Methods We systematically searched Medline, Embase and Cochrane electronic databases up to September 22th, 2022 for observational studies of the diagnostic accuracy of smartphone application, wrist-worn wearables and external devices in detecting AF in primary prevention. Studies with 12-lead ECG or single-lead ECG interpreted by a cardiologist as gold standard were included. We calculated the area under the curve (AUC) of the summary receiver operating characteristic curves (SROC) and pooled sensitivities and specificities. Results A total of 28 studies were included enrolling 13463 patients, 57%(95% CI: 55-59%) male with average age of 65.3years (95% CI: 60.1 – 70.4). The pooled prevalence of AF was found to be 13% (95% CI 10 – 15%). In the overall analysis of all devices, the AUC was 0.99 (95% CI: 0.97-0.99)(Figure 1), the sensitivity 93%(95% CI: 89 – 95%) and the specificity 97%(95% CI: 95 – 98%) (Figure 2). Wrist-worn wearables had AUC of 0.97 (95% CI: 0.94-0.99), the sensitivity 83%(95% CI: 52 – 96%) and the specificity 98%(95% CI: 87 – 100%). Smartphone applications had AUC of 0.97 (95% CI: 0.96-0.98), the sensitivity 92%(95% CI: 77 – 98%) and the specificity 95%(95% CI: 91 – 97%). External devices had AUC of 0.99 (95% CI: 0.97-0.99), the sensitivity 94%(95% CI: 91 – 96%) and the specificity 97%(95% CI: 95 – 98%). Single-lead ECG had AUC of 0.99 (95% CI: 0.97- 0.99), the sensitivity 93%(95% CI: 88 – 96%) and the specificity 91%(95% CI: 78 – 97%). photoplethysmography pulse waveform technology (PPG) had AUC of 0.97 (95% CI: 0.96-0.98), the sensitivity 91%(95% CI: 78 – 97%) and the specificity 95%(95% CI: 91 – 97%). Pulse beat interval technology had AUC of 0.99 (95% CI: 0.98-0.99), the sensitivity 95%(95% CI: 90 – 98%) and the specificity 96%(95% CI: 93 – 98%) Conclusions Smartphone application, wrist-worn devices and external devices have excellent diagnostic accuracy in atrial fibrillation diagnosis in primary prevention.

Resting-state heart rate variability, level of stress and resilience in internet gaming disorder and alcohol use disorder.

Stress and resilience are involved in the pathophysiology of addictive disorders, and heart rate variability (HRV) is an index of an individual's global capability to regulate psychological responses. In this study, we aimed to identify transdiagnostic and disorder-specific markers in people with addictive disorders by analyzing resting-state HRV and associations with the levels of stress and resilience. We compared relevant data between patients with internet gaming disorder (IGD) and/or alcohol use disorder (AUD) and healthy controls (HCs). In all, 163 adults aged 18-35years (53 with IGD, 49 with AUD, 61HCs) participated. The levels of stress and resilience were measured using the Psychosocial Wellbeing Index and the Connor-Davidson Resilience Scale, respectively. The HRV was obtained from each participant during a 5min resting-state. The IGD and AUD patients exhibited increased levels of stress and decreased resilience compared to the HCs. Patients with either addictive disorder exhibited a lower standard deviation of the normal-to-normal beat interval (SDNN) index [SDNNi] compared to HCs even after adjusting for clinical variables such as depression, anxiety, and impulsivity. In multiple comparison tests among the three groups, the AUD group had lower HRV than HCs, but no differences were observed among the groups after adjusting for the clinical variables. The HRV indices were correlated with the levels of stress, resilience, and disease severity. In conclusion, IGD and AUD patients exhibit lower HRV as indicated by the SDNNi compared to HCs, revealing their vulnerability to stress as well as a common transdiagnostic marker of addiction.

Skin sympathetic nerve activity as a potential biomarker for overactive bladder.

Abnormalities in autonomic function are associated with an overactive bladder (OAB). Heart rate variability is generally used as the sole assessment of autonomic activity; however, we utilized neuECG, a novel method of recording skin electrical signals, to assess autonomic nervous function in healthy controls and patients with OAB before and after treatment. The prospective sample included 52 participants: 23 patients newly diagnosed with OAB and 29 controls. Autonomic function was assessed in all participants in the morning using neuECG, which analyzed the average skin sympathetic nerve activity (aSKNA) and electrocardiogram simultaneously. All patients with OAB were administered antimuscarinics; urodynamic parameters were assessed before treatments; autonomic and bladder functions using validated questionnaires for OAB symptoms were evaluated before and after OAB treatment. Patients with OAB had significantly higher baseline aSKNA (p = 0.003), lower standard deviation of the normal-to-normal beat intervals, lower root mean square of the successive differences, lower high-frequency, and higher low-frequency than did controls. Baseline aSKNA had the highest value in predicting OAB (AUROC = 0.783, p < 0.001). The aSKNA was negatively correlated with first desire and normal desire in urodynamic studies (both p = 0.025) and was significantly decreased after treatment at rest, stress, and recovery phases, as compared to those before treatment (p = 0.046, 0.017, and 0.017, respectively). Sympathetic activity increased significantly in patients with OAB compared to that in healthy controls, and decreased significantly post-treatment. Higher aSKNA is associated with decreased bladder volume at which voiding is desired. SKNA may be a potential biomarker for diagnosing OAB.

Synergy between Membrane Currents Prevents Severe Bradycardia in Mouse Sinoatrial Node Tissue

Bradycardia is initiated by the sinoatrial node (SAN), which is regulated by a coupled-clock system. Due to the clock coupling, reduction in the 'funny' current (If), which affects SAN automaticity, can be compensated, thus preventing severe bradycardia. We hypothesize that this fail-safe system is an inherent feature of SAN pacemaker cells and is driven by synergy between If and other ion channels. This work aimed to characterize the connection between membrane currents and their underlying mechanisms in SAN cells. SAN tissues were isolated from C57BL mice and Ca2+ signaling was measured in pacemaker cells within them. A computational model of SAN cells was used to understand the interactions between cell components. Beat interval (BI) was prolonged by 54 ± 18% (N = 16) and 30 ± 9% (N = 21) in response to If blockade, by ivabradine, or sodium current (INa) blockade, by tetrodotoxin, respectively. Combined drug application had a synergistic effect, manifested by a BI prolonged by 143 ± 25% (N = 18). A prolongation in the local Ca2+ release period, which reports on the level of crosstalk within the coupled-clock system, was measured and correlated with the prolongation in BI. The computational model predicted that INa increases in response to If blockade and that this connection is mediated by changes in T and L-type Ca2+ channels.

Construction noise effects on human health: Evidence from physiological measures

Noise pollution caused by construction activities in urban areas is a serious problem. Construction noise can affect human health and well-being negatively. This study utilised physiological data including heart rate parameters, Respiratory Rate (RR), and Electrodermal Activity (EDA) to explore the effects of construction noise on human health. Different construction noise types (saw, jackhammer, pile driver, bulldozer), levels (55, 65, 75 and 85 dBA), and exposure durations (30, 60, 120, and 180 s) were examined in a lab-based experiment. The noise conditions were reproduced for twenty-three participants through speakers. To statistically analyse the changes in the physiological measures caused by the examined noise conditions, mixed models were utilised. The results revealed significant effects of the construction noise types on heart rate parameters including heart rate (HR), high frequency (HF), and standard deviation of the normal beat intervals (SDNN). In addition, the results showed that exposure duration significantly affects physiological responses, including RR and SDNN. This study will help to identify the non-auditory health effects of exposure to construction noise. The outputs of this research will provide critical inputs to revisit the current environmental noise regulations to protect the community against the negative health effects of construction noise more efficiently.

Individuals with a previous symptomatic COVID-19 infection have altered heart rate and blood pressure variability during acute exercise.

Introduction: As the number of COVID-19 cases begin to diminish it is important to turn our attention to any long-term issues that may be associated with a prior infection. Cardiovascular defects have been noted following prior SARS-CoV-2 infections. However, less is known about how a previous infection alters the cardiovascular response to exercise. Further, differences may exist during exercise between previously SARS-CoV-2 positive individuals who had symptoms (symptomatic) relative to those who did not have symptoms (asymptomatic). We hypothesized that previously symptomatic (S) COVID-19 recoveries have an altered cardiovascular response to acute exercise relative to both control (CON; never infected), and previously COVID-19 positive asymptomatic (AS) individuals. Methods: Twenty-seven subjects (CON = 9; AS = 9; S = 9) underwent 30min of submaximal treadmill exercise. During exercise, blood pressure was recorded on the brachial artery every 5min and 3-lead electrocardiography was measured continuously. Indirect indicators of autonomic nervous system health: heart rate variability and blood pressure variability were measured during each session. Baseline mean arterial pressure (MAP) was taken prior to exercise in seated, standing and supine positions. Results: Blood pressure was similar (p > 0.05) amongst all three groups. There were no differences between average heart rate (HR; CON = 104 ± 4 BPM vs AS = 118 ± 6 BPM vs. S = 112 ± 3 BPM), mean arterial pressure (MAP; CON = 108 ± 4mmHg vs. AS = 105 ± 13mmHg vs. S = 108 ± 7mmHg) or oxygen consumption (VO2) between groups during a bout of exercise. However, the standard deviation of the inter beat intervals of normal sinus beats, a measure of heart rate variability (HRV) (CON = 138 ± 2.8m vs. AS = 156 ± 6m vs. S = 77.7 ± 11m; p < 0.05) and blood pressure variability (BPV; CON = 5.18 ± 1.1 vs. AS = 12.1 ± 0.88mmHg vs. S = 10.2 ± 10.7mmHg; p < 0.05) were different in our S group. Further, when HRV was assessed in the frequency domain the very low frequency was different during exercise in the S group relative to the other groups. Discussion: Collectively, these data suggest that a previous symptomatic SARS-CoV-2 infection may alter heart rate and blood pressure regulation during exercise.