Search

Acute ketone monoester (KE) supplementation can alter exercise responses, but the performance effect is unclear. The limited and equivocal data to date are likely related to factors including the KE dose, test conditions, and caliber of athletes studied. We tested the hypothesis that mean power output during a 20-min cycling time trial (TT) would be different after KE ingestion compared to a placebo (PL). A sample size of 22 was estimated to provide 80% power to detect an effect size dz of 0.63 at an alpha level of.05 with a two-tailed paired t test. This determination considered 2.0% as the minimal important difference in performance. Twenty-three trained cyclists (N = 23; peak oxygen uptake: 65 ± 12 ml·kg−1 min−1; M ± SD), who were regularly cycling >5 hr/week, completed a familiarization trial followed by two experimental trials. Participants self-selected and replicated their diet and exercise for ∼24 hr before each trial. Participants ingested either 0.35 g/kg body mass of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate KE or a flavor-matched PL 30 min before exercise in a randomized, triple-blind, crossover manner. Exercise involved a 15-min warm-up followed by the 20-min TT on a cycle ergometer. The only feedback provided was time elapsed. Preexercise venous [β-hydroxybutyrate] was higher after KE versus PL (2.0 ± 0.6 vs. 0.2 ± 0.1 mM, p <.0001). Mean TT power output was 2.4% (0.6% to 4.1%; mean [95% confidence interval]) lower after KE versus PL (255 ± 54 vs. 261 ± 54 W, p <.01; dz = 0.60). The mechanistic basis for the impaired TT performance after KE ingestion under the present study conditions remains to be determined. [ABSTRACT FROM AUTHOR]

Transcranial magnetic stimulation (TMS) is pivotal in the field of major depressive disorder treatment. Due to its unsatisfied response rate, an increasing number of researchers have turned their attention towards optimizing TMS site localization. Since the influence of TMS in reducing heart rate (HR) offers insights into its regulatory impact on the autonomic nervous system, a novel approach, called neurocardiac‐guided TMS (NCG–TMS), has been proposed to pinpoint the brain region eliciting the maximal individual reduction in HR as a personalized optimal stimulation target. The present study intends to systematically explore the effects of stimulation frequency, left and right hemispheres, stimulation positions, and individual differences on HR modulation using the NCG–TMS method. In experiment 1, low‐frequency TMS was administered to 30 subjects, and it was found that low‐frequency NCG–TMS significantly downregulated HR, with more significant effects in the right hemisphere than in the left hemisphere and the prefrontal cortex than in other brain areas. In experiment 2, high‐frequency NCG–TMS stimulation was administered to 30 subjects, showing that high‐frequency NCG–TMS also downregulated HR and had the greatest modulatory effect in the right prefrontal region. Simultaneously, both experiments revealed sizeable individual variability in the optimal stimulation site, which in turn validated the feasibility of the NCG–TMS method. In conclusion, the present experiments independently replicated the effect of NCG–TMS, provided an effect of high‐/low‐frequency TMS stimulation to downregulate HR, and identified a right lateralization of the HR modulation effect. [ABSTRACT FROM AUTHOR]

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain‐imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans. [ABSTRACT FROM AUTHOR]

Introduction Methods and Results Conclusions Closed Loop Stimulation (CLS) is a rate‐responsive algorithm that adjusts heart rate (HR) based on changes in intracardiac impedance measured from the right ventricle lead. However, the use of CLS in conduction system pacing has not been investigated. In this retrospective study, we aimed to assess whether CLS with left bundle branch area pacing (LBBAP) can generate an appropriate distribution of HR in daily life.Our study included 24 patients with CLS pacing and chronotropic incompetence, comparing them with 19 patients receiving DDD pacing, all with LBBAP. Cumulative HR distribution charts were generated using data from a single device interrogation with a minimum follow‐up period of 30 days. In DDD‐CLS mode, there was a higher percentage of atrial pacing compared to DDD mode (median 58% [interquartile range 29%‐83%] vs. 13% [10%‐26%], p = .001), and CLS‐paced beats were present across all frequency bins. The distribution of beats between the groups was similar (p = .643), resulting in comparable mean HR (72 bpm [70‐77] vs. 73 bpm [65‐75], p = .615).In the context of LBBAP, CLS effectively modulates pacing rates over a wide frequency range. This lead position does not adversely affect the rate‐responsive performance of the algorithm. [ABSTRACT FROM AUTHOR]

The ability to flexibly transition between defensive states is crucial for adaptive responding in life‐threatening situations. Potentially threatening situations typically induce a sustained feeling of apprehension in association with hypervigilance, while acute threat is usually characterized by an intense and transient response to cope with the imminent danger. While potential and acute threat states have traditionally been viewed as mutually exclusive, this distinction is being challenged by a growing body of evidence suggesting a more complex interplay during simultaneous activation of these states. However, the interaction between potential and acute threat on a psychophysiological level remains elusive. To fill this gap, 94 healthy individuals participated in one of two contextual fear‐conditioning paradigms. In both paradigms, a differential fear‐learning phase was conducted, followed by a test phase in which the conditioned stimuli were presented in front of either conditioned or inherently aversive contextual images compared to neutral contexts. To capture defensive responses, we recorded subjective (threat and expectancy ratings) and physiological (electrodermal and cardiovascular) activity to the conditioned stimuli as a function of contextual threat. Besides indices of successful fear conditioning, our results revealed stronger threat and unconditioned stimulus expectancy ratings, cardiac deceleration, and skin conductance responses for threat and safety cues presented in inherently aversive compared to neutral contexts. Conditioned contexts had less impact on physiological responses to threat and safety cues than inherently aversive contexts. These findings provide new insights into the additive nature of defensive responses to fear cues and situations of contextual threat. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. Accurate detection of the timing and possibility of AF termination is vital for optimizing rhythm and rate control strategies. The present study evaluated whether the ventricular response (VR) in AF offers a distinctive electrocardiographic indicator for predicting AF termination. Methods: Patients experiencing sustained paroxysmal AF for more than 3 h were observed using 24‐h ambulatory Holter monitoring. VR within 5 min before AF termination (VR 0–5 min, BAFT) was compared with VR observed during the 60th to 65th min (VR 60–65 min, BAFT) and the 120th to 125th min (VR 120–125 min, BAFT) before AF termination. Maximum and minimum VRs were calculated on the basis of the average of the highest and lowest VRs across 10 consecutive heartbeats. Results: Data from 37 episodes of paroxysmal AF revealed that the minimum VR0–5 min, BAFT (64 ± 20 bpm) was significantly faster than both the minimum VR120–125 min, BAFT (56 ± 15 bpm) and the minimum VR60–65 min, BAFT (57 ± 16 bpm, p <.05). Similarly, the maximum VR0–5 min, BAFT (158 ± 49 bpm) was significantly faster than the maximum VR120–125 min, BAFT (148 ± 45 bpm, p <.05). In the daytime, the minimum VR0–5 min, BAFT (66 ± 20 bpm) was significantly faster than both the minimum VR60–65 min, BAFT (58 ± 17 bpm) and minimum VR120–125 min, BAFT (57 ± 15 bpm, p <.05). However, the mean and maximum VR0–5 min, BAFT in the daytime were similar to the mean and maximum VR120–125 min in the daytime, respectively. At night, the minimum, mean, and maximum VR0–5 min, BAFT were similar to the minimum, mean, and maximum VR120–125 min, respectively. Conclusions: Elevated VR rates during AF episodes may be predictors for the termination of AF, especially during the daytime and in patients with nondilated left atria. These findings may guide the development of clinical approaches to rhythm control in AF. [ABSTRACT FROM AUTHOR]

July 2023 has been confirmed as Earth's hottest month on record, and it was characterized by extraordinary heatwaves across southern Europe. Field data collected under real heatwave periods could add important evidence to understand human adaptability to extreme heat. However, field studies on human physiological responses to heatwave periods remain limited. We performed field thermo‐physiological measurements in a healthy 37‐years male undergoing resting and physical activity in an outdoor environment in the capital of Sicily, Palermo, during (July 21; highest level of local heat‐health alert) and following (August 10; lowest level of local heat‐health alert) the peak of Sicily's July 2023 heatwave. Results indicated that ~40 min of outdoor walking and light running in 33.8°C Wet Bulb Globe Temperature (WBGT) conditions (July 21) resulted in significant physiological stress (i.e., peak heart rate: 209 bpm; core temperature: 39.13°C; mean skin temperature: 37.2°C; whole‐body sweat losses: 1.7 kg). Importantly, significant physiological stress was also observed during less severe heat conditions (August 10; WBGT: 29.1°C; peak heart rate: 190 bpm; core temperature: 38.48°C; whole‐body sweat losses: 2 kg). These observations highlight the physiological strain that current heatwave conditions pose on healthy young individuals. This ecologically‐valid empirical evidence could inform more accurate heat‐health planning. [ABSTRACT FROM AUTHOR]

We assessed the feasibility of implementing a virtually guided Neuromuscular Electrical Stimulation (NMES) protocol over the tibialis anterior (TA) muscle while collecting heart rate (HR), Numeric Pain Rating Scale (NPRS), and quality of contraction (QoC) data. We investigated if HR, NPRS, and QoC differ ON and OFF the TA motor point and explored potential relationships between heart rate variability (HRV) and the NPRS. Twelve healthy adults participated in this cross-sectional study. Three NMES trials were delivered ON and OFF the TA motor point. HR, QoC, and NPRS data were collected. There was no significant difference in HRV ON and OFF the motor point (p > 0.05). The NPRS was significantly greater OFF the motor point (p < 0.05). The QoC was significantly different between motor point configurations (p < 0.05). There was no correlation between the NPRS and HRV (p > 0.05, r = −0.129). We recommend non-electrical methods of measuring muscle activity for future studies. The NPRS and QoC can be administered virtually. Time-domain HRV measures could increase the validity of the protocol. The variables should be explored further virtually to enhance the protocol before eventual ICU studies. [ABSTRACT FROM AUTHOR]

Vital sign monitoring is dominated by precise but costly contact-based sensors. Contactless devices such as radars provide a promising alternative. In this article, the effects of lateral radar positions on breathing and heartbeat extraction are evaluated based on a sleep study. A lateral radar position is a radar placement from which multiple human body zones are mapped onto different radar range sections. These body zones can be used to extract breathing and heartbeat motions independently from one another via these different range sections. Radars were positioned above the bed as a conventional approach and on a bedside table as well as at the foot end of the bed as lateral positions. These positions were evaluated based on six nights of sleep collected from healthy volunteers with polysomnography (PSG) as a reference system. For breathing extraction, comparable results were observed for all three radar positions. For heartbeat extraction, a higher level of agreement between the radar foot end position and the PSG was found. An example of the distinction between thoracic and abdominal breathing using a lateral radar position is shown. Lateral radar positions could lead to a more detailed analysis of movements along the body, with the potential for diagnostic applications. [ABSTRACT FROM AUTHOR]

Aim: Circular training is thought to have a motivating feature by distracting the individual from routine and boring training practices with different exercise methods. In this context, the aim of this study was to investigate the effect of different rest periods applied during circular training on blood lactate levels. Method: The pretest-posttest model was used in the study. The sample of the study consisted of 24 (Xage =20,00±1,79; Xheight =171,75 ± 6,22; Xweight =75,01± 6,39) volunteer male basketball athletes. Lactate measurements were taken before, during and after circular training with different rest periods. The data was analyzed in the SPSS 24.0 package program, with a 95% confidence interval and a 0.05 significance level, and normality analysis was performed with the Shapiro-Wilk test. Since the data were not normally distributed, nonparametric tests were applied. The change in heart rate averages and lactate levels of the research group according to resting times were evaluated by Wilcoxon Test. Results: In general, it was determined that the circular training program with different rest intervals caused significant differences in the measurement parameters (Heart Rate, and Lactate) of the participants (p<0.05). It was observed that the average heart rate and lactate values reached during training decreased as the rest period of the research group increased. On the other hand, the effects of long-term circular training programs with different rest intervals on aerobicanaerobic energy metabolism will contribute to the literature. [ABSTRACT FROM AUTHOR]

Seasonal acclimatization is known to result in adaptations that can improve heat tolerance. Staff who operate on burn injuries are exposed to thermally stressful conditions and seasonal acclimatization may improve their thermoeffector responses during surgery. Therefore, the aim of this study was to assess the physiological and perceptual responses of staff who operate on burn injuries during summer and winter, to determine whether they become acclimatized to the heated operating theater. Eight staff members had physiological and perceptual responses compared during burn surgeries conducted in thermoneutral (CON: 24.1 ± 1.2°C, 45 ± 7% relative humidity [RH]) and heated (HOT: 31.3 ± 1.6°C, 44 ± 7% RH) operating theaters, in summer and winter. Physiological parameters that were assessed included core temperature, heart rate, total sweat loss, sweat rate, and urinary specific gravity. Perceptual responses included ratings of thermal sensation and comfort. In summer, CON compared to winter CON, baseline (85 ± 15 bpm VS 94 ± 18 bpm), mean (84 ± 16 bpm VS 93 ± 18 bpm), and peak HR (94 ± 17 bpm VS 105 ± 19 bpm) were lower (p < 0.05), whereas core temperature was not different between seasons in either condition (p > 0.05). In HOT, ratings of discomfort were higher in summer (15 ± 3) than winter (13 ± 3; p > 0.05), but ratings of thermal sensation and sweat rate were similar between seasons (p > 0.05). The surgical team in burns in Western Australia can obtain some of the physiological adaptations that result from seasonal acclimatization, but not all. That is most likely due to a lower than required amount of outdoor heat exposure in summer, to induce all physiological and perceptual adaptations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chorioamnionitis and early onset sepsis (EOS) in very low birth weight (VLBW,< 1500 g) infants may cause a systemic inflammatory response reflected in patterns of heart rate (HR) and oxygenation measured by pulse oximetry (SpO2). Identification of these patterns might inform decisions about duration of antibiotic therapy after birth. OBJECTIVE: Compare early HR and SpO2 patterns in VLBW infants with or without early onset sepsis (EOS) or histologic chorioamnionitis (HC). STUDY DESIGN: Retrospective study of placental pathology and HR and SpO2 in the first 72 h from birth in relation to EOS status for inborn VLBW NICU patients 2012–2019. RESULT: Among 362 VLBW infants with HR and SpO2 data available, clinical, or culture-positive EOS occurred in 91/362 (25%) and HC in 81/355 (22%). In univariate analysis, EOS was associated with higher mean HR, lower mean SpO2, and less negative skewness of HR in the first 3 days after birth. HC was associated with higher standard deviation and skewness of HR but no difference in SpO2. In multivariable modeling, significant risk factors for EOS were mean HR, gestational age, HC, mean SpO2, and skewness of SpO2. CONCLUSION: HR and SpO2 patterns differ shortly after birth in VLBW infants exposed to HC or with EOS, likely reflecting a systemic inflammatory response. [ABSTRACT FROM AUTHOR]

BACKGROUND: Excess heat accrual is perhaps the body's most dangerous exercise-induced stressor. While palm cooling uses conduction to reduce body temperatures, to date the volume of heat transferred by this treatment resulting from exercise is unknown. OBJECTIVE: Asses continuous palm cooling's impact on heat transfer and physiology. METHODS: Thirty-one subjects did two workouts; one with, and one without, palm cooling. Workouts entailed consecutive stages of submaximal pedaling against prescribed workloads. Gloves were worn at workouts; for palm cooling 10.6∘C gel packs were inserted into gloves at the workout's start and conclusion. Heart rate, auditory canal and palm skin temperatures, and heat transfer across the palm were collected. Data were obtained pre-exercise, at the end of a warm-up, and at multiple times during the 25 minutes of pedaling and 30 minutes of recovery. RESULTS: Auditory canal temperatures had a significant treatment effect (palm cooling < non-palm cooling). Palm skin temperature had an interaction, with higher non-palm cooling values at multiple times. Conversely, heat transfer also produced an interaction, but palm cooling had significantly higher values at multiple times. Heat transfer was 32% higher for the palm cooling workout. CONCLUSIONS: Continuous palm cooling produced significantly higher heat transfer from submaximal exercise. [ABSTRACT FROM AUTHOR]

Dysregulation of the autonomic nervous system (ANS) is commonly observed in various mental disorders, particularly when individuals engage in prolonged cognitive‐emotional tasks that require ANS adjustment to workload. Although the understanding of the temporal dynamics of sympathetic and parasympathetic tones in obsessive‐compulsive disorder (OCD) is limited, analyzing ANS reactions to cognitive‐emotional workload could provide valuable insights into one of the underlying causes of OCD. This study investigated the temporal dynamics of heart rate (HR) and pupil area (PA) while participants with OCD and healthy volunteers solved antisaccade tasks, with affective pictures serving as central fixation stimuli. The data of 31 individuals with OCD and 30 healthy volunteers were included in the study, comprising three separate blocks, each lasting approximately 8 min. The results revealed an increase in sympathetic tone in the OCD group, with the most noticeable rise occurring during the middle part of each block, particularly during the presentation of negative stimuli. Healthy volunteers demonstrated adaptive temporal dynamics of HR and PA from the first block to the last block of tasks, whereas individuals with OCD exhibited fewer changes over time, suggesting a reduced adaptation of the ANS sympathetic tone to cognitive‐emotional workload in OCD. Altered autonomic nervous system responses in patients with OCD could potentially underlie the causes of obsessive‐compulsive disorder; however, they have not been sufficiently investigated at present. By examining the temporal dynamics of pupil area and heart rate, we gain deeper insights into how individuals with obsessive‐compulsive disorder react to cognitive‐emotional stimuli. [ABSTRACT FROM AUTHOR]

Background: Changes in cardiovascular health indicators during childhood and adolescence can lead to cardiovascular diseases in adulthood. Excess body fat is one of the main factors for cardiovascular diseases. Thus, new strategies for the practice of physical activity with this population are needed to prevent and/or reverse this situation. Aim: To analyze the effects of 16 weeks of Muay Thai practice on heart rate variability, blood pressure, and resting heart rate in children and adolescents with overweight/obesity. Methods: The sample is composed of 30 children and adolescents of both sexes (17 male and 13 female) aged 12.50 ± 2.12 years. The participants were divided into Muay Thai (n = 17) and control (n = 13). Systolic and diastolic blood pressure and heart rate were measured using an automatic oscillometric device. Heart rate variability was assessed by a frequency meter and was analyzed considering the time domain indices, frequency, and the Poincaré plot. The outcomes were evaluated before (initial time) and after 16 weeks. The Muay Thai group, performed an intervention with Muay Thai training for 16 weeks (three times a week on non-consecutive days). Each training session lasted 90 min and the intensity was maintained from moderate to high using the perceived exertion scale. Results: The Muay Thai group demonstrated lower heart rate values than the control group at the pre-test (p = 0.040). In addition, the Muay Thai group decreased the heart rate in post-test when compared to the pre-test (p < 0.001). Conclusion: 16 weeks of Muay Thai shows a tendency to reduce resting heart rate in children and adolescents with overweight/obesity. [ABSTRACT FROM AUTHOR]

Purpose: Previous studies investigating sinusoidal exercise were not devoted to an analysis of its energetics and of the effects of fatigue. We aimed to determine the contribution of aerobic and anaerobic lactic metabolism to the energy balance and investigate the fatigue effects on the cardiorespiratory and metabolic responses to sinusoidal protocols, across and below critical power (CP). Methods: Eight males (26.6 ± 6.2 years; 75.6 ± 8.7 kg; maximum oxygen uptake 52.8 ± 7.9 ml·min−1·kg−1; CP 218 ± 13 W) underwent exhausting sinusoidal cycloergometric exercises, with sinusoid midpoint (MP) at CP (CPex) and 50 W below CP (CP-50ex). Sinusoid amplitude (AMP) and period were 50 W and 4 min, respectively. MP, AMP, and time-delay (tD) between mechanical and metabolic signals of expiratory ventilation ( V ˙ E ), oxygen uptake ( V ˙ O 2 ), and heart rate ( f H ) were assessed sinusoid-by-sinusoid. Blood lactate ([La−]) and rate of perceived exertion (RPE) were determined at each sinusoid. Results: V ˙ O 2 AMP was 304 ± 11 and 488 ± 36 ml·min−1 in CPex and CP-50ex, respectively. Asymmetries between rising and declining sinusoid phases occurred in CPex (36.1 ± 7.7 vs. 41.4 ± 9.7 s for V ˙ O 2 tD up and tD down, respectively; P < 0.01), with unchanged tDs. V ˙ O 2 MP and RPE increased progressively during CPex. [La−] increased by 2.1 mM in CPex but remained stable during CP-50ex. Anaerobic contribution was larger in CPex than CP-50ex. Conclusion: The lower aerobic component during CPex than CP-50ex associated with lactate accumulation explained lower V ˙ O 2 AMP in CPex. The asymmetries in CPex suggest progressive decline of muscle phosphocreatine concentration, leading to fatigue, as witnessed by RPE. [ABSTRACT FROM AUTHOR]

Background: Unlike tachyarrhythmias, which are common in pregnancy, there is a paucity of data regarding maternal bradycardias. Our objective was to describe the characteristics, associated conditions, and prognosis of women who develop bradycardia post-partum. Method: We conducted a retrospective chart review of patients referred to the Obstetrical Medicine service at British Columbia Women's Hospital from January 2012 to May 2020 for post-partum maternal bradycardia. Results: Twenty-four patients with post-partum bradycardia were included (age 34.2 ± 4.8 years; heart rate 40.4 ± 8.1 beats per minute; blood pressure 131/72 mm Hg). Sinus bradycardia (79.2%) was the most common rhythm. Dyspnea (29.4%) and chest pain (23.5%) were common symptoms. Mean time to resolution of bradycardia was 3.6 ± 3.8 days. Associated conditions potentially explaining the bradycardia were preeclampsia (54.1%), underlying (16.7%), medications (8.3%), and neuraxial anesthesia (8.3%). Conclusions: Maternal bradycardia is an uncommon condition complicating the post-partum period, that is generally self-limiting, with the majority only require clinical observation. [ABSTRACT FROM AUTHOR]

Development and Calibration of a PATCH Device for Monitoring Children's Heart Rate and Acceleration. Med. Sci. Sports Exerc., Vol. 56, No. 6, pp. 1196-1207, 2024. Introduction: Current wearables that collect heart rate and acceleration were not designed for children and/or do not allow access to raw signals, making them fundamentally unverifiable. This study describes the creation and calibration of an open-source multichannel platform (PATCH) designed to measure heart rate and acceleration in children ages 3-8 yr. Methods: Children (N = 63; mean age, 6.3 yr) participated in a 45-min protocol ranging in intensities from sedentary to vigorous activity. Actiheart-5 was used as a comparison measure. We calculated mean bias, mean absolute error (MAE) mean absolute percent error (MA%E), Pearson correlations, and Lin's concordance correlation coefficient (CCC). Results: Mean bias between PATCH and Actiheart heart rate was 2.26 bpm, MAE was 6.67 bpm, and M%E was 5.99%. The correlation between PATCH and Actiheart heart rate was 0.89, and CCC was 0.88. For acceleration, mean bias was 1.16 mg and MAE was 12.24 mg. The correlation between PATCH and Actiheart was 0.96, and CCC was 0.95. Conclusions: The PATCH demonstrated clinically acceptable accuracies to measure heart rate and acceleration compared with a research-grade device. [ABSTRACT FROM AUTHOR]

Objective: This study aimed at assessing the effectiveness of cognitive‐behavioural therapy (CBT) integrated with psychoeducation in a group of hypertensive patients with clinically significant psychopathological symptoms. Methods: One hundred hypertensive patients completed the Symptom Checklist‐90‐Revised. Of them, 17 scored above the clinical range (cut‐off = 0.75) on the Global Severity Index and were included in the study. Psychological distress was assessed again after the intervention (T1) and 6 months after the end of treatment (T2). In addition, the cortisol dosage and the heart rate (HR) measurement were collected at both T0 and T2. Then, mediation analyses were carried out to calculate whether psychopathological distress might predict HR through elevated serum cortisol levels, at both T0 and T2. Results: The psychological intervention (CBT integrated with psychoeducation) reduced most of the psychopathological symptoms (anxiety, depression, somatisations, obsessions and compulsions, hostility, interpersonal sensitivity and paranoid ideation) but not cortisol dosage and HR measurement. However, psychological distress indirectly predicted HR via cortisol at T0 but not at T2. Conclusion: These results suggest and encourage the replicability of data in larger sample sizes and the comparison with a control group. Nevertheless, these results highlight a need for a multidimensional assessment of disorders affecting the mental and physical spheres of patients to support their overall well‐being. [ABSTRACT FROM AUTHOR]

Exercise elicits physiological adaptations, including hyperpnea. However, the mechanisms underlying exercise-induced hyperpnea remain unresolved. Skeletal muscle acts as a secretory organ, releasing irisin (IR) during exercise. Irisin can cross the blood–brain barrier, influencing muscle and tissue metabolism, as well as signaling in the central nervous system (CNS). We evaluated the effect of intracerebroventricular or intraperitoneal injection of IR in adult male rats on the cardiorespiratory and metabolic function during sleep–wake cycle under room air, hypercapnia and hypoxia. Central IR injection caused an inhibition on ventilation (VE) during wakefulness under normoxia, while peripheral IR reduced VE during sleep. Additionally, central IR exacerbates hypercapnic hyperventilation by increasing VE and reducing oxygen consumption. As to cardiovascular regulation, central IR caused an increase in heart rate (HR) across all conditions, while no change was observed following peripheral administration. Finally, central IR attenuated the hypoxia-induced regulated hypothermia and increase sleep episodes, while peripheral IR augmented CO2-induced hypothermia, during wakefulness. Overall, our results suggest that IR act mostly on CNS exerting an inhibitory effect on breathing under resting conditions, while stimulating the hypercapnic ventilatory response and increasing HR. Therefore, IR seems not to be responsible for the exercise-induced hyperpnea, but contributes to the increase in HR. [ABSTRACT FROM AUTHOR]

The autonomic nervous system (ANS) regulates the body's physiology, including cardiovascular function. As the ANS develops during the second to third trimester, fetal heart rate variability (HRV) increases while fetal heart rate (HR) decreases. In this way, fetal HR and HRV provide an index of fetal ANS development and future neurobehavioral regulation. Fetal HR and HRV have been associated with child language ability and psychomotor development behavior in toddlerhood. However, their associations with postbirth autonomic brain systems, such as the brainstem, hypothalamus, and dorsal anterior cingulate cortex (dACC), have yet to be investigated even though brain pathways involved in autonomic regulation are well established in older individuals. We assessed whether fetal HR and HRV were associated with the brainstem, hypothalamic, and dACC functional connectivity in newborns. Data were obtained from 60 pregnant individuals (ages 14-42) at 24-27 and 34-37 weeks of gestation using a fetal actocardiograph to generate fetal HR and HRV. During natural sleep, their infants (38 males and 22 females) underwent a fMRI scan between 40 and 46 weeks of postmenstrual age. Our findings relate fetal heart indices to brainstem, hypothalamic, and dACC connectivity and reveal connections with widespread brain regions that may support behavioral and emotional regulation. We demonstrated the basic physiologic association between fetal HR indices and lower- and higher-order brain regions involved in regulatory processes. This work provides the foundation for future behavioral or physiological regulation research in fetuses and infants. [ABSTRACT FROM AUTHOR]

Background and purpose: The relationship between heart rate and the prognosis of patients with large vessel occlusion strokes treated with mechanical thrombectomy (MT) is not well established. This study aimed to evaluate the association of mean heart rate and heart rate variability (HRV) with the clinical outcomes after MT therapy. Methods: Acute ischemic stroke patients undergoing MT therapy were prospectively recruited from March 2020 to November 2022. Their heart rate was collected every hour for the initial 72 h after MT procedure, and the variability of heart rate was measured by standard deviation (SD) and coefficient of variation (CV). All-cause mortality and worsening of functional outcome (change in modified Rankin Scale (mRS) score) at 3-month were captured. Binary logistic regression was used to evaluate the association between heart rate indicators and all-cause mortality. Ordinal logistic regression was used to evaluate the association between heart rate indicators and worsening of functional outcome. Results: Among 191 MT-treated patients, 51(26.7%) patients died at 3-month after stroke. Increased mean heart rate per 10-bpm, heart rate SD and CV per 5-unit were all associated with the increased risk of mortality (adjusted hazard ratio [aHR] with 95% CI: 1.29 [1.09–1.51], 1.19 [1.07–1.32], 1.14 [1.03–1.27]; respectively). Patients in the highest tertile of heart rate SD had an increased risk of mortality (4.62, 1.70-12.52). After using mRS as a continuous variable, we found increased mean heart rate per 10-bpm, heart rate SD and CV per 5-unit were associated with the worsening of functional outcome (adjusted odds ratio [aOR] with 95% CI: 1.35 [1.11–1.64], 1.27 [1.05–1.53], 1.19 [1.02–1.40]; respectively). A linear relationship was observed between mean heart rate or heart rate SD and mortality; while all of the heart rate measures in this study showed a linear relationship with the worsening of functional outcome. Conclusions: Higher mean heart rate and HRV were associated with the increased risk of 3-month all-cause mortality and worse functional outcome after MT therapy for AIS patients. [ABSTRACT FROM AUTHOR]

Basketball involves frequent high-intensity movements requiring optimal aerobic power. Altitude training can enhance physiological adaptations, but research examining its effects in basketball is limited. This study aimed to characterize the internal/external workload of professional basketball players during preseason and evaluate the effects of altitude and playing position. Twelve top-tier professional male basketball players (Liga Endesa, ACB; guards: n = 3, forwards: n = 5, and centers: n = 4) participated in a crossover study design composed of two training camps with nine sessions over 6 days under two different conditions: high altitude (2320 m) and sea level (10 m). Internal loads (heart rate, %HRMAX) and external loads (total distances covered across speed thresholds, accelerations/decelerations, impacts, and jumps) were quantified via wearable tracking and heart rate telemetry. Repeated-measures MANOVA tested the altitude x playing position effects. Altitude increased the total distance (+10%), lower-speed running distances (+10–39%), accelerations/decelerations (+25–30%), average heart rate (+6%), time in higher-intensity HR zones (+23–63%), and jumps (+13%) across all positions (p < 0.05). Positional differences existed, with guards accruing more high-speed running and centers exhibiting greater cardiovascular demands (p < 0.05). In conclusion, a 6-day altitude block effectively overloads training, providing a stimulus to enhance fitness capacities when structured appropriately. Monitoring workloads and individualizing training by playing position are important when implementing altitude training, given the varied responses. [ABSTRACT FROM AUTHOR]

Background/Objective: The relationship between heart rate and heart rate variability (HRV) indices has been repeatedly studied in adults but limited data are available on the relationship in paediatric populations. Methods: Continuous 12-lead electrocardiograms were recorded in 1016 healthy children and adolescents (534 females) aged 4 to 19 years during postural manoeuvres with rapid changes between 10-min positions of supine → sitting → standing → supine → standing → sitting → supine. In each position, the averaged RR interval was measured together with four HRV indices, namely the SDNN, RMSSD, quasi-normalised high-frequency components (qnHF), and the proportions of low- and high-frequency components (LF/HF). In each subject, the slope of the linear regression between the repeated HRV measurements and the corresponding RR interval averages was calculated. Results: The intra-subject regression slopes, including their confidence intervals, were related to the age and sex of the subjects. The SDNN/RR, RMSSD/RR, and qnHF/RR slopes were significantly steeper (p < 0.001) and the (LF/HF)/RR slopes were significantly shallower (p < 0.001) in younger children compared to older children and adolescents. Conclusions: The study suggests that sympathetic and vagal influences on heart rate are present in both younger and older children. With advancing age, the sympatho-vagal balance gradually develops and allows the vagal control to suppress the sympathetic drive towards higher heart rates seen in younger age children. [ABSTRACT FROM AUTHOR]

Background/aim: Our recent study revealed that the expression of lipoxygenase (LOX) and cyclooxygenase (COX) enzymes in the hypothalamus is activated by nesfatin-1, leading to the liberation of leukotrienes and prostaglandins (PG), respectively. Moreover, our prior report explained that intracerebroventricular (ICV) nesfatin-1 treatment triggers cardiovascular responses mediated by central LOX and COX enzymes. Building upon our prior reports, the present investigation sought to clarify the role of cardiovascularly active central COX products, such as thromboxane (TX) A2, PGF2α, PGE, and PGD, in orchestrating nesfatin-1-evoked reactions in mean arterial pressure (MAP) and heart rate (HR). Materials and methods: The Sprague Dawley rats, which had guide cannula in the lateral ventricle for intracerebroventricular (ICV) injections and catheter in arteria femoralis for monitoring MAP and HR, were underwent central pretreatment with furegrelate (the TXA2 synthase inhibitor), PGF2α-dimethylamine (PGF2α-DA, the PGF2α receptor antagonist), or AH6809 (the PGE and PGD receptor antagonist), 5 min prior to ICV nesfatin-1 administration. The cardiovascular parameters were observed and recorded for 60 min posttreatment Results: Nesfatin-1 induced cardiovascular responses in rats leading to pressor effect in MAP, and tachycardia following bradycardia in HR. Interestingly, ICV furegrelate, PGF2α-DA, or AH6809 pretreatment partially mitigated the cardiovascular effects revealed by nesfatin-1. Conclusion: The findings illuminate the role of nesfatin-1 in modulating MAP and HR through the central activation of specifically TXA2, PGF2α, PGE, and PGD from COX metabolites. Additionally, the study may also suggest the potential involvement of other central COX or LOX metabolites beyond these COX metabolites in mediating the cardiovascular effects produced by nesfatin-1. [ABSTRACT FROM AUTHOR]

Objectives: To calculate the shock index (SI) in dogs with myxomatous mitral valve disease (MMVD) and to evaluate its use to predict the presence of congestive heart failure (CHF). Design: Retrospective study. Setting: Small animal university veterinary teaching hospital. Animals: Ninety‐eight dogs with MMVD and 20 healthy dogs as part of a control group. Interventions: Heart rate (HR) and systolic blood pressure (SBP) were recorded, and SI was calculated by dividing HR by SBP for each dog. Measurements and Main Results: The mean (SD) HR, SBP, and SI were 123/min (32.6), 147 mm Hg (21.5), and 0.86 (0.3), respectively, for dogs with MMVD and 98/min (20.9), 145 mm Hg (18.7), and 0.68 (0.13), respectively, for control dogs. Dogs with MMVD had a significantly higher HR compared with control dogs (P < 0.01), and an elevation in HR was seen as the severity of MMVD increased. Dogs in stage B2 and C/D MMVD had a significantly higher SI value compared with control dogs (P = 0.04 and P < 0.01, respectively). SI was significantly higher in dogs in stage C/D MMVD compared with dogs in stage B2 MMVD (P < 0.01). Ten of 98 (10%) dogs had an arrhythmia. HR, SBP, and SI were not significantly different between dogs with and without arrhythmias (P = 0.13, P = 0.57, and P = 0.07, respectively), but significantly more dogs with CHF had an arrhythmia (P = 0.01). SI (area under the curve [AUC]: 0.98) and HR (AUC: 0.95) were excellent indicators for the presence of CHF. An optimal SI cutoff value ≥1.1 had 92% sensitivity and 95% specificity for predicting the presence of CHF, and an optimal HR cutoff value of ≥157/min had 92% sensitivity and 93% specificity for the prediction of CHF. Conclusions: When there are compatible clinical signs, SI values ≥1.1 may suggest the presence of CHF in dogs with MMVD. [ABSTRACT FROM AUTHOR]

• HR analysis and non-intrusive instrumentation has potential for monitoring driver's status and detecting sleepiness. • Validation and fatigue estimation methods still lacking, contributing to methods insufficiency in providing alarm systems. • Great promise is shown, but still far from being reliably implemented. Fatigue is a complex state resulting in decreased alertness, often accompanied by drowsiness. Driving fatigue has significantly contributed to traffic accidents globally, highlighting the need for effective monitoring techniques. Various technologies exist to enhance driver safety and minimize accident risks, such as fatigue detection systems that alert drivers as drowsiness sets in. In particular, measuring heart rate (HR) patterns may offer valuable insights into the occupant's physiological condition and level of alertness and may allow them to understand their fatigue levels. This review aims to establish the current state of the art of monitoring strategies for vehicle occupants, specifically focusing on fatigue assessed by HR and heart rate variability (HRV). We performed a systematic literature search in the databases of Web of Science, Scopus, and PubMed, using the terms vehicle, driver, physiologic monitoring, fatigue, sleep, electrocardiogram, heart rate, and heart rate variability. We examined articles published between the 1st of January 2018 and the 31st of January 2023. A total of 294 papers were identified from which 71 articles were included in this study. Among the included papers, 57 utilized electrocardiogram (ECG) as the acquired signal for HR measures, with most ECG readings obtained through contact sensors (n = 41), followed by non-intrusive wearable sensors (n = 11). The majority of the works rely on subjective self-reported fatigue ratings (n = 27) and video-based observer ratings (n = 11). Regarding validation, 16 papers do not report validation of any kind. From the included papers, only 13 comprise a fatigue and drowsiness estimation system, 9 with reported validation. Some report acceptable performances, but reduced sample size limits conclusions. This review highlights the potential of HR analysis and non-intrusive instrumentation for continuously monitoring driver's status and detecting sleepiness. One major issue is the lack of sufficient validation and estimation methods for fatigue, contributing to insufficient methods in providing proactive alarm systems. This area shows great promise but is still far from being reliably implemented. [ABSTRACT FROM AUTHOR]

Increased vestibular sensitivity can cause various inconveniences and interfere with a full life; therefore, it is important to study the factors influencing its development and progression. However, in the available scientific literature, this issue is not covered. The aim of our work was to develop a multivariate regression model for predicting increased sensitivity of the vestibular analyzer. For this, we surveyed 120 students of the I. Horbachevsky Ternopil National Medical University. To establish increased vestibular sensitivity, we conducted a survey and a rotation test by using the Barani chair. We assessed the psychophysiological state. Prognostically significant criteria from 50 indicators that indicate increased vestibular sensitivity are the level of neuroticism, well-being, activity, mood, vestibular stability, latent periods of simple and complex visualmotor reactions, functional mobility of nervous processes, and heart rate. The model of mathematical forecasting proposed by us can become one of the stages of the prevention of disorders caused by the increased sensitivity of the vestibular analyzer. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the inter-day reliability of time-domain, frequency-domain, and nonlinear HRV metrics in healthy highly active younger and older adults. The study also assessed the effect of age on the HRV metrics. Methods: Forty-four older adults (34 M, 10F; 59 ± 5 years; V ˙ O 2peak = 40.9 ± 7.6 ml kg−1 min−1) and twenty-two younger adults (16 M, 6F; 22 ± 4 years; V ˙ O 2peak = 47.2 ± 12.8 ml kg−1 min−1) attended the laboratory. Visit one assessed aerobic fitness through an exercise test. In visits two and three, participants completed a 30-min supine RR interval measurement to derive the HRV metrics. Results: The younger group (YG) and older group (OG) demonstrated poor to good day-to-day relative and absolute reliability for all HRV metrics (OG, ICCs = 0.33 to 0.69 and between day CVs = 3.8 to 29.2%; YG, ICCs = 0.37 to 0.93 and between day CVs = 3.5 to 36.5%). There was a significant reduction in ApEn (P < 0.001), SampEn (P = 0.031), RMSSD (P < 0.001), SDNN (P < 0.001), LF power (P < 0.001) and HF power (P < 0.001), HRV metrics with ageing. There was no significant effect of age the complexity metrics DFA α1 (P = 0.107), α2 (P = 0.147) and CI-8 (P = 0.493). Conclusion: HRV metrics are reproducible between days in both healthy highly active younger and older adults. There is a decline in linear and nonlinear HRV metrics with age, albeit there being no age-related change in the nonlinear metrics, DFA α1, α2 and CI-8. [ABSTRACT FROM AUTHOR]

Objective To explore the neurophysiological responses of patients′ fear in real treatment scenarios, and to construct a assessment model of children′s dental fear and anxiety (DFA) based on physiological data. Methods Totally 166 children under the age of 14 who received treatment at the Beijing Children′s Hospital Department of Stomatology were included in the study. The Chinese version of the modified Children′s Fear Survey Schedule-Dental Subscale (CFSS-DS) was used to assess dental fear and anxiety scores in children. A wrist-worn physiological data collection device was used to continuously measure subjects′ heart rate (HR) and galvanic skin response (GSR) during the treatment. Repeated measures analysis of variance was used to test for differences in physiological data before, during and after treatment. Pearson′s correlation analysis was used to analyze the relationship between physiological data and CFSS-DS scores before, during, and after treatment. A Least Absolute Shrinkage and Selection Operator (LASSO) regression model was established to assess dental fear and anxiety among children, and Leave-One-Out (LOO) was used for cross-validation. Results There were significant differences in the changes of each dimension of physiological data before, during, and post treatment(P＜0.05). The Pearson′s correlation coefficient (r) between the LASSO model predictive values and the CFSS-DS scores was 0.30 (P＜0.05), which indicated a good predictive accuracy of the model. Conclusions The assessment model might achieve objective and automated measurement of dental fear and anxiety in children. [ABSTRACT FROM AUTHOR]

This article presents an innovative approach to analyzing and extracting electrocardiogram (ECG) signals from the abdomen and thorax of pregnant women, with the primary goal of isolating fetal ECG (fECG) and maternal ECG (mECG) signals. To resolve the difficulties related to the low amplitude of the fECG, various noise sources during signal acquisition, and the overlapping of R waves, we developed a new method for extracting ECG signals using blind source separation techniques. This method is based on independent component analysis algorithms to detect and accurately extract fECG and mECG signals from abdomen and thorax data. To validate our approach, we carried out experiments using a real and reliable database for the evaluation of fECG extraction algorithms. Moreover, to demonstrate real-time applicability, we implemented our method in an embedded card linked to electronic modules that measure blood oxygen saturation (SpO2) and body temperature, as well as the transmission of data to a web server. This enables us to present all information related to the fetus and its mother in a mobile application to assist doctors in diagnosing the fetus's condition. Our results demonstrate the effectiveness of our approach in isolating fECG and mECG signals under difficult conditions and also calculating different heart rates (fBPM and mBPM), which offers promising prospects for improving fetal monitoring and maternal healthcare during pregnancy. [ABSTRACT FROM AUTHOR]

Past findings have suggested that there is a link between attachment representations and reactions towards stress (subjective and physiological). The aim of this study was to examine the mediating effect of perceived stress on the association between attachment representation and physiological changes, specifically heart rate. As part of a long-term study investigating the transgenerational transmission of childhood maltreatment, n = 163 mothers participated in multiple assessments. The Adult Attachment Projective Picture System (AAP) was used to measure maternal attachment representation, categorizing individuals as securely or insecurely attached. Perceived daily stress was assessed using the Perceived Stress Scale 14 (PSS-14), and maternal baseline heart rate (HR) was measured via electrocardiography during a laboratory visit. The results revealed that the representation of secure attachment had a significant reducing effect on both the mother's perceived daily stress and heart rate. Furthermore, the association between secure attachment representation and heart rate was mediated by perceived stress. This study emphasizes the role of attachment representation in maternal well-being, highlighting its impact on stress and physiological responses. [ABSTRACT FROM AUTHOR]

Simple Summary: Data collected from training sessions has the potential to better understand how well racehorses will perform on race-days. To date, no research has explored whether speed during and heart rate recovery after fast exercise could predict a horse winning a race. This theory was tested by analysing information from fitness trackers worn by 485 racehorses during training sessions in Australia by looking at factors like the horse's speed and heart rate recovery after exercise. The study found that certain factors, like being a colt or a 'stayer', were good indicators of future success on the racetrack. However, heart rate recovery and speed at the start or throughout the final 600 m during training were not as powerful as race predictors. Nevertheless, combining physiological data with other less tangible factors will help professionals identify which horses are more likely to perform at their best in races, aiding decision-making and potentially reducing race-day poor performance. Ultimately, this could lead to more successful outcomes for the horses, trainers and owners. In-training racehorse physiological data can be leveraged to further explore race-day performance prediction. To date, no large retrospective, observational study has analysed whether in-training speed and heart rate recovery can predict racehorse success. Speed (categorised as 'slow' to 'fast' according to the time taken to cover the last 600 m from a virtual finish line) and heart rate recovery (from gallop to 1 min after exercise) of flat racehorses (n = 485) of varying age, sex and type according to distance (e.g., sprinter, miler and stayer) were obtained using a fitness tracker from a single racing yard in Australia. Race-pace training sessions on turf comprised 'fast gallop' (n = 3418 sessions) or 'jumpout' (n = 1419). A posteriori racing information (n = 3810 races) for all 485 racehorses was extracted and combined with training data. Race performance was categorised as win/not-win or podium or not, each analysed by logistic regression. Colts (p < 0.001), stayers (p < 0.001) and being relatively fast over the last 600 m of a benchmark test in training (p < 0.008) were all predictive of race performance. Heart rate recovery after exercise (p = 0.21) and speed recorded at 600 m of a 1 km benchmark test in training (p = 0.94) were not predictive. In-training physiological data analytics used along with subjective experience may help trainers identify promising horses and improve decision-making. [ABSTRACT FROM AUTHOR]

The increased size and enhanced compliance of the aortic bulb—the enlargement of the ascending aorta—are believed to maintain blood flow in pinnipeds during extended periods of diastole induced by diving bradycardia. The aortic bulb has been described ex vivo in several species of pinnipeds, but in vivo measurements are needed to investigate the relationship between structure and function. We obtained ultrasound images using electrocardiogram‐gated transesophageal echocardiography during anesthesia and after atropine administration to assess the relationship between aortic bulb anatomy and cardiac function (heart rate, stroke volume, cardiac output) in northern fur seals (Callorhinus ursinus) and Steller sea lions (Eumetopias jubatus). We observed that the aortic bulb in northern fur seals and Steller sea lions expands during systole and recoils over the entire diastolic period indicating that blood flow is maintained throughout the entire cardiac cycle as expected. The stroke volumes we measured in the fur seals and sea lions fit the values predicted based on body size in mammals and did not change with increased heart rates, suggesting that greater stroke volumes are not needed for aortic bulb function. Overall, our results suggest that peripheral vasoconstriction during diving is sufficient to modulate the volume of blood in the aortic bulb to ensure that flow lasts over the entire diastolic period. These results indicate that the shift of blood into the aortic bulb of pinnipeds is a fundamental mechanism caused by vasoconstriction while diving, highlighting the importance of this unique anatomical adaptation. Research highlights: Aortic bulb expansion and recoil supported continuous blood flow in northern fur seals and Steller sea lions. Stroke volumes in these species matched predictions based on body size, suggesting that having a large aortic bulb does not necessitate having a greater stroke volume to support diving. [ABSTRACT FROM AUTHOR]

Background: Understanding the dynamics of conduction velocity (CV) and voltage amplitude (VA) is crucial in cardiac electrophysiology, particularly for substrate-based catheter ablations targeting slow conduction zones and low voltage areas. This study utilizes ultra-high-density mapping to investigate the impact of heart rate and pacing location on changes in the wavefront direction, CV, and VA of healthy pig hearts. Methods: We conducted in vivo electrophysiological studies on four healthy juvenile pigs, involving various pacing locations and heart rates. High-resolution electroanatomic mapping was performed during intrinsic normal sinus rhythm (NSR) and electrical pacing. The study encompassed detailed analyses at three levels: entire heart cavities, subregions, and localized 5-mm-diameter circular areas. Linear mixed-effects models were used to analyze the influence of heart rate and pacing location on CV and VA in different regions. Results: An increase in heart rate correlated with an increase in conduction velocity and a decrease in voltage amplitude. Pacing influenced conduction velocity and voltage amplitude. Pacing also influenced conduction velocity and voltage amplitude, with varying effects observed based on the pacing location within different heart cavities. Pacing from the right atrium (RA) decreased CV in all heart cavities. The overall CV and VA changes in the whole heart cavities were not uniformly reflected in all subregions and subregional CV and VA changes were not always reflected in the overall analysis. Overall, there was a notable variability in absolute CV and VA changes attributed to pacing. Conclusions: Heart rate and pacing location influence CV and VA within healthy juvenile pig hearts. Subregion analysis suggests that specific regions of the heart cavities are more susceptible to pacing. High-resolution mapping aids in detecting regional changes, emphasizing the substantial physiological variations in CV and VA. [ABSTRACT FROM AUTHOR]

Prolonged elevated heart rate (peHR) is recognized as a risk factor for poor prognosis among critically ill patients. However, there is currently a lack of studies investigating the association between peHR and patients with acute pancreatitis. Multiparameter Intelligent Monitoring in Intensive Care IV (MIMIC-IV) database was used to identify patients with acute pancreatitis. PeHR was defined as a heart rate exceeding 100 beats per minute for at least 11 out of 12 consecutive hours. Cox regression analysis was used to assess the association between peHR and the 90-Day mortality. A total of 364 patients (48.9%) experienced a peHR episode. The 90-day mortality was 25%. PeHR is an independent risk factor for 90-day mortality (HR, 1.98; 95% CI 1.53–2.56; P < 0.001). KM survival curves exhibited a significant decrease in the survival rate at 90 days among patients who experienced a peHR episode (P < 0.001, 84.5% vs. 65.1%). We revealed a significant association of peHR with decreased survival in a large cohort of ICU patients with acute pancreatitis. [ABSTRACT FROM AUTHOR]

Background: Comparatively little is known regarding the initial cardiorespiratory response of young racehorses to training. The objectives were to compare physiological parameters before and after introductory training and determine whether young Thoroughbreds show endoscopic signs of exercise-induced pulmonary hemorrhage (EIPH). Ten Thoroughbreds (20–23 months) underwent 12-weeks of introductory training, including weekly speed sessions. Two 600 m high-speed exercise tests (HSET) were performed following weeks 4 and 12 while wearing a validated ergospirometry facemask. Peak oxygen consumption (V̇O2pk) and ventilatory parameters (tidal volume, VT; peak inspiratory and expiratory flow, PkV̇I, PkV̇E; respiratory frequency, Rf; minute ventilation, V̇E) were measured. The ventilatory equivalent of oxygen (V̇E/V̇O2) and the aerobic and anaerobic contributions to energy production were calculated. Maximal heart rate (HRmax) and HR at maximal speed (HRVmax) were determined. Post-exercise hematocrit, plasma ammonia and blood lactate were measured. Evidence of EIPH was investigated via tracheobronchoscopy post-exercise. Results were compared (paired t-test, P < 0.05). Results: Horses were faster following training (P < 0.001) and V̇O2pk increased 28 ml/(kg total mass.min) (28 ± 16%; P < 0.001). Ventilatory (V̇E, P = 0.0015; Rf, P < 0.001; PkV̇I, P < 0.001; PkV̇E, P < 0.001) and cardiovascular parameters (HRmax, P = 0.03; HRVmax, P = 0.04) increased. The increase in V̇E was due to greater Rf, but not VT. V̇E/V̇O2 was lower (26 ± 3.6 vs 23 ± 3.7; P = 0.02), indicating improved ventilatory efficiency. Anaerobic contribution to total energy production increased from 15.6 ± 6.1% to 18.5 ± 6.3% (P = 0.02). Post-exercise hematocrit (P < 0.001), plasma ammonia (P = 0.03) and blood lactate (P = 0.001) increased following training. Horses showed no signs of EIPH. Conclusions: Young two-year-old Thoroughbreds responded well to introductory training without developing tracheobronchoscopic evidence of EIPH. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a persistent metabolic disorder associated with the hormone insulin. The two main types of DM are type 1 (T1DM) and type 2 (T2DM). Physical activity plays a crucial role in the therapy of diabetes, benefiting both types of patients. The detection, recognition, and subsequent classification of physical activity based on type and intensity are integral components of DM treatment. The continuous glucose monitoring system (CGMS) signal provides the blood glucose (BG) level, and the combination of CGMS and heart rate (HR) signals are potential targets for detecting relevant physical activity from the BG variation point of view. The main objective of the present research is the developing of an artificial intelligence (AI) algorithm capable of detecting physical activity using these signals. Using multiple recurrent models, the best-achieved performance of the different classifiers is a 0.99 area under the receiver operating characteristic curve. The application of recurrent neural networks (RNNs) is shown to be a powerful and efficient solution for accurate detection and analysis of physical activity in patients with DM. This approach has great potential to improve our understanding of individual activity patterns, thus contributing to a more personalized and effective management of DM. [ABSTRACT FROM AUTHOR]

Background: Owing to the association between dysfunctional maternal autonomic regulation and pregnancy complications, assessing non-invasive features reflecting autonomic activity—e.g., heart rate variability (HRV) and the morphology of the photoplethysmography (PPG) pulse wave—may aid in tracking maternal health. However, women with early pregnancy complications typically receive medication, such as corticosteroids, and the effect of corticosteroids on maternal HRV and PPG pulse wave morphology is not well-researched. Methods: We performed a prospective, observational study assessing the effect of betamethasone (a commonly used corticosteroid) on non-invasively assessed features of autonomic regulation. Sixty-one women with an indication for betamethasone were enrolled and wore a wrist-worn PPG device for at least four days, from which five-minute measurements were selected for analysis. A baseline measurement was selected either before betamethasone administration or sufficiently thereafter (i.e., three days after the last injection). Furthermore, measurements were selected 24, 48, and 72 h after betamethasone administration. HRV features in the time domain and frequency domain and describing heart rate (HR) complexity were calculated, along with PPG morphology features. These features were compared between the different days. Results: Maternal HR was significantly higher and HRV features linked to parasympathetic activity were significantly lower 24 h after betamethasone administration. Features linked to sympathetic activity remained stable. Furthermore, based on the PPG morphology features, betamethasone appears to have a vasoconstrictive effect. Conclusions: Our results suggest that administering betamethasone affects maternal autonomic regulation and cardiovasculature. Researchers assessing maternal HRV in complicated pregnancies should schedule measurements before or sufficiently after corticosteroid administration. [ABSTRACT FROM AUTHOR]

Background: We aimed to evaluate whether the administration of remimazolam as a maintenance agent for general anesthesia affects the occurrence of hypotension compared with sevoflurane when switching to the beach chair position (BCP). Methods: We conducted a prospective randomized controlled trial from June 2023 to October 2023 in adult patients undergoing orthopedic surgery under general anesthesia in the BCP. A total of 78 participants were randomly allocated to the remimazolam (R) or sevoflurane (S) groups. The primary outcome was the incidence of hypotension that occurred immediately after switching to a BCP. The secondary outcomes included differences between the study groups in perioperative blood pressure (BP), heart rate (HR), endotracheal tube extubation time, postoperative complications, and hospital length of stay (LOS). Results: The incidence of hypotension immediately after switching to a BCP was significantly higher in the S group. The risk factors associated with hypotension included sevoflurane administration and a high baseline systolic BP. In the receiver operating characteristic curve analysis for the occurrence of hypotension after the transition to a BCP, the cutoff value for systolic BP was 142 mmHg. The perioperative BP and HR were higher in the R group at several timepoints. Postoperative endotracheal tube extubation time was shorter in the R group. There were no significant differences in the postoperative complications or hospital LOS between the two groups. Conclusions: Remimazolam should be considered as an anesthetic agent to prevent hypotension when switching to BCP, and hypotension may occur frequently in patients with high baseline BP. [ABSTRACT FROM AUTHOR]

Objective Delayed cord clamping (DCC) has been recently adopted in neonatal resuscitation. The immediate cardiac hemodynamic effects related to DCC more than 30 seconds was not studied. We aimed to study the effect of DCC at 120 seconds compared with 30 seconds on multiple hemodynamic variables in full-term infants using an electrical cardiometry (EC) device. Study Design Present study is a randomized clinical trial. The study was conducted with full-term infants who were delivered at the Obstetrics and Gynecology Department in Cairo University Hospital. Sixty-eight full term infants were successfully enrolled in this trial. Cardiac output (CO) and other hemodynamic parameters were evaluated in this study by EC device. Hemoglobin, glucose, and bilirubin concentrations were measured at 24 hours. Newborn infants were assigned randomly into group 1: DCC at 30 seconds, and group 2: DCC at 120 seconds, based on the time of cord clamping. Results Stroke volume (SV) (mL) and CO (L/min) were significantly higher in group 2 compared with group 1 at 5 minutes (6.71 vs. 5.35 and 1.09 vs. 0.75), 10 minutes (6.43 vs. 5.59 and 0.88 vs. 0.77), 15 minutes (6.45 vs. 5.60 and 0.89 vs. 0.76), and 24 hours (6.67 vs. 5.75 and 0.91vs. 0.81), respectively. Index of contractility (ICON; units) was significantly increased in group 2 at 5 minutes compared with group1 (114.2 vs. 83.8). Hematocrit (%) and total bilirubin concentrations (mg/dL) at 24 hours were significantly increased in group 2 compared with group 1 (51.5 vs. 40.5 and 3.8 vs. 2.9, respectively). Conclusion Stroke volume and cardiac output are significantly higher in neonates with DCC at 120 seconds compared with 30 seconds that continues for the first 24 hours. Key Points CO is significantly increased with DCC at 120 seconds. SV is significantly increased with DCC at 120 seconds. Such effects continued during the entire 24 hours of life in full-term infants. [ABSTRACT FROM AUTHOR]

Introduction: Low-dose ketamine infusions have shown analgesic effectiveness for the management of postoperative pain. The impact of low-dose ketamine infusions on cardiovascular response is dose-dependent and requires a better knowledge about its effects on this population. Objective: To conduct a systematic review to describe changes in systolic, diastolic and mean arterial pressure, and heart rate 24, 48 and 72 hours after surgery. Methods: Randomized, controlled trials were reviewed in the Cochrane Library, PubMed, EMBASE, SciELO, Lilacs and grey literature on low-dose ketamine infusions for the study variables. The quality of the studies was assessed using the Cochrane's risk of bias tool. Results: Six randomized, controlled trials with 641 patients were included. Low-quality evidence was found suggestive of a lack of certainty of any significant differences in the systolic blood pressure variables at 24 hours (mean standard deviation -1.00, 95 % CI: -7.27 to 5.27). A statistically significant higher mean heart rate at 24 hours was identified in the low-dose ketamine infusion group, (mean standard deviation 1.64 95 % CI: 0.38 to 2.90) which did not reach clinical significance. A lower pain level and less use of opioids was identified in the low-dose ketamine infusion group. Conclusions: Low quality evidence was found, suggesting that low-dose ketamine infusions are not associated with significant changes in blood pressure or heart rate 24 -- 48 hours after surgery. It is important to individualize cardiovascular risk for each case, before initiating treatment. [ABSTRACT FROM AUTHOR]

Purpose: We conducted a meta-analysis to determine the effect of hyperoxia on muscle sympathetic nerve activity in healthy individuals and those with cardio-metabolic diseases. Methods: A comprehensive search of electronic databases was performed until August 2022. All study designs (except reviews) were included: population (humans; apparently healthy or with at least one chronic disease); exposures (muscle sympathetic nerve activity during hyperoxia or hyperbaria); comparators (hyperoxia or hyperbaria vs. normoxia); and outcomes (muscle sympathetic nerve activity, heart rate, blood pressure, minute ventilation). Forty-nine studies were ultimately included in the meta-analysis. Results: In healthy individuals, hyperoxia had no effect on sympathetic burst frequency (mean difference [MD] − 1.07 bursts/min; 95% confidence interval [CI] − 2.17, 0.04bursts/min; P = 0.06), burst incidence (MD 0.27 bursts/100 heartbeats [hb]; 95% CI − 2.10, 2.64 bursts/100 hb; P = 0.82), burst amplitude (P = 0.85), or total activity (P = 0.31). In those with chronic diseases, hyperoxia decreased burst frequency (MD − 5.57 bursts/min; 95% CI − 7.48, − 3.67 bursts/min; P < 0.001) and burst incidence (MD − 4.44 bursts/100 hb; 95% CI − 7.94, − 0.94 bursts/100 hb; P = 0.01), but had no effect on burst amplitude (P = 0.36) or total activity (P = 0.90). Our meta-regression analyses identified an inverse relationship between normoxic burst frequency and change in burst frequency with hyperoxia. In both groups, hyperoxia decreased heart rate but had no effect on any measure of blood pressure. Conclusion: Hyperoxia does not change sympathetic activity in healthy humans. Conversely, in those with chronic diseases, hyperoxia decreases sympathetic activity. Regardless of disease status, resting sympathetic burst frequency predicts the degree of change in burst frequency, with larger decreases for those with higher resting activity. [ABSTRACT FROM AUTHOR]

This work proposes a highly sensitive sandwich heterostructure multimode optical fiber microbend sensor for heart rate (HR), respiratory rate (RR), and ballistocardiography (BCG) monitoring, which is fabricated by combining a sandwich heterostructure multimode fiber Mach–Zehnder interferometer (SHMF-MZI) with a microbend deformer. The parameters of the SHMF-MZI sensor and the microbend deformer were analyzed and optimized in detail, and then the new encapsulated method of the wearable device was put forward. The proposed wearable sensor could greatly enhance the response to the HR signal. The performances for HR, RR, and BCG monitoring were as good as those of the medically approved commercial monitors. The sensor has the advantages of high sensitivity, easy fabrication, and good stability, providing the potential for application in the field of daily supervision and health monitoring. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative non-contact heart rate monitoring method based on Wi-Fi Channel State Information (CSI). This approach integrates both amplitude and phase information of the CSI signal through rotational projection, aiming to optimize the accuracy of heart rate estimation in home environments. We develop a frequency domain subcarrier selection algorithm based on Heartbeat to subcomponent ratio (HSR) and design a complete set of signal filtering and subcarrier selection processes to further enhance the accuracy of heart rate estimation. Heart rate estimation is conducted by combining the peak frequencies of multiple subcarriers. Extensive experimental validations demonstrate that our method exhibits exceptional performance under various environmental conditions. The experimental results show that our subcarrier selection method for heart rate estimation achieves an average accuracy of 96.8%, with a median error of only 0.8 bpm, representing an approximately 20% performance improvement over existing technologies. [ABSTRACT FROM AUTHOR]

Background and Objective: COVID-19 has been associated with more than 770 million cases and 6.9 million deaths worldwide, since the first case was reported in 2019 in Wuhan, China. Various demographic and clinical factors have been associated with high mortality. We retrospectively analyzed data of patients admitted to our Intensive Care Unit (ICU) with moderate to severe disease for association of mortality with baseline clinical parameters and lab values. Methodology: Retrospectively, data was collected for patients admitted to ICU of our hospital from March 2021 to August 2021, with moderate to severe covid infection. A total of 399 patients were included in the analysis after exclusion of patients with incomplete outcome data. Analysis was initially performed to find association of baseline parameters with ICU mortality; stratified analysis was further performed for association with various age groups. Results: There was significant association of increased mortality with higher baseline heart rate (> 100 bpm), respiratory rate (> 30 bpm), low PaO2/FiO2 (< 100), Low oxygen saturation (< 80%), high neutrophil/lymphocyte ratio (> 10) and high baseline proBNP (> 500); however, subgroup analysis in the study showed that increased respiratory rate and increased neutrophil/lymphocyte ratio were not associated with increased mortality in patients with ages less than 50 y. Conclusion: Baseline higher baseline heart rate, respiratory rate, low PaO2/FiO2, Low oxygen saturation, high neutrophil/lymphocyte ratio and high baseline proBNP were found to be associated with higher mortality in COVID patients. However, higher respiratory rate and higher neutrophil/lymphocyte ratio were not associated with increased mortality in patients with age less than 50 y. [ABSTRACT FROM AUTHOR]

Imagery has been associated with cardiovascular and psychological responses to stress; however, the mechanisms underlying this association are not fully understood. The present study examined if the ability to image mastering challenging or difficult situations moderated the relationship between heart rate reactivity and perceptions of stress and physiological arousal experienced during acute stress. Four hundred and fifty‐eight participants completed a standardized laboratory stress protocol with heart rate being measured throughout. After completing an acute psychological stress task, participants rated how stressed and physiologically aroused they felt (i.e., intensity) and whether they perceived the stress and physiological arousal as being helpful/unhelpful to performance (i.e., interpretation). Mastery imagery ability was assessed by questionnaire. Moderation analyses controlling for gender demonstrated that imagery ability moderated the relationship between heart rate reactivity and interpretation of stress (β = 0.015, p =.003) and perceived physiological arousal (β = 0.013, p =.004). Simple slope analysis indicated that in those with higher imagery ability, heart rate reactivity was associated with stress and arousal being perceived as more positive toward performance. Imagery ability did not moderate the relationship between heart rate reactivity and perceived stress intensity or physiological arousal intensity (p's >.05), but imagery ability did predict lower perceived stress intensity (β = −0.217, p <.001) and perceived physiological arousal intensity (β = −0.172, p <.001). Higher mastery imagery ability may possibly help individuals perceive responses to stress as more beneficial for performance and thus be an effective coping technique. While previous research has shown imagery being associated with cardiovascular and psychological responses to stress, the mechanisms underlying this association are not fully understood. By evidencing that imagery ability moderates the relationship between heart rate reactivity and interpretation of stress and perceived physiological arousal, we demonstrate a mechanism through which higher mastery imagery ability could help individuals perceive responses to stress as more beneficial for performance. [ABSTRACT FROM AUTHOR]

Purpose: Intermittent pneumatic compression (IPC) applies gradual pressure to facilitate lymph and blood flow movement to reduce exercise-induced tissue fluid accumulation and plasma volume loss. This study aimed to evaluate the cardiovascular system response during the recovery with IPC compared with passive recovery (Sham). Methods: Sixteen volunteers (7 females and 9 males) executed a cycling-based exhausting sprint interval exercise (8 × 20 s all out), followed by a 30-min IPC or Sham condition. Participants performed two trials in a randomised, counterbalanced, and crossover design. Several cardiovascular parameters (blood pressure, heart function, and peripheral vascular resistance) were recorded at baseline (5ʹ), through the recovery protocol (30ʹ), and afterwards (5ʹ). Results: The use of IPC during the recovery phase led to a faster recovery, stated in relative values to pre-exercise, in mean blood pressure (102.5 ± 19.3% vs. 92.7 ± 12.5%; P < 0.001), and cardiac output (139.8 ± 30.0% vs. 146.2 ± 40.2%; P < 0.05) in comparison to Sham condition. Furthermore, during the IPC-based recovery, there was a slower recovery in cardiac pressure change over time (92.5 ± 25.8% vs. 100.5 ± 48.9%; P < 0.05), and a faster return to pre-exercise values in the peripheral vascular resistance (75.2 ± 25.5% vs. 64.8 ± 17.4%; P < 0.001) compared to Sham. Conclusion: The application of IPC after high-intensity exercise promotes the recovery of the cardiovascular system, reducing cardiovascular strain. Future investigations should consider the effects on the sympathetic-parasympathetic balance, such as heart rate variability, to assess further bonds between the use of IPC and autonomous control. [ABSTRACT FROM AUTHOR]

Objective: To assess the impact of intravascular laser irradiation of blood (ILIB) on the primitive carotid artery (PCA) hemodynamic variables, specifically blood pressure (BP) and heart rate (HR), in mastectomized patients undergoing hormone blocker treatments. Materials and methods: This study is a controlled, experimental, and randomized clinical trial. Patients were allocated into two groups: the experimental group (G1)--patients who received ILIB therapy using a 660 nm laser targeted at the PCA, and the control group (G2)--patients who did not receive ILIB therapy. Clinical research was conducted weekly, with measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR. The Mann-Whitney U test for independent samples was used, with a significance level of a = 0.05. Results: Systemic photobiomodulation on the PCA did not demonstrate a statistically significant difference in relation to SBP and DBP. However, for HR, the p-value was <0.05, indicating a significant difference between G1 and G2. The initial mean p > decreased from 142.3 to 116.4mmHg in G1, and from 130.4 to 119.8mmHg in G2. The DBP varied from 78.8 to 72.8mmHg in G1, and from 79.1 to 74.2mmHg in G2. A statistically significant difference was observed in HR, decreasing from 81.3 to 62.06 bpm in G1, and changing minimally from 74.1 to 75.1 bpm in G2. A considerable reduction was present in the timing of application. Conclusions: ILIB therapy applied to the PCA induces a reduction in BP and, more notably, HR in mastectomized women using the tamoxifen or aromatase inhibitors. [ABSTRACT FROM AUTHOR]

Continuous monitoring of multiple physiological parameters, such as glucose levels, temperature, and heart rate variability (HRV) is crucial for effective diabetes management and mitigating the risks associated with hypoglycemic events. These events often occur without apparent symptoms, posing a challenge for diabetic patients in managing their condition. Therefore, a non‐invasive wearable device capable of continuously measuring multiple body signals to predict hypoglycemic events would be highly beneficial. In this study, a wearable patch that continuously measures glucose, temperature, and HRV is presented. The device uses a novel power harvesting system to convert radiofrequency (RF) signals with the frequency of 2.45 GHz to direct current (DC) signals to extend the battery life for further continuous monitoring. The patch is small and has a conformal structure that can easily fit onto different body parts. The screen‐printed glucose sensor demonstrates a sensitivity of 10.3 nA cm−2 µM−1, a limit of detection (LOD) of 8.9 µM, and a limit of quantification (LOQ) of 27 µM. The device employs a photoplethysmography (PPG) module with a peak‐finding algorithm to calculate the HRV values. In vivo experiments demonstrate the validation of the device's proper operation in glucose, HRV, and temperature measurement. [ABSTRACT FROM AUTHOR]