Changes In Heart Rate Research Articles

ASSESSMENT OF FIREFIGHTERS’ SAFETY DURING EXERCISES AND TRAINING IN A SMOKE CHAMBER

In the process of vocational training, firefighters undergo a series of refresher exercises and tests(examinations) to verify their resilience to factors that may be encountered during actual rescueoperations. One such training is smoke chamber exercises and tests, which examine firefighters’resilience to psychophysical stresses in conditions close to real life. Orientation, the ability tomove in smoke-logged conditions and in confined spaces are all tested during improvementdrills. This article presents the results of a study aiming to establish the safety level of firefightersduring exercises and tests in a smoke chamber, based on selected criteria, which comprised thenumber of firefighters on the training path, the length of the training path, the capacity of thecompressed air cylinders, the change in heart rate while traversing the training path, the BMIindex, the knowledge of operating respiratory protection equipment (RPE), the physical workload,the rate of air consumption while traversing the training path and the cognitive abilities of the testparticipants. This paper examines legal considerations and occupational risks for firefighters duringsmoke chamber exercises and tests. Identified organisational factors and individual behavioursaffecting the safety of trainees and techniques of risk-reducing measures are presented, as well asfirefighters’ own safety assessment criteria. Also presented are the results of experimental, surveyand psychometric studies. The research comprised a group of 50 firefighters, both professional andvolunteer, including 46 men and four women. The results of the research work showed that theeffect of short-term exposure to a psychophysical load generated by smoke chamber conditionshas a significant impact on cognitive abilities. It was shown how organisational factors and theindividual behaviour of each firefighter affect their safety during smoke chamber exercises andtests, and solutions were proposed to improve this safety.

Abstract 4118444: Right Ventricular Contractile Reserve and Right Ventricular-Pulmonary Arterial Coupling Are Impaired in Long-Term Survivors of Childhood Cancers

Background: Childhood cancer survivors are at risk of right ventricular (RV) dysfunction in relation to cardiac toxicity due to chemotherapy and radiation therapy. This study tested the hypothesis that RV contractile reserve and RV-pulmonary arterial (PA) coupling are altered in long-term survivors of childhood cancers. Methods: Thirty survivors (60% men) aged 24.3 ± 5.2 years at 15.3 ± 6.3 years after completion of chemotherapy and thirty healthy control subjects (47% men) were studied. Resting and submaximal supine bicycle stress echocardiography was performed for assessment of RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), left ventricular (LV) and RV longitudinal strain, mitral and tricuspid annular velocities and myocardial acceleration during isovolumic contraction (IVA). The slope of the RV force-frequency relationship was derived from the change in IVA with the change in heart rate during exercise (△IVA/△heart rate), while RV-PA coupling was determined by the ratio between TAPSE and pulmonary arterial acceleration time indexed to RV ejection time (PAATi). Results: At rest, tricuspid annular systolic velocity and RV systolic strain were significantly lower in survivors ( P < 0.05 for both), while RV FAC, TAPSE and IVA were similar between the two groups ( P > 0.05 for all). During submaximal exercise testing, all RV systolic functional indices were significantly lower in survivors than controls ( P < 0.05 for all). The slope of the RV force-frequency relationship was significantly flatter in survivors compared to controls (0.038 ± 0.002 vs 0.059 ± 0.003 m/sec 2 beats/min, P < 0.001). For RV-PA coupling, TAPSE/PAATi was similar between survivors and controls at baseline but became significantly lower in survivors during submaximal exercise ( P = 0.002). Conclusions: The RV contractile reserve and RV-PA coupling are impaired during exercise in long-term survivors of childhood cancers. Future studies aimed at determining the clinical and prognostic significance of these impairments are warranted.

Abstract 4136181: Automated Personalized Modulation of the Sympathetic “fight-or-flight” Reflex In Vivo Using Implantable Microdevices for Enhancing Neurocardiac Function and Reducing Mortality Risk.

Background: The sympathetic nervous system (SNS) is a critical regulator of cardiovascular function. Whereas acute SNS activation elicits positive inotropy and confers survival advantage, persistent SNS hyperactivity is maladaptive and can lead to arrhythmias, cardiac arrest and heart failure. Hypothesis: Automated optogenetic modulation of the sympathetic stress response in vivo enhances neurocardiac function while avoiding sympathetic hyperactivity-mediated pathological effects. Methods: In normal guinea pigs, we virally transduced excitatory and/or inhibitory channelrhodopsins to the stellate ganglia (SG), the primary sympathetic input to the heart. We studied in situ effects of graded activation of SG opsins (e.g., phasic vs tonic) on cardiac function (e.g., ECG, heart rate) with and without perfusing agents (e.g., β-blockers, antioxidants). In vivo studies used novel implanted µLED devices for wireless body signal streaming (e.g., ECG) and neurophotonic SG opsin modulation closed-loop to dynamic analyses of physiological demand versus ECG-based cardiac risk prediction. Results: Compared to baseline heart rate (218±16 bpm), pulsed activation of inhibitory opsins reduced heart rate by ~25% (156±12; delta=67±14 bpm; p<0.0003; N=5). Pulsed activation of excitatory opsins increased heart rate by ~30% (285±28; delta=65±19 bpm; p<0.0002; N=5). Interestingly, prolonged (>20 min) tonic excitation of the SG caused desensitization, possibly as an intrinsic safety mechanism. Whereas graded SG excitation or inhibition at different LED intensities elicited prompt changes in heart rate, repeated activation of excitatory opsins led to quick desensitization. Our ongoing studies are aimed at understanding how and when SG modulation can enhance cardiac function, trigger intrinsic cardioprotective mechanisms, or cause pathological effects. Conclusion: Automated neurophotonic optogenetic excitation or inhibition of the SG is a robust personalized strategy for modulating cardiovascular function. The ability to rapidly and accurately modulate the sympathetic stress reflex in a graded manner can lead to more timely, effective, and appropriate physiological responses while avoiding undesired pathophysiological responses.

Exploring the Multidimensional Influences on Sleep and Active Heart Rate Dynamics: A Comprehensive Study

This study offers an in-depth examination of how various social, personal, physiological, environmental, and behavioral factors are associated with both sleep and active heart rate dynamics among college students. Utilizing data collected from 487 participants over a span of 637 days via wearable technology, this research aims to unravel the intricate relationships that influence heart rate variations. Through the application of latent growth-curve modeling, we meticulously analyzed the trajectory of heart rate changes and their associations with a broad spectrum of influencing factors. This methodological approach allowed for a nuanced understanding of the dynamic interplay between heart rate and its determinants over time. The analysis revealed a consistent increase in both sleep and active heart rates across the study period, accompanied by stable standard deviations. Peer influence significantly impacted sleep and active heart rates, especially at rest. Gender and race/ethnicity were associated with heart rate dynamics, as were conscientiousness and depression levels. Environmental factors, including days of the week, academic periods, and weather conditions, exhibited significant effects. Behavioral factors, such as physical activity and daily class attendance, played a substantial role in heart rate patterns. Our findings underscore the complex interplay of factors influencing heart rate dynamics in young adults. Tailored interventions should consider these multifaceted influences to promote optimal cardiovascular well-being.

Short‐Term Safety of Nutri‐Jelly in Adults Undergoing Hemodialysis

ABSTRACTExcessive water consumption from liquid or reconstituted oral nutrition supplements may increase risk of fluid overload in renal patients. Nutri‐jelly, a ready‐to‐eat texture‐modified diet with 52.8% water, some protein, low potassium, phosphorus, and sodium, could be an alternative. However, its safety is unknown for adults undergoing hemodialysis (HD). This study investigated the short‐term physiological safety of Nutri‐Jelly intake and its preliminary impact on renal outcomes. A randomized open‐label, single‐arm, two‐sequence, two‐period cross‐over trial was conducted in 20 adults undergoing HD with inadequate protein intake (0.50 ‐ 0.70 g/ kg body weight/day). Participants were randomly allocated into 2 groups (n =10 each) and assigned in random sequence into both Without‐Jelly (HD 3 times during 7 days) and With‐Jelly periods (100 g Nutri‐Jelly twice daily along with HD 3 times during 7 days). A two‐week washout was between the periods. Outcome measures included adverse symptoms, changes in body weight, heart rate, blood pressure, and blood biochemical parameters relevant to renal outcomes. The results showed no intervention‐related adverse symptoms or significant changes in body weight, heart rate, systolic blood pressure, creatinine, albumin, and sodium. Potassium level and pre‐HD diastolic blood pressure were better controlled during the With Jelly than the Without Jelly Periods (p < 0.01 and p < 0.05, respectively). The eGFR was improved with no significant difference between the periods. The findings suggest that continuous intake of 100 g Nutri‐Jelly twice daily for 7 days is safe in adults undergoing hemodialysis. Its efficacy on renal‐related parameters warrants further investigations in long‐term studies.

Ciprofol versus propofol for anesthesia induction in cardiac surgery: a randomized double-blind controlled clinical trial.

Ciprofol, a novel intravenous general anesthetic with a chemical structure similar to propofol, exhibits significantly enhanced potency. It offers a rapid onset, reduced incidence of injection pain, and has comparable effects on heart rate and blood pressure to propofol. However, clinical data on its use for anesthesia induction in cardiac surgery remain limited. Seventy-eight patients undergoing coronary artery bypass grafting or valve replacement surgery were randomly assigned to receive either ciprofol (N = 40) or propofol (N = 38) for anesthesia induction. Variables recorded included changes in mean arterial pressure and heart rate during anesthesia, alterations in the oxygenation index and lactic acid concentration before and 10min after anesthesia induction, and the incidence of adverse events such as bradycardia, hypotension, and injection pain. The incidence of anesthesia-induced injection pain was significantly lower in the ciprofol group compared to the propofol group (3% vs. 18%, P < 0.05). The incidence of other adverse events was similar between the groups. No significant differences in hemodynamics or oxygenation index were observed during anesthesia induction between ciprofol and propofol. Ciprofol demonstrated a significantly lower incidence of injection pain compared to propofol, potentially improving patient comfort during anesthesia induction. Additionally, ciprofol showed comparable circulatory stability to propofol during anesthesia induction in cardiac surgery, suggesting it may be a suitable alternative to propofol for this application. The trial was registered at the ClinicalTrials.gov on 03/10/2024 (NCT06312345).

Exposure to Pyriproxyfen Impacts Heart Development Causing Tissue and Cellular Impairments, Heart Arrhythmia and Reduced Embryonic Growth.

In recent years, concerns have been raised regarding the safety of exposure topyriproxyfen (PPF), a larvicide commonly used in drinking water reservoirs to control populations of disease-vector mosquitoes for human safety. These concerns are focused mainly on exposure by pregnant women, since studies have shown deleterious effects of PPF on embryonic development, mainly addressing the central nervous system. However, since previous studies showed reduced growth in embryos exposed to PPF, we hypothesize that PPF exposure impairs the cardiovascular system, responsible for ensuring appropriate blood supply, which leads to stunted growth. This study aimed to investigate the impact of PPF exposure on heart ventricular morphology, its influence on cell proliferation and apoptosis, as well as assess the impact on the functionality of the heart and on embryonic growth. Chicken embryos were used as a model and two sublethal concentrations were tested: 0.01mg/L and 10mg/L PPF. Thinning of cardiac tissue was evident in heart structuresat 10mg/L PPF. Furthermore, DNA double-strand breaks and reduced cell proliferation were observed, combined with decreased apoptosissuggesting cell cycle arrest, especially in the left ventricle for both concentrations. In addition, these PPF concentrations induced heart arrhythmia, although no changes in heart rate were observed. Embryos exposed to 0.01mg/L showed reduced body and heart mass, crown-rump length, and thoracic perimeter, while head circumference was reduced in both exposed groups. Together, combining morphological, molecular, and physiological parameters, this study showed the cardiotoxic effects of PPF exposure and elucidated its impacts on embryonic growth.

ETHOLOGICAL AND VEGETATIVE CORRELATES OF EXPERIMENTAL NEUROGENIC STRESS

The study aimed to comprehensively investigate the ethological and vegetative mechanisms involved in the development of experimental emotional stress, establish the relationship between these correlates, and identify an indicator or group of indicators with prognostic value for the occurrence of cardiac dysfunction under neurogenic stress conditions. Materials and Methods. The study presents the results of research on the ethological and autonomic correlates of emotional stress in 254 sexually mature male Wistar rats, using the "afferent excitation conflict" model. Results. Heart rhythm was studied electrocardiographically as an autonomic correlate of emotional stress. The results of the research have shown that ethological and vegetative reactions that perform regulatory and adaptive functions are constant and natural correlates of emotional stress states. The data obtained allow us to note that animals of all three typological groups responded to the onset of stress with a tendency to increase heart rate. Prolonged exposure to the conflict situation was associated with a return of heart rate to baseline values in animals of groups I and II, and a significant decrease in heart rate in animals of group III. Qualitative analysis of the variation curves showed that vagotonic (right position of the variation curve – right graph) prevailed in animals of group I before stress exposure, and sympathotonic (left graph) regulatory influences on the sinus node prevailed in the animals of group III. The onset of stress exposure led to a leftward shift of the variation curves in animals of all groups. However, in animals of group I, this shift was accompanied by a widening of the variation curves (83%), and in animals of group III – by a narrowing (67%). Conclusion. As a result of the studies, four types of heart rate changes were identified during prolonged (3-hour) exposure to stress. A correlation was established between the ethological and typological characteristics of the animals and the occurrence of cardiac rhythm disorders. In animals with a high frequency of cardiac arrhythmias under stress, there was also an increased influence of the sympathetic nervous system on the sinus node, accompanied by a decrease in heart rate variability. Animals with a high frequency of cardiac arrhythmias under stress also showed an increase in the influence of the sympathetic nervous system on the sinus node but with a decrease in heart rate variability.

Infants show negative changes in affect and physiology when re-experiencing a stressor, its context, and a positive event 24-h later.

Exposure to early life stress shapes further development, affects later stress reactivity, and mental health outcomes. Despite the central role of early experiences, there is little understanding of how these rapidly forgotten events gain their influence. An infant's ability to cope with everyday stressors is founded on successful co-regulation through mother-infant interaction. A significant disruption of this interaction through the Face-to-Face Still-Face paradigm elicits a well-documented behavioral and physiological stress response in infants. What has yet to be explored is whether infants show regulatory adaptions when encountering the situation over again. To fill this gap, 80 mother-infant dyads were observed in the lab on two consecutive days. Infants in the experimental condition (n=40) were exposed to a double Still-Face paradigm on day one. Infants in the control group (n=40) completed time-matched episodes of typical play during their first visit. Mother-infant dyads from both groups returned to the lab 24h later and participated in the double Still-Face paradigm. Changes in behavior (positive and negative affect), physiology (heart rate), and salivary cortisol, compared to day one and between groups, were evaluated and used to infer adaption to the previous experienced laboratory visit. Infants in the experimental condition showed a significant decrease in positive affect (p=0.016) and an increase in heart rate (p<0.001) on day two, compared to controls, even during baseline measures and a neutral first play episode. Infants in the control condition showed a significant decrease in affect (p=0.05) and non-significant increase in heart rate on day two when first encountering the Still-Face paradigm. Infants in the experimental condition showed significant higher heart rate on day two compared to the control group (p=0.046). Infants in the experimental condition also exhibited a marginally significant increase in salivary cortisol on day two, compared to day one (p=0.054). The change in infant heart rate was independent of maternal heart rate which did not differ between day one and day two, or between groups. Findings suggest that a previous stressful experience may elicit a behavioral and physiological adaption in infants 24h later. Our results suggest that even a short, acute stressful event can elicit a lasting stress response in infants 24h later. The effect we observed was specific to the context of the stressful event, not just the stressor. More precisely, the effect "spilled over" from the stressful experience on day one into the baseline measure of day two, usually a neutral experience. The results could have implications for further research on how stressful experiences may shape the stress response.

Comparative efficacy of ciprofol and propofol in reducing respiratory depression during ERCP anesthesia: a randomized controlled trial

BackgroundPropofol is one of the important drug causes of respiratory depression in endoscopic retrograde cholangiopancreatography (ERCP) anesthesia. This study aims to clarify whether Ciprofol in ERCP anesthesia reduces the respiratory depression rate.MethodsIn this randomized controlled trial performed at the Surgical Endoscopy Center, the First Hospital of Lanzhou University between Jun 01, 2022 and Feb 20, 2024, patients undergoing ERCP anesthesia were randomly assigned into ciprofol (study group) or propofol (control group). Primary outcomes included respiratory depression rate during anesthesia, and secondary outcomes included body movement and hypoxemia, awakening time, mean arterial pressure and heart rate changes at key points during surgery.Results20 of the 306 patients had respiratory depression (6.5%). The frequency of respiratory depression was 3.3% in the group C and 9.8% in the group P, with a difference of 6.5% between the two groups (P = 0.035). Ciprofol anesthesia decreased the hyoxemia, injection pain, and circulation and heart rate fluctuations. Multivariable logistic regression analyses showed that Propofol (OR 1.970; 95% CI, 1.121–3.461, P = 0.018), mallampati classification>II (OR 1.594; 95% CI, 1.129–2.249, P = 0.008), and fasting time>10.5 h (OR 3.184; 95% CI, 1.531–6.621, P = 0.002) were independent risk factors for incidence of respiratory depression in ERCP anesthesia.ConclusionsFor patients undergoing anesthesia for ERCP, Ciprofol, compared to Propofol, has been shown to effectively reduce the incidence of intraoperative respiratory depression, thereby enhancing the safety of the anesthesia process.Trial registrationThis study was registered in the Chinese Clinical Trial Registry on 15/01/2022 (ChiCTR2200055629).

Pulsation artifact reduction using compressed sensitivity encoding in Gd-EOB-DTPA contrast-enhanced magnetic resonance imaging.

In Gd-EOB-DTPA-enhanced MRI, cardiac pulsation artifacts in the left lobe often hinder diagnosis, the image quality need to improve. This study aimed to reduce cardiac pulsation artifacts in Gd-EOB-DTPA-enhanced three-dimensional (3D) T1-weighted turbo-field echo (3D-T1TFE) using compressed sensitivity encoding (CS).For phantom evaluation, the cardiac phantom was manually operated using a metronome-synchronized apparatus, comprising a bag-valve mask, a breathing circuit, and a Jackson-Rees system. Transverse images of a liver phantom were acquired using enhanced T1 high-resolution isotropic volumetric excitation with CS (CS-eTHRIVE) and sensitivity encoding (S-eTHRIVE). For evaluation, images obtained during cardiac phantom operation were subtracted from those obtained when the phantom was stationary. Standard deviation (SD) of the difference images was used as the evaluation metric, and assessments were conducted based on changes in heart rate and TFE factor. For clinical image evaluation, artifacts in hepatobiliary phase images acquired 15min after Gd-EOB-DTPA injection in the order of S-eTHRIVE and CS-eTHRIVE were visually evaluated at four levels. In heart-rate evaluation (40, 60, and 80 beats/min), CS-eTHRIVE revealed significantly lower SD values compared to S-eTHRIVE across all heart rates (P < 0.01), with no significant differences between heart rates. For TFE factor evaluation, CS-eTHRIVE with a factor of 35 exhibited the lowest SD, which was significantly different from all other groups (P < 0.01). In clinical image evaluation, CS-eTHRIVE achieved higher visual scores (mean ± SD: 3.72 ± 0.46) compared with S-eTHRIVE (2.72 ± 0.98, P < 0.01).CS reduced pulsation artifacts in Gd-EOB-DTPA-enhanced 3D-T1TFE.

To Hear or Not to Hear: Cognitive Load Theory and Learning

ABSTRACT Background: Cognitive load is the amount of information one’s working memory can process at any given time. Key components of cognitive load include germane load, intrinsic load, and extraneous load. Learning is hindered if overload occurs, thus reducing cognitive performance. This study addresses the impact of auditory stimulation on cognitive load through repeated recognition tasks. Methods: Twenty-eight Queen’s University students were recruited and randomly allocated to control and experimental groups who completed the experiment with noise-cancelling headphones and with ambient noise, respectively. The experiment consisted of learning and testing phases. The learning phase involved memorizing a series of words. Subsequently, the testing phase required participants to recall words from the list. Each trial consisted of one learning and one testing phase, with three trials per participant. Cardiovascular measurements were taken prior to the experiment, at the beginning of each phase, and after each trial was completed. Results: Primary outcomes demonstrated that the experimental group experienced greater percent changes in heart rate and rate pressure product, higher perceived mental effort, and greater within-group variation for heart rate compared to controls. Scores decreased as trials progressed. Secondary outcomes showed that the top 33% of participants were less susceptible to changes in heart rate and blood pressure. Overall, four heart rate or blood pressure responders were identified. Conclusions: Exposure to 70 decibels of ambient noise contributes to cognitive load as noted by elevated cardiovascular measure and perceived mental effort. Results can inform educational platforms and hospital logistics.

Music’s Influence on Cardiovascular Parameters During Cognitive Testing

BackgroundMozart’s music has been found to decrease stress and anxiety by decreasing blood pressure and heart rate in diverse populations. However, the influence on Mozart during cognitive tests remains unclear. Due to its proven anti-stress effects, Mozart’s music may be an effective tool for decreasing cardiovascular parameters during cognitive testing. MethodsThe cognitive test chosen was an untimed pattern-recognition Mensa test. The chosen song was Mozart’s Sonata K448. We included 10 adult participants who met the inclusion criteria. A matched pair study design was incorporated. All participants completed a diagnostic test that assessed relative cardiovascular sensitivities to the acute stress produced by the Mensa test. Participants were matched based on cardiovascular sensitivities, rating of momentary stress, and sex. Pairs were then randomly allocated to take the test again; one took the test while listening to Mozart’s Sonata K448, the other took it in silence. Post-test evaluations were then completed. ResultsIn both groups, the intervention did not induce significant changes in BP or HR, except for a significant decrease in SBP in the no music group (p=0.043). When comparing the difference in relative blood pressure and heart rate changes between the two groups, none were significantly different. There were significant decreases in perceived stress and increases in perceived relaxation in the music group (p=0.024 and p=0.039, respectively). ConclusionOur findings suggest that Mozart’s music does not decrease cardiovascular responses during cognitive testing. Additionally, perceived stress is independent of cardiovascular indicators of stress which has unknown implications.

Spectral EEG and heart rate changes associated with leg movements during the suggested immobilization test in patients with restless legs syndrome.

Restless legs syndrome is usually associated with periodic limb movements during sleep, which are defined as repetitive, stereotyped movements in sleep. Changes in spectral analysis of electroencephalography and heart rate were shown to be associated with periodic limb movements during sleep and non-periodic leg movements in sleep. Considering the circadian distribution of symptoms of restless legs syndrome, we investigated spectral electroencephalography and heart rate accompanying periodic limb movements, isolated leg movements and short-interval leg movements during suggested immobilization test. The mean age of 53 patients was 51.9 ± 13 years, 54.7% were females. Prominent increases in electroencephalography activation were associated with periodic limb movements, isolated leg movements and short-interval leg movements during the suggested immobilization test, which were significant in all spectral bands (p < 0.001). An increase in all electroencephalography bands started ~10 s before periodic limb movements, isolated leg movements and short-interval leg movements; increases in delta and theta band activities ended ~10 s after the movements, while increases in alpha and beta band activities lasted for about ~20 s. Maximum increases in delta, theta, alpha and beta bands were all observed after periodic limb movements and short-interval leg movements, but before isolated leg movements in theta and alpha bands, and after isolated leg movements in delta and beta bands. A notably longer increase in alpha and beta bands was evident for periodic limb movements and short-interval leg movements. An increase in heart rate was prominent at 4-12 s after movement onset in short-interval leg movements, being significantly higher than those associated with periodic limb movements and isolated leg movements. Our study shows that, in patients with restless legs syndrome, periodic limb movements, isolated leg movements and short-interval leg movements during suggested immobilization test are associated with prominent cortical and cardiac activation, which warrants confirmation in larger restless legs syndrome cohorts and requires long-term follow-up studies to delineate its possible clinical consequences.

Systolic Function in the Fontan Circulation is Exercise, but not Preload, Recruitable.

Fontan circulatory failure with impaired systolic function is well documented; however, its mechanisms are not fully understood. We aimed to explore the myocardial functional reserve in adolescent patients with Fontan circulation in response to exercise or acute preload increase. Our study comprised 32 patients (median age: 16.7 years, range: 15.4-17.9 years, 12 females) with Fontan circulation. Echocardiographic imaging was performed during exercise using a recumbent cycle ergometer and during heart catheterization with a rapid infusion of 0.9% saline infusion at 5 mL/kg body weight. We measured myocardial peak longitudinal strain (LS) in a 4-chamber view during specific time intervals before, during, and after the exercise (LSstress) and volume load (LScath). During catheterization, central venous pressure (CVP) and ventricular end-diastolic pressures (VEDP) were simultaneously recorded. A control group of 16 healthy individuals participated in the exercise test. The mean LSstress was less negative for patients than for controls (P≤0.001 at all stages); however, it significantly improved from -18.4±5.5% at baseline to -22.0±6.5% (P=0.004) at maximal loading. LSstress at maximal loading did not correlate with changes in heart rate. During catheterization, the mean LScath was -19.6±6.0% at baseline and did not improve significantly at 1.00-2.00 min and at 4.00-6.00 min after saline infusion. In more than half of the patients, LScath worsened or improved with less than -2% after the saline infusion. Worsening in LScath correlated with CVP and VEDP in all conditions (P≤0.017). There was no difference in LSstress or LScath between the morphological right ventricle and the morphological left ventricle. Patients with Fontan circulation demonstrate systolic myocardial functional reserve that can be recruited with exercise stress but not with an acute increase in preload.

Heart Rate and Rhythm Changes in Dogs Treated in a Hyperbaric Oxygen Chamber

In veterinary medicine, hyperbaric oxygen chamber treatment (HBOT) is gaining popularity. Therefore, an increasing number of patients referred for this therapy are being recorded, mainly due to ischemic events, wound healing support, and a high risk of reperfusion damage. During the HBOT procedure, several changes occur in the body’s micro- and macroenvironments. This study involved 34 dogs of various ages and health statuses. The atmospheric conditions in the test hyperbaric chamber included a pressure of 1.5 atmosphere absolute (ATA) at 100% oxygenation. The individuals were divided into three groups: (1) individuals with degenerative mitral valve disease (DMVD), (2) individuals with diseases other than cardiac issues, and (3) healthy individuals who qualified for the HBOT procedure. The period of measurement using the Holter apparatus was divided into four stages: 30 min before the subject’s placement in the hyperbaric chamber; a 4-min compression period (setting chamber conditions); a 90 min HBOT period; and a 1 min decompression period of the hyperbaric chamber. During the HBOT, there was a statistically significant decrease in heart rate in groups 2 and 3 compared to group 1. The heart rate in group 1 remained unchanged through every period of the study. In addition, some of the dogs developed respiratory arrhythmia; in two dogs, premature ventricle beats occurred. The changes observed during the ventricular period indicate that the HBOT procedure causes a significant change in heart rate in dogs without cardiac diseases.

Electrocardiographic Changes in Second and Third Trimester in Bangladesh: A Comparative Study

Background: During pregnancy, there are notable changes in cardiovascular function to meet the increasing needs of the developing baby. The objective of this study was to compare ECG in pregnant women during their second and third trimesters with a control group of non-pregnant women in Bangladesh. This study aims to offer valuable insights into the cardiovascular changes that happen during pregnancy. This study's findings are important for maternal health research and clinical practice in Bangladesh and beyond. Objective: The purpose of this study is to analyze and compare the ECG variations in women during the second and third trimesters of pregnancy. Methods: The study took place in the gynecology Department at CMH Saidpur, Bangladesh. This study was conducted from March 2023 to August 2023. During this period, 75 pregnant patients in their 2nd trimester and 75 patients in their 3rd trimester were chosen as cases from antenatal outdoor, while 75 non-pregnant women of the same age were selected as the control group. We use the purposive sampling method. Results: During pregnancy, there were notable changes in BMI, heart rate, and PR interval. BMI decreased in the second trimester and increased in the third trimester.22.67% were nulliparous and 77.33% were multiparous in 2nd trimester. In the third trimester, 26.67% were nulliparous and 73.33% multiparous. So, no significant difference in parity. Heart rate increased in both trimesters, while the PR interval shortened in both trimesters. No significant changes were observed in the durations of the QRS complex or QT interval. In our study, the QTc interval displayed a significant rise. ST depression, which may suggest decreased blood flow, was exclusively seen in pregnant women, particularly in the third trimester. Conclusion: We found no significant changes in age, but BMI, heart rate, and PR interval were significantly different from the control group throughout pregnancy. No significant QRS complex or QT interval duration changes were identified. The QTc interval rose. ST depression, more prominent in the third trimester, only affected pregnant women. As shown by ST depression, pregnancy may change cardiac function, electrical activity, and ischemia.

Evaluating the effectiveness of quantitative pupillometry in assessing dynamic aerobic training intensity

Sports injuries often arise from improper scheduling of exercise loads, and timely assessment of these loads is essential for minimizing injury risk. This article investigates the validity of using changes in pupillary light reflex (PLR) during dynamic aerobic training as a novel approach to evaluating exercise load. Dynamic aerobic training was conducted on a power bicycle for 15 min. With a 3-minute interval as the demarcation line, PLR measurement was performed before training and heart rate was recorded throughout the process. The Rating of Perceived Exertion (RPE) scale invented by Borg was used for scoring before training and after training. The normal distribution of data was confirmed through the Shapiro-Wilk test. Pearson correlation analysis was used to quantify the correlation between variables. The Receiver Operating Characteristic (ROC) curve and the area under the curve (AUC) analysis were used to determine the indicators of exercise load. The optimal threshold of the indicators was calculated through the Youden index to evaluate sensitivity and specificity. Thirty male second-tier athletes with a mean age of 23.66 ± 2.21 years, a mean height of 175.3 ± 6.5 cm, and a mean weight of 68.99 ± 10.35 kg participated in this study. Based on the RPE scale results, it was confirmed that the 15-minute dynamic aerobic exercise successfully elicited varying levels of perceived exertion among the athletes. The findings of this study indicate significant changes in PLR and heart rate (HR) with increasing exercise duration and external load. There were strong correlations between RPE and maximum constriction velocity (MCV) (|r| = 0.8309, p < 0.001, negative correlation), maximum diameter (INIT) (r = 0.7641, p < 0.001, positive correlation), time to reach 75% recovery (T75) (|r| = 0.7289, p < 0.001, negative correlation), and HR (r = 0.8170, p < 0.001, positive correlation). Additionally, the results suggest that MCV is the most significant potential indicator for detecting internal load, exhibiting high specificity and sensitivity (AUC = 0.8509, p < 0.001). Further analysis using the Youden index identified 5.07 mm/s as the optimal cutoff value for MCV, indicating that when MCV ≤ 5.07 mm/s, the athletes’ internal load has reached an “Intense” state. PLR may be a potential indicator for assessing internal load Further investigation could involve developing a non-invasive exercise load detection system based on pupillary variable indicators, providing a valuable new approach for accurately measuring exercise load.

Wake-up with no pain: The Impact of Different Wake-up Ringtones on Awakening Status

The awakening process sets the tone for daily performance. Traditional alarm sounds like radar or sirens, are often abrupt and startling, which can trigger stress response and emotional problems. Existing research that focuses on human physiological indicators during arousal has not reached the impact of wake-up alarms. This study aims to apply photoplethysmographic (PPG) and electrodermal activity (EDA) sensors to meticulously assess the physical and emotional impact triggered by different alarm tones during wake-up process. Those includes human stress responses such as heart rate, EDA, and emotional state. We selected four type of alarm clock sounds, bird singing, ocean sound, radar sound and old telephone. Participants in this study will first put on EDA and PPG sensors before they take a quick sleep. Then, they will be awakened by either natural or harsh wake-up alarms without knowing it in advance. During the experiment, EDA and PPG sensors were used to monitor their physiological states and the data will be analyzed to identify stress patterns and trends. We specially focus on the sudden change when the alarm goes off and the recovery process followed by. The results indicate that participants awaken to harsh alarms had a more intense change in heart rate and emotional stress, while the signal in group of natural sounds was smoother. Our findings provide empirical evidence on the relationship between wake-up alarm sounds and stress responses. There is strong evidence(p-value&lt;0.025) that arousal with more natural sounds causes less heart rate and emotional changes.

Visit-to-visit changes in heart rate in heart failure: a pooled participant-level analysis of the PARADIGM-HF and PARAGON-HF trials

Abstract Background Resting heart rate (HR) is a strong established marker of risk in patients with heart failure (HF), but the clinical implications of changes in HR over time are less well established. We aimed to explore the association between visit-to-visit changes in HR and cardiovascular (CV) outcomes in a pooled participant-level dataset of 2 large cohorts of patients with HF across the full range of left ventricular ejection fraction (LVEF). Methods PARADIGM-HF and PARAGON-HF were global, multicenter, randomized clinical trials testing sacubitril/valsartan against an active control (enalapril or valsartan, respectively) in patients with HF and LVEF ≤40% (in PARADIGM-HF) or LVEF ≥45% (in PARAGON-HF). Change in HR was defined as the difference in HR between a visit at any time and the preceding visit. The association between the change in HR and subsequent risk of first HF hospitalization (HFH) or CV death was assessed using Cox proportional hazards models, after adjusting for HR at the preceding visit and potential confounders. HR at any time was also assessed using repeated measures regression models with restricted cubic splines, and was plotted relative to time defined as the number of months prior to or immediately following a HFH event or end of follow-up. Patients who experienced HFH during the study period were compared to a control population who remained free of all-cause hospitalization and all-cause death during the follow-up period. Results A total of 13,194 patients (mean age 67±11 years, 67% men, mean LVEF 40±15%) were included. Heart rates were available in 16 visits in both PARADIGM-HF and PARAGON-HF. Over a median follow-up of 2.4 years, 3,114 patients underwent a first HFH or CV death (10.4 events per 100 patient-years). Any increase in HR from the preceding visit, compared with no change, was associated with a significantly higher risk of first HFH or CV death (Figure 1, adjusted hazard ratio 1.10, 95% confidence interval, CI: 1.08–1.13, P&amp;lt;0.001, per 5 bpm increase in HR). Conversely, a drop in HR was associated with significantly lower risk. This prognostic association between temporal changes of HR and risk of first HFH or CV death was consistent across the range of LVEF (Pinteraction=0.34) and seen irrespective of background use of β-blockers (Pinteraction=0.91). Relative increases in HR were especially prognostic in patients without a history of atrial fibrillation/flutter (Pinteraction=0.01). HR at any time appeared to increase during the 8 months prior to a HFH event, and remained elevated after hospitalization, in comparison to a relatively stable HR observed in the control group (Figure 2). Conclusions Across a broad spectrum of patients with chronic HF, relative increases in HR from a preceding visit strongly and independently predicted both CV and non-CV outcomes. Our findings suggest that detection of notable increases in HR between outpatient visits may help identify patients at heightened risk of adverse events.