Significant Increase In Heart Rate Research Articles

Predictors of neuromodulation during single-shot thermal atrial fibrillation ablation: a computed tomography imaging analysis

Abstract Background Ganglionated plexi (GPs) are part of the cardiac autonomic nervous system (CANS), which play an important role in the induction and maintenance of atrial fibrillation (AF). Because of the anatomic proximity of the pulmonary veins with GPs, pulmonary vein isolation (PVI) using thermal (radiofrequency (RF) or cryo) ablation, has been shown to concomitantly affect the GPs, as suggested by increased heart rate (HR) after ablation. Right superior pulmonary vein (RSPV) isolation has been reported to have the most evident inhibitory responses to the CANS via modulation of the anterior right ganglionated plexus. Nonetheless, there are also cases with little to no effect on neuromodulation post-ablation. Purpose To assess the clinical and anatomical predictors of thermal ablation-induced CANS changes, as assessed via variations in resting HR post-ablation. Methods We retrospectively analyzed consecutive patients with symptomatic paroxysmal AF who underwent first-time PVI by cryoballoon (CB) or RF balloon (RFB) between January 2022 to November 2022. Patients who were not in sinus rhythm, had cardiac implantable electronic devices, or did not have a contrast-enhanced computed tomography before the ablation were excluded. Pre-ablation and 24-hour post-ablation ECGs in sinus rhythm were collected and analyzed to assess HR. Results A total of 83 patients (CB group, n = 43 vs RFB group, n = 40) were included in the analysis. Baseline patients’ characteristics were similar between the two groups (Table 1). A significant HR increase (ΔHR ≥ 15 bpm) at 24h post-ablation occurred in 31 patients [CB group 16 (52 %), RFB group 15 (48 %)]. Predictors of increased HR were the distance between superior vena cava (SVC) and RSPV (OR 0.51, CI 0.35 - 0.75, p value < 0.01) and age (OR 0.94, CI 0.89 - 0.99, p value < 0.01) (Table 2). Conclusions Single-shot thermal PVI influences the CANS, especially in patients with a shorter SVC - RSPV distance and in younger patients.Table 1Table 2

Behaviorally Inhibited Individuals Learn to Avoid Transdermal Stimulation More Quickly, and this Learning Is Accelerated Throughout the Study

Information on how behavioral inhibition (BI) affects the amount of time it takes an individual to avoid a stressful situation could answer many questions about anxiety disorders and whether BI influences avoidance behavior. BI is a temperament characteristic associated with increased vulnerability to stress compared to their non-behaviorally inhibited (NBI) counterparts. Our previous study demonstrated that BI individuals have lower heart rate variability (HRV) than NBI individuals. This suggests that BI individuals have significantly less parasympathetic nervous system (PNS) output at rest; however, it is unknown how BI affects avoidance acquisition using a mildly stressful stimulus. Previous studies have shown differences in the behavior found in Wistar-Kyoto rats, which exhibit BI behavior, compared to Sprague-Dawley control rats. Our current study will test the hypothesis that BI individuals learn to make escape and avoidance responses using subdermal ulnar nerve transdermal electrical stimulation (TES) more rapidly than NBI individuals and also experience a more significant increase in heart rate (HR) and blood pressure (BP). BI individuals were identified through a series of self-reported questionnaires. Three levels (30 mV, 50 mV, and 70 mV) of subdermal ulnar nerve TES were delivered to participants while receiving warning signals that predicted the delivery of the TES. Participants had access to a button that, when pressed during the light, prevented the delivery of the TES. This was scored as an avoidance response. If the button was pressed during the TES, it terminated the stimulation and was scored as an escape. HR and BP were also measured using a BIOPAC data acquisition system during TES. Our preliminary results indicate that BI individuals show a decrease in latency in the amount of time it took them to make an avoidance as the study progressed, while NBI individuals show a slight increase in latency, highlighting the idea that BI individuals are more curious to press the button or they are more likely to want to avoid the TES quicker. We would like to thank the Carthage College Research, Scholarship, and Creativity Committee as well as the Carthage College Neurophysiology Laboratory professors for their continued support throughout the study. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Feasibility of self-measurement telemonitoring using a handheld heart sound recorder in patients with heart failure – SELPH multicenter pilot study

BackgroundMulti-parametric assessment, including heart sounds in addition to conventional parameters, may enhance the efficacy of noninvasive telemonitoring for heart failure (HF). We sought to assess the feasibility of self-telemonitoring with multiple devices including a handheld heart sound recorder and its association with clinical events in patients with HF. MethodsAmbulatory HF patients recorded their own heart sounds, mono‑lead electrocardiograms, oxygen saturation, body weight, and vital signs using multiple devices every morning for six months. ResultsIn the 77 patients enrolled (63 ± 13 years old, 84 % male), daily measurements were feasible with a self-measurement rate of >70 % of days in 75 % of patients. Younger age and higher Minnesota Living with Heart Failure Questionnaire scores were independently associated with lower adherence (p = 0.002 and 0.027, respectively). A usability questionnaire showed that 87 % of patients felt self-telemonitoring was helpful, and 96 % could use the devices without routine cohabitant support. Six patients experienced ten HF events of re-hospitalization and/or unplanned hospital visits due to HF. In patients who experienced HF events, a significant increase in heart rate and diastolic blood pressure and a decrease in the time interval from Q wave onset to the second heart sound were observed 7 days before the events compared with those without HF events. ConclusionsSelf-telemonitoring with multiple devices including a handheld heart sound recorder was feasible even in elderly patients with HF. This intervention may confer a sense of relief to patients and enable monitoring of physiological parameters that could be valuable in detecting the deterioration of HF.

How Much Energy Do E’Athletes Use during Gameplay? Quantifying Energy Expenditure and Heart Rate Variability Within E’Athletes

BackgroundResearch into esports suggests that e’athletes experience physiological stressors and demands during competition and training. The physiological demands of esports are poorly understood and need to be investigated further to inform future training guidelines, optimise performance outcomes, and manage e’athlete wellbeing. This research aimed to quantify the metabolic rate of esports gameplay and compare this outcome with heart rate variability within expert e’athletes.ResultsThirteen healthy male participants ranked within the top 10% of their respective esports title participated in the study (age = 20.7 ± 2.69 years; BMI = 24.6 ± 5.89 kg·m− 2). Expired gas analysis indirect calorimetry measured gas exchange during rest and gaming. Compared to resting conditions, competitive esports gameplay significantly increased median energy expenditure (1.28 (IQR 1.16–1.49) kcal·min− 1 vs. 1.45 (IQR 1.20–1.77) kcal·min− 1, p = .02), oxygen consumption (0.27 (IQR 0.24–0.30) L·min− 1 vs. 0.29 (IQR 0.24–0.35) L·min− 1, p = .02) and carbon dioxide production (0.20 (IQR 0.19–0.27) L·min− 1vs. 0.27 (IQR 0.24–0.33) L·min− 1, p = .01). Competitive gameplay also resulted in a significant increase in heart rate (84.5 (IQR 74.1–96.1) bpm vs. 87.1 (IQR 80.3–104) bpm, p = .01) and decrease in R-R interval’s (710 (IQR 624–810) ms vs. 689 (IQR 579–747) ms, p = .02) when compared to rest. However, there were no significant differences in time or frequency measures of heart rate variability.ConclusionsThe data reveal increased physiological responses to metabolic rate, energy expenditure and cardiovascular function to esports game play within expert e’athletes. Further physiological research into the physical demands on e’athletes, the influence of different training programs to esport performance, and the added multivariate determinants to elite level esport performance are warranted.

Efficacy of endotracheal tube cuff lignocaine in the prevention of postextubation cough in children undergoing elective surgeries - A randomised controlled trial.

Postextubation airway complications are more common in paediatric patients than in adults. Intravenous lignocaine effectively prevents extubation response; however, data on using intracuff lignocaine in microcuff endotracheal tubes is scarce. The primary aim of this study was to compare the incidence of postextubation cough between intracuff lignocaine and intracuff air in the paediatric population during tracheal extubation. This randomised controlled study was conducted in 120 paediatric patients aged 1 month to 12 years who were scheduled to undergo surgeries under general anaesthesia. They were randomised to Group C (intracuff air) and Group L (intracuff 2% lignocaine). After administering general anaesthesia, the airway was secured with an age-appropriate microcuff endotracheal tube. According to groups, the cuff was inflated with air or lignocaine to achieve a cuff pressure of 10 cm H2O. Incidences of cough, desaturation, laryngospasm, apnoea and haemodynamic changes were recorded after tracheal extubation. Categorical variables were compared using the Chi-square or Fisher's exact test, and continuous variables were compared using the Student's t-test or Mann-Whitney U test. Intergroup differences between the variables were analysed by a two-way repeated measure analysis of variance. The incidence of postextubation cough was significantly higher in Group C [17 (28.3%) (confidence interval {CI} = 17.4-41.4)] when compared to Group L [8 (13.3%) (CI = 5.9-24.6)], with P = 0.043. One patient in Group C had laryngospasm compared to none in Group L. In Group C, there was also a significant increase in heart rate at all time points (1-5 min after extubation) from the baseline, and this increase was also significantly higher when compared to Group L (P < 0.05). The incidence of postextubation cough was significantly lower with intracuff lignocaine compared to that with intracuff air in paediatric patients.

The feigned annoyance and frustration test to activate the sympathoadrenal medullary system

When perceived as threatening, social interactions have been shown to trigger the sympathoadrenal medullary system as well as the hypothalamic-pituitary-adrenal axis resulting in a physiologic stress response. The allostatic load placed on human health and physiology in the context of acute and chronic stress can have profound health consequences. The purpose of this study was to develop a protocol for a lab-based stress stimulus using social-evaluative threat. While several valid, stress-stimulating protocols exist, we sought to develop one that triggered a physiologic response, did not require significant lab resources, and could be completed in around 10 min. We included 53 participants (29 men and 24 women) and exposed them to a modified version of the Stroop Color-Word Interference Task during which the participants were made to feel they were performing the task poorly while the lead researcher feigned annoyance and frustration. After exposure to this Feigned Annoyance and Frustration (FAF) Test, both the men and women in this study demonstrated a statistically significant and clinically meaningful increase in subjective stress on the visual analog scale. Additionally, the men in this study demonstrated a statistically significant increase in heart rate and salivary α-amylase concentrations after exposure to the test. The women in this study did not demonstrate a statistically significant increase in the physiologic stress biomarkers. This protocol for the FAF Test shows promise to researchers with limited time and resources who are interested in experimentally activating the sympathoadrenal medullary system.

Local Anesthetics with Vasoconstrictors in Hypertensive Patients Undergoing Dental Extraction Procedures: A Serial Case Report

Background: Systemic absorption of vasoconstrictors and adverse cardiac effects are reasons for not using vasoconstrictors in hypertensive patients. However, several recent studies reported that the use of local anesthetics with vasoconstrictors in hypertensive patients doesn’t cause a statistically significant increase in blood pressure and heart rate. The objective of the study is to evaluate the preoperative, intraoperative and postoperative blood pressure, heart rate and peripheral oxygen saturation in hypertensive patient who undergoing dental extraction procedures with local anesthetics with vasoconstrictors. Case presentation: We reported three serial cases of male patients (40, 45, 47 years old) undergoing radixes lower posterior tooth extracted, with blood pressures 143/88mmHg, 140/86mmHg and 142/86 mmHg. The patient underwent extraction under infiltration local anesthetics with vasoconstrictors (epinephrine). All patient’s blood pressure increased 1-3 points intraoperative and decreased again postoperative. The patient's heart rate also increased 10-25 times per minute intraoperative. The decrease in oxygen saturation (2%) only occurred in one patient, intraoperative. Conclusion: The slight hemodynamic changes in these three patients indicate that the use of local anesthetics with vasoconstrictors in hypertensive patients undergoing dental extraction procedures is relatively safe.

EFFICACY OF TOLAZOLINE AND VATINOXAN IN REDUCING ADVERSE EFFECTS OF BUTORPHANOL-AZAPERONE-MEDETOMIDINE IMMOBILIZATION IN ROCKY MOUNTAIN ELK (CERVUS CANADENSIS).

A mixture of butorphanol, azaperone, and medetomidine (BAM) is frequently used for immobilization of North American hoofstock. Common adverse effects include respiratory depression, hypoxemia, and bradycardia. In this nonblinded crossover study the efficacy of two a-2 adrenergic antagonists, tolazoline and vatinoxan, were evaluated in alleviating adverse effects of BAM in Rocky Mountain elk (Cervus canadensis). Early administration of these antagonists was hypothesized to cause an increase in heart rate, respiratory rate, partial pressure of oxygen (PaO2) and hemoglobin oxygen saturation (SpO2), as well as reduction in mean arterial blood pressure without affecting sedation levels. Eight captive adult female elk were immobilized on three separate occasions at least 14 d apart with 0.15 mg/kg butorphanol, 0.05 mg/kg azaperone, and 0.06 mg/kg medetomidine. Tolazoline (2 mg/kg IM), vatinoxan (3 mg/mg medetomidine IV) or sterile saline (2 ml IM) were administered 20 min postinduction. The BAM caused hypoxemia, bradycardia, and moderate hypertension, and because of the severe hypoxemia observed, all animals received intratracheal oxygen throughout immobilization. Heart rate, respiratory rate, rectal temperature, SpO2, PaO2, and systolic, diastolic, and mean arterial blood pressure were monitored every 5 min throughout the immobilization. Intramuscular tolazoline caused a brief but significant drop in mean arterial pressure compared with controls and a brief but nonsignificant increase in heart rate. Vatinoxan caused a significant drop in blood pressure and a brief significant increase in heart rate. Changes in respiratory rates and PaO2 were not observed with either antagonist; however, all animals received oxygen, which may have influenced this result. The depth of sedation was unchanged after administration of either drug.

Evaluation of the analgesic effects of diclofenac as a premedication drug in dogs undergoing ovariohysterectomy

Pre-emptive analgesia consists of administering drugs such as opioids and nonsteroid anti-inflammatory drugs. This study aims to evaluate the intraoperative antinociceptive effects of diclofenac administered alone in premedication or combined with morphine along with its potential influence on recovery of dogs undergoing ovariohysterectomy. A total of 34 dogs (ASA I or II) admitted for ovariohysterectomy were randomly allocated into three groups according to the drugs given in premedication: Diclofenac (D) (n = 11), Morphine (M) (n = 13) and Diclofenac-Morphine (DM) (n = 10) groups. Induction and maintenance of anesthesia were standardized in all dogs. To assess intraoperative nociception, the heart rate (HR) and mean arterial pressure (MAP) were recorded during the surgery and at predefined time points: St (steady-state), Cut (cutaneous incision), P1 (first ovarian manipulation), P2 (second ovarian manipulation) and Cerv (cervical manipulation). The dynamic variation of HR (ΔHR) and MAP (ΔMAP) over 2 min was calculated at each time point. After extubation, early quality of recovery was assessed.Compared to St, a significant increase in HR and MAP at P1, P2 and Cerv was shown in all groups. MAP in the M group was lower at St than in the other groups. The dynamic variation of HR (ΔHR) and MAP (ΔMAP) was significantly less important at P2 and Cerv compared to P1 only in the DM group. Also, a better quality of recovery was shown in the D group compared to the M and DM groups. Diclofenac may be considered a suitable premedication drug and a part of a multimodal anesthetic approach in dogs.

Cardiodynamic adjustments in skilled civil aircraft pilots while unexpected emergency conditions appeared during a simulated flight within a homemade Airbus A300 cockpit

To highlight which cardiodynamic adjustments take place in civil aircraft pilots when unexpected mechanical accidents occur while they are in flight, in 8 skilled pilots we detected the mean blood arterial pressure (MAP) and heart rate (HR) while a unexpected failing of one engine occurred when they were engaged in a simulated flight with a homemade Airbus A300 cockpit. Comparing these two cardiovascular variables in a simulated flight test, just as when the accident happened, together with the values assessed in a simulated control flight without accidents, by the non-parametric Wilcoxon test for paired data it has been found a significant increase of MAP’s median (+ 20.3%, P = 0.008) without significant increase in HR one. However, in several tested pilots this sudden MAP increase tended to progressively recover baseline values while simulating the flight despite the event triggering this functional response was still present.We concluded that the cardiovascular apparatus of skilled aircraft civil pilots adapts in such a way of sudden respond to unexpected emergency conditions by adjusting mean arterial blood pressure for adequate blood flow to limb muscles, and this happens without a concomitant tachycardia response in order to maintain an optimal mechanical/metabolic efficiency of the heart.

Clinico-Pathological Alterations and Therapeutic Management of Thiram Poisoning in Cattle

As there is very scarce literature on fungicide poisoning in livestock animals and in view of reporting fungicide poisoning in cattle in the study area, the present study was conducted to study the clinico-pathology of thiram poisoning in cattle and to standardize the therapeutic regime for the poisoning cases. Clinical cases suspected for Thiram poisoning on the basis of confirm evidence from animal owner were subjected to clinical examination, hematology and therapeutic management. Cases died of severe poisoning were subjected to post-mortem examination. A total of 17 cattle suspected for Thiram poisoning on the basis of history and evidence showed clinical signs of sudden onset of anorexia, salivation, shivering, teeth grinding, restlessness, prolonged sitting, tympany, colic, dyspnea and constipation or diarrhea in few cases. Significant increase in heart rate and respiration rate was observed while hematological analysis showed non-significant changes compared to healthy counterparts. Post-mortem and histopathological examination of cattle died of thiram poisoning showed mild hepatocellular degeneration, tubular necrosis in kidneys with focal infiltrates while marked edema and congestion was evident in lung tissues. The ailing cattle were treated with fluid therapy, anti-inflammatory drugs, vitamin B complex, atropine sulphate, antihistaminics along with laxative and prebiotics-probiotics showed good response to treatment with complete clinical recovery in 4-5 days of treatment. Being there is no specific antidote, the cases of fungicide like Thiram poisoning could be managed with symptomatic treatment and regular clinical assessment of the severity of the poisoning.

Intravenous infusion of lidocaine as a component of opioid-free anesthesia in thoracic surgery: prospective randomized single-center observational study

BACKGROUND: The possibility of reducing doses of narcotic analgesics during the perioperative period is widely discussed in modern scientific literature. This direction is called opioid-free anesthesia and is used in abdominal surgery, oncology, gynecology, and other areas. Publications on the use of opioid-free anesthesia in thoracic surgery are scarce.&#x0D; OBJECTIVE: To evaluate the analgesic effectiveness of intravenous lidocaine infusion as a component of anesthesia in thoracic surgery.&#x0D; MATERIALS AND METHODS: Ninety patients who underwent open lobectomy or pneumonectomy were examined. Depending on the analgesic component, patients were divided into three groups: group 1 (n=30) received intravenous infusion of lidocaine, group 2 (n=30) received epidural block, and group 3 (n=30) had fentanyl infusion. Blood pressure, heart rate, cortisol, and blood serum glycemia levels were measured. The intensity of postoperative pain syndrome and the need for promedol, tramadol, and sanitation fibrobronchoscopy were assessed. Arterial hypotension and frequency of postoperative nausea and vomiting were recorded. The length of stay of the patients in the intensive care unit and hospital was recorded.&#x0D; RESULTS: Cortisol levels did not differ between groups (p=0.26). The glucose level in the epidural block group was significantly lower than that in other groups (p=0.011). A significant increase in mean blood pressure and heart rate was observed in the opioid analgesia group (p 0.001). The lowest severity of pain 6 h after surgery was observed in the epidural blockade and lidocaine groups (p 0.001). Perioperative hypotension was more common in the epidural analgesia group (p=0.045). The incidence of postoperative nausea and vomiting was higher in the opioid anesthesia group (p=0.004). In the fentanyl infusion group, sanitary fibrobronchoscopy was more often required to eliminate atelectasis (p=0.039). The number of bed days spent in the ICU was significantly higher in the opioid analgesic group (p=0.002); however, no significant differences were noted between the groups regarding the number of days spent in the hospital (p=0.228).&#x0D; CONCLUSION: Opioid-free anesthesia based on intravenous lidocaine infusion, as a component of anesthetic management in thoracic surgery, provides sufficient perioperative stability of hemodynamic and neuroendocrine status, has a pronounced analgesic effect, with less opioid consumption on the first day after surgery, and helps reduce the length of stay in the intensive care unit and hospital.

Effect of "365 Breathing Technique" on Intraocular Pressure and Autonomic Functions in Patients With Glaucoma: A Randomized Controlled Trial.

Patients with primary open angle glaucoma were advised to follow the "365 breathing technique" for 6 weeks in addition to their pharmacological glaucoma treatment. It helped to reduce intraocular pressure (IOP), stress biomarker-cortisol, and improve autonomic dysfunction. To study the effect of the "365 breathing technique" on IOP, autonomic functions, and stress biomarkers in patients with primary open angle glaucoma. In this randomized, controlled, interventional trial, after randomization, 40 patients in the intervention group followed "365 breathing" (three times a day, breathing rate: 6 cycles/min for 5 min) in addition to their pharmacological glaucoma treatment and 40 patients in the control group continued only with their pharmacological glaucoma treatment. IOP, serum cortisol, heart rate variability (HRV), and heart rate response to deep breathing test (DBT) were recorded at preintervention and 6 weeks postintervention. The mean IOP, serum cortisol, parameters of the HRV test, and DBT were comparable between the two groups at baseline. At the 6-week follow-up, in the intervention group, mean IOP was significantly lower (16.09 ± 2.24 vs 18.38 ± 1.58 mm Hg, P = 0.03) and serum cortisol were significantly lower (13.20 ± 3.11 vs 14.95 ± 2.60 mcg/dL, P = 0.038) compared with the control group. In the HRV test, time domain analysis showed a significant difference in the root mean square of the successive difference between RR interval values between both groups at 6 weeks ( P = 0.015) pointing towards higher postintervention parasympathetic activation in the intervention group. In frequency domain analysis (HRV test), the ratio of the low-frequency component to the high-frequency component was significantly lower in the intervention group at 6 weeks (1.65 vs 1.79, P = 0.019) indicating a shift in sympathovagal balance towards greater vagal modulation.There was a significant increase in delta heart rate ( P = 0.019) and expiratory:inspiratory ratio ( P = 0.011) in the intervention group at 6 weeks when compared with baseline values, indicating improved parasympathetic reactivity to DBT. "365 breathing" technique can reduce IOP and serum cortisol, and improve autonomic dysfunction in patients with glaucoma.

Efficacy and safety of dexmedetomidine in attenuating stress response to skull pin holder application in patients undergoing craniotomy

Background: Skull pin holder application during craniotomy can evoke stress response, which might lead to sudden rise in blood pressure (BP), causing intracranial hemorrhage, cerebral edema, and prolonged hospital stay. Dexmedetomidine has been shown to blunt the sympathoadrenal response to surgery. Aims and Objectives: The present study was undertaken to assess the efficacy and safety of dexmedetomidine in attenuating stress responses to skull pin holder application as compared to normal saline. Materials and Methods: After obtaining approval from the institutional ethics committee and written informed consent, patients of either sex undergoing elective craniotomy at the attached hospitals of Bangalore Medical College and Research Institute, Bengaluru, India, were randomized in a 1:1 ratio to receive normal saline or dexmedetomidine as premedication. Hemodynamic parameters, i.e., heart rate (HR), systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP), were monitored at various time points until 30 min after skull pin application. Data were analyzed using the chi-squared test, repeated measure ANOVA, unpaired t-test, and Mann–Whitney U test, wherever applicable. Results: A total of 52 patients were included in the study, with 26 patients in each group. All the baseline parameters were matched. As a stress response, a significant increase in HR was seen after intubation (90.69 bpm) and skull pin insertion (87.92 bpm) in the normal saline group. However, there was no significant variation in HR in the dexmedetomidine group over 30 min (69.19 bpm–74.15 bpm). Dexmedetomidine reduced HR significantly as compared to normal saline after intubation (P = 0.03). Dexmedetomidine lowered SBP and DBP as compared to baseline throughout 30 min without any excursions during intubation and skull pin insertion. The SBP was significantly lower in the dexmedetomidine group after intubation as compared to saline (P = 0.02). Although a reduction in SBP was noted after skull pin insertion in the dexmedetomidine group, it was not statistically significant than saline. No significant difference was noted in DBP, MAP, or blood glucose between the two groups. No incidents of hypotension and bradycardia were noted. Conclusion: Dexmedetomidine maintained basal HR throughout 30 min without any variations in response to intubation and skull pin insertion. It also reduced SBP and DBP over 30 min. HR and SBP were significantly lower in the dexmedetomidine group as compared to saline after intubation. The same effect was noted in the dexmedetomidine group as compared to saline after skull pin insertion, but it was not statistically significant.

Psychophysiological Responses in Soldiers during Close Combat: Implications for Occupational Health and Fitness in Tactical Populations.

This study explores the psychophysiological responses and subjective exertion experiences of soldiers in simulated hand-to-hand combat, aligning these findings with established physiological benchmarks. Active military personnel were monitored for heart rate, blood lactate levels, subjective exertion, cortical arousal, and muscle strength during combat scenarios. The results showed significant increases in heart rate and blood lactate, indicating intense cardiovascular demands and a reliance on anaerobic energy systems. Contrary to these physiological changes, soldiers reported lower levels of exertion, suggesting a possible underestimation of physical effort or individual differences in perception and mental resilience to stress. Notably, a decrease in cortical arousal post-combat was observed, potentially signaling cognitive function deficits in decision-making and information processing in high-stress environments. This decline was more pronounced than typically seen in other high-stress situations, highlighting the unique cognitive demands of hand-to-hand combat. Additionally, an increase in muscle strength was noted, underscoring the physiological adaptations arising from intensive combat training. These findings provide valuable insights into the psychophysiological effects of hand-to-hand combat, emphasizing the complex interplay between physical exertion, cognitive function, and stress response in military contexts. The study underscores the need for comprehensive training strategies that address both physical and psychological aspects to enhance combat readiness and decision-making under stress.

An increase in intercellular crosstalk and electrotonic coupling between cardiomyocytes and nonmyocytes reshapes the electrical conduction in the metabolic heart characterized by short QT intervals in ECGs.

Cardiac conduction abnormalities are disorders in metabolic syndrome (MetS), however, their mechanisms are unknown. Although ventricular arrhythmia reflects the changes in QT-interval of electrocardiograms associated with the changes in cardiomyocyte action potential durations (APDs), recent studies emphasize role of intercellular crosstalk between cardiomyocytes and nonmyocytes via passive (electrotonic)-conduction. Therefore, considering the possible increase in intercellular interactions of nonmyocytes with cardiomyocytes, we hypothesized an early-cardiac-remodeling characterized by short QT-interval via contributions and modulations of changes by nonmyocytes to the ventricular APs in an early-stage MetS hearts. Following the feeding of 8-week-old rats with a high-sucrose diet (32%; MetS rats) and validation of insulin resistance, there was a significant increase in heart rate and changes in the electrical characteristics of the hearts, especially a shortening in action potential (AP) duration of the papillary muscles. The patch-clamp analysis of ventricular cardiomyocytes showed an increase in the Na+ -channel currents while there were decreases in l-type Ca2+ -channel (LTCC) currents with unchanged K+ -channel currents. There was an increase in the phosphorylated form of connexin 43 (pCx43), mostly with lateral localization on sarcolemma, while its unphosphorylated form (Cx43) exhibited a high degree of localization within intercalated discs. A high-level positively-stained α-SMA and CD68 cells were prominently localized and distributed in interfibrillar spaces of the heart, implying the possible contributions of myofibroblasts and macrophages to both shortened APDs and abnormal electrical conduction in MetS hearts. Our data propose a previously unrecognized pathway for SQT induction in the heart. This pathway includes not only the contribution of short ventricular-APDs via ionic mechanisms but also increasing contributions of the electrotonic-cardiomyocyte depolarization, spontaneous electrical activity-associated fast heterogeneous impulse conduction in the heart via increased interactions and relocations between cardiomyocytes and nonmyocytes, which may be an explanation for the development of an SQT in early-cardiac-remodeling.

Cardiac Timeless Trans-Organically Regulated by miR-276 in Adipose Tissue Modulates Cardiac Function.

The interconnection between cardiac function and circadian rhythms is of great importance. While the role of the biological clock gene Timeless (Tim) in circadian rhythm has been extensively studied, its impact on cardiac function remains largely been unexplored. Previous research has provided experimental evidence for the regulation of the heart by adipose tissue and the targeting of miR-276a/b on Timeless. However, the extent to which adipose tissue regulates cardiac Timeless genes trans-organically through miR-276a/b, and subsequently affects cardiac function, remains uncertain. Therefore, the objective of this study was to investigate the potential trans-organ modulation of the Timeless gene in the heart by adipose tissue through miR-276a/b. We found that cardiac-specific Timeless knockdown and overexpression resulted in a significant increase in heart rate (HR) and a significant decrease in Heart period (HP), diastolic intervals (DI), systolic intervals (SI), diastolic diameter (DD), and systolic diameter (SD). miR-276b systemic knockdown resulted in a significant increase in DI, arrhythmia index (AI), and fractional shortening (FS) significantly increased and SI, DD and SD significantly decreased. Adipose tissue-specific miR-276a/b knockdown and miR-276a overexpression resulted in a significant increase in HR and a significant decrease in DI and SI, which were improved by exercise intervention. This study presents a novel finding that highlights the significance of the heart circadian clock gene Timeless in heart function. Additionally, it demonstrates that adipose tissue exerts trans-organ modulation on the expression of the heart Timeless gene via miR-276a/b.

Comparative assessment of effect of two methods of spinal anesthesia on central hemodynamic parameters in elderly and senile patients in emergency vascular surgery

Objective. To improve the results of treatment of comorbid patients with acute arterial ischemia by substantiating the optimal type of spinal anesthesia for surgical intervention on the affected limb.Materials and methods. The study involved 70 patients who were treated in the Department of Vascular Surgery of Clinical Hospital of ‘Russian Railways-Medicine Co.’ in Barnaul. The patients were divided into two groups: group 1 – patients operated under conditions of bilateral (bilateral) spinal anesthesia, group 2 – patients operated under conditions of monolateral (unilateral) spinal anesthesia. All patients underwent an assessment of the level of spinal block on the Bromage scale, monitoring of central hemodynamics using a MARG-10–01 rheograph, postoperative assessment of myocardial ischemia on the ECG, acute kidney damage to control diuresis.Results. In the 2nd group, there was a sufficient sensory and motor block to perform surgery. In the intraoperative period in the group of patients who underwent unilateral blockade, the mean arterial pressure decreased by 3 mm Hg. In this regard, there was no clinically significant increase in heart rate and a decrease in the stroke index and the index of total peripheral vascular resistance. In the 1st group, the decrease in mean arterial pressure reached 20% of the original, which led to an increase in heart rate by 12% and a decrease in stroke index by 11%.Conclusions. During the perioperative period, the indicators of central hemodynamics in the group 2 were more stable compared to the group 1, they did not need the use of vasopressor drugs and crystalloids. And in the early postoperative period, patients who underwent unilateral anesthesia did not show signs of acute kidney injury. Monolateral spinal anesthesia, compared with conventional spinal anesthesia, provides more stable hemodynamics in elderly patients with acute arterial ischemia.

Effect of acute altitude exposure on physiological parameters and glucose metabolism in healthy lowland Peruvians.

High altitude exposure triggers a series of physiological changes to maintain homeostasis. Although longer-term (days to years) acclimatization processes are well studied, less is known about the physiological changes upon rapid ascent. We took advantage of Peru's geography to measure the first physiological changes following rapid transport from a low to a high-altitude environment among lowlanders. Blood glucose, insulin, C-peptide, and salivary cortisol among healthy lowland Peruvians were measured before and after glucose ingestion at 40 m and upon arrival at 3470 m. Resting heart rate, blood oxygen saturation, and blood pressure were also monitored. At high altitude, we find a significant ( p<0.05) increase in heart rate and a decrease in blood oxygen saturation and salivary cortisol. Additionally, baseline levels of blood glucose, plasma C-peptide, and cortisol were reduced ( p<0.05). Blood glucose, plasma insulin, and plasma C-peptide returned to baseline or below faster at high altitude after glucose ingestion. Although many overlapping environmental and physiological factors are present in the high-altitude environment, the first steps of acclimatization in this population appear to be caused by increased energy expenditure and glucose metabolism to maintain oxygen homeostasis until the longer-term acclimatization mechanisms become more significant.

Abstract 15621: Pelvic Vein Compression in Patients Diagnosed With Postural Orthostatic Tachycardia Syndrome

Introduction: Postural Orthostatic Tachycardia Syndrome (POTS) is a condition characterized by chronic orthostatic intolerance and a significant increase in heart rate. Patients with POTS often exhibit symptoms suggestive of pelvic venous congestion. While venography is the standard method for diagnosing venous compression disorders in the abdomen and pelvis, its potential use in identifying undiagnosed venous abnormalities and its relationship in POTS patients has not been studied. Research Question: This study aimed to investigate the findings of antegrade venography and intravascular ultrasound in patients diagnosed with POTS with high suspicion of May-Thurner Syndrome (MTS) and/or pelvic congestion syndrome, based on initial diagnostic tools such as ultrasound, and who exhibited symptoms of pelvic venous insufficiency (PVI). Methods: Patients clinically diagnosed with POTS underwent antegrade venography and intravascular ultrasound due to a high suspicion of PVI. Demographic, clinical presentation, and venography findings were extracted from the electronic medical records of patients referred to Emory University for POTS/dysautonomia/long COVID evaluation. Patients were diagnosed with MTS if they demonstrated stenosis of the left common iliac vein of 50-70% with associated symptoms like pelvic pain and lower extremity swelling. Results: We identified 28 patients with POTS who had symptoms of PVI. The mean age was 31.6 years (range 18-54), and 96% were female. Doppler ultrasonography revealed venous reflux in the common femoral vein in 82% of the patients. All participants met the criteria for MTS and were referred for stenting. Additionally, 21% of those evaluated had significant bilateral iliac vein compression. Conclusions: This is the largest cohort of POTS patients with pelvic venous compression to date, and our findings suggest a potential association between venous disease and the pathophysiology of POTS. Further research is needed to establish a causal link and explore the clinical implications of venography findings after intervention with angioplasty and stenting. Understanding the venous component in POTS may aid clinicians in the earlier diagnosis and management of PVI.