Cardiac Vagal Research Articles

Developing a Five-Minute Normative Database of Heart Rate Variability for Diagnosing Cardiac Autonomic Dysregulation for Patients with Major Depressive Disorder.

Heart rate variability (HRV) is related to cardiac vagal control and emotional regulation and an index for cardiac vagal control and cardiac autonomic activity. This study aimed to develop the Taiwan HRV normative database covering individuals aged 20 to 70 years and to assess its diagnosing validity in patients with major depressive disorder (MDD). A total of 311 healthy participants were in the HRV normative database and divided into five groups in 10-year age groups, and then the means and standard deviations of the HRV indices were calculated. We recruited 272 patients with MDD for cross-validation, compared their HRV indices with the normative database, and then converted them to Z-scores to explore the deviation of HRV in MDD patients from healthy groups. The results found a gradual decline in HRV indices with advancing age in the HC group, and females in the HC group exhibit higher cardiac vagal control and parasympathetic activity than males. Conversely, patients in the MDD group demonstrate lower HRV indices than those in the HC group, with their symptoms of depression and anxiety showing a negative correlation with HRV indices. The Taiwan HRV normative database has good psychometric characteristics of cross-validation.

(118) ORGASM AND HEART RATE VARIABILITY IN FEMALE BREAST CANCER SURVIVORS: RESULTS FROM A PSYCHOPHYSIOLOGY STUDY

Abstract Introduction Over 70 % of female breast cancer survivors suffer from sexual dysfunction. Sexual dysfunction can cause great amounts of stress and negatively impact overall health and well-being. Most studies focus on sexual arousal disorders and hypoactive sexual desire disorders. The research on orgasm in this specific group is limited. A better understanding of sexual function in breast cancer patients may yield potential targets for new treatment strategies for sexual dysfunction in this population. Low heart rate variability (HRV) has been shown to be predictive of erectile dysfunction and female sexual arousal as well as orgasm frequency. Reduced HRV and low cardiac vagal tone have previously been reported in breast cancer survivors during the first year post-treatment. If HRV is a reliable indicator of female sexual dysfunction, it could be used to assess and monitor it in a clinical setting. Objectives This study aimed to explore whether there is a link between HRV and both, sexual arousal and the ability to orgasm. We were expecting to find a difference in HRV between breast cancer survivors and healthy controls as well as orgasmic and anorgasmic women. Methods Participants were prescreened during a telephone interview. We included 40 premenopausal breast cancer survivors currently on hormonal treatment with an age range of 29 to 57 years (M = 43.5, SD = 6.4) and 20 healthy controls with an age range of 22 to 35 (M = 27.6, SD = 3.2). The vaginal pulse amplitude, heart rate variability (SDNN), subjective sexual arousal and self-reported number of orgasms were assessed in response to audiovisual sexual stimuli and vibrotactile clitoral stimulation in breast cancer survivors and healthy controls. Validated patient-reported outcome measures were used to assess sexual dysfunctions (Female Sexual Function Index, Female Sexual Distress Scale − Desire/Arousal/Orgasm), sexual self-esteem (Sexual Self-Esteem Inventory-Short Form), health-related quality of life (Patient-Reported Outcomes Measurement Information System 29 (PROMIS-29) profile questionnaire). Results Breast cancer survivors showed lower sexual function, health-related quality of life, sexual self-esteem and higher sexual distress than healthy controls. Preliminary results show a difference in baseline HRV scores between healthy controls and breast cancer survivors. However, this finding is likely due to age differences between our two groups and not cancer treatment effects. We could find no apparent differences in baseline HRV between anorgasmic and orgasmic women. Further analyses on the predictive value of HRV during sexual arousal for orgasm occurrence will be conducted. Conclusions Our data did not corroborate either of our hypotheses related to baseline HRV. For the evaluation of HRV as a predictor for orgasm occurrence, further exploratory analyses will follow. More research on the physiological parameters of sexual dysfunction is needed to reveal underlying mechanisms and find targets for future therapies.

Cooperation in primary school children: The role of cardiac vagal tone and cognitive control

Cooperation is crucial in classrooms for positive interactions among pupils, but the factors influencing children’s cooperative behaviors remain debated. This study explores the impact of cardiac vagal tone (CVT), a measure of physiological self-regulation, and cognitive control on cooperation among 109 primary school students. Heart rate variability was used to assess self-regulation, and cognitive control was evaluated through an AX-Continuous Performance Task. Cooperative behavior was measured with a child-friendly Stag Hunt game. Results showed that moderate CVT is related to increased cooperative actions, but no direct relationship between cognitive control types and cooperation was found. However, an interaction effect indicated that moderate CVT particularly boosts cooperation in children who employ proactive cognitive control. These findings emphasize the need to develop physiological self-regulation skills to enhance cooperative behavior in educational settings, supporting better social, and emotional well-being, and learning outcomes.

Cardioneuroablation for asystolic reflex syncope with or without the use of extra cardiac vagal stimulation-one year follow-up results

Abstract Background Extra-Cardiac Vagal Stimulation (ECVS) during cardioneuroablation (CNA) has been introduced to confirm total vagal denervation – a clear intra-procedural end-point. However, whether the use of ECVS is associated with better outcome than simple intra-procedural assessment of CNA-induced changes in basic ECG parameters, has not been established. Purpose To compare one-year efficacy of CNA performed with versus without ECVS. Methods This retrospective analysis included 90 patients (age: 37±12 years, 39 males) divided into 2 groups: ECVS(+) (n=41, general anesthesia and total muscle relaxation, settings: 50 Hz, 0.05 ms, 1 V/kg (<70V) for 5 s) and ECVS(-) group (n=49, light sedation). CNA strategy was the same in all patients and was based on presumed anatomical localization of ganglionated plexi, combined with identification of ablation targets at sites with fragmented bipolar atrial electrograms. The end-point in the ECVS (+) group was complete vagal denervation, confirmed by ECVS, whereas in the ECVS (-) group - significant (>30%) acceleration of sinus rate. The primary endpoint was syncope recurrence during one-year follow-up. Results Both groups were comparable concerning clinical and demographic parameters. Primary endpoint occurred in 4 (10%) patients in the ECVS(+) group and in 7 (14%) patients in the ECVS(-) group (p=0.7481) (Figure). No complications were reported. Conclusions These preliminary results suggest that the use of ECVS only slightly improves the one-year CNA efficacy, however, prospective larger studies and longer follow-up are needed to confirm these initial findings.

Racial differences in baroreflex function: Implications for the cardiovascular conundrum

Study objectiveAfrican Americans (AAs) show early signs of vascular dysfunction paired with elevated blood pressure (BP) and total peripheral resistance (TPR), which is thought to underlie their increased rates of cardiovascular health complications relative to European Americans (EAs). AAs paradoxically have higher cardiac vagal tone, indexed by heart rate variability (HRV), which is cardio-protective. This paradox has been termed the Cardiovascular Conundrum. The physiological mechanism underlying this phenomenon is not well understood. We examined race differences in baroreflex function, which might be an important mechanism underlying the Cardiovascular Conundrum. DesignParticipants completed a 5-minute baseline period where resting cardiac metrics were assessed. SettingLaboratory. Participants130 college-aged individuals (54 women, 57 AAs). Main outcome measuresBaroreflex function was indexed as baroreflex sensitivity (BRS; the magnitude of changes in cardiovascular activity in accordance with BP changes) and effectiveness (BEI; the ratio of BP changes that elicit changes in cardiovascular activity) in the cardiac, vascular, and myocardial limbs. Results and conclusionsResults showed AAs to have higher HRV and cardiac BRS in comparison to EAs, suggesting the baroreflex is more sensitive to correcting the heart period for changes in BP among AAs compared to EAs. However, AAs showed lower vascular BEI relative to EAs, suggesting less effective control of TPR. In sum, lower BEI in the vascular branch might be an important mechanism underlying the Cardiovascular Conundrum (i.e., higher HRV and BP) and by extension, health disparities in cardiovascular diseases between AAs and EAs.

Influence of age on the incidence of acute complete atrioventricular block in right coronary artery infarction

Abstract Funding Acknowledgements None. Introduction Bezold-Jarisch is a cardioinhibitory reflex originating in cardiac vagal receptors, more concentrated in the inferoposterior wall of left ventricle, whose stimulation produces bradycardia and hypotension. The limited evidence suggests that vagal tone would predominate in younger individuals, whereas sympathetic tone would predominate in the elderly, resulting in a more striking Bezold-Jarisch reflex response among younger patients. Its maximum expression would be the occurrence of acute complete atrioventricular block (cAVB). Methods Observational, retrospective, single-centre analysis of consecutive patients hospitalised in the CCCU for STEACS with RCA or ADA as culprit artery (CA) between July 2011 and September 2022. We analysed the influence of age on the incidence of acute cAVB. Linear trend analysis and multivariate analysis were performed. Results A total of 723 patients with RCA as CA were included, with the baseline characteristics listed in Table1. Patients were divided into 4 groups: under 60 years (n=316 43.7%), 60-69 (n=223 30.8%), 70-79 (n=122 16.9%) and 80 or older (n=62 8.6%). The incidence of acute cAVB was 10.4%, 14.3%, 16.4% and 25.8% respectively (Fig1). A Cochran-Armitage analysis was performed, showing a significant linear trend between age and the incidence of acute cAVB (p=0.001). A multivariate analysis was performed using stepwise regression including age, sex, diabetes, hypertension, obesity, peripheral arterial disease, systolic blood pressure (SBP) at admission, renal failure, COPD, Killip-Kimbal (KK) score at admission and treatment with ticagrelor (for its described adenosine-like effect). Age (p=0.011), KK score (p<0.001) and lower SBP (p<0.001) were associated with a higher incidence of acute cAVB. Regarding the need for transient pacemaker, 6.2% of patients under 60, 7.7% aged 60-69, 10.1% aged 70-79, and 22.0% aged 80 and over required its implantation. As with cAVB, there was a significant linear trend between age and device implantation (p<0.001). Permanent pacemaker was implanted in only 6 patients. In-hospital mortality was significantly higher in patients with acute cAVB than all other patients with RCA infarction (7.9% vs 2.1%; p=0.001). Finally, as controls, acute cAVB data were analysed in patients with STEACS with ADA as CA (N=837). 366 patients (43.7%) were under 60 years, 204 (24.4%) 60-69, 155 (18.5%) 70-79 and 112 (13.4%) 80 or older. Only 10 patients presented with cAVB (1.2%), with no differences between those younger and older than 75 years (1.0% vs 2.3% respectively; p=0.13). Given the low incidence of cAVB in this group no further analysis was performed. Conclusion In RCA STEACS patients, there is a significant trend towards a higher incidence of acute cAVB with increasing age. These data suggest that older patients do not have a mitigated response to Bezold-Jarisch reflex. The inverse relationship between SBP and occurrence of cAVB supports the reflex nature of the mechanism.Table 1.Baseline characteristics.Fig 1.cAVB incidence among age groups.

The role of the cardiac vagus in maintaining cardiac function during exercise

There is a strong association between parasympathetic nervous system activity (vagal tone) and physical fitness. High vagal tone is associated with increased capacity to exercise and overall cardiovascular health. Evidence for vagal withdrawal during exercise comes from historic studies examining heart rate control and the use of cholinergic blockers. However, more recent studies have challenged this assumption. We hypothesized that cardiac vagal activity increases during exercise and maintains cardiac function via neurotransmitters other than acetylcholine. The left cardiac vagal branch was identified in anesthetized open-chested sheep. Cardiac innervation of the left cardiac vagal branch was confirmed with lipophilic tracer dyes (DiO). Custom-built coil electrodes were placed around the left cardiac vagal branch. 3-10 days after surgery, conscious, direct recordings of cardiac vagal nerve activity (CVNA), cardiac output, coronary artery blood flow and heart rate were recorded in adult female sheep during whole-body treadmill exercise. Sheep were exercised with pharmacological blockers of acetylcholine (atropine, 250 mg), vasoactive intestinal peptide (VIP) ([4Cl−D-Phe6,Leu17]-VIP 25 μg), or saline control, randomized on different days. In a subset of sheep, the left cardiac vagal branch was denervated. Neural innervation from the cardiac vagal branch is seen at major cardiac ganglionic plexi, and within the fat pads associated with the coronary arteries. Directly recorded CVNA increased during exercise. CVNA increases during the lowest exercise intensity and plateaus as exercise intensity increases. Left cardiac vagal branch, denervation attenuated the maximum changes in coronary artery blood flow (maximum exercise, control: 63.5 ± 5.9 ml/min, n = 8, cardiac vagal denervated: 32.7 ± 5.6 ml/min, n = 6, mean ± SEM. P = 2.5x10−7. Two-way ANOVA-interaction), cardiac output and heart rate during exercise. Atropine did not affect any cardiac parameters during exercise, but VIP antagonism significantly reduced coronary artery blood flow during exercise to a similar level to vagal denervation (maximum exercise, paired: control: 68.2 ± 6.0 ml/min, VIP antagonism: 44.9 ± 3.9 ml/min, n = 6, mean ± SEM. P = 4.8x10−3. Two-way ANOVA-interaction). Our study challenges the conventional view and demonstrates that cardiac vagal nerve activity increases and is crucial for maintaining cardiac function during exercise. Furthermore, our findings show that the dynamic modulation of coronary artery blood flow during exercise is mediated by VIP and that acetylcholine has no role in modulating cardiac function during exercise. This work is supported by the Health Research Council of New Zealand 23/119 (Fellowship. JS) and the New Zealand Heart Foundation (JS, RR). 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.

Increases in cardiac vagal modulation following a single session of passive calf stretching

Autonomic cardiovascular responses to mechanoreflex activation by passive muscle stretching have been shown in numerous investigations. These cardiovascular adjustments include cardiac vagal inhibition, sympathetic activation, pressor response, and baroreflex resetting. However, it is currently unclear how the autonomic system responds after a single session of passive muscle stretching. Therefore, we aimed to test the hypothesis that there would be parasympathetic dominance after stretching cessation. Twenty-four volunteers (14 men; 22±3 yr) performed two protocols: 1) five sets of 1 minute of unilateral passive calf stretching with 15 s of rest; and 2) control condition (six minutes of resting at the same position). The autonomic cardiac responses of both control and experimental conditions were assessed before, and immediately, 15 minutes and 30 minutes after stretching cessation. Passive stretching was performed on an isokinetic dynamometer (Biodex System 4, USA). Heart rate, systolic and diastolic blood pressure were continuously measured on a beat-to-beat basis using lead II electrocardiography (BioAmp, MLA2540) and finger photoplethysmography (Human NIBP, Australia). Brachial arterial blood pressure was also measured with an automated digital sphygmomanometer (Dixtal, DX2022, Brazil). Heart rate variability (HRV) was determined following the guidelines of the Task Force of the European Society of Cardiology and the North American Society of Pacing. With regards to the hemodynamics variables, there was no significant difference in the heart rate before and after passive stretching, while mean blood pressure (MBP) was slightly higher (±2mmHg) 30 min following both protocols (control, p=0.027 and stretch, p=0.035). Regarding HRV analysis, in the time domain, RMSSD was significantly increased 30 min following passive stretching (+15%; p=0.029), and this effect was also detected when using the frequency domain (high frequency: +37%, p=0.039). Of note, our major findings were not affected by sex. In conclusion, autonomic cardiovascular control shifts to a parasympathetic dominant state following passive calf stretch, and the effect peaks around 30 minutes after stretching. Passive stretching seems to be a safe, easy, and effective form of exercise that evokes autonomic cardiovascular responses during and following its cessation, even if it is performed in a single session of stretch. CNPq 307764/2022-2; CAPES (001) QUT South America Scholarship. 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.

Role of Angiotensin II on Cardiovascular/Autonomic Function and Cognition in a Novel Mouse Model of Alzheimer’s Disease

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder. Despite being the most common form of dementia in the elderly, mechanisms causing AD remain elusive. Emerging evidence have associated brain renin-angiotensin system (RAS) to AD neuropathology. RAS actions are predominantly mediated by angiotensin II (Ang II) binding to type 1 receptors. Previously, we have observed that human apolipoprotein E4-knockin (risk factor for AD) mice develop progressive hypertension and increases in Ang II levels in CSF with aging [FASEB J 36(S1): R3532]. Thus, we hypothesize that Ang II-mediated hypertension contributes to cognitive decline in AD. We have generated a novel transgenic mouse model of AD i.e. 3XE4 by breeding E4-knockin mouse with APPsw, PS1dE9, and tauP301S transgenes, to mimic human AD pathology in mice. Blood pressure (BP) and heart rate (HR) were measured by radiotelemetry in 3XE4 (n=6) and control 3XE3 (n=6) mice, before and after 28-days of Ang II infusion (1000 ng/kg/min, osmotic pump). Diurnal BP variability was calculated as the difference between night-time (11:00 PM-3:00 AM) and day-time (8:00 AM-12:00 PM). Cardiac vagal and sympathetic tones were calculated as changes in HR with atropine and propranolol (1 mg/kg each, IP), respectively. Cardiac function (echocardiography) and cognitive behavior (novel object recognition test) were measured. At baseline, BP was similar in control (127±11 mmHg) and 3XE4 (123±5 mmHg) mice. Unlike the control mice, 3XE4 mice exhibit reduced vagal tone (ΔHR= +119±22 vs. +25±24 bpm) and increased sympathetic tone (ΔHR= -76±33 vs. -212±40 bpm), which worsens with Ang II (p<0.05 vs. baseline). Interestingly, Ang II increased BP (24%), induced LV hypertrophy (26%), impaired diurnal BP variability, and evoked learning and memory deficits; albeit only in the 3XE4 mice (p<0.05 vs. control mice). These results demonstrate that Ang II-mediated hypertension and autonomic dysfunction likely exacerbate disease progression and cognitive decline in the 3XE4 mouse model of AD. Therefore, our study provides a proof-of- concept in delineating the association of ApoE4 genotype and Ang II with Alzheimer’s disease. NIH R01HL149677 and R21AG070188. 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.

Neuromodulatory co-expression in cardiac vagal motor neurons of the Dorsal Motor Nucleus of the Vagus

Dorsal Motor Nucleus of the Vagus (DMV) activity is required for cardioprotection from physiological interventions such as remote ischemic pre-conditioning (RIPC). Herein, we discover the transcriptomic phenotypes of cardioprotective DMV neurons, by combining high throughput transcriptomics, 3D anatomical mapping, and neural tracing in 12 week old male and female Sprague Dawley rats. We find that DMV neurons appear to participate in neuromodulatory co-expression, including those that project to the heart. To distinguish potential mechanisms of cardioprotection, we highlight the functional significance of several transcripts in cardiac-projecting DMV neurons and we begin to validate these findings at the protein level. In our sc-RNAseq data we find that Snca (α-synuclein), the cardioprotective neuromodulator Adcyap1 (PACAP), and the neuropeptide Cartpt (CART) are enriched in cardiac-projecting DMV neurons. To contrast our molecular findings in cardioprotective DMV neurons, we have also collected single neuron HT-RTqPCR data from the other source of cardiac vagal motoneurons, the Nucleus Ambiguus (NA). Catecholaminergic transcripts, including Slc18a2 (VMAT2), Ddc, and Th, are enriched in cardiac-projecting DMV neurons relative to those of the NA. These findings implicate catecholaminergic processes, synuclein, and these secreted neuropeptides in cardioprotection. At the protein level, we found PACAP, CART, SNCA and TH enrichment, as well as co-localization of PACAP, TH, and ChAT, in cardiac-projecting DMV neurons. There is consistency between our findings from three spatial transcriptomics techniques and across sexes. Based on these results, we propose a 3D anatomical and molecular map of cardiac vagal motoneurons. This work fills a major gap in the understanding of the cellular mechanisms by which parasympathetic drive provides cardioprotection and provides a future translational path to emulating the positive vagal neuromodulatory effects on heart health. Funding was provided by the R01 HL161696 grant through National Heart, Lung, and Blood institute and the National Institutes of Health Common Fund SPARC Program Grant OT2OD030534. 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.

Disruptive mood dysregulation disorder: the relationship between cardiac vagal tone, emotion recognition, and expressive prosody

Children with disruptive mood dysregulation disorder have difficulties with emotion regulation and recognition which impacts their social functioning. Due to its recent definition, there is limited information on the neural mechanisms of this disorder. This exploratory study examined the role of autonomic heart regulation in children with disruptive mood dysregulation disorder, motivated by suggestions of reduced autonomic regulation (measured by heart rate variability) associated with psychiatric disorders in adults and children. The cross-sectional design sampled two groups of children, one with disruptive mood dysregulation disorder ( n = 15; 14 male) and the other with typical development ( n = 15; 14 male). Heart rate variability, facial emotion recognition accuracy and speed, and prosody were measured. There were no significant differences in heart rate variability between the two groups before, or during, the tasks. However, children with disruptive mood dysregulation disorder experienced significantly greater difficulty recognising fear in faces compared to controls and confused other negatively valenced emotions. There was also a significant, negative correlation between heart rate variability and prosody modulation (verbal expression of emotion) in the control group, a relationship that was absent in the disruptive mood dysregulation disorder group. These results suggest that atypical autonomic regulation during emotionally evocative situations and difficulty with facial emotion recognition may contribute to the challenges experienced by children with disruptive mood dysregulation disorder. This is valuable knowledge for psychologists, which can contribute to individualised, effective, and comprehensive care that addresses the child’s emotional, social, and relational well-being.

Changes in cardiovascular autonomic control induced by chronic inhibition of acetylcholinesterase during pyridostigmine or donepezil treatment of spontaneously hypertensive rats

Chronic treatment with acetylcholinesterase inhibitors may be a promising therapeutic strategy for treatment of cardiovascular diseases. The aim of our study was to analyze the changes in blood pressure (BP) and heart rate (HR) during 14 days of treatment with two different acetylcholinesterase inhibitors – pyridostigmine (PYR) having only peripheral effects or donepezil (DON) with both peripheral and central effects. In addition, we studied their effects on the cardiovascular response to restraint stress and on sympathovagal control of HR in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). SHR were characterized by elevated BP and increased low-frequency component of systolic BP variability (LF-SBPV), but their cardiac vagal tone and HR variability (HRV) were reduced compared with WKY. Chronic treatment with either acetylcholinesterase inhibitor decreased HR and increased HRV in both strains. PYR treatment slightly decreased BP and LF-SBPV in the dark phase of the day. Neither drug significantly altered BP response to stress, but PYR attenuated HR increase during restraint stress. Regarding sympathovagal balance, acute methylatropine administration caused a greater increase of HR in WKY than in SHR. Chronic PYR or DON treatment enhanced HRV and HR response to methylatropine (vagal tone) in WKY, whereas PYR but not DON treatment potentiated HRV and vagal tone in SHR. In conclusion, vagal tone was lower in SHR compared with WKY, but was enhanced by chronic PYR treatment in both strains. Thus, chronic peripheral, but not central, acetylcholinesterase inhibition has major effects on HR and its variability in both normotensive and hypertensive rats.

Autonomic Nervous System Activity and Dental Anxiety in the Northern Finland Birth Cohort (NFBC1966) Population.

Autonomic nervous system (ANS) activity may be associated with dental anxiety; however, no studies exist on the topic. The aim of this study was to assess if ANS activity and dental anxiety are associated. Data were collected as part of a Northern Finland Birth Cohort Study, NFBC1966, at the age of 46 years with eligible data on 1905 participants. Dental anxiety was measured using the Modified Dental Anxiety Scale (MDAS) categorized as follows: 19-25 = high, 10-18 = moderate, 5-9 = no to low dental anxiety. Heart rate variability (HRV) data were collected using an HR monitor and a standard lead-II electrocardiogram (ECG). Baroreflex sensitivity (BRS) was calculated from continuous ECG and blood pressure signals. Participants were categorized into three groups as follows: Low = the lowest 20th percentile, Mid = medium 21-79th percentile, and High = the highest 20th percentile according to their ANS variables. The associations between the MDAS and ANS activity parameters were evaluated using unordered multinomial logit models adjusted for comorbidities, β-blockers, BMI, smoking, and education. High heart rate, reduced HRV, low cardiac vagal modulation, and poor BRS were associated with moderate dental anxiety, and high cardiac vagal modulation and good BRS were associated with no to low dental anxiety. Poorer ANS activity might predispose some to dental anxiety, and better ANS activity might protect from dental anxiety.

The Physiological and Clinical-Behavioral Effects of Heart Rate Variability Biofeedback in Adolescents with Autism: A Pilot Randomized Controlled Trial.

Adolescents with autism present lower levels of cardiac vagal modulation. It was hypothesized that Heart Rate Variability Biofeedback (HRVB) increases cardiac vagal modulation in adolescents with autism, resulting in positive effects on physiological and psychosocial parameters. It was also hypothesized that home-based HRVB training is feasible. In a single-blind, randomized sham-controlled pilot trial, adolescents with autism performed supervised HRVB (n = 24) or sham training (n = 20). Subsequently, half of the adolescents received HRVB training at home, whereas the other subset did not practice. Physiological, cortisol and behavioral data were collected during stress-provoking assessments before and after each training period. Supervised HRVB resulted in a late increase in cardiac vagal modulation in adolescents with autism. Heart rate increased and cortisol decreased significantly immediately after supervised HRVB, but none of these effects remained after follow-up. Following supervised HRVB, no significant change in psychosocial functioning was found. Home-based HRVB was feasible, adolescents reported lower symptoms of stress, but a significant decrease in compliance rate was found. HRVB is feasible and effective in adolescents with autism given the late-emerging increases in cardiac vagal modulation and decrease in stress symptoms. Replicating this study with a larger sample and further exploration of the working mechanisms of HRVB are recommended. ClinicalTrials.gov , NCT04628715.

Increased cardiac vagal tone in childhood-only, adolescent-only, and persistently antisocial teenagers: the mediating role of low heart rate.

Cardiac vagal tone is an indicator of parasympathetic nervous system functioning, and there is increasing interest in its relation to antisocial behavior. It is unclear however whether antisocial individuals are characterized by increased or decreased vagal tone, and whether increased vagal tone is the source of the low heart rate frequently reported in antisocial populations. Participants consisted of four groups of community-dwelling adolescent boys aged 15.7 years: (1) controls, (2) childhood-only antisocial, (3) adolescent-only antisocial, and (4) persistently antisocial. Heart rate and vagal tone were assessed in three different conditions: rest, cognitive stressor, and social stressor. All three antisocial groups had both lower resting heart rates and increased vagal tone compared to the low antisocial controls across all three conditions. Low heart rate partially mediated the relationship between vagal tone and antisocial behavior. Results indicate that increased vagal tone and reduced heart rate are relatively broad risk factors for different developmental forms of antisocial behavior. Findings are the first to implicate vagal tone as an explanatory factor in understanding heart rate - antisocial behavior relationships. Future experimental work using non-invasive vagus nerve stimulation or heart rate variability biofeedback is needed to more systematically evaluate this conclusion.

Short-Term Effects of Heart Rate Variability Biofeedback on Working Memory.

Drawing upon the well-documented impact of long-term heart rate variability biofeedback (HRVB) on psychophysiological responses, this study seeks to explore the short-term effects arising from a single HRVB session during and after paced breathing exercise. The research aligns with the neurovisceral integration model, emphasizing the link between heart rate variability (HRV) levels and cognitive performance. Therefore, a randomized controlled trial employing a between-subjects design was conducted with 38 participants. Each participant was assigned to either the paced breathing intervention group or the spontaneous breathing control group. The study assessed various parameters such as cardiac vagal tone, evaluated through vagally mediated HRV measures, and working memory, measured using the N-back task. Additionally, participants' affective states were assessed through self-reported questionnaires, specifically targeting attentiveness, fatigue, and serenity. The results notably reveal enhancements in the working memory task and an elevated state of relaxation and attention following the HRVB session, as evidenced by higher averages of correct responses, serenity and attentiveness scores. However, the findings suggest that this observed improvement is not influenced by changes in cardiac vagal tone, as assessed using a simple mediation analysis. In conclusion, this study presents promising insights into the impact of a single HRVB session, laying the foundation for future research advancements in this domain.

Cardiac autonomic profile, perceived stress and environmental comfort in healthy employees during remote and in-office work

Remote work (REMOTE) causes an overlap between working and domestic demands. The study of the cardiac autonomic profile (CAP) by means of heart rate variability (HRV) provides information about the impact of REMOTE on workers’ health. The primary aim was to determine whether CAP, self-perceived stress, environmental and workstation comfort are modified during REMOTE. The secondary aim was to explore how these indices are influenced by individual and environmental work-related factors. Fifty healthy office employees alternating REMOTE and in-office (OFFICE) working were enrolled, rated self-perceived stress, environmental and workstation comfort using a visual analogue scale and performed a 24-h electrocardiogram during REMOTE and OFFICE. Stress was lower (5.6 ± 2.2 vs. 6.4 ± 1.8), environmental comfort higher (7.7 ± 1.9 vs. 7.0 ± 1.5), and the workstation comfort poorer (6.2 ± 1.8 vs. 7.5 ± 1.2) during REMOTE. CAP was similar during REMOTE and OFFICE. CAP was influenced by some work-related factors, including the presence of offspring, absence of a dedicated workspace during REMOTE and number of working hours. All these variables determined a decreased vagal modulation. The working setting seems to impact the levels of perceived stress and comfort, but not the CAP. However, individual and environmental work-related factors reduce cardiac vagal modulation during REMOTE, potentially increasing the risk of developing cardiovascular diseases.

Childhood Maltreatment and Leukocyte Telomere Length: Cardiac Vagal Activity Influences the Relation in Older Adults.

Childhood maltreatment is associated with shorter leukocyte telomere length (LTL). However, the influence of cardiac vagal control on this relation is unknown. We examined whether cardiac vagal control at rest and in response to stress moderates or cross-sectionally mediates the relationship between childhood maltreatment and LTL. Participants were 1179 men and women (aged 65 [7.2] years) suffering from coronary artery disease or non-cardiovascular chronic disease. They completed a childhood maltreatment questionnaire and underwent a stress protocol while electrocardiogram was monitored. High-frequency heart rate variability (HF-HRV) measures were obtained at rest, during stress, and after stress in absolute and normalized units (nu). LTL was measured using quantitative polymerase chain reaction. Mediation and moderation analyses were performed. HF-HRV and HF-HRV in normalized units (HFnu) measures did not mediate the childhood maltreatment-LTL relation. However, baseline HFnu ( p = .027) and HFnu reactivity ( p = .051) moderated the relation. Specifically, maltreatment was associated with significantly lower LTL among those with baseline HFnu at ( b = -0.059, p = .003) or below the mean ( b = -0.103, p < .001), but not among those with higher baseline HFnu. It was also associated with significantly lower LTL among participants who showed either blunted ( b = -0.058, p = .004) or increased HFnu ( b = -0.099, p = .001) responses to stress but not in those with large decreases in HFnu. Childhood maltreatment was associated with lower LTL in those who showed a distinct cardiac vagal profile at baseline and in response to stress. The mechanisms and implications remain to be determined.

Brain-IT: Targeting the brain using information technology for secondary prevention of mild neurocognitive disorder

Brain-IT: Targeting the brain using information technology for secondary prevention of mild neurocognitive disorder

Adherence to exercise after an acute coronary syndrome: a 6-month randomized controlled trial.

Introduction: Exercise training with well-known health benefits is a key element in the self-management of coronary artery disease (CAD). Although current guidelines for patients with CAD recommend daily exercise training, most of the patients do not follow the guidelines. We tested the hypothesis that an exercise training program guided by a novel technology used at home will improve adherence to exercise training. Methods: One to three weeks after percutaneous coronary intervention (PCI), acute coronary syndrome patients (n = 50) were randomized into traditional (age 65 ± 8years) and novel technology-guided (age 60 ± 8years) exercise rehabilitation groups. The novel technology included a tablet computer with a virtual autonomous physiotherapy agent (VAPA group) for every patient at home; it was used to guide exercise training time, volume, and intensity. Traditional rehabilitation was performed by exercise training prescriptions, phone calls, and diaries (control group). The duration of the rehabilitation program was 6months for both groups. Exercise capacity and 24-h heart rate variability were measured at baseline and at the end of the program. Adherence to exercise was measured over 6months as the percentage of realized training. Results: None of the patients dropped out from the VAPA group, while three patients dropped out from the control group. Adherence to exercise was higher in the VAPA group than in the control group for resistance training (141% ± 56% vs. 50% ± 20%, p < 0.0001), and there were no differences between the groups for aerobic training (144% ± 45% vs. 119% ± 65%, p = 0.22). Exercise capacity increased in both the groups (time p < 0.001, time × group interaction p = ns). High-frequency power of R-R intervals (lnHF) increased in the VAPA group but remained unchanged in the control group (natural logarithm of lnHF power from 5.5 ± 0.7 to 5.8 ± 0.9ms2 and from 5.3 ± 0.8 to 5.2 ± 0.7ms2, respectively, time × group interaction p = 0.014). Conclusion: Compared with the use of traditional methods, the use of novel technology at home results in better adherence to exercise, particularly in resistance training, in acute coronary syndrome patients. Second, the VAPA group showed improved cardiac vagal regulation, documented by increased vagally mediated R-R interval fluctuation, compared with the traditional training group (ClinicalTrials.gov identifier: NCT03704025).