Parasympathetic Modulation Research Articles

Importance of the left superior ganglionated plexus ablation for the denervation of atrioventricular node: the impact of patient gender and bradycardia phenotype

Abstract Background Cardioneuroablation has been proposed as a new therapeutic option in selected patients with symptomatic functional bradyarrhythmia including recurrent neurally-mediated syncope. The contribution of individual ganglionated plexi to cardiac autonomic regulations is not fully established. Purpose It appears that ablation of the left superior ganglionated plexus (LSGP) is inoperable for the denervation of the sinoatrial node (SAN) and infrequently required for the denervation of the atrioventricular node (AVN). We explored the conditions that are associated with the need for LSGP ablation. Methods The study included 177 otherwise healthy patients aged 41 ± 12 years; 55% of males; 36% with predominant AVN disorder (29% in males, 44% in females, P <0.05) who underwent their first cardioneuroablation for symptomatic bradyarrhythmias at our centre between 2019 – 2024. Anatomically-navigated radiofrequency ablation with a bi-atrial approach was performed. In all patients, we ablated first the superior paraseptal (former right superior) ganglionated plexus (SPSGP) and inferior paraseptal (former posteromedial left) ganglionated plexus (IPSGP). Extracardiac vagus nerve stimulation (ECVS) via right and left jugular vein in general anaesthesia was used to assess the residual parasympathetic modulation of the AVN. If AVN was not completely denervated after the SPSGP and IPSGP ablation, the LSGP was targeted. Results Ablation of SPSGP and IPSGP resulted in SAN and AVN denervation in the majority of patients. LSGP ablation was required in 39 / 177 (22%) patients; in 31% of females vs. 14% of males (P <0.01); in 41% vs. 12% (P <0.0001) of patients with predominant AVN vs. SAN disorder, respectively. The corresponding decomposition is provided in the Table. In multivariate analysis, both female gender (P <0.05) and AVN disorder (P <0.001) were independently associated with the need for LSGP ablation. When the population was dichotomized into early (September 2019 – December 2021) and recent period (January 2022 – February 2024), the need for LSGP ablation had a downward trend (28% vs. 16%, P <0.05). Conclusions LSGP ablation to finalize the AVN denervation is required in a minority of patients. This need is independently associated with the female gender and predominant AVN disorder. The ECVS guidance in the ablation of SPSGP and IPSGP contributes to the decreasing trend of LSGP ablation, i.e. minimizing the final lesion set.Rate of LSGP ablation

Linking brain-heart interactions to emotional arousal in immersive virtual reality.

The subjective experience of emotions is linked to the contextualized perception and appraisal of changes in bodily (e.g., heart) activity. Increased emotional arousal has been related to attenuated high-frequency heart rate variability (HF-HRV), lower EEG parieto-occipital alpha power, and higher heartbeat-evoked potential (HEP) amplitudes. We studied emotional arousal-related brain-heart interactions using immersive virtual reality (VR) for naturalistic yet controlled emotion induction. Twenty-nine healthy adults (13 women, age: 26 ± 3) completed a VR experience that included rollercoasters while EEG and ECG were recorded. Continuous emotional arousal ratings were collected during a video replay immediately after. We analyzed emotional arousal-related changes in HF-HRV as well as in BHIs using HEPs. Additionally, we used the oscillatory information in the ECG and the EEG to model the directional information flows between the brain and heart activity. We found that higher emotional arousal was associated with lower HEP amplitudes in a left fronto-central electrode cluster. While parasympathetic modulation of the heart (HF-HRV) and parieto-occipital EEG alpha power were reduced during higher emotional arousal, there was no evidence for the hypothesized emotional arousal-related changes in bidirectional information flow between them. Whole-brain exploratory analyses in additional EEG (delta, theta, alpha, beta and gamma) and HRV (low-frequency, LF, and HF) frequency bands revealed a temporo-occipital cluster, in which higher emotional arousal was linked to decreased brain-to-heart (i.e., gamma→HF-HRV) and increased heart-to-brain (i.e., LF-HRV → gamma) information flow. Our results confirm previous findings from less naturalistic experiments and suggest a link between emotional arousal and brain-heart interactions in temporo-occipital gamma power.

Slow-Paced Breathing Intervention in Healthcare Workers Affected by Long COVID: Effects on Systemic and Dysfunctional Breathing Symptoms, Manual Dexterity and HRV.

Many COVID-19 survivors still experience long-term effects of an acute infection, most often characterised by neurological, cognitive and psychiatric sequelae. The treatment of this condition is challenging, and many hypotheses have been proposed. Non-invasive vagus nerve stimulation using slow-paced breathing (SPB) could stimulate both central nervous system areas and parasympathetic autonomic pathways, leading to neuromodulation and a reduction in inflammation. The aim of the present study was to evaluate physical, cognitive, emotional symptoms, executive functions and autonomic cardiac modulation after one month of at-home slow breathing intervention. 6655 healthcare workers (HCWs) were contacted via a company email in November 2022, of which N = 58 HCWs were enrolled as long COVID (cases) and N = 53 HCWs as controls. A baseline comparison of the two groups was performed. Subsequently each case was instructed on how to perform a resonant SPB using visual heart rate variability (HRV) biofeedback. They were then given a mobile video tutorial breathing protocol and asked to perform it three times a day (morning, early afternoon and before sleep). N = 33 cases completed the FU. At T0 and T1, each subject underwent COVID-related, psychosomatic and dysfunctional breathing questionnaires coupled with heart rate variability and manual dexterity assessments. After one month of home intervention, an overall improvement in long-COVID symptoms was observed: confusion/cognitive impairment, chest pain, asthenia, headache and dizziness decreased significantly, while only a small increase in manual dexterity was found, and no relevant changes in cardiac parasympathetic modulation were observed.

Relationship between autonomic nervous function and brain functions such as memory and attention

This study aimed to evaluate the relationship between autonomic nervous function (ANF) and cognitive abilities, such as memory and attention, using the Kana pick-out test (KPT). The participants were 11 female college students aged 21 years old. Each participant completed the KPT ten times, during which their ANF was assessed via heart rate variability analysis. During the KPT, participants circled Japanese vowels in a 400-character story written in hiragana. We measured attention using the KPT score and assessed memory using a memory score based on ten descriptive questions about the story. Statistical analysis revealed a significant positive correlation between higher KPT and memory scores, indicating a link between memory and attention. The parasympathetic sinus modulation marker, high-frequency component power (HF), decreased during the kana-picking task (Interval B) and recovered during the subsequent content verification task (Interval C). In Interval A (before the kana-picking task), the HF showed a positive correlation with both the KPT and memory scores. Additionally, a positive correlation was observed between HF and memory scores during interval B. Other autonomic nervous indices, including low-frequency component power (LF), total power (TP), and LF/HF ratio, also showed significant correlations with KPT and memory scores. Our findings strongly suggest that ANF is intricately connected to cognitive functions, such as memory and attention. This indicates that monitoring ANF could provide a novel methodology for assessing learning and occupational efficiency.

Adiposity and cardiac autonomic function in children with a family history of obesity.

Data on associations between adiposity and heart rate variability (HRV) in prepubertal children are limited. We examined the associations between adiposity indices and HRV, independent of lifestyle behaviors, comparing multiple indicators of adiposity, and explored differences between boys and girls. Data stem from 469 participants of the QUALITY cohort (630 children aged 8-10 years with a parental history of obesity). Adiposity indices included waist-to-height ratio, body mass index (BMI) percentiles and categories (overweight, obesity), dual-energy x-ray absorptiometry (DEXA) defined fat mass percentage and android/gynoid ratio. HRV indices in the frequency and the spectral domain were derived from a daytime 3-h Holter recording. Multivariable linear regression models were adjusted for age, sex, Tanner stage, physical activity, screen time, and fitness. Interactions between sex and adiposity were tested. Greater adiposity was associated with decreased parasympathetic modulation and increased sympathetic dominance. Waist-to-height ratio was associated with lower parasympathetic activity: root mean square of the successive differences (RMSSD) [B = -23.32, 95% confidence interval (CI) -42.42, -4.22], pNN50 (B = -16.93, 95% CI - 28.58, - 5.27), LF/HF ratio (B = 1.83, 95% CI 0.97-2.70). Patterns of association were similar for android/gynoid ratio. Overweight was not associated with altered HRV. Obesity was negatively associated with RMSSD and pNN50 and positively with LF/HF ratio. Greater fat mass percentage was associated with lower RMSSD, pNN50, and HF, and increased LF/HF ratio. There were no differences between boys and girls. Specific markers of adiposity relate to altered HRV in childhood, with waist-to-height ratio being potentially a more relevant marker of HRV than BMI and more pragmatic than percent body fat. NCT03356262, 11 November 2017.

Long-term effects of siponimod on cardiovascular and autonomic nervous system in secondary progressive multiple sclerosis.

Siponimod, a second-generation, selective sphingosine 1-phosphate receptor (S1PR) 1 and 5 modulator, represents an important therapeutic choice for active secondary progressive multiple sclerosis (SPMS). Besides the beneficial immunomodulatory effects, siponimod impacts cardiovascular function through S1PR1 modulation. Short-term vagomimetic effects on cardiac activity have proved to be mitigated by dose titration. However, long-term consequences are less known. This study aimed to investigate the long-term impact of siponimod on cardiac autonomic modulation in people with SPMS (pwSPMS). Heart rate variability (HRV) and vascular hemodynamic parameters were evaluated using Multiple Trigonometric Regressive Spectral analysis in 47 pwSPMS before siponimod therapy and after one, three, six and 12months of treatment. Autonomic activation tests (tilt test for the sympathetic and deep breathing test for the parasympathetic cardiac modulation) were performed at each examination. pwSPMS preserved regular cardiovascular modulation responses during the autonomic tests reflected in the variation of several HRV parameters, such as RMSSD, pNN50, total power of HRV, high-frequency and low-frequency bands of the spectral domain or hemodynamic vascular parameters (Cwk, Zao, TPR, MAP) and baroreflex sensitivity (BRS). In the long-term follow-up, RMSSD, pNN50, total power, BRS and CwK presented a significant decrease, underlining a reduction of the parasympathetic and a shift towards sympathetic predominance in cardiac autonomic modulation that tends to stabilise after 1year of treatment. Due to dose titration, the short-term effects of siponimod on cardiac autonomic modulation are mitigated. The long-term impact on cardiac autonomic modulation is similar to fingolimod. The autonomic activation tests showed normal cardiovascular responses during 1-year follow-up in pwSPMS, confirming the safety profile of siponimod. Further research on autonomic function could reveal whether the observed sympathetic activation is a compensatory response to S1P signaling intervention or a feature of the disease, while also shedding light on the role of S1PR modulation in MS.

Heart rate variability in horses with and without severe equine asthma.

Equine asthma in severe form (severe equine asthma [sEA]) shares remarkable similarities with human asthma. Human studies detected changes in the autonomic nervous system function in asthmatic patients based on heart rate variability (HRV) analysis. Observational study. To investigate the relationship between sEA and HRV in horses. Twenty horses diagnosed with sEA and 20 asymptomatic (non-sEA) horses were investigated. SEA horses showed clinical signs. The RR intervals of the ECG were recorded for 1 h at rest between 9 AM and 11 AM using a heart rate (HR) monitor. HRV data were calculated using Kubios software. Parameters recorded for the sEA and non-sEA groups were compared using one-way MANOVA model. The significance level was set at α = 0.05. SD2 (mean 99.6 ± SD 25.3 vs. 42.5 ± 17.1), SDNN (82.7 ± 20.7 vs. 41.3 ± 14.3), TINN (398.1 ± 104.9 vs. 209.3 ± 71.9), SD2/SD1 ratio (1.7 ± 0.2 vs. 1.1 ± 0.3), Total power (4740.2 ± 1977.9 vs. 1503.0 ± 1179.3), LF (2415.3 ± 1072.4 vs. 707.4 ± 649.9), SD1 (60.9 ± 15.9 vs. 39.2 ± 14.1), RMSSD (86.0 ± 22.6 vs. 55.3 ± 19.8) and HF (1575.8 ± 902.5 vs. 578.1 ± 491.1) were lower in sEA horses compared with the non-sEA horses (p < 0.01 for each variable). SD2, SDNN, TNN, the SD2/SD1 ratio and Total power showed the greatest discriminatory power in differentiating the sEA and non-sEA groups. Small sample size. Our findings indicate that like humans, asthmatic horses show an overall reduction in autonomic control. A relative increase of the parasympathetic modulation of the heart was also observed. After further investigations, HRV measurement might be a non-invasive approach to monitor autonomic nervous system responses of sEA horses.

Improved Sympathetic Activity With Short-Term Effects of Yoga in Young Adults.

The purpose of this study was to clarify the heart rate variability (HRV) transition after a single yoga program. Participants were 22 females who were healthy university students and had never practiced yoga before. They practiced yoga while recording their HRV. Heart rate (HR), high frequency (HF; 0.15-0.4Hz) as parasympathetic and low frequency (LF; 0.04-0.15Hz) components were extracted, and then the LF/HF ratio as sympathetic and normalized units of HF HFnu = HF/(LF + HF) as parasympathetic modulation in autonomic activity were calculated. HR and HRV indices after yoga were divided into four 5-minute periods (after 5, 10, 15, and 20minutes) and compared before yoga. HR and LF/HF at all periods after yoga were significantly lower than before yoga (P <.01, all). HF after yoga was not significantly changed, but HFnu after 5, 10, and 15minutes was significantly higher than before yoga (P <.01, <.01, and =.02, respectively). The short-term effects of yoga on HRV implied a decrease in sympathetic modulation and a relative increase in parasympathetic modulation. Therefore, yoga may be used as a fast-acting alternative therapy to significantly improve sympathetic activity.

Short-term heart rate variability: A potential approach to frailty assessment in older adults.

This study aimed to evaluate cardiac autonomic modulation using short-term heart rate variability (HRV) and compare it among frailty statuses in older Indian adults. A total of 210 subjects aged 60 years and above were recruited into three groups: frail (n = 70), pre-frail (n = 70), and non-frail (n = 70) from the outpatient department of Geriatric Medicine at a tertiary care hospital in India. Frailty status was assessed using the Rockwood frailty index (FI) criteria. HRV was derived from a 5-min ECG recording of standard limb leads and assessed using time domain, frequency domain, and nonlinear analysis of cardiac interval variability. The HRV parameters indicative of parasympathetic modulation such as SDNN, SDSD, rMSSD, NN50, pNN50, absolute HF power, and SD1 were significantly lower in frail subjects compared with both pre-frail and non-frail subjects (P < 0.05). Absolute LF power and SD2 were also lower in frail subjects compared with pre-frail and non-frail subjects (P < 0.05). Measures of sympatho-vagal balance (LF/HF and SD1/SD2 ratios) did not show statistical significance. The FI demonstrated negative correlations with all HRV parameters. Frail individuals exhibit decreased sympathetic and parasympathetic modulation compared with pre-frail and non-frail individuals, although maintaining a balanced sympatho-vagal state. Furthermore, autonomic modulation declines progressively with increasing frailty.

Effects of voluntary exercise and electrical muscle stimulation on reaction time in the Go/No-Go task.

Acute exercise improves cognitive performance. However, it remains unclear what triggers cognitive improvement. Electrical muscle stimulation (EMS) facilitates the examination of physiological changes derived from peripheral muscle contraction during exercise. Thus, we compared the effects of EMS and voluntary exercise at low- or moderate-intensity on reaction time (RT) in a cognitive task to understand the contribution of central and peripheral physiological factors to RT improvement. Twenty-four young, healthy male participants performed a Go/No-Go task before and after EMS/exercise. In the EMS condition, EMS was applied to the lower limb muscles. In the low-intensity exercise condition, the participants cycled an ergometer while maintaining their heart rate (HR) at the similar level during EMS. In the moderate-intensity exercise condition, exercise intensity corresponded to ratings of perceived exertion of 13/20. The natural log-transformed root mean square of successive differences between adjacent inter-beat (R-R) intervals (LnRMSSD), which predominantly reflects parasympathetic HR modulation, was calculated before and during EMS/exercise. RT improved following moderate-intensity exercise (p = 0.002, Cohen' d = 0.694), but not following EMS (p = 0.107, Cohen' d = 0.342) and low-intensity exercise (p = 0.076, Cohen' d = 0.380). Repeated measures correlation analysis revealed that RT was correlated with LnRMSSD (Rrm(23) = 0.599, p = 0.002) in the moderate-intensity exercise condition. These findings suggest that the amount of central neural activity and exercise pressor reflex may be crucial for RT improvement. RT improvement following moderate-intensity exercise may, at least partly, be associated with enhanced sympathetic nervous system activity.

The Effects of Caffeine on Heart Rate and Heart Rate Variability at Rest and During Submaximal Cycling Exercise

ABSTRACT The aim of this study was to investigate the effects of caffeine on heart rate and heart rate variability (HRV) at rest and during submaximal exercise. Using a balanced, double-blind, randomized, crossover design, 16 male cyclists (age: 37 ± 9 years; V ˙ O2max: 4.44 ± 0.67 L·min−1) completed three trials in an air-conditioned laboratory. In Trial 1, cyclists completed two incremental cycling tests to establish the V ˙ O2-power output relationship and V ˙ O2max. In trials 2 and 3, cyclists were evaluated for heart rate and HRV at rest, after which they ingested a capsule containing 5 mg·kg−1 of caffeine or placebo. Thirty-five minutes post-supplementation, additional resting heart rate and HRV readings were taken after which cyclists completed a submaximal incremental cycling test (6 min stages) at 40–80% of V ˙ O2max; with HR and HRV measurements taken in the last 5 min of each increment. HRV was determined from the root mean square of successive differences between R–R intervals. There were significant supplement × exercise intensity interactions on heart rate (p = .019) and HRV (p = .023), with post hoc tests on the latter showing that caffeine increased HRV at 40%, 50%, and 60% of V ˙ O2max by 3.6 ± 4.9, 2.6 ± 2.8, and 0.6 ± 1.7 ms, respectively. There was a supplement × time interaction effect on resting HRV (p < .001), but not on heart rate (p = .351). The results of this study support the suggestion that caffeine increases the parasympathetic modulation of heart rate.Clinical trial registration number: NCT05521386.

Autism spectrum disorder in young patients with congenital central hypoventilation syndrome: role of the autonomic nervous system dysfunction

BackgroundCongenital central hypoventilation syndrome (CCHS) is a rare condition characterized by alveolar hypoventilation and autonomic nervous system (ANS) dysfunction requiring long-term ventilation. CCHS could constitute a risk factor of autism spectrum disorder (ASD) due to birth injury related to respiratory failure, which remains to be determined. ANS dysfunction has also been described in ASD and there are indications for altered contribution of ANS-central nervous system interaction in processing of social information; thus, CCHS could be a risk factor for ASD based on pathophysiological background also. Our study aimed to determine the prevalence of ASD among CCHS patients, identify risk factors, and explore the relationship between the ANS, evaluated by heart rate variability indices, and adaptative functioning.ResultsOur retrospective study, based on the analysis of records of a French national center of patients with CCHS under 20 years of age, determined that the prevalence of ASD (diagnosed by a psychiatrist, following the criteria of DSM-4 or DSM-5) was 6/69 patients, 8.7% (95% confidence interval: 3.3–18.0%). In a case (CCHS with ASD, n = 6) – control (CCHS without ASD, n = 12) study with matching on sex, longer neonatal hospitalization stay and glycemic dysfunction were associated with ASD. Adaptative functioning was assessed using Vineland Adaptative behavioral scales (VABS) and heart rate variability indices (including daytime RMSSD as an index of parasympathetic modulation) were obtained from ECG Holter performed the same day. In 19 young subjects with CCHS who had both ECG Holter and VABS, significant positive correlations were observed between RMSSD and three of four sub-domains of the VABS (communication: R = 0.50, p = 0.028; daily living skills: R = 0.60, p = 0.006; socialization: R = 0.52, p = 0.021).ConclusionOur study suggests a high prevalence of ASD in patients with CCHS. Glycemic dysfunction and longer initial hospitalization stays were associated with ASD development. A defect in parasympathetic modulation was associated with worse adaptative functioning.

Immediate Increase in the Root Mean Square of Successive Differences after Three Bouts of Remote Ischemic Preconditioning: A Randomized Controlled Trial.

(1) Background: Remote ischemic preconditioning (RIPC) is an intervention involving the application of brief episodes of ischemia and reperfusion to distant tissues to activate protective pathways in the heart. There is evidence suggesting the involvement of the autonomic nervous system (ANS) in RIPC-induced cardioprotection. This study aimed to investigate the immediate effects of RIPC on the ANS using a randomized controlled trial. (2) Methods: From March 2018 to November 2018, we conducted a single-blinded randomized controlled study involving 51 healthy volunteers (29 female, 24.9 [23.8, 26.4] years). Participants were placed in a supine position and heart rate variability was measured over 260 consecutive beats before they were randomized into either the intervention or the SHAM group. The intervention group underwent an RIPC protocol (3 cycles of 5 min of 200 mmHg ischemia followed by 5 min reperfusion) at the upper thigh. The SHAM group followed the same protocol but on the right upper arm, with just 40 mmHg of pressure inflation, resulting in no ischemic stimulus. Heart rate variability measures were reassessed afterward. (3) Results: The intervention group showed a significant increase in RMSSD, the possible marker of the parasympathetic nervous system (IG: 14.5 [5.4, 27.5] ms vs. CG: 7.0 [-4.3, 23.1 ms], p = 0.027), as well as a significant improvement in Alpha 1 levels compared to the control group (IG: -0.1 [-0.2, 0.1] vs. CG: 0.0 [-0.1, 0.2], p = 0.001). (4) Conclusions: Our results hint that RIPC increases the RMSSD and Alpha 1 parameters showing possible immediate parasympathetic modulations. RIPC could be favorable in promoting cardioprotective or/and cardiovascular effects by ameliorating ANS modulations.

From One's Heart to the Mind of Others: A Study in School-Aged Children.

Studies have shown a significant association between effective parasympathetic modulation of the heart and processes linked to social cognition. Particularly, Quintana and colleagues documented a relation between vagally-mediated heart rate variability (vmHRV) and performance on a theory of mind (ToM) task, namely, the Reading the Mind in the Eyes Test (RMET), in a sample of university students. The purpose of the present study was to test whether such result would extend to a sample of school-aged children (7-9 years old) using the child version of the RMET. In addition, the Eyes Test Revised was administered as it is more suitable to evaluate ToM during childhood. Results supported the positive association between vmHRV and ToM abilities, replicating and extending previous results obtained in young adults. The current study adds to the existing literature pointing to HRV as a putative biomarker of social cognition abilities.

Differences in Heart Rate Variability in the Frequency Domain between Different Groups of Patients.

Background and Objectives: Heart rate variability (HRV) is defined as a physiological variation in duration between sinus beats. The aim of this study was to research and analyze the HRV between various groups of patients. Materials and Methods: A retrospective study was conducted in an outpatient setting. Patients who had undergone a tilt-table test were selected for this study and were divided into three groups based on their self-reported health anamnesis: group 1 (n = 84, mean age 45.8 ± 17.8) consisted of patients with no known orthostatic intolerance or neurodegenerative disease, group 2 consisted of patients with a known or suspected orthostatic intolerance (n = 50, mean age 46.5 ± 18.6), and group 3 consisted of patients with a known or suspected neurodegenerative disorder (n = 29, mean age 55.6 ± 20.4). During the tilt-table test, HRV frequency-domain parameters-normalized low frequency (LFnu) and high frequency (HFnu), absolute powers-absolute low frequency (LF-RRI), absolute high frequency (HF-RRI), and LF/HF ratio-were recorded during 5 min rest in the supine position. Results: Group 1 had a reduced LFnu at 52.93% (SD: 18.00) compared to group 2 at 58.57% (18.06) and group 3 at 61.80% (SD: 17.74), and group 1 had increased HFnu: group 1-47.08% (SD: 17.97), group 2-41.41% (SD: 18.03), and group 3-38.16% (SD: 14.7). LFnu and HFnu differences were statistically significant (p < 0.05). LF-RRI was reported as follows: group 1-531.32 ms2 (SD: 578.57), group 2-346.2 ms2 (SD: 447.96), and group 3-143.21 ms2 (SD: 166.96). HF-RRI was reported as follows: group 1-835.87 ms2 (SD: 1625.42), group 2-297.46 ms2 (SD: 507.15), and group 3-70.83 ms2 (SD: 75.67). LF-RRI and HF-RRI comparisons between groups were statistically significant (p < 0.001). LF/HF ratios were reported as follows: group 1-1.91 (SD: 2.29), group 2-2.43 (SD: 2.33), and group 3-2.54 (SD: 2.17). LF/HF ratio comparisons between groups were statistically significant at p < 0.05. Conclusions: This study shows that patients with known or suspected orthostatic intolerance and neurodegenerative disorders have reduced HRV, possibly caused by reduced parasympathetic modulation. HRV in patients with known or suspected neurodegenerative disorders is reduced more severely than in patients with orthostatic disorders. Other studies in HRV have indicated a possible increase of risk in cardiovascular disorders in patients with reduced HRV, and therefore, HRV analysis could be a potential clinical diagnostic tool. However, the lack of universally agreed upon methodology, reference values, and possible external and internal factor influence hinders the introduction of HRV examinations into wider clinical practice.

Anatomic-guided ablation of the right ganglionated plexi validated by the automatic fractionation map

Abstract Background and aim Cardiac autonomic modulation through endocardial ablation of atrial ganglionated plexi (GP) is an alternative strategy in selected patients with severe vagal induced bradyarrhythmias. A strictly anatomical approach targeting the right GPs has demonstrated good success rates but is an empirical approach and has yet to be validated. The presence of fractionated electrograms has been associated with the areas of GPs and can be automatically mapped (fractionation map). The aim of this study was to compare the empirical ablated area, to the automatically assessed area of GPs based on the presence of fractionated electrograms (FEs). Methods We studied eight consecutive patients referred for parasympathetic modulation. A high-density map of the left and right atria (LA, RA) in sinus rhythm was performed. The settings for the automatic map were as follows: bipolar high pass filter of 500 Hz, a fractionation threshold of 4, and a width of 5 ms. The ablation was empirically performed by an operator blinded to the results of the fractionation map, as per site protocol. The ablation was aimed at the anatomic locations of the right GPs in the LA and RA. At the anterior and inferior aspect of the right superior pulmonary vein and inferior aspect of the right inferior pulmonary vein on the LA, and posterior RA opposite to the LA RF applications and around the coronary sinus ostium on the RA (Figure). Before ablation, 2 mg of atropine was administered in bolus, and the increase in heart rate was registered and repeated at the end of the procedure. After the operator completed the ablation, access to the fractionation map was available, and additional radiofrequency (RF) applications were applied as needed (Figure). The number of additional RF applications to cover all the areas with FEs was assessed. Success was defined as an absence of response to atropine after the procedure. Results Three patients underwent autonomic system modulation only, and five underwent additional pulmonary vein isolation (PVI). The mean age was 66 (50-77) years, five males. The median mapping time of the LA and RA was 11 (17-7) and 14 (9-18) min. All patients underwent successful parasympathetic modulation. The initial median (Q1-Q3) increase in heart rate with atropine was 34 (23-39)% versus 0 (0-2)% after ablation, p=0.012. The differences between empiric and FEs map-guided ablation are depicted in the Table. The additional number of points was low. However, a median of 9 (5-15) additional points were added. Conclusions A purely anatomic-guided procedure directed only at the atrial right GPs is usually enough as a therapeutic approach for cardiac autonomic modulation, however, the fractionation map tool helped validate the method and ensure success at the first pass.

The 24‐h movement behaviours composition is associated with parasympathetic modulation in preschoolers

AbstractAimTo investigate the associations between 24‐h movement behaviours and heart rate variability (HRV) in preschool children.MethodsA total of 123 preschoolers (4.52 ± 0.25 years old; 62 girls) were assessed for physical activity (PA) and sedentary behaviour (SB) using an accelerometer (Actigraph WGT3x). Sleep duration (SD) was parent‐reported. Children were laid down in a supine position for 10 min to assess HRV data. The R–R intervals recorded during the last 5 min of this period were analysed. We conducted compositional analysis in R studio, and the significance level was 95%. All ethical procedures were followed, and the study had the approval of the local ethical board.ResultsWhen considered as a composition, adjusted for age, body mass index and sex, the 24‐h movement composition (PA, SB and SD) significantly predicted better parasympathetic modulation (Root mean square of the successive differences [RMSSD] [p = 0.04; r2 = 0.13]), but not high frequency (HF) (nu) (p = 0.51, r2 = 0.01), low frequency (nu) (p = 0.52, r2 = 0.02),or standard deviation (standard deviation of normal‐to‐normal intervals) (p = 0.55, r2 = 0.02), respectively.ConclusionThese results suggest the 24‐h movement composition predicted the RMSSD time‐domain index related to parasympathetic activity.

Analysis of Sinus Variability in a Group of Cameroonian Athletes.

Heart rate variability (HRV) analysis is a useful method for assessing the heart's ability to adapt to endogenous and exogenous loads. Data from African population on HRV are scarce and even more so in sports populations. This study aimed to compare cardiac autonomic modulation response in Cameroonian athletes and sedentary. Methodology. We conducted a prospective and analytical study in sports teams in the city of Yaoundé, Cameroon. The participants in our study were divided in three groups; people who practiced little or no sporting activity (sedentary as group 1) or who were regularly physically active as part of a sports team (footballers or handballers as second and third groups). They had to be aged 18 or over and have given their informed consent. Heart rate (HR) was continuously recorded at rest for ten minutes and then transferred to a computer equipped with Kubios HRV Standard software for analysis. Means ± mean standard errors were compared using the one-way ANOVA test, followed by Tukey's post-test. The significance threshold was set at 0.05. Of the 60 people selected to participate to our study, 75.0% were sportsmen (40.0% handball players and 35.0% footballers). The resting HR of sedentary people was higher (p < 0.001) than that of footballers and handball players. The SDNN, RMSSD, and pNN50 of sedentary people (16.22 ± 1.04; 9.97 ± 0.46; and 0.16 ± 0.06) were lower than those of footballers (30.13 ± 2.93; 20.61 ± 2.46; and 2.99 ± 0.63, with p < 0.001) and handball players (29.00 ± 1.86; 16.44 ± 1.16; and 2.15 ± 0.38, with p < 0.001 and p < 0.05 respectively). Absolute and relative very-low-frequency (VLF) power, absolute low and high-frequency (LF and HF) power, as well as total power (TP) were lower in sedentary people (3.66 ± 0.08 and 16.21 ± 0.64; 5.04 ± 0.15 and 2.50 ± 0.16 and 246.40 ± 18.04) compared to footballers (5.09 ± 0.24 and 26.87 ± 1.76; 5.85 ± 0.32 and 3.92 ± 0.22 and 836.10 ± 103.70, with p < 0.001, p < 0.01, and p < 0.001) and handball players (4.86 ± 0.16 and 30.82 ± 2.67; 6.03 ± 0.19 and 3.46 ± 0.16 and 927.30 ± 94.12, with p < 0.001, p < 0.05, p < 0.01, and p < 0.001). The LF/HF ratio was 12.1% and 20.1% lower in sedentary people (7.55 ± 0.58) compared with footballers (8.46 ± 0.50) and handball players (9.07 ± 0.60), respectively. Sportsmen showed greater parasympathetic and global modulation when compared to sedentary people.

Cardiac Autonomic and Endothelial Function in Acute Lymphoblastic Leukaemia Patients Immediately After Chemotherapy and at the Three-Month Follow-up.

Acute lymphoblastic leukemia (ALL) is a malignant uncontrolled overproduction of immature lymphoid cells in blood and bone marrow. The primary treatment of ALL is chemotherapy. Chemotherapy can have myriad systemic side effects, notably cardiovascular derangement. Autonomic derangement occurrence in cancer patients signifies cardiovascular risk in them and is a determinant of cardiovascular morbidity and mortality. Elevated soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) levels implicated in the regulation of inflammation indicate endothelial dysfunction. High levels of high-sensitivity C-reactive protein (hsCRP) can be indicative of low-grade inflammation. Hence, in this study the cardiac autonomic function and endothelial and inflammatory biomarker levels in adult patients with ALLwere assessed immediately and three months after chemotherapy. In this longitudinal study, 30 ALL patients (23 males, seven females) aged between 18 to 50 years, who had completed chemotherapy regimens, and 30 age and gender-matched healthy participants (controls) were recruited. Cardiac autonomic function tests (short-term heart rate variability (HRV), 30:15 ratio, synaptic excitation and inhibition (E/I) ratio, diastolic blood pressure (DBP) response to isometric hand grip), endothelial markers (sVCAM-1 and sICAM-1), and inflammatory marker (hsCRP) were assessed immediately and at three months after chemotherapy. Magnitudes of time domain and frequency domain indices, conventional autonomic function test indices, and biomarkers were deranged in ALL patients immediately after chemotherapy. After three months, cardiac autonomic function parameters were found to improve in the form of increased root mean square of successive differences between normal heartbeats (RMSSD), standard deviation of the interbeat intervals of normal sinus beats (SDNN), total power, high-frequency (HF)nu, and decreased low-frequency(LF)nu & LF-HF ratio. Endothelial (sVCAM-1) and inflammatory markers (hsCRP) were lower in the patient group as compared to the controls immediately after chemotherapy. Three months after chemotherapy, the levels of endothelial and inflammatory markers did not show much change. In this study, we found ALL patients showed higher sympathetic drive, decreased parasympathetic modulation, and sympathovagal imbalance immediately after chemotherapy as compared to the controls, indicating cardiovascular risk. After three months, improvement in cardiovascular autonomic function was observed. ALL itself is a state of inflammation with elevated endothelial and inflammatory markers; thus, the decreased endothelial and inflammatory markers could be attributed to the immediate effect of chemotherapy.

Effects of exposition to glycol ethers on heart rate recovery, parasympathetic modulation and oxygen diffusion at rest and during exercise

Introduction Daily exposition to ether glycols is common. Caretakers using cleaning products are critically exposed by combining physical activity with exposition to highly concentrated products. Previous animal studies showed hemato-, respiratory and autonomic nervous system toxicity amongst others. Yet, no controlled study explored the combination of an exposition to glycol ethers with physical activity in humans. Methods 30 young healthy participants were exposed a control condition (ambient air) and to one of three vaporized glycol ethers: propylene glycol n-propyl ether (PGPE, 25 ppm, n = 10) or propylene glycol ethyl ether (PGEE, 35 ppm, n = 10) or propylene glycol monomethyl ether (PGME, 35 ppm, n = 10) in a single-blind cross-over design. They performed an orthostatic test (5-min supine, 5-min standing) and a 6-min steady-state exercise at 1.5 W/kg followed by 10-min recovery in PGPE/PGEE conditions. In addition, an incremental exercise to exhaustion followed in PGME condition. Heart rate variability (HRV) was measured throughout the protocol, Heart rate recovery (HRR) was assessed during the 10-min recovery post steady-state exercise. Root-mean-square of the successive differences (RMSSD), power spectrum of the low- (LF) and high-frequency (HF) bands, tau, amplitude and T30 were computed for HRR. Near Infrared spectroscopy (NIRS) and cardiac output (using thoracic impedance) were measured for PGME exposition. PO2, PCO2 and pH were measured regularly via arterialized and venous blood sampling. Results Resting values of supine LF (1,180 ± 851 vs. 2,993 ± 2,259 ms2) and standing RMSSD (32 ± 17 vs. 41 ± 17 ms) increased under PGEE. Supine and standing HR decreased under PGPE (65.5 ± 4.8 vs. 61.3 ± 6.9 and 83.8 ± 7.0 vs. 76.1 ± 10.0 bpm) whereas standing RMSSD (26.6 ± 10.0 vs. 37.0 ± 14.9 ms) and LF (825 ± 474 vs. 2,028 ± 1,471 ms2) increased. Parasympathetic reactivation (e.g., RMSSD, LF and HF) was increased post-exercise under exposition to all three glycol ethers. In addition, amplitude significantly increased when exposed to PGEE. However, unexpectedly, HRR was neither slowed nor speeded. Finally, no differences were observed in any NIRS variables or cardiac output. Accordingly, the modelled muscle oxygen diffusion coefficient was not modified between any solvent conditions. Arterialized blood pH (7.35 ± .06 vs. 7.39 ± .04) and PaCO2 (34.1 ± 5.0 vs. 35.7 ± 4.3 mmHg) increased whilst PaO2 (81.8 ± 9.7 vs. 77.9 ± 10.6 mmHg) decreased. Discussion/Conclusion: The decrease in supine/standing HR associated with a general increase in HRV during recovery likely indicate an increase in parasympathetic modulation, which is compatible with the sedative effects of glycol ethers previously described in animal models. However, HR recovery was not altered. Despite no change in the O2 diffusion coefficient, there was an increase in PaCO2, a decrease in PaO2 and an increase in blood pH, all indicative of potential impaired blood oxygenation during exercise, to be further investigated. To conclude, exposition to different glycol ethers induced an enhanced parasympathetic activation without any changes in HR recovery or O2 diffusion.