Vagus nerve stimulation as a therapeutic option in inflammatory rheumatic diseases

The vagus nerve forms intricate neural connections with an extensive number of organs, particularly the digestive system. The vagus nerve has a pivotal role as a fundamental component of the autonomic nervous system, exhibiting an essential effect. It establishes a direct link with the parasympathetic system, consequently eliciting the synaptic release of acetylcholine. Recent studies have revealed the potential anti-inflammatory function of the vagus nerve. The activation of the hypothalamic system through the stimulation of vagal afferents is fundamentally involved in regulating inflammation. This activation process leads to the production of cortisol. The other mechanism, defined as the cholinergic anti-inflammatory pathway, is characterized by the involvement of vagal efferents. These fibers release the neurotransmitter acetylcholine at particular synaptic connections, involving interactions with macrophages and enteric neurons. The mechanism under consideration is ascribed to the α-7-nicotinic acetylcholine receptors. The fusion of acetylcholine receptors is responsible for the restricted secretion of inflammatory mediators by macrophages. A potential mechanism for anti-inflammatory effects involves the stimulation of the sympathetic system through the vagus nerve, leading to the control of immunological responses within the spleen. This article offers an extensive summary of the present knowledge regarding the therapeutic effectiveness of stimulating the vagus nerve in managing inflammatory rheumatic conditions based on the relationship of inflammation with the vagus nerve. Furthermore, the objective is to present alternatives that may be preferred while applying vagus nerve stimulation approaches.

Autonomic Dysfunction and Cardiovascular Risk in Patients with Rheumatoid Arthritis: Can Heart Rate Variability Analysis Contribute to a Better Evaluation of the Cardiovascular Profile of a Patient?

(1) Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune etiology. Increased scientific evidence suggests that immune-mediated inflammatory dis-eases are associated with autonomic nervous system (ANS) dysfunction. Studies proved that autonomic imbalance is correlated with RA evolution and may explain augmented cardiovascular pathology and mortality not attributable to classical risk factors. (2) Methods: 75 patients (25 males, 50 females) with RA were submitted to standard ECG recording and 24 h Holter monitoring. Twenty-five healthy patients were used as controls. Both time (SDNN, SDANN, SDANN Index, RRmed, rMSSD, and pNN50) and frequency domain (TP, VLF, HF, LF and LF/HF) heart rate variability (HRV) parameters were obtained. Parameters were compared to controls, and correlations with the QTc-interval and inflammatory status expressed through the C-reactive protein (CRP) were evaluated. (3) Results: In patients with a CRP > 5 mg/L, HRV parameters were lower compared to controls and to patients with a CRP ≤ 5 mg/L. All HRV parameters generated by Holter monitoring are negatively correlated with CRP levels and QTc values. The number of premature ventricular contractions (PVC) recorded is correlated with SDNN, SDANN, and LF/HF values. (4) Conclusions: Our study supports recent data suggesting that in RA there is an autonomic system dysfunction strongly connected with the inflammatory status of the patient. The autonomic dysfunction can contribute to the increased risk of cardiovascular death observed in patients with RA.

Identity affirmation is associated with adaptive cardiovascular flexibility in response to stress among sexual and gender minority people of color

BACKGROUND

Research with sexual and gender minority (e.g., lesbian, gay, bisexual, queer, asexual, trans, non-binary) people of Color (SGM-PoC) has largely focused on risk and negative health outcomes. The existing strengths-based mental health research suggests that identity affirmation may be associated with psychological resilience and good mental health among SGM-PoC, but little is known about predictors of physiological resilience and biomarkers of physical health in this population. Adaptive cardiovascular flexibility is an indicator of physiological resilience and physical health in that it enables the body to mobilize resources to adapt to challenges. This study explored the association between identity affirmation and physiological resilience, observed through cardiovascular flexibility in response to stress among SGM-PoC.

METHODS

Participants were 95 SGM-PoC of varying ethnoracial backgrounds, sexual orientations, and gender identities, residing in Canada. Participants completed questionnaires on sociodemographic and psychosocial variables, including a measure of identity affirmation, the Queer People of Color Identity Affirmation Scale (QPIAS). In a laboratory setting, we induced stress using the Trier Social Stress Test and measured heart rate variability (HRV) over time using wearable electrocardiogram devices.

RESULTS

Results from multilevel modeling analyses revealed that high QPIAS scores were associated with adaptive cardiovascular flexibility, as evidenced by reduced HRV during stress exposure, followed by HRV increase during recovery. As QPIAS scores increased, the shape of HRV trajectory increasingly reflected our predicted pattern of adaptive cardiovascular flexibility. Meanwhile, low QPIAS scores were not associated with this pattern and appeared to predict a more flatlined HRV activity during the experiment.

CONCLUSIONS

Findings indicate that Queer People of Color identity affirmation may be related to physiological resilience, observed through a more adaptive cardiovascular profile when responding to stress. Identity affirmation may thus be a protective factor for SGM-PoC, pointing to the critical importance of affirming resources and strengths-based health research.

Heart rate and heart rate variability in patients with chronic inflammatory joint disease: the role of pain duration and the insular cortex

Background

Chronic inflammatory joint diseases (CIJD) have been linked to increased cardiovascular morbidity and mortality. A decisive reason could be a dysregulation of the autonomic nervous system, which is responsible for the control of cardiovascular function. So far, the cause of changes in autonomic nervous system functions remains elusive. In this study, we investigate the role of chronic pain and the insular cortex in autonomic control of cardiac functioning in patients with CIJD.

Methods

We studied the autonomic nervous system through the assessment of heart rate and heart rate variability (HRV) at rest and under cognitive stimulation. Furthermore, we investigated insular cortex volume by performing surface-based brain morphometry with FreeSurfer. For this study, 47 participants were recruited, 22 individual age- and sex-matched pairs for the magnetic resonance imaging analyses and 14 for the HRV analyses. All available patients’ data were used for analysis.

Results

Pain duration was negatively correlated with the resting heart rate in patients with chronic inflammatory joint diseases (n = 20). In a multiple linear regression model including only CIJD patients with heart rate at rest as a dependent variable, we found a significant positive relationship between heart rate at rest and the volume of the left insular cortex and a significant negative relationship between heart rate at rest and the volume of the right insular cortex. However, we found no significant differences in HRV parameters or insular cortex volumes between both groups.

Conclusions

In this study we provide evidence to suggest insular cortex involvement in the process of ANS changes due to chronic pain in CIJD patients.

The study was preregistered with the German Clinical Trials Register (https://www.drks.de; DRKS00012791; date of registration: 28 July 2017).

Assessment of proarrhythmic ventricular electrophysiological remodeling in patients with rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is related to cardiovascular disease and results in increased mortality rates. Ischemia, autonomic nervous system dysfunction, impaired cardiac ionic currents, and genetic predisposition may be the underlying mechanisms. Proarrhythmic ventricular electrophysiological remodeling detected on the basis of Tp‑e interval, Tp-e/QT, and Tp-e/QTc ratios plays a key role in the prognosis. Our aim was to assess proarrhythmic ventricular electrophysiological remodeling in patients with RA, a well-known chronic inflammatory disorder.

MATERIALS AND METHODS

A total of 163 patients with RA and 47 patients as a control group were included in this retrospective study. Proarrhythmic ventricular electrophysiological remodeling markers were evaluated in both groups along with baseline demographic and clinical variables. Patients using medication or with chronic disorders that can affect ventricular repolarization markers were excluded.

RESULTS

The patients with RA had prolonged Tp‑e interval (66 ms [44-80]; 80 ms [78-96], p < 0.001) and increased Tp-e/QT ratio (0.18 [0.12-0.22]; 0.22 [0.20-0.24], p < 0.001) and Tp-e/QTc ratio (0.16 [0.11-0.19]; 0.20 [0.17-0.22], p < 0.001) compared to the control group.

CONCLUSION

The Tp‑e interval and Tp-e/QT ratio, which may help to clarify the pathophysiological mechanisms of ventricular arrhythmias, were increased in patients with RA.

Assessment of Ventricular Repolarization in Sickle Cell Anemia Patients: The Role of QTc Interval, Tp-e Interval and Tp-e/QTc Ratio and Its Gender Implication

Background

Many specific and non-specific electrocardiographic abnormalities including ventricular arrhythmias have been reported in subjects with sickle cell anemia (SCA). In SCA patients, cardiac electrical abnormalities may be the leading cause of increased risk of arrhythmias. The corrected QT (QTc) interval, peak to the end of the T wave (Tp-e) interval and associated Tp-e/QTc ratio are promising measures of altered ventricular repolarization and increased arrhythmogenesis risk.

Aim

This study assessed ventricular repolarization abnormalities in subjects with SCA using the QTc interval, Tp-e interval and Tp-e/QTc ratio, and also evaluated the gender differences in these parameters, as well as their determinants.

Methods

Sixty subjects with SCA and 60 healthy control subjects, matched for age and gender, were studied. All participants underwent physical examination, hematological and biochemical evaluation, and 12-lead electrocardiography (ECG) recording. QT and Tp-e intervals were measured from the ECG, and the QTc interval was calculated using Bazett’s formula. Tp-e/QT and Tp-e/QTc ratios were also derived.

Results

QT and QTc intervals were prolonged in subjects with SCA. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in male SCA subjects, with a paradoxical shortening in female SCA subjects. Plasminogen activator inhibitor-1 (PAI-1) was an independent determinant of QTc, while body mass index (BMI) was an independent determinant of both Tp-e interval and Tp-e/QTc ratio.

Conclusion

Our results suggest an elevated risk for ventricular arrhythmogenesis in male SCA subjects. Furthermore, increased BMI and PAI-1 level are possible markers of ventricular repolarization abnormalities in SCA subjects.

Cardiac Autonomic Control in Women with Rheumatoid Arthritis During the Glittre Activities of Daily Living Test

Background: Cardiovascular autonomic dysfunction is one of the most common complications in rheumatoid arthritis (RA), which can be assessed by heart rate variability (HRV) analysis. Because the autonomic nervous system plays an important role in orchestrating the cardiovascular response to stressors, assessing HRV during exercise is critical. The Glittre Activities of Daily Living test (GA-T) was recently proposed as a multitask field test that requires the performance of the upper and lower limbs, both of which are affected in individuals with RA. Objectives: This study was conducted to evaluate autonomic impairment by HRV in women with RA using the GA-T and to correlate these changes with physical functioning and muscle strength. Methods: This cross-sectional study enrolled 20 women (median [interquartile range]: age 55 [47.5 - 68.8] years) with RA (time since diagnosis: 15 [6.50 - 23.5] years) who underwent HRV assessment during GA-T. They also underwent physical functioning assessment through the Health Assessment Questionnaire Disability Index (HAQ-DI) and handgrip strength (HGS) and quadriceps strength (QS) measures. Results: The GA-T time exhibited significant correlations with the following HRV indices: root mean square of successive differences (RMSSD, rs = -0.451, P = 0.041), proportion of iRR differing by > 50 ms from previous intervals (pNN50, rs = -0.697, P = 0.0006), high frequency (HF, rs = -0.693, P = 0.0007), standard deviation of the points perpendicular to the line-of-identity (SD1, rs = -0.476, P = 0.034), and approximate entropy (ApEn, rs = 0.545, P = 0.013). In addition, the HAQ-DI exhibited significant correlations with the following HRV indices: pNN50 (rs = -0.467, P = 0.038) and HF (rs = -0.444, P = 0.049). We did not observe significant correlation between the HRV indices during the GA-T and the muscle strength measures (HGS and QS). Conclusions: In women with RA, the longer the required to perform the GA-T the worse their parasympathetic modulation, sympathetic-vagal imbalance, and complexity of the autonomic nervous system (i.e., increased index of ApEn) were. Physical functioning level was also related to vagal modulation.

A Systematic Review and Meta-Analysis of Within-Person Changes in Cardiac Vagal Activity across the Menstrual Cycle: Implications for Female Health and Future Studies

Interest in cardiac vagal activity (CVA; e.g., parasympathetically-mediated heart rate variability) as a biomarker of physical and mental health has increased exponentially in recent years. However, the understanding of sources of within-person change (i.e., intra-individual variance) in CVA is lagging behind. This systematic review and meta-analysis summarizes and quantifies current empirical evidence of within-person changes in measures of CVA across the menstrual cycle in naturally-cycling premenopausal females. We conducted an extensive literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement in five databases to identify observational studies with repeated measures of CVA in at least two menstrual cycle phases. A broad meta-analysis (n_studies = 37; n_individuals = 1,004) revealed a significant CVA decrease from the follicular to luteal phase (d = −0.39, 95% CI (−0.67, −0.11)). Furthermore, 21 studies allowed for finer-grained comparisons between each of two cycle phases (menstrual, mid-to-late follicular, ovulatory, early-to-mid luteal, and premenstrual). Significant decreases in CVA were observed from the menstrual to premenstrual (n_studies = 5; n_individuals = 200; d = −1.17, 95% CI (−2.18, −0.17)) and from the mid-to-late follicular to premenstrual phases (n_studies = 8; n_individuals = 280; d = −1.32, 95% CI (−2.35, −0.29)). In conclusion, meta-analyses indicate the presence of CVA fluctuations across the menstrual cycle. Future studies involving CVA should control for cycle phase. Recommendations for covarying or selecting cycle phase are provided.

Systemic inflammation and arrhythmic risk: lessons from rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic immuno-mediated disease primarily affecting the joints, characterized by persistent high-grade systemic inflammation. Cardiovascular morbidity and mortality are significantly increased in RA, with >50% of premature deaths attributable to cardiovascular disease. In particular, RA patients were twice as likely to experience sudden cardiac death compared with non-RA subjects, pointing to an increased propensity to develop malignant ventricular arrhythmias. Indeed, ventricular repolarization (QT interval) abnormalities and cardiovascular autonomic nervous system dysfunction, representing two well-recognized risk factors for life-threatening ventricular arrhythmias in the general population, are commonly observed in RA. Moreover, large population-based studies seem to indicate that also the prevalence of atrial fibrillation is significantly higher in RA subjects than in the general population, thus suggesting that these patients are characterized by an abnormal diffuse myocardial electrical instability. Although the underlying mechanisms accounting for the pro-arrhythmogenic substrate in RA are probably intricate, the leading role seems to be played by chronic systemic inflammatory activation, able to promote arrhythmias both indirectly, by accelerating the development of ischaemic heart disease and congestive heart failure, and directly, by affecting cardiac electrophysiology. In this integrated mechanistic view, lowering the inflammatory burden through an increasingly tight control of disease activity may represent the most effective intervention to reduce arrhythmic risk in these patients. Intriguingly, these considerations could be more generally applicable to all the diseases characterized by chronic systemic inflammation, and could help elucidate the link between low-grade chronic inflammation and arrhythmic risk in the general population.

Sympathetic Nerve Hyperactivity in the Spleen: Causal for Nonpathogenic-Driven Chronic Immune-Mediated Inflammatory Diseases (IMIDs)?

Immune-Mediated Inflammatory Diseases (IMIDs) is a descriptive term coined for an eclectic group of diseases or conditions that share common inflammatory pathways, and for which there is no definitive etiology. IMIDs affect the elderly most severely, with many older individuals having two or more IMIDs. These diseases include, but are not limited to, type-1 diabetes, obesity, hypertension, chronic pulmonary disease, coronary heart disease, inflammatory bowel disease, and autoimmunity, such as rheumatoid arthritis (RA), Sjőgren's syndrome, systemic lupus erythematosus, psoriasis, psoriatic arthritis, and multiple sclerosis. These diseases are ostensibly unrelated mechanistically, but increase in frequency with age and share chronic systemic inflammation, implicating major roles for the spleen. Chronic systemic and regional inflammation underlies the disease manifestations of IMIDs. Regional inflammation and immune dysfunction promotes targeted end organ tissue damage, whereas systemic inflammation increases morbidity and mortality by affecting multiple organ systems. Chronic inflammation and skewed dysregulated cell-mediated immune responses drive many of these age-related medical disorders. IMIDs are commonly autoimmune-mediated or suspected to be autoimmune diseases. Another shared feature is dysregulation of the autonomic nervous system and hypothalamic pituitary adrenal (HPA) axis. Here, we focus on dysautonomia. In many IMIDs, dysautonomia manifests as an imbalance in activity/reactivity of the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS). These major autonomic pathways are essential for allostasis of the immune system, and regulating inflammatory processes and innate and adaptive immunity. Pathology in ANS is a hallmark and causal feature of all IMIDs. Chronic systemic inflammation comorbid with stress pathway dysregulation implicate neural-immune cross-talk in the etiology and pathophysiology of IMIDs. Using a rodent model of inflammatory arthritis as an IMID model, we report disease-specific maladaptive changes in β₂-adrenergic receptor (AR) signaling from protein kinase A (PKA) to mitogen activated protein kinase (MAPK) pathways in the spleen. Beta₂-AR signal "shutdown" in the spleen and switching from PKA to G-coupled protein receptor kinase (GRK) pathways in lymph node cells drives inflammation and disease advancement. Based on these findings and the existing literature in other IMIDs, we present and discuss relevant literature that support the hypothesis that unresolvable immune stimulation from chronic inflammation leads to a maladaptive disease-inducing and perpetuating sympathetic response in an attempt to maintain allostasis. Since the role of sympathetic dysfunction in IMIDs is best studied in RA and rodent models of RA, this IMID is the primary one used to evaluate data relevant to our hypothesis. Here, we review the relevant literature and discuss sympathetic dysfunction as a significant contributor to the pathophysiology of IMIDs, and then discuss a novel target for treatment. Based on our findings in inflammatory arthritis and our understanding of common inflammatory process that are used by the immune system across all IMIDs, novel strategies to restore SNS homeostasis are expected to provide safe, cost-effective approaches to treat IMIDs, lower comorbidities, and increase longevity.

Evidence of reduced parasympathetic autonomic regulation in inflammatory joint disease: A meta-analyses study

BACKGROUND

Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are inflammatory joint disorders (IJD) with increased risk of cardiovascular disease (CVD). Autonomic dysfunction (AD) is a risk factor for CVD, and parasympathetic AD is linked to key features of IJD such as inflammation, physical inactivity and pain. Heart-rate variability (HRV) is a marker of cardiac AD. The study objective was to compare parasympathetic cardiac AD, measured by HRV, between patients with IJD and healthy controls, using meta-analysis methodology, and to examine the impact of inflammation, physical inactivity and pain on HRV in IJD.

METHODS

Medline, Embase and Amed were searched. Inclusion criteria were adult case-control studies published in English or a Scandinavian language, presenting HRV data in IJD. Two measures of HRV and 3 from the Ewing protocol were selected: square root of mean squared difference of successive R-R intervals (RMSSD), high frequency (HF), Ewing protocol; standing (E-S), breathing (E-B) and Valsalva (E-V). Patients with RA, SpA and healthy controls were compared separately using random-effects meta-analyses of standardized mean differences (SMD).

RESULTS

In all, 35 papers were eligible for inclusion. For RMSSD the pooled SMD (95% CI) RA vs. controls was -0.90 (-1.35 to -0.44), for SpA vs. controls; -0.34 (-0.73 to 0.06). For HF pooled SMD RA vs. controls was -0.78 (-0.99 to -0.57), for SpA vs. controls; -0.04 (-0.22 to 0.13). All Ewing parameters were significantly lower in cases, except for E-V which was comparable between cases and controls in patients with RA.

CONCLUSION

Patients with IJD have cardiac parasympathetic AD which is related to inflammation.

Can natural ways to stimulate the vagus nerve improve seizure control?

The vagus nerve (VN) is the longest cranial nerve, innervating the neck, thorax and abdomen, with afferent fibers transmitting a range of interoceptive stimuli and efferent fibres to somatic structures and autonomic preganglions. Over the last few decades, electrical stimulation of the VN using implanted devices (VNS) has been developed leading to its approval for the treatment of epilepsy and depression. More recently, non-invasive devices to stimulation the VN have been developed. The VN has many functions and the activity that is most amenable to assessment is its effect in controlling the cardiac rhythm. This can be easily assessed by measuring heart rate variability (HRV). Decreased HRV is a result of poorer vagal parasympathetic tone and is associated with a wide range of ill health conditions including a higher risk of early mortality. People with epilepsy, particularly those with poorly controlled seizures, have been shown to have impaired parasympathetic tone. So, might natural ways to stimulate the VN, shown to improve parasympathetic tone as indicated by increased HRV, improve seizure control? There are numerous natural ways that have been shown to stimulate the VN, improving HRV and hence parasympathetic tone. These natural ways fall mainly into 3 categories - stress reduction, exercise, and nutrition. Though the natural ways to stimulate the VN have been shown to increase HRV, they have not been shown to reduce seizures. The exception is listening to Mozart's music, which has been shown to increase parasympathetic tone and decrease seizures. Clearly much more work is required to examine the effect of the various ways to increase HRV on seizure occurrence.

Proarrhythmic risk and determinants of cardiac autonomic dysfunction in collagen-induced arthritis rats

Backgrounds

Patients with rheumatoid arthritis (RA) have increased risk of sudden cardiac death (SCD), which is two-fold higher than general population. The driving cause of SCD was considered due to lift-threatening arrhythmia where systemic inflammation acts as the pathophysiological basis linking RA to autonomicdysfunction.

Methods

To assess the sympathetic over-activity of “inflammatory reflex”, we measured heart rate variability (HRV) in a rat collagen-induced arthritis (CIA) model, whose arthritis is induced in Lewis rats by intradermal injection of emulsion of type II collagen. Single-lead electrocardiogram (ECG) was recorded for 30 min every two days. Time and frequency-domain parameters, detrended fluctuation analysis (DFA), deceleration (DC) and acceleration capacity (AC) were analyzed.

Results

Compared with 9 control rats, many of HRV parameters of 9 CIA rats revealed significant different. At the beginning of arthritis, LF/HF was significant higher than controls (1st week: 2.41 ± 0.7 vs. 1.76 ± 0.6, p < 0.05; 2nd week: 2.24 ± 0.5 vs. 1.58 ± 0.5, p < 0.05) indicating intensive inflammatory reflex at the initial phase of inflammation but no significant difference was observed in the following recover phase. The similar trend of DFA parameters was noted. However, the DC appeared progressive lower despite of no significant increase of the LF/HF compared with controls since 4th week.

Conclusions

We observed sympathetic over-activation of inflammatory reflex during early stage of arthritis in CIA rats. The ongoing decline of DC indicated advanced cardiac autonomic dysfunction regardless of remission of acute arthritis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1347-6) contains supplementary material, which is available to authorized users.

Anti-Inflammatory Effects and Prediction of Blood Pressure Response by Baseline Inflammatory State in Catheter-Based Renal Denervation

This retrospective analysis aimed to examine off-target effects on inflammatory and renal function parameters in n=78 subsequent patients treated with renal denervation (RDN) for resistant hypertension. Ambulatory and office blood pressure (ABP/OBP), serum creatinine, glomerular filtration rate (GFR), cystatin C, C-reactive protein (CRP), interleukin-6 (IL-6), and white blood cell count (WBC) were assessed before, 6 and 12 months after RDN. ABP was significantly reduced by -8.2/-3.8 mm Hg (P=.002/.021) at 1 year after RDN, while an initial OBP reduction was not sustained during follow-up. IL-6 levels significantly decreased by -0.5 pg/mL (P=.042) and by -1.7 pg/mL (P<.001) at 6 and 12 months, baseline IL-6 levels possibly predicting ABP response to RDN (r=-0.295; P=.020). Concurrently, leukocyte count was reduced by -0.5 × 103 /μL (P=.017) and -0.8 × 103 /μL (P<.001), respectively. Serum creatinine and GFR remained unchanged, but we observed a significant increase in cystatin C by 0.04 mg/L (P=.026) and 0.14 mg/L (P<.001) at 6 and 12 months after the intervention.

Factors associated with parasympathetic activation following exercise in patients with rheumatoid arthritis: a cross-sectional study

BACKGROUND

Patients with rheumatoid arthritis (RA) have an increased risk for cardiovascular disease (CVD) with poor parasympathetic function being implicated as an underlying factor. Factors related to parasympathetic function, commonly assessed by heart rate recovery (HRR) following maximal exercise, are currently not known in RA. We aimed to explore the association between HRR with CVD risk factors, inflammatory markers, and wellbeing in patients with RA.

METHODS

Ninety-six RA patients (54.4 ± 12.6 years, 68 % women) completed a treadmill exercise test, during which heart rate (HR) was monitored. HRR1 and HRR2 were defined as the absolute change from HR peak to HRR 1 min post HR peak and 2 min post HR peak, respectively. Cardiorespiratory fitness, CVD risk factors, and serological markers of inflammation were measured in all patients. The Framingham Risk Score (FRS) was used as an assessment of global risk for CVD events, and wellbeing was assessed by questionnaires.

RESULTS

Mean HRR1 and HRR2 were 29.1 ± 13.2 bpm and 46.4 ± 15.3 bpm, respectively. CVD risk factors as well as most inflammatory markers and measures of wellbeing were inversely correlated with HRR1 and HRR2. Multivariate regression analyses revealed that 27.9 % of the variance in HRR1 and 37.9 % of the variance in HRR2 was explained collectively by CVD risk factors, measures of inflammation, and wellbeing (p = 0.009, p = 0.001 respectively), however no individual measure was independently associated with HRR1 or HRR2.

CONCLUSION

Parasympathetic activation was associated with overall CVD risk, arthritis-related burden and wellbeing in patients with RA.

TRIAL REGISTRATION

[Exercise, cardiovascular disease and rheumatoid arthritis, ISRCTN04121489 ].

Cardiac autonomic functions in children with familial Mediterranean fever

Familial Mediterranean fever (FMF) is the most common inherited autoinflammatory disease in the world. The long-term effects of subclinical inflammation in FMF are not well recognized. Some studies have suggested that FMF is associated with cardiac autonomic dysfunction in adult FMF patients. The objective of this study was to investigate the cardiac autonomic functions in pediatric FMF patients by using several autonomic tests. Thirty-five patients with FMF and 35 healthy controls were enrolled in this cross-sectional study. Demographic data, disease-specific data, and orthostatic symptoms were recorded. In all participants, 12-lead electrocardiography (ECG), 24 h ambulatory electrocardiographic monitoring, transthoracic echocardiography, treadmill exercise test, and head upright tilt-table (HUTT) test were performed. The heart rate recovery (HRR) indices of the two groups were similar. Also, chronotropic response was similar in both groups. The time-domain parameters of heart rate variability (HRV) were similar in both groups, except mean RR (p = 0.024). Frequencies of ventricular and supraventricular ectopic stimuli were similar in both groups. There were no statistically significant differences between the groups in average QT and average corrected QT interval length, average QT interval dispersion, and average QT corrected dispersion. There was no significant difference between the two groups regarding the ratio of clinical dysautonomic reactions on HUTT. However, we observed a significantly higher rate of dysautonomic reactions on HUTT in patients with exertional leg pain than that in patients without (p = 0.013). When the fractal dimension of time curves were compared, FMF patients exhibited significantly lower diastolic blood pressure parameters than controls in response to HUTT. Cardiovascular autonomic dysfunction in children with FMF is not prominent. Particularly, patients with exertional leg pain are more prone to have dysautonomic features. Further studies are needed to elucidate the exact mechanisms leading to impaired cardiac autonomic functions in FMF.

Evidence of different mediators of central inflammation in dysfunctional and inflammatory pain--interleukin-8 in fibromyalgia and interleukin-1 β in rheumatoid arthritis

The purpose of this study was to relate central inflammation to autonomic activity (heart rate variability (HRV)) in patients with rheumatoid arthritis (RA) and fibromyalgia (FM). RA patients had reduced parasympathetic activity and FM patients had increased sympathetic activity compared to healthy controls. Comparisons between RA and FM showed higher cerebrospinal fluid (CSF) interleukin (IL)-1β inversely correlated to parasympathetic activity in RA. The FM patients had higher concentrations of CSF IL-8, IL-1Ra, IL-4 and IL-10, but none of these cytokines correlated with HRV. In conclusion, we found different profiles of central cytokines, i.e., elevated IL-1β in inflammatory pain (RA) and elevated IL-8 in dysfunctional pain (FM).

Association between corrected QT interval and inflammatory cytokines in rheumatoid arthritis

OBJECTIVE

Corrected QT (QTc) interval predicts all-cause and cardiovascular mortality and may contribute to the increased mortality risk in rheumatoid arthritis (RA). Animal experiments have shown that proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin 1 (IL-1)] can prolong cardiomyocyte action potential. We sought to determine whether elevations in circulating inflammatory cytokines were independently associated with QTc prolongation in patients with RA.

METHODS

One hundred twelve patients [median age 62 (interquartile range 17) yrs; 80 women (71%)] from a well-characterized RA cohort underwent baseline 12-lead electrocardiograms for QT interval measurement and contemporary blood sampling to assess concentrations of inflammatory markers including C-reactive protein (CRP), TNF-α, and interleukins (IL-1α, IL-1β, IL-6, IL-10). QTc was calculated using the Bazett (QTBAZ = QT ÷ √RR) and Framingham Heart Study (QTFHS = QT + 0.154 × [1 - RR]) heart rate correction formulas.

RESULTS

Inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-10) were positively correlated with QTBAZ (Spearman rank correlation coefficient rho = 0.199, 0.210, 0.222, 0.333; all p < 0.05). In multivariable regression analysis, these associations were all confounded by age except IL-10, where higher tertile groups were independently and positively associated with QTBAZ (β = 0.202, p = 0.023) and QTFHS (β = 0.223, p = 0.009) when compared to the lower tertile. CRP (per unit increase) was independently associated with QTBAZ (β = 0.278, p = 0.001), but not QTFHS.

CONCLUSION

To our knowledge, ours is the first study demonstrating a contemporary link between inflammatory cytokines and QT interval in humans. Our results suggest that a lower inflammatory burden may protect against QTc prolongation in patients with RA. However, further studies are required to confirm the effects of pro- and antiinflammatory cytokines on QTc interval.

Autonomic function and rheumatoid arthritis: a systematic review

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic inflammatory condition with increased all-cause and cardiovascular mortality. Accumulating evidence indicates that the immune and autonomic nervous systems (ANS) are major contributors to the pathogenesis of cardiovascular disease. We performed the first systematic literature review to determine the prevalence and nature of ANS dysfunction in RA and whether there is a causal relationship between inflammation and ANS function.

METHODS

Electronic databases (MEDLINE, Central and Cochrane Library) were searched for studies of RA patients where autonomic function was assessed.

RESULTS

A total of 40 studies were included. ANS function was assessed by clinical cardiovascular reflex tests (CCTs) (n = 18), heart rate variability (HRV) (n = 15), catecholamines (n = 5), biomarkers of sympathetic activity (n = 5), sympathetic skin responses (n = 5), cardiac baroreflex sensitivity (cBRS) (n = 2) and pupillary light reflexes (n = 2). A prevalence of ~60% (median, range: 20-86%) of ANS dysfunction (defined by abnormal CCTs) in RA was reported in 9 small studies. Overall, 73% of studies (n = 27/37) reported at least one of the following abnormalities in ANS function: parasympathetic dysfunction (n = 20/26, 77%), sympathetic dysfunction (n = 16/30, 53%) or reduced cBRS (n = 1/2, 50%). An association between increased inflammation and ANS dysfunction was found (n = 7/19, 37%), although causal relationships could not be elucidated from the studies available to date.

CONCLUSIONS

ANS dysfunction is prevalent in ~60% of RA patients. The main pattern of dysfunction is impairment of cardiovascular reflexes and altered HRV, indicative of reduced cardiac parasympathetic (strong evidence) activity and elevated cardiac sympathetic activity (limited evidence). The literature to date is underpowered to determine causal relationships between inflammation and ANS dysfunction in RA.

Arrhythmic risk in rheumatoid arthritis: the driving role of systemic inflammation

When compared to the general population, patients with rheumatoid arthritis (RA) have an overall standard mortality ratio of approximately two, with more than 50% of premature deaths attributable to cardiovascular disease (CVD). Moreover, RA patients were twice as likely to experience sudden cardiac death (SCD) compared with non-RA subjects, as a putative consequence of an increased incidence of malignant arrhythmias. Accordingly, mounting data indicate that in patients affected with RA the risk of developing rhythm disturbances, particularly tachyarrhythmias, is high. Although a number of papers reviewing the problem of cardiovascular involvement in RA are currently available, the main focus is on the mechanisms of accelerated atherosclerosis and related ischemic consequences in the clinical setting. On the contrary, only little consideration has been specifically given to the arrhythmic risk so far. In the light of this concern, in the present paper we reviewed the topic with the aim to put together the apparently fragmentary existing information, with particular attention to the putative role of chronic systemic inflammation characterizing the disease. In fact, although the underlying mechanisms accounting the arrhythmogenic substrate in RA are probably intricate, the leading role seems to be played by inflammatory activation, able to promote arrhythmias either indirectly, by accelerating the development of structural CVD, and directly by affecting cardiac electrophysiology. In this view, lowering inflammatory burden through an increasingly tight control of disease activity may represent the most effective intervention to reduce arrhythmic risk and prevent life-threatening complications in these patients.

Impaired aerobic exercise capacity and cardiac autonomic control in primary antiphospholipid syndrome

Primary antiphospholipid syndrome (PAPS) is associated with increased risk of cardiovascular disease and mortality. Aerobic capacity and cardiac autonomic control are also associated with these risks. The aim of our study was to assess aerobic capacity and cardiac autonomic control in PAPS patients. Thirteen women with PAPS and 13 healthy controls matched for age, gender, and body mass index were enrolled for the study. Both groups were sedentary and were not under chronotropic, antidepressants and hypolipemiant drugs. All subjects performed a treadmill-graded maximal exercise. Aerobic capacity was assessed by peak oxygen uptake (VO2peak), time at anaerobic ventilatory threshold (VAT) and respiratory compensation point (RCP) and time-to-exhaustion, whereas cardiac autonomic control was assessed by chronotropic reserve (CR) and heart rate recovery at the first and second minutes after graded exercise (HRR1min and HRR2min, respectively). All aerobic capacity indexes were reduced more in PAPS patients than in healthy subjects: VO2peak (30.2 ± 4.7 vs 34.6 ± 4.3 ml.kg−1.min−1, p = 0.021), time at VAT (3.0 ± 1.5 vs 5.0 ± 2.0 min, p = 0.016), time at RCP (6.5 ± 2.0 vs 8.0 ± 2.0 min, p = 0.050), time-to-exhaustion (8.5 ± 2.0 vs 11.0 ± 2.5 min, p = 0.010). HRR1min (22 ± 9 vs 30 ± 7 bpm, p = 0.032) and HRR2min (33 ± 9 vs 46 ± 8 bpm, p = 0.002) were delayed in PAPS patients compared to healthy controls but CR was not significantly different ( p = 0.272). In conclusion, an impaired aerobic capacity and cardiac autonomic control was identified in PAPS.