Circadian studies of autonomic nervous balance in patients with fibromyalgia: a heart rate variability analysis

Fibromyalgia in obstructive sleep apnea-hypopnea syndrome: a systematic review and meta-analysis

Introduction: Fibromyalgia (FM) is a common condition in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). This meta-analysis aimed to evaluate differences in sleep monitoring indicators between patients with OSAHS and positive FM and patients with OSAHS and negative FM and to determine the incidence of FM in patients with OSAHS. Methods: An exhaustive literature review was conducted to analyze the incidence of FM in patients with OSAHS, using online databases, including PubMed, EMBASE, Web of Science, CNKI, and Wanfang, both in English and Chinese. The quality of the included studies was assessed by two researchers using the Newcastle-Ottawa Scale scores. The acquired data were analyzed using Stata 11.0 software. Continuous variables were combined and analyzed using the weighted mean difference as the effect size. Conjoint analyses were performed using random-effects (I2 > 50%) or fixed-effect (I2 ≤ 50%) models based on I2 values. Results: Fourteen studies met the inclusion criteria. This study showed that 21% of patients with OSAHS experienced FM. Subgroup analyses were performed based on race, age, sex, body mass index, and diagnostic criteria for patients with OSAHS. These findings indicate that obese patients with OSAHS have a higher risk of FM, similar to females with OSAHS. Regarding most sleep monitoring indicators, there were no discernible differences between patients with OSAHS with positive FM and those with negative FM. However, patients with positive FM had marginally lower minimum arterial oxygen saturation levels than those with negative FM. The current literature suggests that patients with OSAHS have a high incidence of FM (21%), and FM has little effect on polysomnographic indicators of OSAHS. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024510786, identifier CRD42024510786.

The existence of a bidirectional link between ischemic heart disease and fibromyalgia

STUDY OBJECTIVES

Fibromyalgia (FM) is one of the most common causes of chronic widespread musculoskeletal pain, but also sleep disturbances, cognitive and psychological disorders. It has been suggested that FM may have a correlation with cardiovascular events. In this study, we aimed to assess the association between FM and ischemic heart disease (IHD).

METHODS

A population-based cross-sectional study was conducted utilizing data retrieved from the largest medical records database in Israel, Clalit Health Services. Patients were defined as having FM or IHD when there were at least two such documented diagnoses in their medical records. The occurrence of IHD was compared between FM and age- and sex-frequency-matched healthy controls. A logistic regression model was used to estimate this association following an adjustment for conventional cardiovascular risk factors and depression.

RESULTS

An overall population of 18 598 FM patients and 36 985 age- and gender-matched controls were included in the study. The proportion of IHD amongst FM patients was increased in comparison to controls (9.2% and 6.2%, respectively; P  < 0.001). Furthermore, FM demonstrated an independent association with IHD on multivariate analysis (odds ratio [OR], 1.43; 95% confidence intervals [CI], 1.33-1.54; P  < 0.0001). Finally, IHD was also found to be independently associated with the diagnosis of FM (OR, 1.40; CI, 1.31-1.51; P  < 0.0001).

CONCLUSION

Our data suggest a bidirectional link between FM and IHD even after the adjustment for conventional cardiovascular risk factors. These findings should be considered when treating patients with either FM or IHD, and their routine interactional screening may be of clinical importance.

Clinical overlap between fibromyalgia and myalgic encephalomyelitis. A systematic review and meta-analysis

Myalgic encephalomyelitis is an illness characterized by profound malaise after mental or physical effort occurring in patients already suffering from constant fatigue. On the other hand, widespread pain and widespread allodynia are the core fibromyalgia clinical features. There is controversy on these two syndromes alikeness. Through the years, different diagnostic and/or classification criteria have been put forward to appraise both fibromyalgia and myalgic encephalomyelitis. The epidemiology of these two illnesses, and their overlap, may vary accordingly to the used definition. The most recent Wolfe et al. 2016 fibromyalgia diagnostic criteria incorporates three myalgic encephalomyelitis features including fatigue, waking unrefreshed and dyscognition. The objective of this meta-analysis was to define the clinical overlap between fibromyalgia and myalgic encephalomyelitis based on a systematic literature review.

METHODS

PubMed, Embase, Lilacs, and Cochrane data bases were searched on January 25, 2021 linking the medical subject heading "Fibromyalgia" to the following terms "chronic fatigue syndrome", "myalgic encephalomyelitis" and "systemic exertion intolerance disease". Our review included all original articles in which the clinical overlap between fibromyalgia and myalgic encephalomyelitis could be quantified based on recognized diagnostic or classification criteria. Articles scrutiny and selection followed the PRISMA guidelines. Each study quality was assessed according to GRADE recommendations. The global clinical overlap was calculated using a fixed effect model with inverse variance-weighted average method.

RESULTS

Twenty one publications were included in the meta-analysis. Reviewed studies were highly dissimilar in their design, objectives, sample size, diagnostic criteria, and/or outcomes yielding a 98% heterogeneity index. Nevertheless, the clinical overlap between fibromyalgia and myalgic encephalomyelitis was a well defined outcome that could be reliably calculated despite the high heterogeneity value. All reviewed publications had moderate GRADE evidence level. Most evaluated articles used the old 1990 Wolfe et al. fibromyalgia diagnostic criteria. Myalgic encephalomyelitis and fibromyalgia diagnoses overlapped in 47.3% (95% CI: 45.97-48.63) of the reported cases.

CONCLUSION

This meta-analysis found prominent clinical overlap between fibromyalgia and myalgic encephalomyelitis. It seems likely that this concordance would be even higher when using the most recent Wolfe et al. 2016 fibromyalgia diagnostic criteria.

A Systematic Review and Meta-Analysis of the Prevalence of Small Fibre Impairment in Patients with Fibromyalgia

Converging evidence shows that patients with fibromyalgia syndrome have signs of small fibre impairment, possibly leading to pain and autonomic symptoms, with a frequency that has not yet been systematically evaluated. To fill this gap, our review aims to define the frequency of somatic and autonomic small fibre damage in patients with fibromyalgia syndrome, as assessed by objective small fibre-related testing. We found 360 articles on somatic and autonomic small fibre assessment in patients with fibromyalgia. Out of the 88 articles assessed for eligibility, 20 were included in the meta-analysis, involving 903 patients with fibromyalgia. The estimated prevalence of somatic small fibre impairment, as assessed with skin biopsy, corneal confocal microscopy, and microneurography, was 49% (95% confidence interval (CI): 39–60%, I² = 89%), whereas the estimated prevalence of autonomic small fibre impairment, as assessed with heart rate variability, sympathetic skin response, skin conductance, and tilt testing, was 45% (95% CI: 25–65%, I² = 91%). Our study shows that a considerable proportion of patients with fibromyalgia have somatic and autonomic small fibre impairment, as assessed by extensive small fibre-related testing. Nevertheless, the heterogeneity and inconsistencies across studies challenge the exact role of small fibre impairment in fibromyalgia symptoms.

Dependence of Heart Rate Variability Indices on the Mean Heart Rate in Women with Well-Controlled Type 2 Diabetes

Heart rate variability (HRV) is a method used to evaluate the presence of cardiac autonomic neuropathy (CAN) because it is usually attributed to oscillations in cardiac autonomic nerve activity. Recent studies in other pathologies suggest that HRV indices are strongly related to mean heart rate, and this does not depend on autonomic activity only. This study aimed to evaluate the correlation between the mean heart rate and the HRV indices in women patients with well-controlled T2DM and a control group. HRV was evaluated in 19 T2DM women and 44 healthy women during basal supine position and two maneuvers: active standing and rhythmic breathing. Time-domain (SDNN, RMSSD, pNN20) and frequency-domain (LF, HF, LF/HF) indices were obtained. Our results show that meanNN, age, and the maneuvers are the main predictors of most HRV indices, while the diabetic condition was a predictor only for pNN20. Given the known reduced HRV in patients with T2DM, it is clinically important that much of the HRV indices are dependent on heart rate irrespective of the presence of T2DM. Moreover, the multiple regression analyses evidenced the multifactorial etiology of HRV.

Neurophysiological and ultrasonographic comparative study of autonomous nervous system in patients suffering from fibromyalgia and generalized anxiety disorder

BACKGROUND

Fibromyalgia (FM) and generalized anxiety disorder (GAD) share common clinical features: they both affect women more than men, their diagnosis is based solely on clinical criteria, and some of the symptoms such as anxiety, aches and muscle tension, sleep disorders, and cognitive dysfunction occur in both diseases. For both conditions, an underlying dysregulation of the autonomic nervous system (ANS) has been proposed.

OBJECTIVE

The aims of this study were to investigate ANS dysfunction in FM and GAD and compare them with controls.

METHODS

Sympathetic skin response (SSR) from palm and sole and cross-sectional area (CSA) of bilateral vagus nerves (VN) were measured in 28 healthy controls, 21 FM patients, and 24 GAD patients.

RESULTS

CSA of VN was significantly smaller in FM patients (right: 1.97 ± 0.74mm², left: 1.75 ± 0.65 mm2) and GAD patients (right: 2.12 ± 0.97mm², left: 1.71 ± 0.86 mm²) compared to controls (right: 3.21 ± 0.75 mm², left: 2.65 ± 1.13 mm², p < 0.001, but did not differ between the two patient groups. SSR parameters were similar between patients and controls. SSR latency correlated to clinical scales (FM Widespread Pain Index) in the FM group (r = 0.515, p = 0.02 and r = 0.447, p = 0.05) for the upper and lower limbs respectively, but no other correlation between clinical and neurophysiological parameters was identified.

CONCLUSION

This study confirms similar ANS abnormalities in FM and GAD that fairly distinguish them from controls and support the hypothesis of a common pathophysiological substrate underlying both conditions.

Impaired Cardiac Autonomic Control in Women With Fibromyalgia Is Independent of Their Physical Fitness

BACKGROUND/OBJECTIVE

Evidence has suggested abnormal cardiac autonomic responses to exercise in patients with fibromyalgia (FM). However, it is not clear whether the dysautonomia represents a reduced physical fitness rather directly related to FM pathogenesis. Thus, we aimed to verify the cardiac autonomic responses before, during, and after a maximal incremental exercise in women with FM and whether these hypothesized alterations would be dependent with their physical fitness.

METHODS

This is a cross-sectional study with 23 FM women and 17 healthy women. The participants performed a maximal incremental cycling test to determine their maximal workload (Wmax) and were further matched by their Wmax (14 FM patients, Wmax: 128.6 ± 16.2 W; and 14 healthy women, Wmax: 131.9 ± 15.9 W). Beat-to-beat heart rate (HR) was continuously monitored to calculate HR variability indexes at rest, chronotropic reserve during exercise, and HR recovery.

RESULTS

Heart rate variability indexes related to vagal modulation were significantly lower in FM patients than in healthy women (p < 0.05). The chronotropic reserve and the HR recovery at 30, 120, 180, 300, and 600 seconds after exercise were all lower in FM patients compared with those of healthy women (p < 0.05). Similar findings were found when analysis was performed using the matched physical fitness subgroup.

CONCLUSIONS

The documented cardiac autonomic abnormalities at rest, during, and after exercise in FM patients persist even when physical fitness status is taken in account. Thus, strategies to attenuate the dysautonomia in FM patients must be considered.

Holistic Treatment of Fibromyalgia Based on Physiopathology: An Expert Opinion

Patients suffering from fibromyalgia have many vexing symptoms; in contrast, physicians do not have a logical physiopathological framework to explain the multiple complaints. The objective of this writing is to discuss a patient-centered holistic fibromyalgia therapy based on a coherent physiopathological model.The rationale proposing fibromyalgia as stress-related sympathetically maintained neuropathic pain syndrome has solid research foundations. Autoimmunity is evident in a subset of fibromyalgia cases. Dorsal root ganglia are likely the crucial sympathetic-nociceptive short circuit sites. Skin biopsy and corneal confocal microscopy have demonstrated small nerve fiber pathology in fibromyalgia cases.Patient empowerment through information and symptom validation is the first step for a successful fibromyalgia therapy.

POINTS TO HIGHLIGHT

Fibromyalgia is a genuine painful neuropathic pain syndrome. In fibromyalgia stress becomes pain. Autonomic (sympathetic) dysfunction explains the multiplicity of fibromyalgia symptoms.The well-informed patient (and her/his family) must take on the leading role in her/his own rehabilitation. Fibromyalgia treatment often requires important lifestyle changes. Physicians and allied health care personnel facilitate this adjustment. Specific fibromyalgia drivers are discussed. Common modern bad habits alter autonomic nervous system balance and worsen fibromyalgia symptoms. Currently used drugs for fibromyalgia are rudimentary and with low retention rates. Autoimmune fibromyalgia requires focused therapeutic approach.

CONCLUSION

A patient-centered holistic therapy aimed to regain autonomic nervous system resilience remains the most effective fibromyalgia therapy.

FUTURE DIRECTIONS

Corneal confocal microscopy will likely become an objective fibromyalgia diagnostic and follow-up procedure. More specific analgesic antineuropathic medications for fibromyalgia are on the horizon.

Heart Rate Variability Analysis in Episodic Migraine: A Cross-Sectional Study

Objective: It has been reported that autonomic nervous dysfunction is more prevalent in migraineurs. Heart rate variability (HRV) is a commonly used method to evaluate the cardiac autonomic nervous function modulation. However, HRV changes in migraine are still contradictory. The main objective of this study was to explore the potential HRV change patterns in episodic migraine (EM) and whether there were differences in HRV between EM ictal period and the interictal period.

Patients and Methods: We conducted a cross-sectional study including 18 patients with EM and 18 age- and sex-matched controls. The characteristics of demographics, some lifestyle factors, and psychological conditions were assessed at baseline. HRVs including time-domain analysis and frequency-domain analysis were performed in all participants. HRV analyses in migraine were recorded not only in the interictal period but also in the ictal period.

Results: All the HRV parameters showed a decreased trend in migraine than controls. Time-domain parameters standard deviation of all NN intervals in 24 h (SDNN) and triangular index were significantly lower in the migraine ictal period than controls separately (SDNN, 56.94 ± 22.09 ± 7.76 vs. 135.78 ± 35.16, p < 0.001; triangular index, 12.61 ± 3.20 vs. 22.11 ± 6.90, p < 0.001). Frequency-domain parameter low-frequency power was also lower in the migraine ictal period than controls (351.28 ± 206.71 vs. 559.61 ± 281.24, p = 0.02). SDNN was much lower in the migraine ictal period than migraine interictal period (56.94 ± 22.09 vs. 115.94 ± 46.88, p < 0.001). HRV changes during migraine interictal period did not differ from the control group. The correlation analysis revealed a negative correlation between visual analog scale and HRV parameters in the migraine ictal period (p = 0.04).

Conclusions: The present cross-sectional study indicates that HRV was significantly decreased in EM population especially during the migraine ictal period, which means unbalance of autonomic system in EM. Perhaps larger prospective cohort studies are wanted to validate these findings.

Reduced Heart Rate Variability in Patients With Medically Unexplained Physical Symptoms: A Meta-Analysis of HF-HRV and RMSSD

OBJECTIVE

Medically unexplained physical symptoms (MUPS) and related syndromes are common and place a substantial burden on both patients and society. Chronic psychological distress and dysregulation of the autonomic nervous system may be common factors associated with MUPS, although previous studies have reported mixed results. The aims of this meta-analysis are to provide an updated synthesis of studies investigating heart rate variability (HRV) indices associated with autonomic nervous system functioning in three common MUPS syndromes and to explain inconsistencies in previous study findings.

METHODS

Literature search yielded 58 studies comparing HRV indices of reduced parasympathetic activity of healthy individuals with those of patients with chronic fatigue syndrome (npatients = 271), irritable bowel syndrome (npatients = 1005), and fibromyalgia (npatients = 534). Separate random-effects meta-analyses were conducted on studies measuring root mean square of successive differences (RMSSD) and high-frequency HRV (HF-HRV).

RESULTS

Regardless of syndrome type, patients had significantly lower RMSSD (k = 22, Hedges g = -0.37 [-0.53 to -0.21], p < .001) and HF-HRV (k = 52, Hedges g = -0.69 [-1.03 to -0.36], p < .001) than did healthy individuals. Sample age and publication year explained a substantial variation in RMSSD, whereas controlling for confounders in statistical analyses explained variation in HF-HRV.

CONCLUSIONS

Lower RMSSD and HF-HRV in patients with MUPS versus healthy controls indicates that autonomic nervous system dysregulation, particularly lower parasympathetic activity, may play a role in patients with these conditions. This conclusion may have important implications for the underlying mechanisms and treatment of MUPS and related syndromes.

Fibromyalgia: practical considerations for oral health care providers

Fibromyalgia is a syndrome characterized by chronic pain in the skeletal system accompanied by stiffness, sleep disturbance, fatigue, and psychiatric problems, such as anxiety and depression. Fibromyalgia commonly affects orofacial health, presenting with a variety of oral manifestations, including temporomandibular disorder, xerostomia, glossodynia, and dysgeusia. Therefore, oral healthcare providers need to be aware of this clinical entity to effectively manage oral symptoms and provide proper oral self-care modification and education on the nature of fibromyalgia. This review focuses on the epidemiology, pathophysiology, clinical manifestation, diagnosis, orofacial concerns, and treatment of fibromyalgia.

A Cross-Sectional Study on Central Sensitization and Autonomic Changes in Fibromyalgia

Fibromyalgia is a multi-symptomatic disorder characterized by generalized pain. The pathophysiology of fibromyalgia is supposedly an interplay between central nervous system hyper-responsiveness, autonomic dysfunction, and peripheral pain. In this cross-sectional study, the objective was to assess central sensitization and autonomic activity in patients with fibromyalgia compared with control. Fifty adults diagnosed with fibromyalgia by the modified American College of Rheumatology 2010 criteria and an equal number of age- and sex-matched controls participated in the study in an urban tertiary care hospital. Central sensitization was assessed by history and by evidence of increased prefrontal cortical activity as measured by cortical oxygenation using functional near-infrared spectroscopy. Autonomic activity was assessed by heart rate variability, electrodermal activity, and deep breathing test in three physiological states: rest, sympathetic stress (cold pressor test), and deep breathing. Mann–Whitney U-test, paired t-test, Wilcoxon test, and Friedman test with Bonferroni a priori were used to analyze the data. Cortical activity was significantly higher in the fibromyalgia group than control. There was no significant difference in autonomic activity between the fibromyalgia and control groups. In the fibromyalgia group, variable degrees of sympathetic hyperactivity and normal parasympathetic activity were observed. Central sensitization may be playing a primary role in the pathophysiology of generalized pain in fibromyalgia.

Multifractal Analysis Reveals Decreased Non-linearity and Stronger Anticorrelations in Heart Period Fluctuations of Fibromyalgia Patients

Objective: To characterize the multifractal behavior of the beat to beat heart-period or RR fluctuations in fibromyalgia patients (FM) in comparison with healthy-matched subjects.

Methods: Multifractral detrended fluctuation analysis (MDFA) was used to study multifractality in heartbeat times-series from 30 female healthy subjects and 30 female patients with fibromyalgia during day and night periods.The multifractal changes as derived from the magnitude and sign analysis of these RR fluctuations were also assessed.

Results: The RR fluctuations dynamics of healthy subjects showed a broad multifractal spectrum. By contrast, a noticeable decrease in multifractality and non-linearity was observed for patients with fibromyalgia. In addition, the spectra corresponding to FM subjects were located on the average to the right of the spectra of healthy individuals, indicating that the local scaling exponents reflect a smoother behavior compared to healthy dynamics. Moreover, the multifractal analysis as applied to the magnitude and sign heartbeat series confirmed that, in addition to a decreased nonlinearity, fibromyalgia patients presented stronger anticorrelation in directionality, which did not remain invariant for small or rather larger fluctuations as it occurred in healthy subjects.

Conclusion: When compared to healthy controls, fibromyalgia patients display decreased nonlinearity and stronger anticorrelations in heart period fluctuations. These findings reinforce the hypothesis of the potential role of the dysfunctional autonomic nervous system in the pathogenesis of fibromyalgia.

Choroidal thickness in patients with fibromyalgia and correlation with disease severity

Purpose:

To evaluate and compare choroidal thickness in patients with fibromyalgia (FM) and healthy controls.

Methods:

In this prospective, cross-sectional study, forty eyes of 40 patients with FM and 40 eyes of 40 age- and sex-matched healthy subjects were enrolled. FM was diagnosed according to the American College of Rheumatology criteria. The choroidal thickness measurements of the subjects were obtained using spectral-domain optical coherence tomography (RTVue-100, Optovue). Widespread pain index (WPI), symptom severity scale (SSS), and fibromyalgia impact questionnaire (FIQ) scores were recorded. The choroidal thickness measurements of the groups were compared, and correlations among the WPI, SSS, and FIQ scores and these measurements were calculated.

Results:

Choroidal thicknesses at 1500 μm nasally were 198.5 ± 46.7 μm and 306.3 ± 85.4 μm; at 1000 μm nasally were 211.7 ± 50.2 μm and 310.05 ± 87.26 μm; at 500 μm nasally were 216 ± 55.05 μm and 311.5 ± 83.4 μm; at subfoveal region were 230.9 ± 58.4 μm and 332.4 ± 91.3 μm; at 500 μm temporally 227.5 ± 58.1 μm and 318.15 ± 92.3 μm; at 1000 μm temporally 224.5 ± 57.07 μm and 315.1 ± 84.2 μm; at 1500 μm temporally 212.5 ± 56.08 μm and 312.9 ± 87.8 μm in the FM and control groups, respectively (P < 0.001). Choroidal thicknesses were thinner at all measurement location, except temporal 1000 and 1500 in patients with FIQ score ≥50 than in FIQ score <50.

Conclusion:

The results of this study demonstrated that choroidal thickness decreases in patients with FM and correlated with disease activity. This choroidal changes might be related with the alterations in autonomic nervous system functioning. Further studies are needed to evaluate the etiopathologic relationship between choroidal thickness and FM.

Effectiveness of Tai Chi on Cardiac Autonomic Function and Symptomatology in Women With Fibromyalgia: A Randomized Controlled Trial

The present study examined the effects of a 12-week Tai Chi (TC) training regimen on heart rate variability (HRV), symptomatology, muscle fitness and body composition in women with fibromyalgia. Participants were randomly assigned to either a TC training group (n = 18) or a control group (n = 19). HRV, symptomatology, muscle fitness and body composition were measured before and after 12 weeks. There were significant decreases (p < 0.05) in sympathovagal balance (LnLF/LnHF), sympathetic tone (LnLF, nLF), pain, and fatigue, and significant increases (p < 0.05) in parasympathetic tone (LnHF, nHF), strength and flexibility following TC compared with no changes after control. The changes in LnLF and LnLF/LnHF were correlated with changes in pain. There were no significant changes in HR, sleep quality and body composition after TC or control. TC may be an effective therapeutic intervention for improving sympathovagal balance, pain, fatigue, strength and flexibility in women with fibromyalgia.

The degree of cardiac baroreflex involvement during active standing is associated with the quality of life in fibromyalgia patients

Fibromyalgia syndrome (FMS) is a rheumatologic disorder characterized by chronic widespread pain, fatigue and other symptoms. Baroreflex dysfunction has been observed in women with FMS. However, it is unknown whether the limited involvement of the baroreflex control during an orthostatic stimulus has some impact on the quality of life of the FMS patient. Therefore, the aim of the study is evaluate the relationship between the quality of life of the FMS patient and indexes of the cardiovascular autonomic control as estimated from spontaneous fluctuations of heart period (HP) and systolic arterial pressure (SAP). We enrolled 35 women with FMS (age: 48.8±8.9 years; body mass index: 29.3±4.3 Kg/m²). The electrocardiogram, non-invasive finger blood pressure and respiratory activity were continuously recorded during 15 minutes at rest in supine position (REST) and in orthostatic position during active standing (STAND). Traditional cardiovascular autonomic control markers were assessed along with a Granger causality index assessing the strength of the causal relation from SAP to HP (CR_SAP→HP) and measuring the degree of involvement of the cardiac baroreflex. The impact of FMS on quality of life was quantified by the fibromyalgia impact questionnaire (FIQ) and visual analog score for pain (VAS pain). No significant linear association was found between FIQ scores and the traditional cardiovascular indexes both at REST and during STAND (p>0.05). However, a negative relationship between CR_SAP→HP during STAND and FIQ score was found (r = -0.56, p<0.01). Similar results were found with VAS pain. In conclusion, the lower the degree of cardiac baroreflex involvement during STAND in women with FMS, the higher the impact of FMS on the quality of life, thus suggesting that Granger causality analysis might be clinically helpful in assessing the state of the FMS patient.

QT dispersion and P wave dispersion in patients with fibromyalgia

OBJECTIVE

Fibromyalgia (FM) is a chronic disease characterized by widespread pain. Somatic complaints associated with the cardiovascular system, such as chest pain and palpitations, are frequently seen in FM patients. P and QT dispersions are simple and inexpensive measurements reflecting the regional heterogeneity of atrial and ventricular repolarization, respectively. QT dispersion can cause serious ventricular arrhythmias. The aim of the present study was to evaluate QT dispersion and P wave dispersion in patients with FM.

MATERIAL AND METHODS

The study involved 48 FM patients who fulfilled the established criteria and 32 healthy controls (HC). A standard 12-lead electrocardiogram was performed on all participants. QT dispersion was defined as the difference between the longest and the shortest QT intervals. Similarly, the differences between the shortest and longest P waves were defined as P wave dispersion.

RESULTS

The QT dispersion and corrected QT dispersion were shorter in the FM group compared with the HC group (p<0.001 for both). In terms of the P wave dispersion value, there was no significant difference between the FM and HC groups (p=0.088).

CONCLUSION

Longer QT and P wave dispersions are not problems in patients with FM. Therefore, it may be concluded that fibromyalgia does not include an increased risk of atrial and/or ventricular arrhythmias.

Prevalence of Fibromyalgia Syndrome and Its Correlations with Arrhythmia in Patients with Palpitations

OBJECTIVE

It is aimed to determine the prevalence of fibromyalgia syndrome (FMS) and its correlations with arrhythmia in patients with palpitations.

MATERIAL AND METHODS

Sixty-two patients who underwent electrophysiological study (EPS) due to palpitation complaints in Cardiology department and 40 healthy controls were included in the study. The precise diagnosis of arrhythmia was established using EPS. All participants were screened for FMS using American College of Rheumatology 2010 Fibromyalgia diagnostic criteria. Clinical assessments included measurement of severity of pain, fatigue and morning fatigue with visual analog scale (VAS), functional status with Fibromyalgia Impact Questionnaire (FIQ), and anxiety/depression with Hospital Anxiety and Depression Scale (HAD).

RESULTS

FMS was diagnosed in 22 of the 62 patients (36%), and 4 of the 40 healthy controls (10%) (p 0.05). EPS+ patients with FMS had higher fatigue levels, HAD and FIQ scores than EPS- patients, although statistically insignificant. HV durations were statistically longer in the EPS- subgroup (p < 0.05) but other EPS data were similar.

CONCLUSION

FMS frequency and HAD anxiety scores were found to be higher in patients with palpitation complaints. However, we found no association between arrhythmia, EPS parameters and FMS. In our clinical practice we should keep in mind to carry out assessments in terms of FMS in patients with palpitation.

Hemorheological parameters in patients with fibromyalgia syndrome

AIM

To evaluate hemorheological parameters in patients with fibromyalgia syndrome (FMS) in order to elucidate the etiology of the disease.

METHODS

Twenty-three adult FMS patients and 20 healthy controls were enrolled in the study. Diabetics, hypertensives and those with any rheumatological disorder or use drugs or smoking cigarette were excluded from the study. Following parameters were analyzed in each subject; erythrocyte deformability, erythrocyte aggregation, plasma viscosity, complete blood count, fasting blood glucose, fibrinogen, albumin, globulin and lipid profile.

RESULTS

Erythrocyte elongation indices indicating deformability of erythrocytes were higher in FMS patients (0.564±0.002 at 16.87 mPa and 0.605±0.002 at 30 mPa shear rate) than controls (0.558±0.001 at 16.87 mPa and 0.600±0.003 at 30 mPa shear rate). Erythrocyte aggregation speed was higher in FMS patients (2.1±0.1 s) than controls (2.3±0.2 s). Erythrocyte aggregation index was also higher in FMS patients (65.5±1.3) than controls (62.9±1.5). Erythrocyte aggregation amplitude and plasma viscosity values were similar in both groups (both p > 0.05). Among the complete blood count and biochemical parameters, only albumin levels were lower in the FM patients than controls (p < 0.05).

CONCLUSION

Our results indicate higher erythrocyte deformability and quicker erythrocyte aggregation in FM patients.

Exercise prevents development of autonomic dysregulation and hyperalgesia in a mouse model of chronic muscle pain

Chronic musculoskeletal pain (CMP) conditions, like fibromyalgia, are associated with widespread pain and alterations in autonomic functions. Regular physical activity prevents the development of CMP and can reduce autonomic dysfunction. We tested if there were alterations in autonomic function of sedentary mice with CMP, and whether exercise reduced the autonomic dysfunction and pain induced by CMP. Chronic musculoskeletal pain was induced by 2 intramuscular injections of pH 5.0 in combination with a single fatiguing exercise task. A running wheel was placed into cages so that the mouse had free access to it for either 5 days or 8 weeks (exercise groups) and these animals were compared to sedentary mice without running wheels. Autonomic function and nociceptive withdrawal thresholds of the paw and muscle were assessed before and after induction of CMP in exercised and sedentary mice. In sedentary mice, we show decreased baroreflex sensitivity, increased blood pressure variability, decreased heart rate variability, and decreased withdrawal thresholds of the paw and muscle 24 hours after induction of CMP. There were no sex differences after induction of the CMP in any outcome measure. We further show that both 5 days and 8 weeks of physical activity prevent the development of autonomic dysfunction and decreases in withdrawal threshold induced by CMP. Thus, this study uniquely shows the development of autonomic dysfunction in animals with chronic muscle hyperalgesia, which can be prevented with as little as 5 days of physical activity, and suggest that physical activity may prevent the development of pain and autonomic dysfunction in people with CMP.

Comparison of heart rate variability and classic autonomic testing for detection of cardiac autonomic dysfunction in patients with fibromyalgia

AIM

Cardiac autonomic dysfunction (CAD) is frequently found in patients with fibromyalgia (FM). Thus, we evaluated whether heart rate variability (HRV) is superior to the Ewing tests in detecting CAD in FM patients.

METHODS

We studied 35 females with FM and 25 age-matched healthy females. In Ewing tests, results were added to yield an overall score. An abnormal result on deep breathing, the Valsalva maneuver, or orthostatic standing was counted as 1 point. A change in systolic blood pressure (SBP) of > 10 mmHg while standing counted as 1 point, and a change of > 20 mmHg as 2 points. A score of 0 was regarded as no CAD, a score of ≥ 2 as severe CAD and a score of 1 as mild CAD. HRV was measured in two ways: by R-R intervals (time-domain analysis) and by spectral analysis of a series of successive R-R intervals (frequency-domain analysis).

RESULTS

FM patients had significantly lower expiratory/inspiratory (E/I) ratios, lower Valsalva ratios and higher SBP values than healthy controls (P < 0.05, P < 0.05, P < 0.01, respectively). In the frequency domain, very low-frequency and low-frequency bands were also lower in FM patients than controls (both P < 0.05). Based on the discriminant analysis of the Ewing tests, 54.4% of cases were correctly classified. The addition of HRV parameters did not improve the reclassification.

CONCLUSION

HRV does not improve detection of CAD in FM patients over classic autonomic testing.

Heart Rate Variability for Quantification of Autonomic Dysfunction in Fibromyalgia

Objective

To quantify autonomic dysfunction in fibromyalgia patients compared to healthy controls using heart rate variability (HRV).

Methods

Sixteen patients with fibromyalgia and 16 healthy controls were recruited in this case control study. HRV was measured using the time-domain method incorporating the following parameters: total heartbeats, the mean of intervals between consecutive heartbeats (R-R intervals), the standard deviation of normal to normal R-R intervals (SDNN), the square root of the mean squared differences of successive R-R intervals (RMSSD), ratio of SDNN to RMSSD (SDNN/RMSSD), and difference between the longest and shortest R-R interval under different three conditions including normal quiet breathing, rate controlled breathing, and Valsalva maneuver. The severity of autonomic symptoms in the group of patients with fibromyalgia was measured by Composite Autonomic Symptom Scale 31 (COMPASS 31). Then we analyzed the difference between the fibromyalgia and control groups and the correlation between the COMPASS 31 and aforementioned HRV parameters in the study groups.

Results

Patients with fibromyalgia had significantly higher SDNN/RMSSD values under both normal quiet breathing and rate controlled breathing compared to controls. Differences between the longest and shortest R-R interval under Valsalva maneuver were also significantly lower in patients with fibromyalgia than in controls. COMPASS 31 score was negatively correlated with SDNN/RMSSD values under rate controlled breathing.

Conclusion

SDNN/RMSSD is a valuable parameter for autonomic nervous system function and can be used to quantify subjective autonomic symptoms in patients with fibromyalgia.

Stress exacerbates pain in the everyday lives of women with fibromyalgia syndrome--The role of cortisol and alpha-amylase

OBJECTIVE

Although fibromyalgia syndrome (FMS) is a chronic condition, its cardinal symptom pain is known to fluctuate over the day. Stress has often been claimed to exacerbate pain; however, there is barely any evidence on whether or not this is true on a day-to-day basis (and, alternatively, on whether pain leads to increased stress levels). Using an ecologically valid measurement design, we tested whether and how stress and pain are intertwined in participants with FMS. We additionally examined the role of the two major stress-responsive systems, the hypothalamic-pituitary-adrenal axis and the autonomic nervous system, as potential mediators of this relationship.

METHODS

An ambulatory assessment study was conducted over the course of 14 days. On each day, 32 females with FMS provided six diary entries on momentary stress and pain levels. Saliva samples were collected at the same time points to determine cortisol and alpha-amylase as indicators of stress-responsive systems.

RESULTS

Higher stress at a given measurement time point was associated with higher reported pain levels at the subsequent time point (UC=1.47, p<0.001), but not vice versa (UC<0.01, p=0.179). The stress-pain relationship was neither mediated by momentary cortisol nor by alpha-amylase; however, momentary cortisol was independently associated with momentary pain (UC=0.27, p=0.009).

CONCLUSION

Stress seems to be a powerful exacerbating factor for pain as experienced by patients with FMS in their everyday lives. Cortisol may be involved in the diurnal fluctuation of pain levels in patients with FMS. Future studies should identify relevant daily stressors in persons with FMS and scrutinize the mechanisms underlying the cortisol-pain relationship.

Clinical Manifestations Associated with Overweight/Obesity in Puerto Ricans with Fibromyalgia Syndrome

Objective. To determine the clinical manifestations associated with overweight/obesity in Hispanics from Puerto Rico with fibromyalgia syndrome (FMS). Methods. A cross-sectional study was performed in 144 patients with FMS (per American College of Rheumatology (ACR) classification criteria). Sociodemographic features, FMS-related symptoms, tender points (per ACR criteria), comorbidities, and FMS treatment were examined. BMI was calculated and patients were grouped into two categories: BMI ≤ 24.9 kg/m(2) (nonoverweight/obese) and BMI ≥ 25 kg/m(2) (overweight/obese). Bivariate and multivariate analyses were used to evaluate differences between the study groups. Results. The mean (standard deviation (SD)) age of patients was 50.2 (9.9) years; 95.1% were females and 75.7% were overweight/obese. In the bivariate analysis, overweight/obese patients were more likely to have self-reported memory impairment, anxiety, shortness of breath, and urinary frequency than nonoverweight/obese patients. In addition, the tender point count was higher in the overweight/obese group. In the logistic regression analyses, self-reported memory impairment and urinary frequency differences remained significant after adjusting for confounding variables. Conclusion. In this population of Puerto Ricans with FMS, overweight/obese patients experienced more FMS-related manifestations than nonoverweight/obese individuals. However, prospective studies are needed to confirm these associations and to elucidate if weight reduction interventions could favorably impact the severity of FMS.

Increased Risk of Coronary Heart Disease in Patients with Primary Fibromyalgia and Those with Concomitant Comorbidity-A Taiwanese Population-Based Cohort Study

OBJECTIVES

Fibromyalgia has seldom been associated with coronary heart disease (CHD). The aim of this study was to evaluate the risk of CHD in patients with fibromyalgia.

METHODS

We used a dataset of one million participants, systemically scrambled from the Taiwanese national insurance beneficiaries, to identify 61,612 patients with incident fibromyalgia (ICD-9-CM 729.0-729.1) and 184,834 reference subjects matched by sex, age and index date of diagnosis in a 1:3 ratio from 2000 to 2005, with a mean 8.86 ± 2.68 years of follow-up until 2011. Risk of CHD was analyzed by Cox proportional hazard modeling.

RESULTS

Patients with fibromyalgia had a mean age of 44.1 ± 16.5 years. CHD events developed in fibromyalgia patients (n = 8,280; 15.2 per 103 person-years) and reference subjects (n = 15,162; 9.26 per 103 person-years) with a significant incidence rate ratio of 1.64 (95% confidence interval: 1.61-1.68). The adjusted hazard ratio for CHD in fibromyalgia patients relative to reference subjects was 1.47 (1.43-1.51), after adjusting for age, gender, occupation, monthly income, traditional cardiovascular comorbidities, depression and anxiety. We noted that fibromyalgia and cardiovascular comorbidities had a significant interaction effect on CHD risk (p for interaction <0.01), which was markedly enhanced in fibromyalgia patients with concomitant comorbidities relative to patients with primary fibromyalgia and reference subjects (no fibromyalgia, no comorbidity).

CONCLUSIONS

Our report shows that fibromyalgia patients have an independent risk for CHD development. Fibromyalgia patients with concomitant comorbidities have markedly increased CHD risk relative to those with primary fibromyalgia.

Fibromyalgia and its clinical relevance in renal transplant recipients

OBJECTIVE

Recent evidence suggests that fibromyalgia syndrome (FS) is associated with inflammation and endothelial dysfunction. Our aim was to determine the prevalence of FS in renal transplant recipients and to identify possible links between FS and clinical and laboratory parameters.

METHODS

Ninety-nine kidney transplant recipients with normal graft functions (37.15 ± 10.83 years old, 67 male) were enrolled in the study. All subjects completed the Fibromyalgia Impact Questionnaire (FIQ). The biochemical and clinical parameters in the 1st post-transplantation year were retrospectively recorded. Cardiovascular parameters, including body composition analyses (Tanita), ambulatory blood pressure monitoring data, and pulse-wave velocity, were cross-sectionally analyzed.

RESULTS

Mean FIQ score for the whole group was 21.4 ± 14.7. Eight patients had FIQ score >50, and these patients had significantly higher left ventricular mass index than patients with lower FIQ score (P = .048). Patients were divided according to their physical impairment score (PIS): PIS ≥5 (n = 50) and PIS <5 (n = 49). Patients with higher PIS had significantly higher serum creatinine (P = .047) and lower eGFR values (P = .008) than patients with lower PIS. Patients were also evaluated with the use of the stiffness score (SS): patients with (n = 41) and without (n = 58) stiffness. Patients with stiffness had significantly higher office systolic (P = .027) and diastolic (P = .044) blood pressure, body mass index (P = .033), and sagittal abdominal diameter (P = .05) than patients without stiffness. Decline in estimated glomerular filtration rate levels were significantly higher in patients with higher FIQ (7.6% vs 9.4%; P = .0001) than in other patients.

CONCLUSIONS

FS in renal transplant recipients was strongly associated with hypertension, arterial stiffness, obesity, and renal allograft dysfunction.

Vagally mediated heart rate variability in headache patients—a systematic review and meta-analysis

Objective

Vagal nerve activity—indexed by heart rate variability (HRV)—has been linked to altered pain processing and inflammation, both of which may underpin headache disorders and lead to cardiovascular disease (CVD). Here we examined the evidence for differences in parasympathetic (vagal) activity indexed by time- and frequency-domain measures of HRV in patients with headache disorders compared to healthy controls (HCs).

Methods

A systematic review and meta-analysis was conducted on studies investigating group differences in vagally mediated HRV (vmHRV) including time- (root-mean-square of successive R-R-interval differences (RMSSD)) and frequency- (high-frequency HRV) domain measures. Studies eligible for inclusion were identified by a systematic search of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

Seven studies reporting a total of 10 comparisons of patients with headache disorders (HF-HRV n = 67, RMSSD n = 122) and HCs (HF-HRV n = 64, RMSSD n = 125) were eligible for inclusion. Random-effects meta-analysis revealed a significant main effect on RMSSD ( Z = 2.03, p = 0.04; Hedges’ g = −0.63; 95% CI (−1.24, –0.02); k = 6) and similar pooled effect size estimates for HF-HRV when breathing was controlled ( g = −0.30; 95% CI (−0.69; 0.10)) but not when breathing was not controlled ( g = 0.02; 95% CI (−0.69; 0.74)). Controlling for breathing had no effect on RMSSD.

Conclusion

vmHRV is reduced in patients with headache disorders, findings associated with a medium effect size. Suggestions for future research in this area are provided, emphasizing a need to investigate the impact of headache disorders and commonly comorbid conditions—including mental disorders—as well as the investigation of the risk for CVD in migraine in particular. We further emphasize the need for large-scale studies to investigate HRV as a mechanism mediating the association of migraine and CVD.

Cardiovascular control in women with fibromyalgia syndrome: do causal methods provide nonredundant information compared with more traditional approaches?

The cardiovascular autonomic control and the baroreflex sensitivity (BRS) have been widely studied in fibromyalgia syndrome (FMS) patients through the computation of linear indices of spontaneous heart period (HP) and systolic arterial pressure (SAP) variabilities. However, there are many methodological difficulties regarding the quantification of BRS by the traditional indices especially in relation to the issue of causality. This difficulty has been directly tackled via a model-based approach describing the closed-loop HP-SAP interactions and the exogenous influences of respiration. Therefore, we aimed to assess whether the BRS assessed by the model-based causal closed-loop approach during supine and active standing in patients with FMS could provide complementary information to those obtained by traditional indices based on time and frequency domains. The findings of this study revealed that, at difference with the traditional methods to quantify BRS, the causality analysis applied to the HP, SAP, and respiratory series, through the model-based closed-loop approach, detected lower BRS in supine position, as well as a blunted response to the orthostatic stimulus in patients with FMS compared with healthy control subjects. Also, the strength of the causal relation from SAP to HP (i.e., along the cardiac baroreflex) increased during the active standing only in the control subjects. The model-based closed-loop approach proved to provide important complementary information about the cardiovascular autonomic control in patients with FMS.

Heart rate turbulence analysis in female patients with fibromyalgia

OBJECTIVE

Fibromyalgia is characterized by diffuse musculoskeletal pain and discomfort. There are several reports regarding autonomic nervous system dysfunction in patients with fibromyalgia. Heart rate turbulence is expressed as ventriculophasic sinus arrhythmia and has been considered to reflect cardiac autonomic activity. Heart rate turbulence has been shown to be an independent and powerful predictor of sudden cardiac death in various cardiac abnormalities. The aim of this study is to determine whether heart rate turbulence is changed in female patients with fibromyalgia compared with healthy controls.

METHODS

Thirty-seven female patients (mean age, 40±11 years) with fibromyalgia, and 35 age- and sex-matched healthy female control subjects (mean age, 42±9 years) were included. Twenty-four hours of ambulatory electrocardiography recordings were collected for all subjects, and turbulence onset and turbulence slope values were automatically calculated.

RESULTS

The baseline clinical characteristics of the two groups were similar. There were no significant differences in turbulence onset and turbulence slope measures between patients and control subjects (turbulence onset: -1.648±1.568% vs. -1.582±1.436%, p ϝ 0.853; turbulence slope: 12.933±5.693 ms/RR vs. 13.639±2.505 ms/RR, p ϝ 0.508). Although body mass index was negatively correlated with turbulence slope (r ϝ -0.258, p ϝ 0.046), no significant correlation was found between body mass index and turbulence onset (r ϝ 0.228, p ϝ 0.054).

CONCLUSION

To the best of our knowledge, this is the first study to evaluate heart rate turbulence in patients with fibromyalgia. It appears that heart rate turbulence parameters reflecting cardiac autonomic activity are not changed in female patients with fibromyalgia.

Altered Autonomic Nervous System Reactivity to Pain in Trigeminal Neuralgia

Background: In the past two decades, there has been increasing evidence to suggest that trigeminal neuralgia (TN) may be linked to a dysfunction of the autonomic nervous system (ANS). The aim of the present study was to formally test this hypothesis by comparing the reactivity of the ANS to experimental pain in a population of TN patients and healthy controls. Methods: Twelve patients diagnosed with classical TN and 12 healthy controls participated in the study. Cardiac activity was assessed while participants were instructed to rest and again during a cold pressor test (CPT). Heart rate variability analyses were performed off-line to obtain parasympathetic (high-frequency) and sympathetic (low-frequency) indices. Results: At baseline, ANS measures did not differ between healthy controls and TN patients, and both groups showed a similar increase in heart rate during the CPT (all p values >0.05). However, TN patients showed a greater increase in cardiac sympathetic activity and a greater decrease in cardiac parasympathetic activity during CPT compared with healthy controls (all p values <0.05). Importantly, changes in sympathetic reactivity, from baseline to CPT, were negatively associated with the number of pain paroxysms experienced each day by TN patients in the preceding week (r=−.58, p<0.05). Conclusions: These results suggest that TN, like many other short-lasting, unilateral facial pain conditions, is linked to ANS alterations. Future studies are required to determine if the altered ANS response observed in TN patients is a cause or a consequence of TN pain

Parasympathetic reactivity in fibromyalgia and temporomandibular disorder: associations with sleep problems, symptom severity, and functional impairment

Despite evidence of autonomic disturbances in chronic multisymptom illnesses such as temporomandibular disorder (TMD) and fibromyalgia, additional work is needed to characterize the role of parasympathetic reactivity in these disorders. Given the high levels of comorbidity with psychiatric disorders characterized by stronger parasympathetic decline than controls in safe contexts (leading to higher arousal), it was hypothesized that individuals with TMD and fibromyalgia would respond similarly. In this preliminary investigation, 43 women with TMD (n = 17), TMD + fibromyalgia (n = 11), or neither (controls; n = 15) completed a baseline assessment of respiratory sinus arrhythmia (a measure of parasympathetic activity) followed by ongoing parasympathetic assessment during a questionnaire period. As predicted, patients showed greater parasympathetic decline during psychosocial assessment, suggesting an autonomic stance that supports defensive rather than engagement behaviors. Individual differences in parasympathetic reduction during the questionnaire period were related to a variety of physical and psychosocial variables. Although this study has a number of key limitations, including a convenience sampling approach and small group sizes, if replicated in larger samples, the findings would have important implications for the treatment of patients with these disorders.

PERSPECTIVE

Compared to controls, individuals with TMD or TMD and fibromyalgia demonstrated greater parasympathetic decline during psychosocial assessment, and individual differences in parasympathetic decline predicted negative patient outcomes. Such parasympathetic decline may demonstrate a tendency to readily perceive danger in safe environments.

Review of overlap between thermoregulation and pain modulation in fibromyalgia

Fibromyalgia (FM) syndrome is characterized by widespread pain that is exacerbated by cold and stress but relieved by warmth. We review the points along thermal and pain pathways where temperature may influence pain. We also present evidence addressing the possibility that brown adipose tissue activity is linked to the pain of FM given that cold initiates thermogenesis in brown adipose tissue through adrenergic activity, whereas warmth suspends thermogenesis. Although females have a higher incidence of FM and more resting thermogenesis, they are less able to recruit brown adipose tissue in response to chronic stress than males. In addition, conditions that are frequently comorbid with FM compromise brown adipose activity making it less responsive to sympathetic stimulation. This results in lower body temperatures, lower metabolic rates, and lower circulating cortisol/corticosterone in response to stress--characteristics of FM. In the periphery, sympathetic nerves to brown adipose also project to surrounding tissues, including tender points characterizing FM. As a result, the musculoskeletal hyperalgesia associated with conditions such as FM may result from referred pain in the adjacent muscle and skin.

Fibromyalgia and nondipper circadian blood pressure variability

BACKGROUND AND OBJECTIVES

Aberrant circadian rhythm with persistent nocturnal sympathetic hyperactivity has pointed out malfunctioning autonomic nervous system in fibromyalgia (FM) patients. This is a common pathogenesis shared also by patients with nondipping blood pressure (BP) pattern. Therefore, we aimed to investigate the frequency of nondipping BP pattern in normotensive women with newly diagnosed FM compared with healthy women.

METHODS

Sixty-seven normotensive women with new diagnosis of FM and 38 age-matched healthy volunteer women were recruited into the study. All subjects underwent 24-hour ambulatory BP monitoring on a usual working day. Individuals were defined as "dippers" if their nocturnal BP values decreased by more than 10% compared with daytime values; defined as "nondippers" in case of a decline less than 10%. Serum creatinine, fasting blood glucose, cholesterol levels, albumin, and thyroid-stimulating hormone levels were assessed.

RESULTS

Ambulatory measurements showed significantly higher diastolic BP values in patients with FM for both average of 24-hour recordings. Patients with FM had significantly lower systolic (9.1 ± 3.9 vs 11.5 ± 4.9, P = 0.010) and diastolic dipping ratios (12.3 ± 6.1 vs 16.1 ± 6.4, P = 0.004). The number of nondippers in the FM group was significantly higher than that of controls for both systolic (66% vs 34%, P = 0.002) and diastolic BP measurements (42% vs 21%, P=0.031). Patients with FM were 3.68 times more likely to be systolic nondipper and 2.69 times more likely to be diastolic nondipper.

CONCLUSIONS

We have demonstrated a significant relationship between FM and nondipping BP pattern, and we suggest that nondipping profile, which has been closely associated with cardiovascular morbidity, may appear as an additional risk factor in patients with FM.

The effect of relaxation therapy on autonomic functioning, symptoms and daily functioning, in patients with chronic fatigue syndrome or fibromyalgia: a systematic review

Objective:

To establish the effects of relaxation therapy on autonomic function, pain, fatigue and daily functioning in patients with chronic fatigue syndrome or fibromyalgia.

Method:

A systematic literature study was performed. Using specific keywords related to fibromyalgia or chronic fatigue syndrome and relaxation therapy, the electronic databases PubMed and Web of Science were searched. Included articles were assessed for their risk of bias and relevant information regarding relaxation was extracted. The review was conducted and reported according to the PRISMA-statement.

Results:

Thirteen randomized clinical trials of sufficient quality were included, resulting in a total of 650 fibromyalgia patients (11 studies) and 88 chronic fatigue syndrome patients (3 studies). None of the studies reported effects on autonomic function. Six studies reported the effect of guided imagery on pain and daily functioning in fibromyalgia. The acute effect of a single session of guided imagery was studied in two studies and seems beneficial for pain relief. For other relaxation techniques (eg. muscle relaxation, autogenic training) no conclusive evidence was found for the effect on pain and functioning in fibromyalgia patients comparison to multimodal treatment programs. For fatigue a multimodal approach seemed better than relaxation, as shown in the sole three studies on chronic fatigue syndrome patients.

Conclusion:

There is moderate evidence for the acute effect of guided imagery on pain, although the content of the visualization is a matter of debate. Other relaxation formats and the effects on functionality and autonomic function require further study.

Strengthening exercises improve symptoms and quality of life but do not change autonomic modulation in fibromyalgia: a randomized clinical trial

Objective

Autonomic dysfunction is an important mechanism that could explain many symptoms observed in fibromyalgia (FM). Exercise is an effective treatment, with benefits potentially mediated through changes in autonomic modulation. Strengthening is one of the less studied exercises in FM, and the acute and chronic effects of strengthening on the autonomic system remain unknown. The objective of this study was to assess the chronic effects of strengthening exercises (STRE) on autonomic modulation, pain perception and the quality of life (QOL) of FM patients.

Methods

Eighty sedentary women with FM (ACR 1990) were randomly selected to participate in STRE or flexibility (FLEX) exercises in a blinded controlled trial. The intensity of STRE was set at 45% of the estimated load of 1 Repetition Maximum (RM) in 12 different exercises. Outcomes were Visual Analog Scale (VAS) for pain, Heart Rate Variability (HRV) analysis, treadmill test, the sit and reach test (Wells and Dillon’s Bench), maximal repetitions test and handgrip dynamometry; and quality of life by the Fibromyalgia Impact Questionnaire (FIQ), the Beck and Idate Trait-State Inventory (IDATE), a short-form health survey (SF-36).

Results

The STRE group was more effective to strength gain for all muscles and pain control after 4 and 16 weeks (p<0.05). The FLEX group showed higher improvements in anxiety (p<0.05). Both groups showed improvements in the QOL, and there was no significant difference observed between the groups. There was no change in the HRV of the STRE and FLEX groups.

Conclusions

Strengthening exercises show greater and more rapid improvements in pain and strength than flexibility exercises. Despite the benefits in fitness, pain, depression, anxiety and quality of life, no effect was observed on the autonomic modulation in both groups. This observation suggests that changes in autonomic modulation are not a target tobe clinically achieved in fibromyalgia.

Trial Registration

ClinicalTrials.gov NCT02004405

Urinary albumin, protein excretion and circadian blood pressure in patients with fibromyalgia

Recent evidence suggests that patients with fibromyalgia (FM) have increased oxidative stress, inflammation, endothelial dysfunction and autonomic dysfunction. These factors are also shown to be responsible for increased urinary albumin and protein excretion and deranged circadian blood pressure (BP). However, no study has examined the 24-h urinary albumin excretion (UAE), 24-h urinary protein excretion (UPE) and 24-h ambulatory BP measurements in FM patients. The sociodemographic, laboratory parameters, depressive symptoms, sleep problems and 24-h ambulatory BPs were measured for all patients. Diagnosis of FM was based on the criteria for the classification of FM by the American College of Rheumatology. After diagnosis of FM, these patients underwent to complete the Fibromyalgia Impact Questionnaire (FIQ). In total, 30 patients with FM and 61 patients without FM were included. Among FM patients, the average number of tender points was 13.1 ± 1.57 and the mean FIQ score was 57.9 ± 8.86. The number of tender points did not show any correlation with office and ambulatory BPs. There were also no correlations between the number of tender points, UPE and UAE. The stepwise linear regression did not show any relation between UPE and FM. However, 24-h UAE was independently correlated with office systolic BP (P 0.008) and the presence of FM (P 0.045). The logistic regression analysis revealed no association between FM and non-dipping status. We suggest that circadian blood pressure and UPE are not independently associated with FM. However, UAE was related with the presence of FM. Studies are needed to confirm our findings and to highlight pathophysiologic mechanisms.

Effect of experimental stress in 2 different pain conditions affecting the facial muscles

Chronic facial muscle pain is a common feature in both fibromyalgia (FM) and myofascial (MF) pain conditions. In this controlled study, a possible difference in the mode of deregulation of the physiological response to a stressing stimulus was explored by applying an acute mental stress to FM and MF patients and to controls. The effects of the stress test were observed on pain, sympathetic variables, and both tonic and reflex electromyographic activities of masseteric and temporal muscles. The statistical analyses were performed through a generalized linear model including mixed effects. Painful reaction to the stressor was stronger (P < .001) and longer (P = .011) in FM than in MF independently of a higher pain level at baseline. The stress-induced autonomic changes only seen in FM patients did not reach significance. The electromyographic responses to the stress test were strongest for controls and weakest for FM. The stress test had no effect on reflex activity (area under the curve [AUC]) or latency, although AUC was high in FM and latencies were low in both pain groups. It is suggested that FM is characterized by a lower ability to adapt to acute stress than MF.

PERSPECTIVE

This study showed that an acute psychosocial stress triggered several changes in 2 pain conditions including an increase in pain of larger amplitude in FM than in MF pain. Similar stress-induced changes should be explored as possible mechanisms for differentiation between dysfunctional pain conditions.