Lower ambulatory blood pressure in chronic fatigue syndrome

Cross-Sectional Study Evaluating the Role of Autonomic Nervous System Functional Diagnostics in Differentiating Post-Infectious Syndromes: Post-COVID Syndrome, Chronic Fatigue Syndrome, and Lyme Disease

Background/Objectives: Post-infectious syndromes, including Post-COVID syndrome, Chronic Fatigue Syndrome, and late-stage Lyme disease, are associated with overlapping clinical features and autonomic dysfunction. Despite shared symptoms such as fatigue and orthostatic intolerance, the underlying pathophysiology and specific patterns of autonomic dysfunction may differ. This study aimed to evaluate and compare autonomic nervous system function in these syndromes using multiple diagnostic modalities to identify unique characteristics and improve differentiation between these conditions. Methods: This cross-sectional study included 758 patients, which were divided into four groups: Post-COVID syndrome, Chronic Fatigue Syndrome following Post-COVID syndrome, Chronic Fatigue Syndrome unrelated to COVID-19, and late-stage Lyme disease. Autonomic nervous system function was assessed using cardiovascular reflex tests, the Head-Up Tilt Test, beat-to-beat analysis, five-minute electrocardiogram recordings, 24 h Holter electrocardiogram monitoring, and 24 h ambulatory blood pressure monitoring. Statistical analyses compared parameters across the groups, focusing on patterns of sympathetic and parasympathetic dysfunction. Results: The patients with Lyme disease showed distinct autonomic patterns, including a higher prevalence of orthostatic hypotension (53.4%) and changes in heart rate variability during the Head-Up Tilt Test suggestive of adrenergic failure. Compared to the other groups, patients with Lyme disease exhibited reduced baroreceptor sensitivity and diminished changes in frequency domain heart rate variability parameters during orthostatic stress. Parasympathetic dysfunction was less prevalent in the Lyme disease group, while the Post-COVID syndrome and Chronic Fatigue Syndrome groups showed more pronounced autonomic imbalances. Conclusions: The patients with Post-COVID syndrome, Chronic Fatigue Syndrome, and late-stage Lyme disease exhibited varying degrees and types of autonomic dysfunction. Late-stage Lyme disease is characterized by adrenergic failure and distinct hemodynamic responses, differentiating it from other syndromes. The functional assessment of autonomic nervous system function could aid in understanding and managing these conditions, offering insights for targeted therapeutic interventions.

Assessment of Autonomic Nervous System Function in Patients with Chronic Fatigue Syndrome and Post-COVID-19 Syndrome Presenting with Recurrent Syncope

Background/Objectives: Chronic fatigue syndrome and post-COVID-19 syndrome are associated with dysfunction of the autonomic nervous system, which may manifest as syncope and orthostatic intolerance. This study aimed to compare autonomic nervous system function in patients with chronic fatigue syndrome of unknown etiology and those with chronic fatigue syndrome secondary to post-COVID-19 syndrome using multiple diagnostic modalities, and to assess the prevalence and characteristics of syncope in these populations. Methods: This cross-sectional study included 440 patients examined at the Neurocardiological Laboratory of the Institute for Cardiovascular Diseases "Dedinje". Patients were divided into three groups: chronic fatigue syndrome of unknown etiology (Group 1, n = 210), chronic fatigue syndrome secondary to post-COVID-19 syndrome (Group 2, n = 137), and healthy controls (Group 3, n = 91). Diagnostic modalities included cardiovascular reflex tests, the head-up tilt test, beat-to-beat analysis, 24 h Holter electrocardiogram monitoring, and 24 h ambulatory blood pressure monitoring. Statistical analyses were performed using analysis of variance, Tukey's honestly significant difference test, and the Mann-Whitney U test. Results: Both chronic fatigue syndrome groups demonstrated significant autonomic nervous system dysfunction compared to healthy controls (p < 0.05), including reduced baroreceptor sensitivity and impaired heart rate variability parameters. Syncope prevalence was high in both chronic fatigue syndrome groups, with extreme blood pressure variability observed in 45-47% of patients during the head-up tilt test. Patients with post-COVID-19 chronic fatigue syndrome exhibited greater blood pressure increases during the head-up tilt test than those with chronic fatigue syndrome of unknown etiology (p < 0.05). Conclusions: Patients with chronic fatigue syndrome, irrespective of etiology, exhibit significant autonomic nervous system dysfunction and a high prevalence of syncope. Post-COVID-19 chronic fatigue syndrome demonstrates distinct hemodynamic patterns, suggesting unique pathophysiological mechanisms that warrant further investigation.

Association between chronic fatigue syndrome/myalgic encephalomyelitis and cardiovascular disease

Chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) is a medical condition characterized by severe and prolonged fatigue that is not relieved by rest or attributed to any underlying medical or psychological condition. Individuals with CFS/ME are considered to have an increased risk of a wide range of comorbid conditions, including cardiovascular disease (CVD). The association between CFS/ME and CVD is not fully understood. To determine the prevalence of CFS/ME in a sample population and examine its association with CVD. Weighted sample size data of 114,834 was analyzed from the 2021-2022 national health interview survey (NHIS). Information on sociodemographic factors, CVD risk factors, and history of CFS/ME and CVD were collected. Multivariable logistic regression model was used to determine the association between CFS/ME and CVD, adjusting for traditional CVD risk factors (age, sex, race, hypertension, diabetes, dyslipidemia, smoking, and body mass index (BMI). Median age of participants was 53 years, and majority of participants were female (53.9%). Prevalence of CFS/ME was 1.2%. A history of CFS/ME was significantly associated with CVD (aOR 3.26, 95%CI 2.85, 3.72, p-value: <0.001) after adjusting for traditional CVD risk factors. A history of CFS/ME was independently associated with CVD after adjusting for traditional CVD risk factors. Patients with CFS/ME need close evaluation for CVD. Further studies are needed to better understand the relationship between CFS/ME and CVD.

Orthostatic chronotropic incompetence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Background

Orthostatic intolerance (OI) is a core diagnostic criterion in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The majority of ME/CFS patients have no evidence of hypotension or postural orthostatic tachycardia syndrome (POTS) during head-up tilt, but do show a significantly larger reduction in stroke volume index (SVI) when upright compared to controls. Theoretically a reduction in SVI should be accompanied by a compensatory increase in heart rate (HR). When there is an incomplete compensatory increase in HR, this is considered chronotropic incompetence. This study explored the relationship between HR and SVI to determine whether chronotropic incompetence was present during tilt testing in ME/CFS patients.

Methods

From a database of individuals who had undergone tilt testing with Doppler measurements for SVI both supine and end-tilt, we selected ME/CFS patients and healthy controls (HC) who had no evidence of POTS or hypotension during the test. To determine the relation between the HR increase and SVI decrease during the tilt test in patients, we calculated the 95% prediction intervals of this relation in HC. Chronotropic incompetence in patients was defined as a HR increase below the lower limit of the 95th % prediction interval of the HR increase in HC.

Results

We compared 362 ME/CFS patients with 52 HC. At end-tilt, tilt lasting for 15 (4) min, ME/CFS patients had a significantly lower SVI (22 (4) vs. 27 (4) ml/m²; p < 0.0001) and a higher HR (87 (11) vs. 78 (15) bpm; p < 0.0001) compared to HC. There was a similar relationship between HR and SVI between ME/CFS patients and HC in the supine position. During tilt ME/CFS patients had a lower HR for a given SVI; 37% had an inadequate HR increase. Chronotropic incompetence was more common in more severely affected ME/CFS patients.

Conclusion

These novel findings represent the first description of orthostatic chronotropic incompetence during tilt testing in ME/CFS patients.

Cardiovascular and haematological pathology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): A role for viruses

ME/CFS is a debilitating chronic condition that often develops after viral or bacterial infection. Insight from the study of Long COVID/Post Acute Sequelae of COVID-19 (PASC), the post-viral syndrome associated with SARS-CoV-2 infection, might prove to be useful for understanding pathophysiological mechanisms of ME/CFS. Disease presentation is similar between the two conditions, and a subset of Long COVID patients meet the diagnostic criteria for ME/CFS. Since Long COVID is characterized by significant vascular pathology - including endothelial dysfunction, coagulopathy, and vascular dysregulation - the question of whether or not the same biological abnormalities are of significance in ME/CFS arises. Cardiac abnormalities have for a while now been documented in ME/CFS cohorts, with recent studies demonstrating major deficits in cerebral blood flow, and hence vascular dysregulation. A growing body of research is demonstrating that ME/CFS is accompanied by platelet hyperactivation, anomalous clotting, a procoagulant phenotype, and endothelial dysfunction. Endothelial damage and dysregulated clotting can impair substance exchange between blood and tissues, and result in hypoperfusion, which may contribute to the manifestation of certain ME/CFS symptoms. Here we review the ME/CFS literature to summarize cardiovascular and haematological findings documented in patients with the condition, and, in this context, briefly discuss the potential role of previously-implicated pathogens. Overall, cardiac and haematological abnormalities are present within ME/CFS cohorts. While atherosclerotic heart disease is not significantly associated with ME/CFS, suboptimal cardiovascular function defined by reduced cardiac output, impaired cerebral blood flow, and vascular dysregulation are, and these abnormalities do not appear to be influenced by deconditioning. Rather, these cardiac abnormalities may result from dysfunction in the (autonomic) nervous system. Plenty of recently published studies are demonstrating significant platelet hyperactivity and endothelial dysfunction in ME/CFS, as well as anomalous clotting processes. It is of particular importance to determine to what extent these cardiovascular and haematological abnormalities contribute to symptom severity, and if these two systems can be targeted for therapeutic purposes. Viral reservoirs of herpesviruses exist in ME/CFS, and most likely contribute to cardiovascular and haematological dysfunction directly or indirectly. This review highlights the potential of studying cardiac functioning, the vasculature, and coagulation system in ME/CFS.

Markers of Cardiac Autonomic Function During Consecutive Day Peak Exercise Tests in People With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have been shown to exhibit altered ventilatory characteristics on the second of two progressive maximal cardiopulmonary exercise tests (CPET) performed on consecutive days. However, maximal exercise can exacerbate symptoms for ME/CFS patients and cause significant post-exertional malaise. Assessment of heart rate (HR) parameters known to track post-exertional fatigue may represent more effective physiological markers of the condition and could potentially negate the need for maximal exercise testing. Sixteen ME/CFS patients and 10 healthy controls underwent a sub-maximal warm-up followed by CPET on two consecutive days. Ventilation, ratings of perceived exertion, work rate (WR) and HR parameters were assessed throughout on both days. During sub-maximal warm-up, a time effect was identified for the ratio of low frequency to high frequency power of HR variability (p=0.02) during sub-maximal warm-up, and for HR at ventilatory threshold (p=0.03), with both being higher on Day Two of testing. A significant group (p<0.01) effect was identified for a lower post-exercise HR recovery (HRR) in ME/CFS patients. Receiver operator characteristic curve analysis of HRR revealed an area under the curve of 74.8% (p=0.02) on Day One of testing, with a HRR of 34.5bpm maximising sensitivity (63%) and specificity (40%) suggesting while HRR values are altered in ME/CFS patients, low sensitivity and specificity limit its potential usefulness as a biomarker of the condition.

Chronic Fatigue Syndrome and Cardiovascular Disease: JACC State-of-the-Art Review

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities for at least 6 months accompanied by problems with unrefreshing sleep, exacerbation of symptoms following physical or mental efforts (postexertional malaise [PEM]), and either cognitive reports or physiological evidence of orthostatic intolerance in the form of either orthostatic tachycardia and/or hypocapnia. Although rarely considered to have cardiac dysfunction, ME/CFS patients frequently have reduced stroke volume with a significant inverse relation between cardiac output and PEM severity. Magnetic resonance imaging of ME/CFS patients compared with normal control subjects found significantly reduced stroke, end-systolic, and end-diastolic volumes together with reduced end-diastolic wall mass. Another cardiovascular abnormality is reduced nocturnal blood pressure assessed by 24-hour monitoring. Autonomic dysfunction is also frequently observed with postural orthostatic tachycardia and/or hypocapnia. Two consecutive cardiopulmonary stress tests may provide metabolic data substantiating PEM.

Changes in the Allostatic Response to Whole-Body Cryotherapy and Static-Stretching Exercises in Chronic Fatigue Syndrome Patients vs. Healthy Individuals

This study represents a comparison of the functional interrelation of fatigue and cognitive, cardiovascular and autonomic nervous systems in a group of Chronic Fatigue Syndrome (CFS) patients compared with those in healthy individuals at different stages of analysis: at baseline and after changes induced by whole-body cryotherapy (WBC) combined with a static-stretching (SS) program. The study included 32 patients (Fukuda criteria) and 18 healthy controls. Fatigue, cognitive, cardiovascular and autonomic function and arterial stiffness were measured before and after 10 sessions of WBC with SS. In the patients, a disturbance in homeostasis was observed. The network relationship based on differences before and after intervention showed comparatively higher stress and eccentricity in the CFS group: 50.9 ± 56.1 vs. 6.35 ± 8.72, p = 0.002, r = 0.28; and 4.8 ± 0.7 vs. 2.4 ± 1, p < 0.001, r = 0.46, respectively. Before and after intervention, in the CFS group increased fatigue was related to baroreceptor function, and baroreceptor function was in turn related to aortic stiffness, but no such relationships were observed in the control group. Differences in the network structure underlying the interrelation among the four measured criteria were observed in both groups, before the intervention and after ten sessions of whole cryotherapy with a static stretching exercise.

Post-Exertional Malaise May Be Related to Central Blood Pressure, Sympathetic Activity and Mental Fatigue in Chronic Fatigue Syndrome Patients

Post-exertional malaise (PEM) is regarded as the hallmark symptom in chronic fatigue syndrome (CFS). The aim of the current study is to explore differences in CFS patients with and without PEM in indicators of aortic stiffness, autonomic nervous system function, and severity of fatigue. One-hundred and one patients met the Fukuda criteria. A Chronic Fatigue Questionnaire (CFQ) and Fatigue Impact Scale (FIS) were used to assess the level of mental and physical fatigue. Aortic systolic blood pressure (sBPaortic) and the autonomic nervous system were measured with the arteriograph and Task Force Monitor, respectively. Eighty-two patients suffered prolonged PEM according to the Fukuda criteria, while 19 did not. Patients with PEM had higher FIS scores (p = 0.02), lower central systolic blood pressure (p = 0.02) and higher mental fatigue (p = 0.03). For a one-point increase in the mental fatigue component of the CFQ scale, the risk of PEM increases by 34%. For an sBPaortic increase of 1 mmHg, the risk of PEM decreases by 5%. For a one unit increase in sympathovagal balance, the risk of PEM increases by 330%. Higher mental fatigue and sympathetic activity in rest are related to an increased risk of PEM, while higher central systolic blood pressure is related to a reduced risk of PEM. However, none of the between group differences were significant after FDR correction, and therefore conclusions should be treated with caution and replicated in further studies.

The SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: analysis of high-throughput epigenetic and gene expression studies

Patients affected by Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) show specific epigenetic and gene expression signatures of the disease. However, it is unknown whether these signatures include abnormal levels of the human angiotensin-converting enzymes, ACE and ACE2, the latter being the main receptor described for the host-cell invasion by SARS-CoV-2. To investigate that, we first re-analyzed available case-control epigenome-wide association studies based on DNA methylation data, and case-control gene expression studies based on microarray data. From these published studies, we found an association between ME/CFS and 4 potentially hypomethylated probes located in the ACE locus. We also found another disease association with one hypomethylated probe located in the transcription start site of ACE2. The same disease associations were obtained for women but not for men after performing sex-specific analyses. In contrast, a meta-analysis of gene expression levels could not provide evidence for a differentially expression of ACE and ACE2 in affected patients when compared to healthy controls. In line with this negative finding, the analysis of a new data set on the gene expression of ACE and ACE2 in peripheral blood mononuclear cells did not find any differences between a female cohort of 37 patients and 34 age-matched healthy controls. Future studies should be conducted to extend this investigation to other potential receptors used by SARS-CoV-2. These studies will help researchers and clinicians to improve the understanding of the health risk imposed by this virus when infecting patients affected by this debilitating disease.

In-vehicle carbon dioxide and adverse effects: An air filtration-based intervention study

Drowsiness is considered a potential risk for traffic accidents. Exposure to high carbon dioxide (CO₂) levels in vehicles may result in unpleasant feeling, fatigue, drowsiness or lethargy among drivers and passengers. However, little is known about whether reducing CO₂ levels in vehicles by air filtration can relieve adverse effects among human subjects during driving. We recruited a panel of 84 healthy participants to drive a vehicle equipped with a CO₂ filtration system for 1 h on a coastal road in a Northern Taiwan rural area. The operation modes of the CO₂ filtration system, including fresh air from open windows without a CO₂ filtration system (Control-mode), fresh air from an air conditioning (AC) system with closed windows and a false CO₂ filtration system in operation (Off-mode) or a true CO₂ filtration system in operation (On-mode), were examined. The repeated measurements of heart rate (HR), blood pressure (BP), CO₂, total volatile organic compounds (TVOCs), particulate matter ≤2.5 μm in aerodynamic diameter (PM_2.5) and a simple question about drowsiness were obtained for each participant in three different modes. We found that decreased HR, systolic BP (SBP) and diastolic BP (DBP) and increased drowsiness were associated with increased levels of in-vehicle CO₂. The effects of in-vehicle CO₂ on adverse effects were highest in the Off-mode during driving. In the On-mode, the participants showed slight decreases in HR, SBP and DBP and slight increases in drowsiness. We concluded that the utilization of a CO₂ filtration system can reduce in-vehicle CO₂ levels and modify the effect of in-vehicle CO₂ on HR, BP and drowsiness among human subjects during driving.

Fatigue in Parkinson's Disease Associates with Lower Ambulatory Diastolic Blood Pressure

BACKGROUND/OBJECTIVE

Fatigue is a common debilitating symptom in Parkinson's disease (PD) of unclear etiology. Hypotension and blood pressure variability are common in PD though their relationship to other non-motor symptoms is less well understood.

METHODS

We conducted a cross-sectional study to explore differences in 24-hour ambulatory blood pressure measurements in PD subjects (n = 35) with and without fatigue. Subjects underwent hourly systolic (SBP) and diastolic (DBP) blood pressure testing in their home environment. The presence of fatigue was assessed using the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part 1. We compared blood pressure measurements in fatigued vs. non-fatigued PD subjects, assessed over 4 epochs: overnight, morning, midday, and evening.

RESULTS

PD subjects with symptoms of fatigue demonstrated lower mean DBP, compared to those without fatigue (67.8±4.8 mmHg vs. 75.6±9.4 t = 2.57, p = 0.014). These intergroup differences were most notable in the morning. The two groups did not differ in scoring on the Survey of Autonomic Symptoms or on an office-based blood assessment of SBP or DBP performed on the day of 24-hour monitor initiation.

CONCLUSIONS

Fatigue in PD may be a clinical manifestation of low-grade systemic hypotension.

Evidence of altered cardiac autonomic regulation in myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and meta-analysis

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition with no reliable diagnostic biomarkers. Studies have shown evidence of autonomic dysfunction in patients with ME/CFS, but results have been equivocal. Heart rate (HR) parameters can reflect changes in autonomic function in healthy individuals; however, this has not been thoroughly evaluated in ME/CFS.

METHODS

A systematic database search for case-control literature was performed. Meta-analysis was performed to determine differences in HR parameters between ME/CFS patients and controls.

RESULTS

Sixty-four articles were included in the systematic review. HR parameters assessed in ME/CFS patients and controls were grouped into ten categories: resting HR (RHR), maximal HR (HRmax), HR during submaximal exercise, HR response to head-up tilt testing (HRtilt), resting HR variability (HRVrest), HR variability during head-up tilt testing (HRVtilt), orthostatic HR response (HROR), HR during mental task(s) (HRmentaltask), daily average HR (HRdailyaverage), and HR recovery (HRR) Meta-analysis revealed RHR (MD ± 95% CI = 4.14 ± 1.38, P < .001), HRtilt (SMD ± 95% CI = 0.92 ± 0.24, P < .001), HROR (0.50 ± 0.27, P < .001), and the ratio of low frequency power to high frequency power of HRVrest (0.39 ± 0.22, P < .001) were higher in ME/CFS patients compared to controls, while HRmax (MD ± 95% CI = -13.81 ± 4.15, P < .001), HR at anaerobic threshold (SMD ± 95% CI = -0.44 ± 0.30, P = 0.005) and the high frequency portion of HRVrest (-0.34 ± 0.22, P = .002) were lower in ME/CFS patients.

CONCLUSIONS

The differences in HR parameters identified by the meta-analysis indicate that ME/CFS patients have altered autonomic cardiac regulation when compared to healthy controls. These alterations in HR parameters may be symptomatic of the condition.

Fatigue in chronic liver disease: New insights and therapeutic approaches

The management of fatigue associated with chronic liver disease is a complex and major clinical challenge. Although fatigue can complicate many chronic diseases, it is particularly common in diseases with an inflammatory component. Fatigue can have both peripheral (i.e., neuromuscular) and central (i.e., resulting from changes in neurotransmission within the brain) causes. However, fatigue in chronic liver disease has strong social/contextual components and is often associated with behavioural alterations including depression and anxiety. Given the increasing awareness of patient-reported outcomes as important components of treatment outcomes and clinical research, there is a growing need to better understand and manage this poorly understood yet debilitating symptom. Although several pathophysiological mechanisms for explaining the development of fatigue have been generated, our understanding of fatigue in patients with chronic liver disease remains incomplete. A better understanding of the pathways and neurotransmitter systems involved may provide specific directed therapies. Currently, the management of fatigue in chronic liver disease can involve a combined use of methods to beneficially alter behavioural components and pharmacological interventions, of which several treatments have potential for the improved management of fatigue in chronic liver disease. However, evidence and consensus are lacking on the best approach and the most appropriate biochemical target(s) whilst clinical trials to address this issue have been few and limited by small sample size. In this review, we outline current understanding of the impact of fatigue and related symptoms in chronic liver disease, discuss theories of pathogenesis, and examine current and emerging approaches to its treatment.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-Metabolic Disease or Disturbed Homeostasis due to Focal Inflammation in the Hypothalamus?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease characterized by debilitating fatigue, lasting for at least 6 months, with associated malaise, headaches, sleep disturbance, and cognitive impairment, which severely impacts quality of life. A significant percentage of ME/CFS patients remain undiagnosed, mainly due to the complexity of the disease and the lack of reliable objective biomarkers. ME/CFS patients display decreased metabolism and the severity of symptoms appears to be directly correlated to the degree of metabolic reduction that may be unique to each individual patient. However, the precise pathogenesis is still unknown, preventing the development of effective treatments. The ME/CFS phenotype has been associated with abnormalities in energy metabolism, which are apparently due to mitochondrial dysfunction in the absence of mitochondrial diseases, resulting in reduced oxidative metabolism. Such mitochondria may be further contributing to the ME/CFS symptomatology by extracellular secretion of mitochondrial DNA, which could act as an innate pathogen and create an autoinflammatory state in the hypothalamus. We propose that stimulation of hypothalamic mast cells by environmental, neuroimmune, pathogenic and stress triggers activates microglia, leading to focal inflammation in the brain and disturbed homeostasis. This process could be targeted for the development of novel effective treatments.

Autonomic Nervous System Functioning Related to Nocturnal Sleep in Patients With Chronic Fatigue Syndrome Compared to Tired Controls

STUDY OBJECTIVES

Autonomic nervous system (ANS) dysfunction is common in chronic fatigue syndrome (CFS). One of the main complaints in CFS is unrefreshing sleep. We aimed to study the nocturnal cardiac ANS in different sleep stages in patients filling the 2015 Institute of Medicine CFS diagnostic criteria.

METHODS

In this case series study, the nocturnal heart rate variability and blood pressure (BP) variables in polysomnography were studied in groups of patients with CFS (n = 8) and tired controls (n = 8) aged 16-49 years. Five of the patients with CFS and controls were female. The heart rate variability and BP parameters and heart rate were studied in all sleep stages and wake.

RESULTS

The amount of low-frequency oscillations of the electrocardiography R-R-intervals spectra (LF; predominantly reflects sympathetic activity) was higher for patients with CFS in all sleep stages compared to controls (P < .001). During wake, the amount of LF was lower for the patients with CFS (P < .05). The amount of high-frequency oscillations (HF; reflects parasympathetic activity) was lower in stage N3 sleep in the patients with CFS than for the controls (P < .0001), but, in total, HF was higher in patients with CFS (P < .001). Patients with CFS had higher overall nocturnal systolic and mean BP (P < .0001) and lower heart rate (P < .0001) than controls. No significant differences were found in sleep stage distributions.

CONCLUSIONS

The results suggest a nocturnal dysfunction of the cardiac ANS in CFS, presenting as lower parasympathetic tone in deep sleep and higher sympathetic tone asleep.

Cardiovascular characteristics of chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) commonly exhibit orthostatic intolerance. Abnormal sympathetic predominance in the autonomic cardiovascular response to gravitational stimuli was previously described in numerous studies. The aim of the current study was to describe cardiological and clinical characteristics of Italian patients with CFS. All of the patients were of Caucasian ethnicity and had been referred to our center, the Cardiology Department of the University Hospital of Pavia (Pavia, Italy) with suspected CFS. A total of 44 patients with suspected CFS were included in the present study and the diagnosis was confirmed in 19 patients according to recent clinical guidelines. The characteristics at baseline of the population confirm findings from various previous reports regarding the prevalence in females with a female to male ratio of 4:1, the age of onset of the pathology and the presence of previous infection by the Epstein-Barr virus, cytomegalovirus and other human herpesviruses. Despite the current data indicating that the majority of the cardiological parameters investigated are not significantly different in patients with and without CFS, a significant association between the disease and low levels of blood pressure was identified. Other pilot studies revealed a higher prevalence of hypotension and orthostatic intolerance in patients with CFS. Furthermore, many of the CFS symptoms, including fatigue, vertigo, decreased concentration, tremors and nausea, may be explained by hypotension.

Mortality in Patients with Myalgic Encephalomyelitis and Chronic Fatigue Syndrome

BACKGROUND

There is a dearth of research examining mortality in individuals with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Some studies suggest there is an elevated risk of suicide and earlier mortality compared to national norms. However, findings are inconsistent as other researchers have not found significant increases in all-cause mortality for patients.

OBJECTIVE

This study sought to determine if patients with ME or CFS are reportedly dying earlier than the overall population from the same cause.

METHODS

Family, friends, and caregivers of deceased individuals with ME or CFS were recruited through social media, patient newsletters, emails, and advocate websites. This study analyzed data including cause and age of death for 56 individuals identified as having ME or CFS.

RESULTS

The findings suggest patients in this sample are at a significantly increased risk of earlier all-cause (M = 55.9 years) and cardiovascular-related (M = 58.8 years) mortality, and they had a directionally lower mean age of death for suicide (M = 41.3 years) and cancer (M =66.3 years) compared to the overall U.S. population [M = 73.5 (all-cause), 77.7 (cardiovascular), 47.4 (suicide), and 71.1 (cancer) years of age].

CONCLUSIONS

The results suggest there is an increase in risk for earlier mortality in patients with ME and CFS. Due to the small sample size and over-representation of severely ill patients, the findings should be replicated to determine if the directional differences for suicide and cancer mortality are significantly different from the overall U.S. population.

Reduced cardiac volumes in chronic fatigue syndrome associate with plasma volume but not length of disease: a cohort study

Objectives

To explore potential mechanisms that underpin the cardiac abnormalities seen in chronic fatigue syndrome (CFS) using non-invasive cardiac impedance, red cell mass and plasma volume measurements.

Methods

Cardiac MR (MR) examinations were performed using 3 T Philips Intera Achieva scanner (Best, NL) in participants with CFS (Fukuda; n=47) and matched case-by-case controls. Total volume (TV), red cell volume (RCV) and plasma volume (PV) measurements were performed (41 CFS and 10 controls) using the indicator dilution technique using simultaneous 51-chromium labelling of red blood cells and 125-iodine labelling of serum albumin.

Results

The CFS group length of history (mean±SD) was 14±10 years. Patients with CFS had significantly reduced end-systolic and end-diastolic volumes together with reduced end-diastolic wall masses (all p<0.0001). Mean±SD RCV was 1565±443 mL with 26/41 (63%) having values below 95% of expected. PV was 2659±529 mL with 13/41 (32%) <95% expected. There were strong positive correlations between TV, RCV and PV and cardiac end-diastolic wall mass (all p<0.0001; r²=0.5). Increasing fatigue severity correlated negatively with lower PV (p=0.04; r²=0.2). There were no relationships between any MR or volume measurements and length of history, suggesting that deconditioning was unlikely to be the cause of these abnormalities.

Conclusions

This study confirms an association between reduced cardiac volumes and blood volume in CFS. Lack of relationship between length of disease, cardiac and plasma volumes suggests findings are not secondary to deconditioning. The relationship between plasma volume and severity of fatigue symptoms suggests a potential therapeutic target in CFS.

The role of the hippocampus in the pathogenesis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a severe acquired illness characterized by a profound sensation of fatigue, not ameliorated by rest and resulting in a substantial decrease in the amount and quality of occupational, social and recreational activities. Despite intense research, the aetiology and pathogenesis of ME/CFS is still unknown and no conclusive biological markers have been found. As a consequence, an accepted curative treatment is still lacking and rehabilitation programmes are not very effective, as few patients recover. Increased knowledge of the mechanisms leading to the emergence and maintenance of the illness is called for. In this study, I will put forth an alternative hypothesis to explain some of the pathologies associated with ME/CFS, by concentrating on one of the major strategic organs of the brain, the hippocampus. I will show that the ME/CFS triggering factors also impact the hippocampus, leading to neurocognitive deficits and disturbances in the regulation of the stress system and pain perception. These deficits lead to a substantial decrease in activity and to sleep disorders, which, in turn, impact the hippocampus and initiate a vicious circle of increased disability.

A systematic review of the comorbidity between Temporomandibular Disorders and Chronic Fatigue Syndrome

The most common cause of chronic oro-facial pain is a group of disorders collectively termed temporomandibular disorders (TMDs). Chronic painful TMD is thought to be a 'central sensitivity syndrome' related to hypersensitivity of the nervous system, but the cause is unknown. A similar understanding is proposed for other unexplained conditions, including chronic fatigue syndrome (CFS). Exploring the comorbidity of the two conditions is a valuable first step in identifying potential common aetiological mechanisms or treatment targets.

METHOD

Systematic literature review. Studies were included if they recruited community or control samples and identified how many reported having both TMD and CFS, or if they recruited a sample of patients with either TMD or CFS and measured the presence of the other condition.

RESULTS

Six papers met inclusion criteria. In studies of patients with CFS (n = 3), 21-32% reported having TMD. In a sample of people with CFS and fibromyalgia, 50% reported having TMD. Studies in people with TMD (n = 3) reported 0-43% having CFS. Studies in samples recruited from oro-facial pain clinics (n = 2) reported a lower comorbidity with CFS (0-10%) than a study that recruited individuals from a TMD self-help organisation (43%).

CONCLUSION

The review highlights the limited standard of evidence addressing the comorbidity between oro-facial pain and CFS. There is a valuable signal that the potential overlap in these two conditions could be high; however, studies employing more rigorous methodology including standardised clinical assessments rather than self-report of prior diagnosis are needed.

A concept mapping study evaluating the UK's first NHS generic fatigue clinic

Importance

Fatigue is a significant and debilitating symptom affecting 25% of the population. It occurs in those with a range of chronic diseases, can be idiopathic and in 0.2–0.4% of the UK population occurs in combination with other symptoms that together constitute chronic fatigue syndrome (CFS). Until recently, NHS clinical services only focussed upon CFS and excluded the majority of fatigued patients who did not meet the CFS diagnostic criteria. The CRESTA Fatigue interdisciplinary clinic was established in 2013 in response to this unmet need.

Objective

To identify the service needs of the heterogeneous group of patients accessing the CRESTA Fatigue Clinic, to prioritize these needs, to determine whether each is being met and to plan targeted service enhancements.

Design

Using a group concept mapping approach, we objectively identified the shared understanding of service users accessing this novel clinic.

Setting

NHS Clinics for Research & Service in Themed Assessment (CRESTA) Fatigue Clinic, Newcastle Upon Tyne, UK.

Participants

Patients (n = 30) and referrers (n = 10) to the CRESTA Fatigue Clinic contributed towards a statement generation exercise to identify ways the clinic could support service users to improve their quality of life. Patients (n = 46) participated in the sorting and rating task where resulting statements were sorted into groups similar in meaning and rated for ‘importance’ and ‘current success’.

Main outcome and measure

We mapped the needs of patients attending the CRESTA Fatigue Clinic and identified which high‐priority needs were being successfully met and which were not.

Results

Multidimensional scaling and hierarchical cluster analysis depicted the following eight themed clusters from the data which related to various service‐user requirements: ‘clinic ethos’, ‘communication’, ‘support to self‐manage’, ‘peer support’, ‘allied health services’, ‘telemedicine’, ‘written information’ and ‘service operation’. Service improvement targets were identified within value bivariate plots of the statements.

Conclusion and Relevance

Service development concepts were grouped into thematic clusters and prioritized for both importance and current success. The resulting concept maps depict where the CRESTA Fatigue Clinic successfully addresses issues which matter to patients and highlights areas for service enhancement. Unmet needs of patients have been identified in a rigorous service evaluation, and these are currently being addressed in collaboration with a service‐user group.

Malfunctioning of the autonomic nervous system in patients with chronic fatigue syndrome: a systematic literature review

INTRODUCTION

It is hypothesised that the autonomic nervous system responds differently to various stressors in patients with chronic fatigue syndrome (CFS) compared with healthy controls. The goal is to systematically review the scientific literature addressing the functioning of the autonomic nervous system in patients with CFS.

MATERIALS AND METHODS

All studies that were identified through electronic databases (PubMed and Web of Science) were screened for eligibility based on the selection criteria and assessed (two independent raters) for methodological quality using a methodological checklist for case-control studies.

RESULTS

Twenty-seven case-control studies were included. The methodological quality varied between 50% and 71·4%. Some studies showed different responses to head-up tilt and other autonomous testing.

CONCLUSION

Although comparison between the included case-control studies was difficult, we can conclude that there are differences in autonomous response between patients with CFS and healthy controls. The heart rate dynamic response during the head-up tilt test differs between patients with CFS and healthy controls, supporting the increased prevalence of postural orthostatic tachycardia syndrome. The autonomic response can be useful for the diagnosis of CFS.

Cardiac dysfunction and orthostatic intolerance in patients with myalgic encephalomyelitis and a small left ventricle

The etiology of chronic fatigue syndrome (CFS) is unknown. Myalgic encephalomyelitis (ME) has been recently postulated to be the cause of CFS. Orthostatic intolerance (OI) has been known as an important symptom in predicting quality of life in CFS patients. Cardiac function may be impaired in patients with ME. The presence or absence of OI was determined both symptomatically and by using a 10-min stand-up test in 40 ME patients. Left ventricular (LV) dimensions and function were determined echocardiographically in the ME patients compared to 40 control subjects. OI was noted in 35 (97%) of the 36 ME patients who could stand up quickly. The mean values for the cardiothoracic ratio, systemic systolic and diastolic pressures, LV end-diastolic diameter (EDD), LV end-systolic diameter, stroke volume index, cardiac index and LV mass index were all significantly smaller in the ME group than in the controls. Both a small LVEDD (<40 mm, 45 vs. 3%) and a low cardiac index (<2 l/ min/mm2, 53 vs. 8%) were significantly more common in the ME group than in the controls. Both heart rate and LV ejection fraction were similar between the groups. In conclusion, a small LV size with a low cardiac output was common in ME patients, in whom OI was extremely common. Cardiac dysfunction with a small heart appears to be related to the symptoms of ME.

Primary Sjogrens syndrome is associated with impaired autonomic response to orthostasis and sympathetic failure

BACKGROUND

Symptoms in keeping with autonomic dysfunction are commonly described by primary Sjögrens syndrome patients (pSS); whether objective abnormalities of autonomic function occur is unclear. This study set out to explore dynamic cardiovascular autonomic responses in pSS and their relationship with symptoms and quality of life.

METHODS

Twenty-one people from the UK pSS registry, 21 community controls and 21 patients with the autoimmune liver disease primary biliary cirrhosis (PBC) (matched case-wise for age and sex) attended for assessment of autonomic responses to orthostasis and Valsalva manoeuvre (VM). pSS patients also completed EULAR Sjögrens Syndrome patient-reported index (ESSPRI), EULAR Sjögren's syndrome disease activity index (ESSDAI), fatigue impact scale and EURO-QOL 5-dimension (EQ-5D).

RESULTS

Compared with controls, pSS patients had significantly lower baseline systolic blood pressure (SBP) (114 ± 13 vs. 127 ± 20; P = 0.02), which dropped to a significantly lower value (98 ± 22 vs. 119 ± 24, P = 0.009). When area under the curve (AUC) was calculated for when the SBP was below baseline this was significantly greater in pSS compared to both control groups (pSS vs. control vs. PBC: 153 ± 236 vs. 92 ± 85 vs. 1.2 ± 0.3, P = 0.005). Peak phase IV SBP during the VM was significantly lower in pSS (P = 0.007) indicating early sympathetic failure. Increased heart rate associated with fatigue (P = 0.02; r(2) = 0.2) and EQ-5D. A shift in sympathetic-vagal balance associated with overall symptom burden (ESSPRI) (P = 0.04, r(2) = 0.3) and EULAR sicca score (P = 0.016; r(2) = 0.3), the latter also correlated with baroreceptor effectiveness (P = 0.03; r(2) = 0.2) and diastolic blood pressure variability (P = 0.003; r(2) = 0.4).

CONCLUSION

pSS patients have impaired blood pressure response to standing. Dysautonomia correlates with PSS-associated symptoms and quality of life.

Impaired blood pressure variability in chronic fatigue syndrome--a potential biomarker

INTRODUCTION

Autonomic dysfunction is common in chronic fatigue syndrome (CFS). This study set out to derive an autonomic biomarker using a comprehensive assessment of heart rate and blood pressure variability.

METHODS

Heart rate and non-invasive continuous blood pressure measurements (task force monitor) at rest and on standing were performed in CFS (Fukuda n = 68) and matched controls (n = 68) to derive high frequency (HF; parasympathetic) and low frequency (LF; sympathetic) heart rate variability (HRV), systolic (SBPV) and diastolic (DBPV) blood pressure variability. Variables of significance were combined using receiver operator curves to explore the diagnostic utility of parameters particularly at rest.

RESULTS

At rest, LF-HRV (sympathetic) was significantly increased in CFS compared to controls, while parasympathetic markers were significantly reduced (P = 0.006). Total DBP spectral power was increased (P = 0.0003) across all domains, with a shift towards sympathetic and away from parasympathetic SBPV (P = 0.05). On standing, overall SBPV response was significantly reduced with reductions in both sympathetic and parasympathetic components of SBPV (all P < 0.0001). Change in LF-DBP and relative balance of LF/HF DBP on standing differed between CFS and controls (P < 0.0001). Using the 85% sensitivity levels, we determined a threshold for three chosen resting BPV parameters of LF DBP >3.185, rest HF DBP >0.86, rest total DBP >7.05. Achieving all of these differentiated between CFS and controls with 77% sensitivity and 53% specificity.

CONCLUSION

This study has shown that there are objectively measured abnormalities of blood pressure variability in CFS and that these abnormalities have the potential to be a bedside diagnostic tool.

In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome

BACKGROUND

Central sensitisation entails several top-down and bottom-up mechanisms, all contributing to the hyperresponsiveness of the central nervous system to a variety of inputs. In the late nineties, it was first hypothesised that chronic fatigue syndrome (CFS) is characterised by hypersensitivity of the central nervous system (i.e. central sensitisation). Since then, several studies have examined central sensitisation in patients with CFS. This study provides an overview of such studies.

MATERIALS AND METHODS

Narrative review.

RESULTS

Various studies showed generalised hyperalgesia in CFS for a variety of sensory stimuli, including electrical stimulation, mechanical pressure, heat and histamine. Various tissues are affected by generalised hyperalgesia: the skin, muscle tissue and the lungs. Generalised hyperalgesia in CFS is augmented, rather than decreased, following various types of stressors like exercise and noxious heat pain. Endogenous inhibition is not activated in response to exercise and activation of diffuse noxious inhibitory controls following noxious heat application to the skin is delayed.

CONCLUSIONS

The observation of central sensitisation in CFS is in line with our current understanding of CFS. The presence of central sensitisation in CFS corroborates with the presence of several psychological influences on the illness, the presence of infectious agents and immune dysfunctions and the dysfunctional hypothalamus-pituitary-adrenal axis as seen in these severely debilitated patients.

A brain MRI study of chronic fatigue syndrome: evidence of brainstem dysfunction and altered homeostasis

To explore brain involvement in chronic fatigue syndrome (CFS), the statistical parametric mapping of brain MR images has been extended to voxel-based regressions against clinical scores. Using SPM5 we performed voxel-based morphometry (VBM) and analysed T(1) - and T(2) -weighted spin-echo MR signal levels in 25 CFS subjects and 25 normal controls (NC). Clinical scores included CFS fatigue duration, a score based on the 10 most common CFS symptoms, the Bell score, the hospital anxiety and depression scale (HADS) anxiety and depression, and hemodynamic parameters from 24-h blood pressure monitoring. We also performed group × hemodynamic score interaction regressions to detect locations where MR regressions were opposite for CFS and NC, thereby indicating abnormality in the CFS group. In the midbrain, white matter volume was observed to decrease with increasing fatigue duration. For T(1) -weighted MR and white matter volume, group × hemodynamic score interactions were detected in the brainstem [strongest in midbrain grey matter (GM)], deep prefrontal white matter (WM), the caudal basal pons and hypothalamus. A strong correlation in CFS between brainstem GM volume and pulse pressure suggested impaired cerebrovascular autoregulation. It can be argued that at least some of these changes could arise from astrocyte dysfunction. These results are consistent with an insult to the midbrain at fatigue onset that affects multiple feedback control loops to suppress cerebral motor and cognitive activity and disrupt local CNS homeostasis, including resetting of some elements of the autonomic nervous system (ANS).

Small heart with low cardiac output for orthostatic intolerance in patients with chronic fatigue syndrome

BACKGROUND

The etiology of chronic fatigue syndrome (CFS) is unknown. Orthostatic intolerance (OI) is common in CFS patients. Recently, small heart with low cardiac output has been postulated to be related to the genesis of both CFS and OI.

HYPOTHESIS

Small heart is associated with OI in patients with CFS.

METHODS

Study CFS patients were divided into groups of 26 (57%) CFSOI(+) and 20 (43%) CFSOI(-) according to the presence or absence of OI. In addition, 11 OI patients and 27 age- and sex-matched control subjects were studied. Left ventricular (LV) dimensions and function were determined echocardiographically.

RESULTS

The mean values of cardiothoracic ratio, systemic systolic and diastolic pressures, LV end-diastolic dimension, LV end-systolic dimension, stroke volume index, cardiac index, and LV mass index were all significantly smaller in CFSOI(+) patients than in CFSOI(-) patients and healthy controls, and also in OI patients than in controls. A smaller LV end-diastolic dimension (<40 mm) was significantly (P<0.05) more prevalently noted in CFSOI(+) (54%) and OI (45%) than in CFSOI(-) (5%) and controls (4%). A lower cardiac index (<2 L/min/mm(2)) was more prevalent in CFSOI(+) (65%) than in CFSOI(-) (5%, P<0.01), OI (27%), and controls (11%, P<0.01).

CONCLUSIONS

A small size of LV with low cardiac output was noted in OI, and its degree was more pronounced in CFSOI(+). A small heart appears to be related to the genesis of OI and CFS via both cerebral and systemic hypoperfusion. CFSOI(+) seems to constitute a well-defined and predominant subgroup of CFS.

Myalgic encephalomyelitis: International Consensus Criteria

The label 'chronic fatigue syndrome' (CFS) has persisted for many years because of the lack of knowledge of the aetiological agents and the disease process. In view of more recent research and clinical experience that strongly point to widespread inflammation and multisystemic neuropathology, it is more appropriate and correct to use the term 'myalgic encephalomyelitis' (ME) because it indicates an underlying pathophysiology. It is also consistent with the neurological classification of ME in the World Health Organization's International Classification of Diseases (ICD G93.3). Consequently, an International Consensus Panel consisting of clinicians, researchers, teaching faculty and an independent patient advocate was formed with the purpose of developing criteria based on current knowledge. Thirteen countries and a wide range of specialties were represented. Collectively, members have approximately 400 years of both clinical and teaching experience, authored hundreds of peer-reviewed publications, diagnosed or treated approximately 50 000 patients with ME, and several members coauthored previous criteria. The expertise and experience of the panel members as well as PubMed and other medical sources were utilized in a progression of suggestions/drafts/reviews/revisions. The authors, free of any sponsoring organization, achieved 100% consensus through a Delphi-type process. The scope of this paper is limited to criteria of ME and their application. Accordingly, the criteria reflect the complex symptomatology. Operational notes enhance clarity and specificity by providing guidance in the expression and interpretation of symptoms. Clinical and research application guidelines promote optimal recognition of ME by primary physicians and other healthcare providers, improve the consistency of diagnoses in adult and paediatric patients internationally and facilitate clearer identification of patients for research studies.

Physical activity intensity but not sedentary activity is reduced in chronic fatigue syndrome and is associated with autonomic regulation

BACKGROUND

Chronic fatigue syndrome (CFS) is a common debilitating condition associated with reduced function and impaired quality of life. The cause is unknown and treatments limited. Studies confirm that CFS is associated with impaired autonomic regulation and impaired muscle function.

AIM

Define the relationship between sedentary behaviour, physical activity and autonomic regulation in people with CFS.

DESIGN

Cohort study.

METHODS

Physical activity was assessed objectively in 107 CFS patients (Fukuda) and age, sex and body mass index (BMI)-matched sedentary controls (n= 107). Fatigue severity was determined using the Fatigue Impact Scale in all participants and heart rate variability performed in the CFS group.

RESULTS

The CFS group had levels and patterns of sedentary behaviour similar to non-fatigue controls (P > 0.05). Seventy-nine percent of the CFS group did not achieve the WHO recommended 10,000 steps per day. Active energy expenditure [time >3 METs (metabolic equivalents)] was reduced in CFS when compared with controls (P < 0.0001). Physical activity duration was inversely associated with resting heart rate (P = 0.04; r(2) = 0.03), with reduced activity significantly associating with reduced heart rate variability in CFS. There were no relationships between fatigue severity and any parameter of activity. Thirty-seven percent of the CFS group were overweight (BMI 25-29.9) and 20% obese (BMI ≥ 30).

CONCLUSION

Low levels of physical activity reported in CFS represent a significant and potentially modifiable perpetuating factor in CFS and are not attributable to high levels of sedentary activity, rather a decrease in physical activity intensity. The reduction in physical activity can in part be explained by autonomic dysfunction but not fatigue severity.

Neurochemical and neuropharmacological aspects of circadian disruptions: an introduction to asynchronization

Circadian disruptions are common in modern society, and there is an urgent need for effective treatment strategies. According to standard diagnostic criteria, most adolescents showing both insomnia and daytime sleepiness are diagnosed as having behavioral-induced sleep efficiency syndrome resulting from insomnia due to inadequate sleep hygiene. However, a simple intervention of adequate sleep hygiene often fails to treat them. As a solution to this clinical problem, the present review first overviews the basic neurochemical and neuropharmachological aspects of sleep and circadian rhythm regulation, then explains several circadian disruptions from similar viewpoints, and finally introduces the clinical notion of asynchronization. Asynchronization is designated to explain the pathophysiology/pathogenesis of exhibition of both insomnia and hypersomnia in adolescents, which comprises disturbances in various aspects of biological rhythms. The major triggers for asynchronization are considered to be a combination of light exposure during the night, which disturbs the biological clock and decreases melatonin secretion, as well as a lack of light exposure in the morning, which prohibits normal synchronization of the biological clock to the 24-hour cycle of the earth and decreases the activity of serotonin. In the chronic phase of asynchronization, involvement of both wake- and sleep-promoting systems is suggested. Both conventional and alternative therapeutic approaches for potential treatment of asynchronization are suggested.

Elevated nocturnal blood pressure and heart rate in adolescent chronic fatigue syndrome

AIM

To compare ambulatory recordings of heart rate (HR) and blood pressure in adolescents with chronic fatigue syndrome (CFS) and healthy controls. We hypothesized both HR and blood pressure to be elevated among CFS patients.

METHODS

Forty-four CFS patients aged 12-18 years were recruited from our paediatric outpatient clinic. The controls were 52 healthy adolescents having similar distribution of age and gender. 24-h ambulatory blood pressure and HR were recorded using a validated, portable oscillometric device.

RESULTS

At night (sleep), HR, mean arterial blood pressure and diastolic blood pressure were significantly higher in CFS patients as compared with controls (p < 0.01). During daytime, HR was significantly higher among CFS patients (p < 0.05), whereas blood pressures were equal among the two groups.

CONCLUSIONS

The findings support previous experimental evidence of sympathetic predominance of cardiovascular control in adolescent CFS patients. Also, the findings prompt increased focus on cardiovascular risk assessment and suggest a possible target for therapeutic intervention.

Home orthostatic training in chronic fatigue syndrome--a randomized, placebo-controlled feasibility study

BACKGROUND

Orthostatic (Tilt)-training is an effective treatment for neurally mediated hypotension (NMH). NMH is a frequent finding in chronic fatigue syndrome (CFS). We evaluated home orthostatic training (HOT) in CFS in a randomized placebo-controlled feasibility study.

METHODS

Thirty-eight patients with CFS (Fukuda Criteria) were randomly allocated to daily tilt training (n = 19) or sham training (n = 19) for 6 months. Haemodynamic responses to standing were performed in all subjects using continuous technology (Taskforce) at enrolment, week 1, 4 and 24. Symptom response and compliance were assessed using diaries.

RESULTS

Two patients (one from each arm) withdrew from the study. Fourteen patients in each group complied completely or partially, and patients found the training manageable and achievable. Compared to the sham group, blood pressure while standing dropped to 8.0 mmHg less in the HOT group at 4 weeks (95% CI: 1.0 to 15.0, P = 0.03). At 4 weeks, the HOT group had higher total peripheral resistance compared to the sham group; mean difference 70.2, 95% CI: -371.4 to 511.8. Changes were maintained at 6 months. There was no significant difference in fatigue between groups at 4 weeks (mean difference 1.4, 95% CI: -13.5 to 16.2), but there was a trend towards improvement in fatigue at 6 months. Compliers had lower fatigue compared to non-compliers.

CONCLUSIONS

A placebo-controlled study of HOT in CFS is feasible. HOT is well tolerated and generally complied with. A likely physiological rationale for HOT in CFS is related to reductions in orthostatic intolerance. An adequately powered study including strategies to enhance compliance is warranted.