Tag: orthostatic intolerance

ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing

Abstract

Introduction: Mechanisms underlying exercise and orthostatic intolerance in myalgic encephalomyelitis/chronic
fatigue syndrome (ME/CFS) have been uncovered by invasive cardiopulmonary exercise testing (iCPET) and
autonomic function testing (AFT), but the relationships between the two are not known. This study aims to determine
if there is overlap of cardiovascular and respiratory pathophysiology in patients who have undergone both
tests.

Methods: Between January 2017 and April 2022, 62 patients were identified with a contemporary iCPET and
AFT. Key variables from the iCPET included peak oxygen uptake (pVO2), cardiac output (pQc), right atrial pressure
(pRAP), and systemic oxygen extraction (Ca-vOy/Hgb) at peak exercise. Key variables from the autonomic testing
included epidermal and sweat gland small fiber neurite density, electrochemical skin conductance, and change in
heart rate (AH) and end tidal carbon dioxide (AETCO2) from supine to upright during the tilt table test
(TTT).

Results: All 62 patients demonstrated preload failure (pRAP < 6.5mmHg). Of this group, 54 patients (87.1%) fulfilled NAM criteria for ME/CFS, with 32 testing positive (59.3%) for small fiber neuropathy (SFN) using either morphological and/or functional testing. Significant correlations were found between pVOg and both AH (r=-0.439. P<0.05) and AETCO, (r=0.474, P<0.05) during TTT. The same tilt table variables were found to be significantly correlated with pQc (r=-0.365, P<0.05 and r=0.351, P<0.05) from the iCPET. It should be noted that 8 of the ME/CFS SFN patients (25%) fulfilled diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) based on the tilt table test.

Conclusion: Decreased oxygen uptake and cardiac output at peak exercise during iCPET correlated with a greater change in heart rate and ETCO from supine to upright during TTT. There appears to be significant overlap of cardiopulmonary pathophysiology in ME/CFS underlying exercise and orthostatic symptoms.

Source: J. Squires, K. Wichmann Madsen, M.C. Stovall, S. Al-Zayer, W. Xiao, C.-J. Chang, P. Novak, D.M. Systrom. ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing. American Journal of Respiratory and Critical Care Medicine 2023;207:A2996. https://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2996

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

Highlights:

  • Adults with ME/CFS experience a 3-fold greater reduction in cerebral blood flow during end-tilt tilt compared to healthy controls, confirming orthostatic intolerance.
  • During tilt testing we found that in 134/362 (37%) patients with ME/CFS without POTS or hypotension, the heart rate increase was below the lower limit of the 95% prediction interval of the heart rate increase of controls, indicative of orthostatic chronotropic incompetence.
  • These novel findings represent the first description of orthostatic chronotropic incompetence during tilt testing, confirming another abnormality in the circulatory response to upright posture in ME/CFS.

Abstract:

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.

Source: C. (Linda) M.C. van Campen, Freek W.A. Verheugt, Peter C. Rowe, Frans C. Visser. Orthostatic chronotropic incompetence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). IBRO Neuroscience Reports [In Press, Journal Pre-proof]  Available online 2 May 2023 https://www.sciencedirect.com/science/article/pii/S2667242123000374 (Full text)

Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a multisystem chronic illness characterized by severe muscle fatigue, pain, dizziness, and brain fog. Many patients with ME/CFS experience orthostatic intolerance (OI), which is characterized by frequent dizziness, light-headedness, and feeling faint while maintaining an upright posture.
Despite intense investigation, the molecular mechanism of this debilitating condition is still unknown. OI is often manifested by cardiovascular alterations, such as reduced cerebral blood flow, reduced blood pressure, and diminished heart rate. The bioavailability of tetrahydrobiopterin (BH4), an essential cofactor of endothelial nitric oxide synthase (eNOS) enzyme, is tightly coupled with cardiovascular health and circulation.
To explore the role of BH4 in ME/CFS, serum samples of CFS patients (n = 32), CFS patients with OI only (n = 10; CFS + OI), and CFS patients with both OI and small fiber polyneuropathy (n = 12; CFS + OI + SFN) were subjected to BH4 ELISA. Interestingly, our results revealed that the BH4 expression is significantly high in CFS, CFS + OI, and CFS + OI + SFN patients compared to age-/gender-matched controls.
Finally, a ROS production assay in cultured microglial cells followed by Pearson correlation statistics indicated that the elevated BH4 in serum samples of CFS + OI patients might be associated with the oxidative stress response. These findings suggest that the regulation of BH4 metabolism could be a promising target for understanding the molecular mechanism of CFS and CFS with OI.
Source: Gottschalk CG, Whelan R, Peterson D, Roy A. Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study. International Journal of Molecular Sciences. 2023; 24(10):8713. https://doi.org/10.3390/ijms24108713 (Full text)

Exaggerated blood pressure elevation in response to orthostatic challenge, a post-acute sequelae of SARS-CoV-2 infection (PASC) after hospitalization

Abstract:

Objective: Post-acute sequelae of SARS-COV-2 (PASC) are emerging as a major health challenge. Orthostatic intolerance secondary to autonomic failure has been found in PASC patients. This study investigated the effect of COVID-19 after recovery on blood pressure (BP) during the orthostatic challenge.

Research design and methods: Thirty-one out of 45 patients hospitalized due to COVID-19-related pneumonia that developed PASC and did not have hypertension at discharge were studied. They underwent a head-up tilt test (HUTT) at 10.8 ± 1.9 months from discharge. All met the PASC clinical criteria, and an alternative diagnosis did not explain the symptoms. This population was compared with 32 historical asymptomatic healthy controls.

Results: Exaggerated orthostatic blood pressure response (EOPR)/orthostatic hypertension (OHT) was detected in 8 out of 23 (34.7 %) patients, representing a significantly increased prevalence (7.67-fold increase p = 0.009) compared to 2 out of 32 (6.4 %) asymptomatic healthy controls matched by age, who underwent HUTT and were not infected with SARS-CoV-2.

Conclusions: This prospective evaluation in patients with PASC revealed abnormal blood pressure rise during the orthostatic challenge, suggesting of autonomic dysfunction in a third of the studied subjects. Our findings support the hypothesis that EOPR/OHT may be a phenotype of neurogenic hypertension. Hypertension in PASC patients may adversely affect the cardiovascular burden in the world.

Source: González-Hermosillo G JA, Galarza EJ, Fermín OV, González JMN, Tostado LMFÁ, Lozano MAE, Rabasa CR, Martínez Alvarado MDR. Exaggerated blood pressure elevation in response to orthostatic challenge, a post-acute sequelae of SARS-CoV-2 infection (PASC) after hospitalization. Auton Neurosci. 2023 Apr 21;247:103094. doi: 10.1016/j.autneu.2023.103094. Epub ahead of print. PMID: 37137186; PMCID: PMC10121145. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10121145/ (Full text)

Autoimmunity in Long Covid and POTS

Abstract:

Orthostatic intolerance and other autonomic dysfunction syndromes are emerging as distinct symptom clusters in Long Covid. Often accompanying these are common, multi-system constitutional features such as fatigue, malaise and skin rashes which can signify generalised immune dysregulation. At the same time, multiple autoantibodies are identified in both Covid-related autonomic disorders and non-Covid autonomic disorders, implying a possible underlying autoimmune pathology. The lack of specificity of these findings precludes direct interpretations of cause and association, but prevalence with its supporting evidence is compelling.

In this review, we discuss the role of the autonomic nervous and immune systems in Covid and Long Covid and their potential influence on symptoms and clinical practice. Additionally, overlap with non-Covid autonomic dysfunction is considered. Understanding these new disorders can inform both neuro-immunology and Long Covid management.

Source: Fatema-Zahra El-Rhermoul, Artur Fedorowski, Philip Eardley, Patricia Taraborrelli, Dimitrios Panagopoulos, Richard Sutton, Phang Boon Lim, Melanie Dani, Autoimmunity in Long Covid and POTS, Oxford Open Immunology, 2023;, iqad002, https://doi.org/10.1093/oxfimm/iqad002 (Full text available as PDF file)

Post-acute sequelae of SARS-CoV-2 (PASC) syndrome presenting as postural orthostatic tachycardia syndrome (POTS)

Abstract:

The novel SARS-CoV-2 emerged in 2019, and the global COVID-19 pandemic continues into 2022. It has been known that a subset of patients develops chronic, debilitating symptoms after otherwise complete recovery from acute infection of COVID-19.

Multiple terms have been used to describe this constellation of symptoms, including long COVID, long-haul COVID, and post-acute sequelae of SARS-CoV-2 syndrome (PASC). PASC is broadly defined as a wide range of new, returning, or ongoing symptoms at least four weeks after infection. Those patients are often seen in emergency departments after acute COVID- 19 infection, but their symptoms are not adequately managed because the underlying pathophysiology of PASC is not well understood.

Among patients with PASC, postural orthostatic tachycardic syndrome (POTS) has been increasingly recognized. POTS is one of the most common forms of autonomic dysfunction and defined by a sustained orthostatic tachycardia during active standing or head-up tilt test in the absence of orthostatic hypotension or other cardiopulmonary diseases. Because POTS is a treatable condition, it is important to recognize POTS among PASC patients. Herein, we reviewed the current literature on POTS and dysautonomia in PASC in order to better understand the overlap and distinction between these pathologies.

Source: Diekman S, Chung T. Post-acute sequelae of SARS-CoV-2 (PASC) syndrome presenting as postural orthostatic tachycardia syndrome (POTS). Clin Exp Emerg Med. 2023 Jan 30. doi: 10.15441/ceem.22.409. Epub ahead of print. PMID: 36718484. https://pubmed.ncbi.nlm.nih.gov/36718484/ (Full text available as PDF file)

Orthostatic Intolerance and Chronotropic Incompetence in Patients With Myalgic Encephalomyelitis or Chronic Fatigue Syndrome

Abstract:

Background: Orthostatic intolerance markedly affects the day-to-day activities of patients with myalgic encephalomyelitis (ME) or chronic fatigue syndrome. Chronotropic incompetence (CI), defined as an impaired chronotropic response or reduced increases in heart rate during exercise and resulting in lower exercise capacity, may also be observed during orthostasis in patients with ME.

Methods and Results: In this study, the recordings of 101 adult patients with ME (36 men, 65 women; mean [±SD] age 37±12 years) who underwent conventional active 10-min standing tests at least 3 times to determine the presence of CI were analyzed. Recordings were selected for 13 patients who experienced tests both with and without exhibiting postural orthostatic tachycardia syndrome (POTS; an increase in heart rate of ≥30 beats/min or an actual heart rate of ≥120 beats/min) while also both successfully completing and failing to complete 10-min standing on different occasions. Subjects in whom failure without POTS was observed in any test(s) while success was associated with POTS on other occasions were considered positive for CI during orthostasis. Of the 13 patients, 12 (92%) were CI positive, 5 (38%) of whom exclusively failed the tests without experiencing POTS.

Conclusions: Some patients with ME were CI positive during standing tests, suggesting impaired sympathetic activation. The presence of POTS appears to be essential for maintaining orthostasis in these patients.

Source: Kunihisa Miwa. Orthostatic Intolerance and Chronotropic Incompetence in Patients With Myalgic Encephalomyelitis or Chronic Fatigue Syndrome. Circulation Reports, Article ID CR-22-0114. https://www.jstage.jst.go.jp/article/circrep/advpub/0/advpub_CR-22-0114/_html/-char/en (Full text)

Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect?

Abstract:

Following COVID-19 infection, a substantial proportion of patients suffer from persistent symptoms known as Long COVID. Among the main symptoms are fatigue, cognitive dysfunction, muscle weakness and orthostatic intolerance (OI). These symptoms also occur in myalgic encephalomyelitis/chronic fatigue (ME/CFS).
OI is highly prevalent in ME/CFS and develops early during or after acute COVID-19 infection. The causes for OI are unknown and autonomic dysfunction is hypothetically assumed to be the primary cause, presumably as a consequence of neuroinflammation. Here, we propose an alternative, primary vascular mechanism as the underlying cause of OI in Long COVID.
We assume that the capacitance vessel system, which plays a key role in physiologic orthostatic regulation, becomes dysfunctional due to a disturbance of the microvessels and the vasa vasorum, which supply large parts of the wall of those large vessels. We assume that the known microcirculatory disturbance found after COVID-19 infection, resulting from endothelial dysfunction, microthrombus formation and rheological disturbances of blood cells (altered deformability ), also affects the vasa vasorum to impair the function of the capacitance vessels.
In an attempt to compensate for the vascular deficit, sympathetic activity overshoots to further worsen OI, resulting in a vicious circle that maintains OI. The resulting orthostatic stress, in turn, plays a key role in autonomic dysfunction and the pathophysiology of ME/CFS.
Source: Wirth KJ, Löhn M. Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect? Medicina. 2022; 58(12):1807. https://doi.org/10.3390/medicina58121807 https://www.mdpi.com/1648-9144/58/12/1807 (Full text)

Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Abstract:

Background: As complaints of long-haul COVID patients are similar to those of ME/CFS patients and as orthostatic intolerance (OI) plays an important role in the COVID infection symptomatology, we compared 14 long-haul COVID patients with 14 ME/CFS patients with a post-viral Ebstein-Barr (EBV) onset and 14 ME/CFS patients with an insidious onset of the disease.
Methods: In all patients, OI analysis by history taking and OI assessed during a tilt test, as well as cerebral blood flow measurements by extracranial Doppler, and cardiac index measurements by suprasternal Doppler during the tilt test were obtained in all patients.
Results: Except for disease duration no differences were found in clinical characteristics. The prevalence of POTS was higher in the long-haul patients (100%) than in post-EBV (43%) and in insidious-onset (50%) patients (p = 0.0002). No differences between the three groups were present in the prevalence of OI, heart rate and blood pressure changes, changes in cerebral blood flow or in cardiac index during the tilt test.
Conclusion: OI symptomatology and objective abnormalities of OI (abnormal cerebral blood flow and cardiac index reduction during tilt testing) are comparable to those in ME/CFS patients. It indicates that long-haul COVID is essentially the same disease as ME/CFS.
Source: van Campen CMC, Visser FC. Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Healthcare. 2022; 10(10):2058. https://doi.org/10.3390/healthcare10102058 (Full text)

Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

Objectives: The Institute of Medicine (IOM 2015. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington: The National Academies Press) suggested new criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), which requires an endorsement of either neurocognitive impairment or orthostatic intolerance (OI) in addition to other core symptoms. While some research supports the inclusion of OI as a core symptom, others argue that overlap with neurocognitive impairment does not justify the either/or option. The current study assessed methods of operationalizing OI using items from the DePaul Symptom Questionnaire (DSQ-1 and -2) as a part of the IOM criteria. Evaluating the relationship between OI and neurocognitive symptoms may lead to a better understanding of diagnostic criteria for ME/CFS.

Methods: Two-hundred and forty-two participants completed the DSQ. We examined how many participants met the IOM criteria while endorsing different frequencies and severities of various OI symptoms.

Results: Neurocognitive impairment was reported by 93.4% of respondents. OI without concurrent neurocognitive symptoms only allowed for an additional 1.7–4.5% of participants to meet IOM criteria.

Conclusions: Neurocognitive symptoms and OI overlap in ME/CFS, and our results do not support the IOM’s inclusion of neurocognitive impairment and OI as interchangeable symptoms. Furthermore, our findings highlight the need for a uniform method of defining and measuring OI via self-report in order to accurately study OI as a symptom of ME/CFS.

Source: Gaglio, Caroline L., Islam, Mohammed F., Cotler, Joseph and Jason, Leonard A.. “Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)” Epidemiologic Methods, vol. 11, no. 1, 2022, pp. 20210033. https://doi.org/10.1515/em-2021-0033