Tag: POTS

Possible Role of Fibrinaloid Microclots in Postural Orthostatic Tachycardia Syndrome (POTS): Focus on Long COVID

Abstract:

Postural orthostatic tachycardia syndrome (POTS) is a common accompaniment of a variety of chronic, inflammatory diseases, including long COVID, as are small, insoluble, ‘fibrinaloid’ microclots.
We here develop the argument, with accompanying evidence, that fibrinaloid microclots, through their ability to block the flow of blood through microcapillaries and thus cause tissue hypoxia, are not simply correlated with but in fact, by preceding it, may be a chief intermediary cause of POTS, in which tachycardia is simply the body’s exaggerated ‘physiological’ response to hypoxia. Similar reasoning accounts for the symptoms bundled under the term ‘fatigue’.
Amyloids are known to be membrane disruptors, and when their targets are nerve membranes, this can explain neurotoxicity and hence the autonomic nervous system dysfunction that contributes to POTS. Taken together as a system view, we indicate that fibrinaloid microclots can serve to link POTS and fatigue in long COVID in a manner that is at once both mechanistic and explanatory. This has clear implications for the treatment of such diseases.
Source: Kell DB, Khan MA, Kane B, Lip GYH, Pretorius E. Possible Role of Fibrinaloid Microclots in Postural Orthostatic Tachycardia Syndrome (POTS): Focus on Long COVID. Journal of Personalized Medicine. 2024; 14(2):170. https://doi.org/10.3390/jpm14020170 https://www.mdpi.com/2075-4426/14/2/170 (Full text)

The Head-Up Tilt Table Test as a Measure of Autonomic Functioning among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) often experience autonomic symptoms. In the present study, we evaluated 193 adults seeking treatment for ME/CFS, who were recruited from an outpatient clinic. The participants completed a head-up tilt table test to assess two common types of orthostatic intolerance, namely, postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH).
During the tilt test, 32.5% of the participants demonstrated POTS or OH. The participants with either of these two common types of orthostatic intolerance were found to have more problems with sleep and post-exertional malaise as assessed by the DePaul Symptom Questionnaire; these patients also reported more physical and health function limitations. The implications of the findings are discussed.
Source: Jason LA, McGarrigle WJ, Vermeulen RCW. The Head-Up Tilt Table Test as a Measure of Autonomic Functioning among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Journal of Personalized Medicine. 2024; 14(3):238. https://doi.org/10.3390/jpm14030238 https://www.mdpi.com/2075-4426/14/3/238 (Full text)

Gut microbiota composition is altered in postural orthostatic tachycardia syndrome and post-acute COVID-19 syndrome

Abstract:

Postural Orthostatic Tachycardia Syndrome (POTS) reflects an autonomic dysfunction, which can occur as a complication to COVID-19. Our aim was to examine gastrointestinal symptoms and gut microbiota composition in patients with POTS and post-acute COVID-19 syndrome (PACS), compared with controls. POTS patients (n = 27), PACS patients (n = 32) and controls (n = 39) delivered fecal samples and completed a 4-day food diary, irritable bowel syndrome-severity scoring system (IBS-SSS), and visual analog scale for IBS (VAS-IBS).

A total of 98 DNA aliquots were sequenced to an average depth of 28.3 million (M) read pairs (Illumina 2 × 150 PE) per sample. Diversity and taxonomic levels of the microbiome, as well as functional abundances were calculated for POTS and PACS groups, then compared with controls. There were several differences in taxonomic composition between POTS and controls, whereas only the abundance of Ascomycota and Firmicutes differed between PACS and controls. The clinical variables total IBS-SSS, fatigue, and bloating and flatulence significantly correlated with multiple individual taxa abundances, alpha diversity, and functional abundances.

We conclude that POTS, and to a less extent PACS, are associated with differences in gut microbiota composition in diversity and at several taxonomic levels. Clinical symptoms are correlated with both alpha diversity and taxonomic and functional abundances.

Source: Hamrefors V, Kahn F, Holmqvist M, Carlson K, Varjus R, Gudjonsson A, Fedorowski A, Ohlsson B. Gut microbiota composition is altered in postural orthostatic tachycardia syndrome and post-acute COVID-19 syndrome. Sci Rep. 2024 Feb 9;14(1):3389. doi: 10.1038/s41598-024-53784-9. PMID: 38336892; PMCID: PMC10858216. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10858216/ (Full text)

Post-COVID Postural Orthostatic Tachycardia Syndrome and Inappropriate Sinus Tachycardia in the Pediatric Population

Abstract:

Purpose of Review: Long COVID, or post-COVID Condition, is increasingly recognized in children and adolescents, despite being less studied compared with the adult population. Recent studies are documenting that inappropriate sinus tachycardia (IST) or postural orthostatic tachycardia syndrome (POTS) may be key clinical problems in patients with long COVID, and preliminary findings have shown that these may be important features also in children. However, POTS and IST are poorly known among non-specialized pediatricians, and this gap may limit access to appropriate care for children and adolescents with long COVID or other post-viral fatigue syndromes. In this review, we critically evaluate the available literature investigating the burden of post-COVID-19 IST and POTS in children and young people, their pathogenesis, and available evidence for their management in the pediatric population.

Recent Findings: In line with adult studies, there is increasing evidence that also children with long COVID may suffer from IST and POTS. Case reports and case series, as well as pediatric experience from other conditions, suggest that IST and POTS can be treated also in the pediatric population

Summary: IST and POTS are under-recognized conditions in children. Clinical findings as well as diagnostics like 24-h ECG and heart rate variability are non-invasive tests to diagnose IST and POTS. If properly recognized, these conditions are treatable.

Source: Spera, F.R., Mistrulli, R., Salerno, L. et al. Post-COVID Postural Orthostatic Tachycardia Syndrome and Inappropriate Sinus Tachycardia in the Pediatric Population. Curr Clin Micro Rpt (2024). https://doi.org/10.1007/s40588-024-00217-w (Full text available as PDF file)

Mismatch between subjective and objective dysautonomia

Abstract:

Autonomic symptom questionnaires are frequently used to assess dysautonomia. It is unknown whether subjective dysautonomia obtained from autonomic questionnaires correlates with objective dysautonomia measured by quantitative autonomic testing. The objective of our study was to determine correlations between subjective and objective measures of dysautonomia.

This was a retrospective cross-sectional study conducted at Brigham and Women’s Faulkner Hospital Autonomic Laboratory between 2017 and 2023 evaluating the patients who completed autonomic testing. Analyses included validated autonomic questionnaires [Survey of Autonomic Symptoms (SAS), Composite Autonomic Symptom Score 31 (Compass-31)] and standardized autonomic tests (Valsalva maneuver, deep breathing, sudomotor, and tilt test). The autonomic testing results were graded by a Quantitative scale for grading of cardiovascular reflexes, sudomotor tests and skin biopsies (QASAT), and Composite Autonomic Severity Score (CASS). Autonomic testing, QASAT, CASS, and SAS were obtained in 2627 patients, and Compass-31 in 564 patients.

The correlation was strong between subjective instruments (SAS vs. Compass-31, r = 0.74, p < 0.001) and between objective instruments (QASAT vs. CASS, r = 0.81, p < 0.001). There were no correlations between SAS and QASAT nor between Compass-31 and CASS. There continued to be no correlations between subjective and objective instruments for selected diagnoses (post-acute sequelae of COVID-19, n = 61; postural tachycardia syndrome, 211; peripheral autonomic neuropathy, 463; myalgic encephalomyelitis/chronic fatigue syndrome, 95; preload failure, 120; post-treatment Lyme disease syndrome, 163; hypermobile Ehlers-Danlos syndrome, 213; neurogenic orthostatic hypotension, 86; diabetes type II, 71, mast cell activation syndrome, 172; hereditary alpha tryptasemia, 45).

The lack of correlation between subjective and objective instruments highlights the limitations of the commonly used questionnaires with some patients overestimating and some underestimating true autonomic deficit. The diagnosis-independent subjective–objective mismatch further signifies the unmet need for reliable screening surveys. Patients who overestimate the symptom burden may represent a population with idiosyncratic autonomic-like symptomatology, which needs further study. At this time, the use of autonomic questionnaires as a replacement of autonomic testing cannot be recommended.

Source: Novak, P., Systrom, D., Marciano, S.P. et al. Mismatch between subjective and objective dysautonomia. Sci Rep 14, 2513 (2024). https://doi.org/10.1038/s41598-024-52368-x https://www.nature.com/articles/s41598-024-52368-x (Full text)

Long COVID in pediatrics-epidemiology, diagnosis, and management

Abstract:

This review summarizes current knowledge on post-acute sequelae of COVID-19 (PASC) and post-COVID-19 condition (PCC) in children and adolescents. A literature review was performed to synthesize information from clinical studies, expert opinions, and guidelines. PASC also termed Long COVID — at any age comprise a plethora of unspecific symptoms present later than 4 weeks after confirmed or probable infection with severe respiratory syndrome corona virus type 2 (SARS-CoV-2), without another medical explanation. PCC in children and adolescents was defined by the WHO as PASC occurring within 3 months of acute coronavirus disease 2019 (COVID-19), lasting at least 2 months, and limiting daily activities.

Pediatric PASC mostly manifest after mild courses of COVID-19 and in the majority of cases remit after few months. However, symptoms can last for more than 1 year and may result in significant disability. Frequent symptoms include fatigue, exertion intolerance, and anxiety. Some patients present with postural tachycardia syndrome (PoTS), and a small number of cases fulfill the clinical criteria of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). To date, no diagnostic marker has been established, and differential diagnostics remains challenging. Therapeutic approaches include appropriate self-management as well as the palliation of symptoms by non-pharmaceutical and pharmaceutical strategies.

Conclusion: PASC in pediatrics present with heterogenous severity and duration. A stepped, interdisciplinary, and individualized approach is essential for appropriate clinical management. Current health care structures have to be adapted, and research was extended to meet the medical and psychosocial needs of young people with PASC or similar conditions.

Source: Toepfner N, Brinkmann F, Augustin S, Stojanov S, Behrends U. Long COVID in pediatrics-epidemiology, diagnosis, and management. Eur J Pediatr. 2024 Jan 27. doi: 10.1007/s00431-023-05360-y. Epub ahead of print. PMID: 38279014. https://link.springer.com/article/10.1007/s00431-023-05360-y (Full text available as PDF file)

Long post-COVID-19 postural tachycardia syndrome (PoTS): A novel case

Introduction

There are no established ESC/NICE guidelines for early risk preventive strategies for postural tachycardia syndrome following long COVID-19 infection.1 A lack of early multi-disciplinary input and risk preventive strategies for this population has led to significant cardiovascular implications such as postural tachycardia and syncope, contributing to long-term emotional distress in recent years.1,2

Case presentation

A previously fit 36-year-old woman was admitted to our tertiary centre with a 3-month history of palpitations, chest discomfort and dizziness that were prominent while standing and improved with recumbence. She also described her palpitations, which were sometimes associated with missed beats, and it took longer than expected (at least 10–15 minutes) to settle after postural changes. These symptoms had all significantly impacted on her daily physical activities and caused emotional distress. She gave a history of serious COVID-19 infection requiring hospital admission 4 months previously. She reported that she was treated as having COVID pneumonitis requiring antibiotics, oxygen and steroids but no intensive care admission. Since then, she had noticed frequent episodes of postural palpitations with chest tightness, which had led to her recent admission. On examination, she has normal cardiorespiratory findings and no features of systemic involvement. She has no other significant family and social history with regard to other cardiovascular risk factors.

Initially, she was enrolled into a postural assessment of resting heart rate and blood pressure when she had her symptoms of palpitations. Her resting heart rate was 100 bpm while standing. Interestingly, her resting heart rate returned to normal (54 bpm) after 10 minutes of supine position. Her blood pressure 100/60 while supine and 98/74 when standing, which had ruled out postural hypotension. Following this, an active stand test (tilt table test) was administered on subsequent day. Her electrocardiogram (Fig 1) revealed sinus tachycardia when she had episodes of palpitation but it returned to normal sinus rhythm with heart rate 60 bpm after 10 minutes of recumbent position from standing. All blood investigations, including full blood count, troponins, inflammatory markers and renal profile including electrolytes, revealed normal findings, which had ruled out other differentials.

Discussion

As a whole, these postural assessments (Tables 1 and 2) had met the criteria for definition of postural tachycardia syndrome2 (typical symptoms with significant heart rate increase of >30 beats per minute within 10 minutes of standing and without orthostatic hypotension). To support this, her echocardiogram showed no significant signs of structural heart disease and satisfactory blood investigations. Given her timing of her postural cardiovascular symptoms related to post-COVID-19 infection and criteria being met for postural assessment, she was finally diagnosed as having postural tachycardia syndrome as a cause for long-COVID-19 symptoms.3 Overall, she was advised to increase her fluid intake to 3 litres per day with increased salt intake, to use lower body compression garments and to take non-upright exercise.1 This was followed by early multidisciplinary team (MDT) input, including the recommendation of webinars on living with POTS and psychological counselling.2

Conclusion

It is well-recognised in recent literature that a diagnosis of PoTS post-COVID infection is easily overlooked as it does not associate with structural or arrhythmic heart disease and its specific aetiology is poorly defined apart from autonomic dysregulation.1,3 Therefore, more epidemiology study and detailed prospective research in long-COVID-19 patients are crucial for early recognition of this syndrome and long-term risk prevention.1,2

Source: Khin Kay Kay Kyaw. Long post-COVID-19 postural tachycardia syndrome (PoTS): A novel case. Clinical Medicine Nov 2023, 23 (Suppl 6) 48-49; DOI: 10.7861/clinmed.23-6-s48 https://www.rcpjournals.org/content/clinmedicine/23/Suppl_6/48 (Full text)

Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden

Abstract:

Cardiovascular autonomic dysfunction (CVAD) is a malfunction of the cardiovascular system caused by deranged autonomic control of circulatory homeostasis. CVAD is an important component of post-COVID-19 syndrome, also termed long COVID, and might affect one-third of highly symptomatic patients with COVID-19. The effects of CVAD can be seen at both the whole-body level, with impairment of heart rate and blood pressure control, and in specific body regions, typically manifesting as microvascular dysfunction.

Many severely affected patients with long COVID meet the diagnostic criteria for two common presentations of CVAD: postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. CVAD can also manifest as disorders associated with hypotension, such as orthostatic or postprandial hypotension, and recurrent reflex syncope. Advances in research, accelerated by the COVID-19 pandemic, have identified new potential pathophysiological mechanisms, diagnostic methods and therapeutic targets in CVAD. For clinicians who daily see patients with CVAD, knowledge of its symptomatology, detection and appropriate management is more important than ever.

In this Review, we define CVAD and its major forms that are encountered in post-COVID-19 syndrome, describe possible CVAD aetiologies, and discuss how CVAD, as a component of post-COVID-19 syndrome, can be diagnosed and managed. Moreover, we outline directions for future research to discover more efficient ways to cope with this prevalent and long-lasting condition.

Key points:

  • Cardiovascular autonomic dysfunction (CVAD), in particular postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia, are among the most frequent and distinct phenotypes of post-COVID-19 syndrome; one-third of highly symptomatic patients can be affected.
  • CVAD arises from a malfunction of the autonomic control of the circulation, and can involve failure or inadequate or excessive activation of the sympathetic and parasympathetic components of the autonomic nervous system.
  • As well as global circulatory disturbances, CVAD in post-COVID-19 syndrome can manifest as microvascular and endothelial dysfunction, with local symptoms such as headache, brain fog, chest pain, dyspnoea and peripheral circulatory symptoms, including skin discolouration, oedema, Raynaud-like phenomena, and heat and cold intolerance.
  • A structured diagnostic work-up based on a detailed patient history, cardiovascular autonomic testing, long-term electrocardiogram and blood-pressure monitoring, and ancillary cardiac and peripheral vascular tests will lead to an appropriate diagnosis.
  • Management of CVAD in post-COVID-19 syndrome should involve a correct diagnosis, patient education, and both non-pharmacological and pharmacological methods; a tailored exercise training programme, blood volume expansion and compression garments are especially effective.
  • Pharmacological approaches target heart rate control, blood volume expansion, promotion of vasoconstriction and venoconstriction, and reduction of hyperadrenergic drive.

Source: Fedorowski, A., Fanciulli, A., Raj, S.R. et al. Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden. Nat Rev Cardiol (2024). https://doi.org/10.1038/s41569-023-00962-3 https://www.nature.com/articles/s41569-023-00962-3

Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective cohort study

Abstract:

Background: Accumulating evidence suggests that autonomic dysfunction and persistent systemic inflammation are common clinical features in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID. However, there is limited knowledge regarding their potential association with circulating biomarkers and illness severity status.

Methods: This prospective, cross-sectional, case-control cohort study aimed to distinguish between the two patient populations by using self-reported outcome measures and circulating biomarkers to assess endothelial function and systemic inflammation. Thirty-one individuals with ME/CFS, 23 individuals with long COVID, and 31 matched healthy subjects were included. Regression analysis was used to examine associations between self-reported outcome measures and circulating biomarkers in study participants. Classification across groups was based on principal component and discriminant analyses.

Results: Four ME/CFS patients (13%), 1 with long COVID (4%), and 1 healthy control (3%) presented postural orthostatic tachycardia syndrome (POTS) with the 10-min NASA lean test. Compared with healthy controls, ME/CFS and long COVID subjects showed higher levels of ET-1 (p < 0.05) and VCAM-1 (p < 0.001), and lower levels of nitrites (NOx assessed as NO2– + NO3–) (p < 0.01). ME/CFS patients also showed higher levels of serpin E1 (PAI-1) and E-selectin than did both long COVID and control subjects (p < 0.01 in all cases). Long COVID patients had lower TSP-1 levels than did ME/CFS patients and healthy controls (p < 0.001). As for inflammation biomarkers, both long COVID and ME/CFS subjects had higher levels of TNF-α than did healthy controls (p < 0.01 in both comparisons). Compared with controls, ME/CFS patients had higher levels of IL-1β (p < 0.001), IL-4 (p < 0.001), IL-6 (p < 0.01), IL-10 (p < 0.001), IP-10 (p < 0.05), and leptin (p < 0.001). Principal component analysis supported differentiation between groups based on self-reported outcome measures and endothelial and inflammatory biomarkers.

Conclusions: Our findings revealed that combining biomarkers of endothelial dysfunction and inflammation with outcome measures differentiate ME/CFS and Long COVID using robust discriminant analysis of principal components. Further research is needed to provide a more comprehensive characterization of these underlying pathomechanisms, which could be promising targets for therapeutic and preventive strategies in these conditions.

Source: Joan Carles Domingo, Federica Battistini, Begoña Cordobilla et al. Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective cohort study, 16 December 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3736031/v1] https://www.researchsquare.com/article/rs-3736031/v1 (Full text)

Dysregulations in hemostasis, metabolism, immune response, and angiogenesis in post-acute COVID-19 syndrome with and without postural orthostatic tachycardia syndrome: a multi-omic profiling study

Abstract:

Post-acute COVID-19 (PACS) are associated with cardiovascular dysfunction, especially postural orthostatic tachycardia syndrome (POTS). Patients with PACS, both in the absence or presence of POTS, exhibit a wide range of persisting symptoms long after the acute infection. Some of these symptoms may stem from alterations in cardiovascular homeostasis, but the exact mechanisms are poorly understood.

The aim of this study was to provide a broad molecular characterization of patients with PACS with (PACS + POTS) and without (PACS-POTS) POTS compared to healthy subjects, including a broad proteomic characterization with a focus on plasma cardiometabolic proteins, quantification of cytokines/chemokines and determination of plasma sphingolipid levels.

Twenty-one healthy subjects without a prior COVID-19 infection (mean age 43 years, 95% females), 20 non-hospitalized patients with PACS + POTS (mean age 39 years, 95% females) and 22 non-hospitalized patients with PACS-POTS (mean age 44 years, 100% females) were studied. PACS patients were non-hospitalized and recruited ≈18 months after the acute infection.

Cardiometabolic proteomic analyses revealed a dysregulation of ≈200 out of 700 analyzed proteins in both PACS groups vs. healthy subjects with the majority (> 90%) being upregulated. There was a large overlap (> 90%) with no major differences between the PACS groups. Gene ontology enrichment analysis revealed alterations in hemostasis/coagulation, metabolism, immune responses, and angiogenesis in PACS vs. healthy controls.

Furthermore, 11 out of 33 cytokines/chemokines were significantly upregulated both in PACS + POTS and PACS-POTS vs. healthy controls and none of the cytokines were downregulated. There were no differences in between the PACS groups in the cytokine levels. Lastly, 16 and 19 out of 88 sphingolipids were significantly dysregulated in PACS + POTS and PACS-POTS, respectively, compared to controls with no differences between the groups.

Collectively, these observations suggest a clear and distinct dysregulation in the proteome, cytokines/chemokines, and sphingolipid levels in PACS patients compared to healthy subjects without any clear signature associated with POTS. This enhances our understanding and might pave the way for future experimental and clinical investigations to elucidate and/or target resolution of inflammation and micro-clots and restore the hemostasis and immunity in PACS.

Source: Mahdi, A., Zhao, A., Fredengren, E. et al. Dysregulations in hemostasis, metabolism, immune response, and angiogenesis in post-acute COVID-19 syndrome with and without postural orthostatic tachycardia syndrome: a multi-omic profiling study. Sci Rep 13, 20230 (2023). https://doi.org/10.1038/s41598-023-47539-1 https://www.nature.com/articles/s41598-023-47539-1 (Full study)