Postural orthostatic tachycardia syndrome (POTS): State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting - Part 1

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

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.

Autonomic Dysfunction from Diagnosis to Treatment

Autonomic disorders can present with hypotension, gastrointestinal, genitourinary symptoms, and heat intolerance. Diabetes is the most common causes of autonomic failure, and management should focus on glucose control to prevent developing autonomic symptoms. The most prevalent cause of dysautonomia, or autonomic dysfunction, is Postural Orthostatic Tachycardia Syndrome (POTS). Autonomic testing characterizes causes for nonspecific symptoms but is not necessary in patients with classic presentations. Treatment for autonomic dysfunction and failure focus on discontinuing offending medications, behavioral modification, and pharmacologic therapy to decrease symptom severity. Autonomic failure has no cure; therefore, the focus remains on improving quality of life.

Tilt Table Testing

This Diagnostic Test Interpretation uses a patient case to illustrate tilt table testing, useful for evaluating patients with syncope of unknown cause or postural orthostatic tachycardia syndrome (POTS).

Complete remission with histamine blocker in a patient with intractable hyperadrenergic postural orthostatic tachycardia syndrome secondary to long coronavirus disease syndrome

The COVID-19 pandemic caused by the novel severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), has emerged as a global public health concern and its sequels have barely started to outcrop. A good percentage of patients who suffered from COVID-19 are prone to develop long-COVID or post-COVID condition (PCC), a multisystemic, heterogeneous, chronic disorder. Patients with PCC may experience diverse manifestations, of which cardiovascular and neurological symptoms are among the most frequently reported. Indeed, dysautonomia presented as orthostatic intolerance has gained room following recent reports linking postural orthostatic tachycardia syndrome (POTS) with PCC. Disturbances in heart rate (HR) and blood pressure (BP) during postural changes are the cornerstones of orthostatic intolerance seen in patients suffering from PCC. A subtype of POTS, hyperadrenergic POTS, has been widely studied because of its association with mast cell activation syndrome (MCAS). Although a causative relationship between PCC, hyperadrenergic POTS, and MCAS remains unrevealed, these syndromes can overlap. We want to propose here a correlation produced by a close-loop mechanism with positive feedback established after SARS-CoV-2 infection in a previously healthy young patient.

Exploring the complexities of illness identity and symptom management in seeking a diagnostic label of postural orthostatic tachycardia syndrome (POTS): An inductive approach

OBJECTIVES

Postural orthostatic tachycardia syndrome (POTS) is a debilitating and under-recognized condition of the autonomic nervous system. This study applied Leventhal's Common-Sense Model of Illness Representations to explore the journey to a diagnosis of POTS and to understand its relevance to poorly understood conditions which have common comorbidities.

DESIGN

An inductive qualitative approach was used to explore the processes by which patients formulate explanations and management of symptoms within the search for a diagnostic label and to investigate illness identity in the context of existing diagnoses or multimorbidity.

METHODS

Participants (n = 29) for this nested qualitative study were recruited from a larger longitudinal study of people who had been newly referred to a specialist POTS service. Semi-structured interviews were conducted via video call. Three researchers coded and analysed data using Reflexive Thematic Analysis and elements of Grounded Theory.

RESULTS

The analysis resulted in three overarching themes: 'Seeking physiological coherence and validation', 'Individual persistence', and 'Navigating the cumulative burden'. 'Accessibility and disparities of health care' was noted as a contextual factor. Receiving a POTS diagnosis was regarded by participants as providing legitimacy and increased access to treatment. Overall, delays in the diagnostic journey and the lack of a clear diagnosis impacted negatively on patients through increased uncertainty and a lack of clear guidance on how to manage symptoms. Findings also suggested there were great complexities in assigning symptoms to labels in the context of multimorbidity.

CONCLUSIONS

Participants' stories highlighted the urgent need for better recognition of POTS so that the self-regulatory process can be initiated from the early stages of symptom detection.

Autoimmunity in Syndromes of Orthostatic Intolerance: An Updated Review

Orthostatic intolerance is a broad term that represents a spectrum of dysautonomic disorders, including postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH), as manifestations of severe autonomic failure. While the etiology of orthostatic intolerance has not yet fully been uncovered, it has been associated with multiple underlying pathological processes, including peripheral neuropathy, altered renin-aldosterone levels, hypovolemia, and autoimmune processes. Studies have implicated adrenergic, cholinergic, and angiotensin II type I autoantibodies in the pathogenesis of orthostatic intolerance. Several case series have demonstrated that immunomodulation therapy resulted in favorable outcomes, improving autonomic symptoms in POTS and OH. In this review, we highlight the contemporary literature detailing the association of autoimmunity with POTS and OH.

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

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 in these conditions.

METHODS

This single-site, prospective, cross-sectional, pilot cohort study aimed to distinguish between the two patient populations by using self-reported outcome measures and circulating biomarkers of endothelial function and systemic inflammation status. Thirty-one individuals with ME/CFS, 23 individuals with long COVID, and 31 matched sedentary healthy controls were included. All study participants underwent non-invasive cardiovascular hemodynamic challenge testing (10 min NASA lean test) for assessment of orthostatic intolerance. Regression analysis was used to examine associations between outcome measures and circulating biomarkers in the 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) using the 10-min NASA lean test. Compared with matched 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 matched control subjects (p < 0.01 in all cases). Long COVID patients had lower TSP-1 levels than did ME/CFS patients and matched sedentary healthy controls (p < 0.001). As for inflammation biomarkers, both long COVID and ME/CFS subjects had higher levels of TNF-α than did matched 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 biomarkers of endothelial function and inflammatory status in the study population.

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.

Exploring quality of life in postural orthostatic tachycardia syndrome: A conceptual analysis

Postural Orthostatic Tachycardia Syndrome (POTS) is a complex autonomic disorder characterized by an abnormal increase in heart rate upon orthostatic change. While primarily described in its effect on the autonomic and cardiovascular system, it can cause significant functional impairment, leading to a diminished quality of life (QoL). This review paper aims to delve into the multifaceted dimensions of QoL in individuals with POTS by providing a conceptual model to discuss factors influencing QoL. Current QoL assessments used in the POTS population and their findings are described for each domain in this conceptual model. Limitations to this body of research include the literature having no consensus in the most appropriate measure of QoL to use for individuals with POTS, the absence of a POTS-specific measure of QoL, and current measures not assessing concerns germane to this population. The authors emphasize the necessity of a POTS-specific measure to be developed to improve our assessment and understanding of how living with POTS impacts QoL.

The use and effectiveness of exercise for managing postural orthostatic tachycardia syndrome in young adults with joint hypermobility and related conditions: A scoping review

PURPOSE

Postural Orthostatic Tachycardia Syndrome (POTS) is a form of dysautonomia. It may occur in isolation, but frequently co-exists in individuals with hypermobile variants of Ehlers-Danlos Syndrome (EDS) and related conditions (chronic fatigue syndrome [CFS] and fibromyalgia). Exercise is recommended for non-pharmacological POTS management but needs to be individualised. This scoping review explores the current literature on use and effectiveness of exercise-based management for POTS, with specific focus on individuals with joint hypermobility and related conditions who experience hypermobility, and/or pain, and/or fatigue.

METHODS

A systematic search, to January 2023, of Medline, EMBASE, AMED, CINAHL and the Cochrane library was conducted. Studies that reported on adolescents and adults who had been diagnosed with POTS using standard criteria and underwent an exercise-based training intervention were included.

RESULTS

Following full-text screening, 10 articles were identified (2 randomised control trials, 4 comparative studies and 4 case reports). One comparative study reported a small subset of participants with EDS and one case report included an individual diagnosed with CFS; the remainder investigated a wider POTS population. Overall, 3 months of endurance followed by resistance exercise, graduating from the horizontal-to-upright position reduced POTS symptoms and improved quality-of-life.

CONCLUSION

The findings highlight a paucity of higher-level studies documenting exercise for POTS management in people with joint hypermobility and related conditions. Results from the wider POTS population demonstrate exercise is safe and effective. Large, well-designed clinical studies exploring exercise for POTS management adapting to meet the complex musculoskeletal and non-musculoskeletal features of symptomatic joint hypermobility are needed.

Head-down tilt reduces the heart rate in postural tachycardia syndrome in acute setting: a pilot study

BACKGROUND

Reduced preload and thoracic blood volume accompany postural tachycardia syndrome (POTS). Head-down tilt (HDT) increases both preload and intrathoracic blood volume. The objective of this study was to assess the safety and efficacy of HDT in POTS in acute settings.

METHODS

This retrospective study evaluated POTS patients. Analyzed data included heart rate, blood pressure, cerebral blood flow velocity (CBFv) in the middle cerebral artery, and capnography. The baseline supine hemodynamic data were compared with the data obtained at the second minute of the -10° HDT. A linear mixed-effects model was used to assess the effect of HDT on hemodynamic variables.

RESULTS

The HDT was explored in seven POTS patients and an additional seven POTS patients without HDT served as controls. In the HDT arm, four POTS patients had overlapping diagnoses of myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) and one patient had comorbidity of post-acute sequelae of SARS-CoV-2 infection (PASC). HDT lowered heart rate by 10% and increased end-tidal CO2 by 8%. There was no change in other cardiovascular variables.

CONCLUSIONS

In the acute setting, HDT is safe. HDT reduces the heart rate presumably by modulating baroreflex by enhancing preload and stroke volume, which in turn increases thoracic blood volume with a net effect of parasympathetic cardiovagal activation and/or sympathetic withdrawal. This pilot study provides a foundation to proceed with longitudinal studies exploring the long-term effect of repetitive HDT in conditions associated with preload failure such as POTS, ME/CSF, and PASC.

Functional Limitations and Exercise Intolerance in Patients With Post-COVID Condition: A Randomized Crossover Clinical Trial

Importance

Many patients with post-COVID condition (PCC) experience persistent fatigue, muscle pain, and cognitive problems that worsen after exertion (referred to as postexertional malaise). Recommendations currently advise against exercise in this population to prevent symptom worsening; however, prolonged inactivity is associated with risk of long-term health deterioration.

Objective

To assess postexertional symptoms in patients with PCC after exercise compared with control participants and to comprehensively investigate the physiologic mechanisms underlying PCC.

Design, Setting, and Participants

In this randomized crossover clinical trial, nonhospitalized patients without concomitant diseases and with persistent (≥3 months) symptoms, including postexertional malaise, after SARS-CoV-2 infection were recruited in Sweden from September 2022 to July 2023. Age- and sex-matched control participants were also recruited.

Interventions

After comprehensive physiologic characterization, participants completed 3 exercise trials (high-intensity interval training [HIIT], moderate-intensity continuous training [MICT], and strength training [ST]) in a randomized order. Symptoms were reported at baseline, immediately after exercise, and 48 hours after exercise.

Main Outcomes and Measures

The primary outcome was between-group differences in changes in fatigue symptoms from baseline to 48 hours after exercise, assessed via the visual analog scale (VAS). Questionnaires, cardiopulmonary exercise testing, inflammatory markers, and physiologic characterization provided information on the physiologic function of patients with PCC.

Results

Thirty-one patients with PCC (mean [SD] age, 46.6 [10.0] years; 24 [77%] women) and 31 healthy control participants (mean [SD] age, 47.3 [8.9] years; 23 [74%] women) were included. Patients with PCC reported more symptoms than controls at all time points. However, there was no difference between the groups in the worsening of fatigue in response to the different exercises (mean [SD] VAS ranks for HIIT: PCC, 29.3 [19.5]; controls, 28.7 [11.4]; P = .08; MICT: PCC, 31.2 [17.0]; controls, 24.6 [11.7]; P = .09; ST: PCC, 31.0 [19.7]; controls, 28.1 [12.2]; P = .49). Patients with PCC had greater exacerbation of muscle pain after HIIT (mean [SD] VAS ranks, 33.4 [17.7] vs 25.0 [11.3]; P = .04) and reported more concentration difficulties after MICT (mean [SD] VAS ranks, 33.0 [17.1] vs 23.3 [10.6]; P = .03) compared with controls. At baseline, patients with PCC showed preserved lung and heart function but had a 21% lower peak volume of oxygen consumption (mean difference: -6.8 mL/kg/min; 95% CI, -10.7 to -2.9 mL/kg/min; P < .001) and less isometric knee extension muscle strength (mean difference: -37 Nm; 95% CI, -67 to -7 Nm; P = .02) compared with controls. Patients with PCC spent 43% less time on moderate to vigorous physical activity (mean difference, -26.5 minutes/d; 95% CI, -42.0 to -11.1 minutes/d; P = .001). Of note, 4 patients with PCC (13%) had postural orthostatic tachycardia, and 18 of 29 (62%) showed signs of myopathy as determined by neurophysiologic testing.

Conclusions and Relevance

In this study, nonhospitalized patients with PCC generally tolerated exercise with preserved cardiovascular function but showed lower aerobic capacity and less muscle strength than the control group. They also showed signs of postural orthostatic tachycardia and myopathy. The findings suggest cautious exercise adoption could be recommended to prevent further skeletal muscle deconditioning and health impairment in patients with PCC.

Trial Registration

ClinicalTrials.gov Identifier: NCT05445830.

Post-COVID postural orthostatic tachycardia syndrome (POTS): a new phenomenon

Background

The impact of COVID-19 has been far-reaching, and the field of neurology is no exception. Due to the long-hauler effect, a variety of chronic health consequences have occurred for some post-COVID patients. A subset of these long-hauler patients experienced symptoms of autonomic dysfunction and tested positive for postural orthostatic tachycardia syndrome (POTS) via autonomic testing.

Methods

We conducted a chart review of a convenience sample from patients seen by neurologists at our tertiary care center for suspicion of post-COVID POTS. Patients included in our study had clearly defined POTS based on clinical criteria and positive tilt table test, were 81.25% female, and had an average age of approximately 36. Out of 16 patients, 12 had a confirmed positive COVID test result, with the remaining 4 having strong clinical suspicion for COVID infection. Our analysis examined the most bothersome 3 symptoms affecting each patient per the neurologist's note at their initial visit for post-COVID POTS, clinical presentation, comorbidities, neurological exam findings, autonomic testing results, and COMPASS-31 autonomic questionnaire and PROMIS fatigue survey results.

Results

Palpitations (68.75%) and fatigue (62.5%) were the most common of the impactful symptoms reported by patients in their initial Cleveland Clinic neurology visit. The most frequent comorbidities in our sample were chronic migraines (37.5%), irritable bowel syndrome (IBS) (18.75%), and Raynaud's (18.75%). Neurological exam findings and autonomic testing results other than tilt table yielded variable findings without clear trends. Survey results showed substantial autonomic symptom burden (COMPASS-31 autonomic questionnaire average score 44.45) and high levels of fatigue (PROMIS fatigue survey average score 64.64) in post-COVID POTS patients.

Conclusion

Our sample of post-COVID POTS patients are similar to the diagnosed POTS general population including in comorbidities and autonomic testing. Fatigue was identified by patients as a common and debilitating symptom. We hope that our study will be an early step toward further investigation of post-COVID POTS with focus on the trends identified in this chart review.

Clinical-Genomic Analysis of 1261 Patients with Ehlers-Danlos Syndrome Outlines an Articulo-Autonomic Gene Network (Entome)

Systematic evaluation of 80 history and 40 history findings diagnosed 1261 patients with Ehlers-Danlos syndrome (EDS) by direct or online interaction, and 60 key findings were selected for their relation to clinical mechanisms and/or management. Genomic testing results in 566 of these patients supported EDS relevance by their differences from those in 82 developmental disability patients and by their association with general rather than type-specific EDS findings. The 437 nuclear and 79 mitochondrial DNA changes included 71 impacting joint matrix (49 COL5), 39 bone (30 COL1/2/9/11), 22 vessel (12 COL3/8VWF), 43 vessel-heart (17FBN1/11TGFB/BR), 59 muscle (28 COL6/12), 56 neural (16 SCN9A/10A/11A), and 74 autonomic (13 POLG/25porphyria related). These genes were distributed over all chromosomes but the Y, a network analogized to an 'entome' where DNA change disrupts truncal mechanisms (skin constraint, neuromuscular support, joint vessel flexibility) and produces a mirroring cascade of articular and autonomic symptoms. The implied sequences of genes from nodal proteins to hypermobility to branching tissue laxity or dysautonomia symptoms would be ideal for large language/artificial intelligence analyses.

Pediatric and adult patients with ME/CFS following COVID-19: A structured approach to diagnosis using the Munich Berlin Symptom Questionnaire (MBSQ)

A subset of patients with post-COVID-19 condition (PCC) fulfill the clinical criteria of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). To establish the diagnosis of ME/CFS for clinical and research purposes, comprehensive scores have to be evaluated. We developed the Munich Berlin Symptom Questionnaires (MBSQs) and supplementary scoring sheets (SSSs) to allow for a rapid evaluation of common ME/CFS case definitions. The MBSQs were applied to young patients with chronic fatigue and post-exertional malaise (PEM) who presented to the MRI Chronic Fatigue Center for Young People (MCFC). Trials were retrospectively registered (NCT05778006, NCT05638724). Using the MBSQs and SSSs, we report on ten patients aged 11 to 25 years diagnosed with ME/CFS after asymptomatic SARS-CoV-2 infection or mild to moderate COVID-19. Results from their MBSQs and from well-established patient-reported outcome measures indicated severe impairments of daily activities and health-related quality of life.    Conclusions: ME/CFS can follow SARS-CoV-2 infection in patients younger than 18 years, rendering structured diagnostic approaches most relevant for pediatric PCC clinics. The MBSQs and SSSs represent novel diagnostic tools that can facilitate the diagnosis of ME/CFS in children, adolescents, and adults with PCC and other post-infection or post-vaccination syndromes. What is Known: • ME/CFS is a debilitating disease with increasing prevalence due to COVID-19. For diagnosis, a differential diagnostic workup is required, including the evaluation of clinical ME/CFS criteria. • ME/CFS after COVID-19 has been reported in adults but not in pediatric patients younger than 19 years. What is New: • We present the novel Munich Berlin Symptom Questionnaires (MBSQs) as diagnostic tools to assess common ME/CFS case definitions in pediatric and adult patients with post-COVID-19 condition and beyond. • Using the MBSQs, we diagnosed ten patients aged 11 to 25 years with ME/CFS after asymptomatic SARS-CoV-2 infection or mild to moderate COVID-19.

The Contribution of Psychological Symptoms to Cognitive Difficulties in Youth With Postural Orthostatic Tachycardia Syndrome and Chronic Pain

INTRODUCTION

Subjectively experienced cognitive difficulties are common in youth with postural orthostatic tachycardia syndrome. The pathophysiological and psychological contributions of these cognitive impairments remain unclear.

METHOD

Participants were 96 adolescents and young adults diagnosed with postural orthostatic tachycardia syndrome and admitted to an intensive pain treatment program. Participants completed cognitive assessment and measures of postural orthostatic tachycardia syndrome symptoms, pain intensity, pain catastrophizing, anxiety, depression, and functional disability.

RESULTS

Self-reported autonomic symptom intensity, but not severity of heart rate change, was associated with cognitive performance. Symptoms of depression were associated with decreases in most measures of cognitive functioning. Pain intensity, pain catastrophizing, and depression but not cognitive scores and physiological measures, were significant predictors of disability.

CONCLUSION

Depression appears to be a significant contributor to the cognitive difficulties in youth with postural orthostatic tachycardia syndrome. These findings highlight the importance of assessing and treating affective symptoms in this population along with medical and lifestyle approaches to treating postural orthostatic tachycardia syndrome symptoms.

Comorbid anxiety is associated with more changes in the Management of Postural Orthostatic Tachycardia Syndrome

OBJECTIVE

Postural Orthostatic Tachycardia Syndrome (POTS) is not an anxiety disorder, but it shares similar symptomatology. The impact of this comorbidity on management is unknown. This information may lead to better strategies to improve the care of this subgroup.

METHOD

The electronic medical records of 322 patients seen at our institution between 2018 and 2022 with confirmed POTS diagnoses were analyzed. Demographics, anxiety comorbidities, questionnaire responses, and treatment course changes were collected. Negative binomial regression models examined if the presence of an anxiety disorder was associated with the number of POTS treatment course changes offset by observation time.

RESULTS

When adjusted for sex, age, baseline GAD-7 score, and baseline PROMIS global mental health score, those with a diagnosis of an anxiety disorder had2.6 times the incident rate of treatment changes for POTS management (IRR = 2.66 (95% CI: 1.43-4.95)).

CONCLUSION

Individuals carrying the diagnosis of an anxiety disorder had an increase in the incident rate of treatment changes for POTS therapy. This finding may be due to the underlying pathophysiology and treatment of anxiety disorders, the effect of bias, and difficulty with symptom differentiation. More work needs to be done to determine how to best care for POTS patients with comorbid anxiety.

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

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.

Establishment and validation of a multivariate predictive model for the efficacy of oral rehydration salts in children with postural tachycardia syndrome

BACKGROUND

The therapeutic effectiveness of the empirical and unselected use of oral rehydration salts (ORS) on postural tachycardia syndrome (POTS) is not satisfactory in children. Therefore, looking for suitable predictors of the therapeutic effects of ORS before treatment is extremely necessary to implement individualised treatment for paediatric patients with POTS.

METHODS

A retrospective case-control analysis of 130 patients (aged 5-18 years) who suffered from POTS with a 3-month treatment of ORS was conducted. A nomogram model was developed in the training set (n = 87) to predict the therapeutic response to ORS. Univariate analysis and logistic regression were applied to select the most useful predictors. ROC curves were applied to evaluate the discriminative performance of the nomogram model. The nomogram was then evaluated by calibration curves and the Hosmer-Lemeshow (H-L) test. The results were further validated using 1000 bootstrap resamples. External validation was performed in an independent validation set (n = 43).

FINDINGS

Among the ten variables with significant differences between the responders and non-responders in univariate analysis, five variables were found to be independently associated factors for ORS therapeutic efficacy among POTS children in the further logistic regression, including mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (MCV), mean arterial pressure (MAP) at the first minute of the upright position, urine specific gravity (SG), and P-wave voltage peaking ratio (PWP). The nomogram model was established in the training set (AUC 0.926 [95% CI: 0.865-0.988], yielding a sensitivity of 87.8% and a specificity of 86.8%). The calibration curves showed good agreement between the prediction of the nomogram and actual observation in both the training and validation sets. The nomogram also effectively predicted the external validation set (sensitivity 82.1%, specificity 73.3%, and accuracy 79.1%).

INTERPRETATION

We established a feasible and high-precision nomogram model to predict the efficacy of ORS, which would help implement individualised treatment for children with POTS.

FUNDING

This study was supported by National High-Level Hospital Clinical Research Funding (Multi-centre Clinical Research Project of Peking University First Hospital) (2022CR59).

[Neuropathic pain as a symptom in autonomic neuropathies and other rare diseases : Small fiber neuropathy: its recognition, diagnosis, and treatment]

BACKGROUND

Neuropathic pain is difficult to diagnose and treat. Small fiber neuropathy (SFN) flies under the radar of nerve conduction studies.

OBJECTIVES

The importance of a structured patient history and physical examination in the context of neuropathic pain is emphasized. Describing SFN as an important cause, the authors consider rare but partially treatable differential diagnoses. They conclude that autonomic symptoms are frequently associated, often presenting with diverse symptoms.

METHODS

A selective literature research to present SFN symptoms as well as differential diagnostic and therapeutic steps in the context of SFN and rare diseases focusing on the autonomic nervous system.

RESULTS

Neuropathic pain significantly reduces quality of life. To shorten the time until diagnosis and to initiate therapy, the authors recommend a structured patient history including sensory plus and minus symptoms and non-specific autonomic signs. If the initial search for the cause is not successful, rare causes such as treatable transthyretin (ATTR) amyloidosis and Fabry's disease or autoimmune causes should be considered, particularly in the case of progressive and/or autonomic symptoms.

CONCLUSION

The diagnosis and therapy of rare SFN requires interdisciplinary collaboration and, in many cases, a referral to specialized centers to achieve the best patient care.

Novel pharmacotherapeutic options for the treatment of postural orthostatic tachycardia syndrome

INTRODUCTION

Postural tachycardia syndrome (POTS) is a disorder characterized by a constellation of symptoms including lightheadedness, fatigue, and palpitations when upright, associated with an increase in the heart rate (HR) of > 30 beats per minute when changing from a lying down to standing position or head-up tilt position and not associated with orthostatic hypotension. The causes as well as the management of POTS are not quite fully understood.

AREAS COVERED

We performed a literature review on the diagnosis and management of POTS, and this article includes an overview of novel pharmacotherapeutic options for the treatment of (POTS), although an effective treatment has not been established.

EXPERT OPINION

POTS is a clinical syndrome characterized by a constellation of symptoms that are nonspecific. No single etiology or unified hypothesis could be identified. In fact, multiple pathophysiological mechanisms have been proposed, and none of the suggested medications have been approved by the FDA for this indication. Further understanding of the autonomic nervous system and its adjustment to standing position is needed to provide better management strategies.

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

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.

Mismatch between subjective and objective dysautonomia

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.

Gastrointestinal symptoms in patients with postural orthostatic tachycardia syndrome in relation to hemodynamic findings and immunological factors

Gastrointestinal (GI) symptoms are common in postural orthostatic tachycardia syndrome (POTS). We aimed to explore the prevalence and severity of GI symptoms in POTS, and to investigate immunological factors, hemodynamic findings, and their possible association with GI symptoms in POTS. Forty-three patients (93% female, median age 30.6 (26.0-41.0) years), previously diagnosed with POTS and 74 healthy controls (78% female, median age 35.6 (28.8-41.7) years) were included. The participants completed a questionnaire including prevalence of GI symptoms, the irritable bowel syndrome severity scoring system (IBS-SSS), and visual analog scale for IBS (VAS-IBS). All POTS patients were previously examined by tilt test (2010-2021) and the vast majority with more recent active standing test (2017-2021), which included monitoring of heart rate (HR). ΔHR was calculated as difference between supine and upright position. Continuous variables from IBS-SSS and VAS-IBS were correlated to ΔHR. A microarray containing several autoantigens commonly targeted in systemic autoimmune disorders was used to assess prevalent autoantibodies in POTS and controls. Total IgE and S-tryptase were analyzed. GI symptoms were more prevalent and severe in POTS than in controls; nausea being the most prevalent (79.1% vs 4.9%, p < 0.001) and bloating and flatulence being the most severe (median 65 (25-88) vs 0 (0-14), p < 0.001). The median total IBS-SSS was 213 (135-319) in POTS vs 13 (0-54) in controls (p < 0.001). Total IBS-SSS was associated with low psychological wellbeing (r = 0.539, p < 0.001) in POTS. ΔHRmax correlated inversely with abdominal pain (r = -0.406, p = 0.007). After adjustments for psychological wellbeing, total IBS-SSS still associated inversely with ΔHR10min (β: 4.748; 95% CI: -9.172 to -0.324; p = 0.036). Similar results were seen with active standing test. The prevalence of autoantibodies did not differ between POTS and controls (29.4% vs 33.3%, p = 0.803). There was no association between GI symptoms and autoantibody status. Total IgE and tryptase were elevated in a few cases. This study confirms the high prevalence of GI symptoms in POTS. More pronounced tachycardia upon tilt table testing seems to be inversely correlated with severity of chronic GI symptoms in POTS. This study did not support the hypothesis that POTS is associated with immunological factors.

Recent Advances and Future Directions in Syncope Management: A Comprehensive Narrative Review

Syncope is a highly prevalent clinical condition characterized by a rapid, complete, and brief loss of consciousness, followed by full recovery caused by cerebral hypoperfusion. This symptom carries significance, as its potential underlying causes may involve the heart, blood pressure, or brain, leading to a spectrum of consequences, from sudden death to compromised quality of life. Various factors contribute to syncope, and adhering to a precise diagnostic pathway can enhance diagnostic accuracy and treatment effectiveness. A standardized initial assessment, risk stratification, and appropriate test identification facilitate determining the underlying cause in the majority of cases. New technologies, including artificial intelligence and smart devices, may have the potential to reshape syncope management into a proactive, personalized, and data-centric model, ultimately enhancing patient outcomes and quality of life. This review addresses key aspects of syncope management, including pathogenesis, current diagnostic testing options, treatments, and considerations in the geriatric population.

Cardiovascular Symptoms, Dysautonomia, and Quality of Life in Adult and Pediatric Patients with Hypermobile Ehlers-Danlos Syndrome: A Brief Review

BACKGROUND

Hypermobile Ehlers-Danlos Syndrome (hEDS) is a connective tissue disorder characterized by joint hypermobility and other systemic manifestations, such as cardiovascular symptoms, musculoskeletal pain, and joint instability. Cardiovascular symptoms, such as lightheadedness and palpitations, and types of dysautonomia, including postural orthostatic tachycardia syndrome (POTS), are frequently reported in adults with hEDS and have been shown to negatively impact quality of life (QoL).

OBJECTIVE

This brief review will be an overview of co-occurring symptoms in POTS and hEDS to inform potential cardiovascular screening procedures.

RESULTS

While many patients with hEDS report cardiovascular symptoms, few have structural abnormalities, suggesting that dysautonomia is likely responsible for these symptoms. One validated screening measure for dysautonomia symptom burden is the Composite Autonomic Symptom Scale (COMPASS-31). Studies have found that adults with POTS, hEDS, and both POTS and hEDS have higher COMPASS-31 scores than the general population, suggesting a high symptom burden due to dysautonomia, which leads to impaired QoL.

CONCLUSION

While studies have examined cardiovascular symptoms and the impact of dysautonomia in adults with and without hEDS, there is scant literature on dysautonomia in pediatric patients with hEDS. Therefore, more studies on cardiovascular symptoms and dysautonomia, as they relate to the quality of life in pediatric patients with hEDS, are needed. This brief review summarizes the current literature on dysautonomia and cardiovascular symptoms in pediatric and adult populations with hEDS.

Comparisons of heart rate variability responses to head-up tilt with and without abdominal and lower-extremity compression in healthy young individuals: a randomized crossover study

Introduction: Abdominal and lower-extremity compression techniques can help reduce orthostatic heart rate increases. However, the effects of body compression on the cardiac autonomic systems, which control heart rate, remain unclear. The primary objective of this study was to compare heart rate variability, a reflection of cardiac autonomic regulation, during a head-up tilt test with and without abdominal and lower-extremity compression in healthy young individuals. The secondary objective was to conduct a subgroup analysis, considering participant sex, and compare heart rate and heart rate variability responses to head-up tilt with and without compression therapy. Methods: In a randomized crossover design, 39 healthy volunteers (20 females, aged 20.9 ± 1.2 years) underwent two head-up tilt tests with and without abdominal and lower-extremity compression. Heart rate and heart rate variability parameters were measured during the head-up tilt tests, including the Stress Index, root mean square of successive differences between adjacent R-R intervals, low- and high-frequency components, and low-to-high frequency ratio. Results: Abdominal and lower-extremity compression reduced the orthostatic increase in heart rate (p < 0.001). The tilt-induced changes in heart rate variability parameters, except for the low-frequency component, were smaller in the compression condition than in the no-compression condition (p < 0.001). These results were consistent regardless of sex. Additionally, multiple regression analysis with potentially confounding variables revealed that the compression-induced reduction in Stress Index during the head-up tilt position was a significant independent variable for the compression-induced reduction in heart rate in the head-up tilt position (coefficient = 0.411, p = 0.025). Conclusion: Comparative analyses revealed that abdominal and lower-extremity compression has a notable impact on the compensatory sympathetic activation and vagal withdrawal typically observed during orthostasis, resulting in a reduction of the increase in heart rate. Furthermore, this decrease in heart rate was primarily attributed to the attenuation of cardiac sympathetic activity associated with compression. Our findings could contribute to the appropriate application of compression therapy for preventing orthostatic tachycardia. This study is registered with UMIN000045179.

Treatment of long COVID complicated by postural orthostatic tachycardia syndrome-Case series research

Background

Coronavirus disease 2019 (COVID-19) sequelae, also known as long COVID, can present with various symptoms. Among these symptoms, autonomic dysregulation, particularly postural orthostatic tachycardia syndrome (POTS), should be evaluated. However, previous studies on the treatment of POTS complicated by COVID-19 are lacking. Therefore, this study aimed to investigate the treatment course of long COVID complicated by POTS.

Methods

The medical records of patients who complained of fatigue and met the criteria for POTS diagnosis were reviewed. We evaluated the treatment days, methods and changes in fatigue score, changes in heart rate on the Schellong test, and social situation at the first and last visits.

Results

Thirty-two patients with long COVID complicated by POTS were followed up (16 males; median age: 28 years). The follow-up period was 159 days, and the interval between COVID-19 onset and initial hospital attendance was 97 days. Some patients responded to β-blocker therapy. Many patients had psychiatric symptoms that required psychiatric intervention and selective serotonin reuptake inhibitor prescription. Changes in heart rate, performance status, and employment/education status improved from the first to the last visit. These outcomes were believed to be because of the effects of various treatment interventions and spontaneous improvements.

Conclusions

Our study suggests that the condition of 94% of patients with POTS complicated by long COVID will improve within 159 days. Therefore, POTS evaluation should be considered when patients with long COVID complain of fatigue, and attention should be paid to psychological symptoms and the social context.

Postural orthostatic tachycardia syndrome after COVID-19 vaccination

BACKGROUND

There is an association between coronavirus disease 2019 (COVID-19) mRNA vaccination and the incidence or exacerbation of postural orthostatic tachycardia syndrome (POTS).

OBJECTIVE

The purpose of this study was to characterize patients reporting new or exacerbated POTS after receiving the mRNA COVID-19 vaccine.

METHODS

We prospectively collected data from sequential patients in a POTS clinic between July 2021 and June 2022 reporting new or exacerbated POTS symptoms after COVID-19 vaccination. Heart rate variability (HRV) and skin sympathetic nerve activity (SKNA) were compared against those of 24 healthy controls.

RESULTS

Ten patients (6 women and 4 men; age 41.5 ± 7.9 years) met inclusion criteria. Four patients had standing norepinephrine levels > 600 pg/mL. All patients had conditions that could raise POTS risk, including previous COVID-19 infection (N = 4), hypermobile Ehlers-Danlos syndrome (N = 6), mast cell activation syndrome (N = 6), and autoimmune (N = 7), cardiac (N = 7), neurological (N = 6), or gastrointestinal conditions (N = 4). HRV analysis indicated a lower ambulatory root mean square of successive differences (46.19 ±24 ms; P = .042) vs control (72.49 ± 40.8 ms). SKNA showed a reduced mean amplitude (0.97 ± 0.052 μV; P = .011) vs control (1.2 ± 0.31 μV) and burst amplitude (1.67 ± 0.16 μV; P = .018) vs control (4. 3 ± 4.3 μV). After 417.2 ± 131.4 days of follow-up, all patients reported improvement with the usual POTS care, although 2 with COVID-19 reinfection and 1 with small fiber neuropathy did have relapses of POTS symptoms.

CONCLUSION

All patients with postvaccination POTS had pre-existing conditions. There was no evidence of myocardial injuries or echocardiographic abnormalities. The decreased HRV suggests a sympathetic dominant state. Although all patients improved with guideline-directed care, there is a risk of relapse.

Redo procedures after sinus node sparing hybrid ablation for inappropriate sinus tachycardia/postural orthostatic sinus tachycardia

AIMS

A novel sinus node (SN) sparing hybrid ablation for inappropriate sinus node tachycardia (IST)/postural orthostatic tachycardia syndrome (POTS) has been demonstrated to be an effective and safe therapeutic option in patients with symptomatic drug-resistant IST/POTS. The aim of this study was to evaluate the long-term rate of redo procedures after hybrid IST ablation and procedural strategy, outcomes and safety of redo procedures.

METHODS AND RESULTS

All consecutive patients from 2015 to 2023 were prospectively enrolled in the UZ Brussel monocentric IST/POTS registry. They were analysed if the following inclusion criteria were fulfilled: 1) diagnosis of IST or POTS, 2) symptomatic IST/POTS refractory or intolerant to drugs, and 3) hybrid SN sparing ablation performed. The primary endpoint was redo procedure. The primary safety endpoint was pacemaker (PM) implantation. A total of 220 patients undergone to hybrid IST ablation were included, 185 patients (84.1%) were treated for IST and 61 patients (27.7%) for POTS.After a follow-up of 73.3 ± 16.2 months, 34 patients (15.4%) underwent a redo. A total of 23 patients (67.6%) had a redo for IST recurrence and 11 patients (32.4%) for other arrhythmias. Pacemaker implantation was performed in 21 patients (9.5%). Nine patients (4.1%) had no redo procedure and experienced sick sinus syndrome requiring a PM. Twelve patients (5.4%) received a PM as a shared therapeutic choice combined with SN ablation procedure.

CONCLUSION

In a large cohort of patients the long-term free survival from redo procedure after hybrid IST ablation was 84.6% with a low PM implantation rate.

Evaluation and management of orthostatic headache in hypermobility disorders

Headache is a frequent symptom among patients with hypermobility spectrum disorders. This mini review focuses specifically on a challenging aspect of headache evaluation in all patients, but especially those with hypermobility - the orthostatic headache. While the differential for an orthostatic headache is overall limited, patients with hypermobility disorders have risk factors for all of the most commonly encountered orthostatic headache disorders. The most common conditions to produce orthostatic headaches are discussed - spontaneous intracranial hypotension, cervicogenic headache, and postural orthostatic tachycardia syndrome. Less common etiologies of orthostatic headache pertinent to any patient are presented in table format.

Non-invasive Vagus Nerve Simulation in Postural Orthostatic Tachycardia Syndrome

Postural orthostatic tachycardia syndrome (POTS) is a chronic debilitating condition of orthostatic intolerance, predominantly affecting young females. Other than postural tachycardia, symptoms of POTS include a spectrum of non-cardiac, systemic and neuropsychiatric features. Despite the availability of widespread pharmacological and non-pharmacological therapeutic options, the management of POTS remains challenging. Exaggerated parasympathetic withdrawal and sympathetic overdrive during postural stress are principal mechanisms of postural tachycardia in POTS. Non-invasive, transcutaneous, vagus nerve stimulation (tVNS) is known to restore sympathovagal balance and is emerging as a novel therapeutic strategy in cardiovascular conditions including arrhythmias and heart failure. Furthermore, tVNS also exerts immunomodulatory and anti-inflammatory effects. This review explores the effects of tVNS on the pathophysiology of POTS and its potential as an alternative non-pharmacological option in this condition.

Recognizing postural orthostatic tachycardia syndrome in primary care

ABSTRACT

Postural orthostatic tachycardia syndrome (POTS) is a complex autonomic disorder characterized by abnormal tachycardia on standing. This disorder predominantly affects young women, with a peak incidence between ages 20 and 30 years. POTS often is associated with a variety of symptoms, including dizziness, palpitations, fatigue, generalized weakness, anxiety, and exercise intolerance, which can significantly impair patient quality of life. Primary care providers (PCPs) often are the first healthcare professionals to whom patients present. This article provides an overview of POTS, including diagnostic criteria and the importance of a thorough clinical evaluation to rule out other causes of symptoms. PCPs play a critical role in the comprehensive approach to care, involving patient education, lifestyle modifications, and treatment to improve outcomes and enhance patient quality of life.

Pooled rates and demographics of POTS following SARS-CoV-2 infection versus COVID-19 vaccination: Systematic review and meta-analysis

PURPOSE

To address recent concerns of postural orthostatic tachycardia syndrome (POTS) occurring after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination.

METHODS

We searched PubMed, Web of Science, and Scopus as of 1st June 2023. We performed a systematic review and meta-analysis of pooled POTS rate in SARS-CoV-2-infected and COVID-19-vaccinated groups from epidemiological studies, followed by subgroup analyses by characteristic. Meta-analysis of risk ratio was conducted to compare POTS rate in infected versus uninfected groups. Meta-analysis of demographics was also performed to compare cases of post-infection and post-vaccination POTS from case reports and series.

RESULTS

We estimated the pooled POTS rate of 107.75 (95 % CI: 9.73 to 273.52) and 3.94 (95 % CI: 0 to 16.39) cases per 10,000 (i.e., 1.08 % and 0.039 %) in infected and vaccinated individuals based on 5 and 2 studies, respectively. Meta-regression revealed age as a significant variable influencing 86.2 % variance of the pooled POTS rate in infected population (P < 0.05). Moreover, POTS was 2.12-fold more likely to occur in infected than uninfected individuals (RR = 2.12, 95 % CI: 1.71 to 2.62, P < 0.001). Meta-analyzed demographics for cases of post-infection (n = 43) and post-vaccination (n = 17) POTS found no significant differences in several variables between groups, except that the time from exposure to symptom onset was shorter for cases of post-vaccination POTS (P < 0.05).

CONCLUSION

Although evidence is limited for post-vaccination POTS, our study showed that POTS occur more frequently following SARS-CoV-2 infection than COVID-19 vaccination.

Validation of symptom measures in patients under investigation for postural orthostatic tachycardia syndrome (POTS): The Orthostatic Grading Scale (OGS) and the Symptom Screen for Small-fiber Polyneuropathy (SSS)

OBJECTIVES

Postural Orthostatic Tachycardia Syndrome (POTS) presents with a range of poorly delineated symptoms across several domains. There is an urgent need for standardized symptom reporting in POTS, but a lack of validated symptom burden instruments. Our aim was to evaluate the psychometric properties of two symptom burden measures: the Orthostatic Grading Scale (OGS) and the Symptom Screen for Small-Fiber Polyneuropathy (SSS), in patients under investigation for suspected POTS.

DESIGN

Psychometric validation study.

METHODS

Confirmatory factor analysis (CFA) tested the factor structure of the SSS and OGS completed by 149 patients under investigation for POTS. Scale reliability and validity were assessed. The uni-dimensionality of the SSS was assessed through principal component analysis (PCA).

RESULTS

CFA of the OGS revealed that a 1-factor structure had adequate fit. CFA of the SSS revealed that a 5-factor structure had generally appropriate fit supporting the originally proposed 5 factors (1: Gastrointestinal, 2: Somatosensory, 3: Miscellaneous, 4: Microvascular, and 5: Urological). In addition, the SSS demonstrated sufficient uni-dimensionality in the PCA, warranting use of a single total score. Omega coefficients of both measures indicated satisfactory internal reliability (0.668-0.931). Correlations with related constructs (distress (K10 score), r = 0.317-0.404, p < 0.001) and heart rate indices (with the OGS, r = 0.211-0.294, p < 0.05) suggested sound convergent and divergent validity.

CONCLUSIONS

Initial evidence suggests that the OGS and SSS have good psychometric properties for use in populations with suspected and confirmed POTS.

Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and post-COVID condition can present similarities such as fatigue, brain fog, autonomic and neuropathic symptoms.

METHODS

The study included 87 patients with post-COVID condition, 50 patients with ME/CFS, and 50 healthy controls (HC). The hemodynamic autonomic function was evaluated using the deep breathing technique, Valsalva maneuver, and Tilt test. The presence of autonomic and sensory small fiber neuropathy (SFN) was assessed with the Sudoscan and with heat and cold evoked potentials, respectively. Finally, a complete neuropsychological evaluation was performed. The objective of this study was to analyze and compare the autonomic and neuropathic symptoms in post-COVID condition with ME/CFS, and HC, as well as, analyze the relationship of these symptoms with cognition and fatigue.

RESULTS

Statistically significant differences were found between groups in heart rate using the Kruskal-Wallis test (H), with ME/CFS group presenting the highest (H = 18.3; p ≤ .001). The Postural Orthostatic Tachycardia Syndrome (POTS), and pathological values in palms on the Sudoscan were found in 31% and 34% of ME/CFS, and 13.8% and 19.5% of post-COVID patients, respectively. Concerning evoked potentials, statistically significant differences were found in response latency to heat stimuli between groups (H = 23.6; p ≤ .01). Latency was highest in ME/CFS, and lowest in HC. Regarding cognition, lower parasympathetic activation was associated with worse cognitive performance.

CONCLUSIONS

Both syndromes were characterized by inappropriate tachycardia at rest, with a high percentage of patients with POTS. The prolonged latencies for heat stimuli suggested damage to unmyelinated fibers. The higher proportion of patients with pathological results for upper extremities on the Sudoscan suggested a non-length-dependent SFN.

Cardiorespiratory dysautonomia in post-COVID-19 condition: Manifestations, mechanisms and management

A significant proportion of COVID-19 patients experience debilitating symptoms for months after the acute infection. According to recent estimates, approximately 1 out of 10 COVID-19 convalescents reports persistent health issues more than 3 months after initial recovery. This 'post-COVID-19 condition' may include a large variety of symptoms from almost all domains and organs, and for some patients it may mean prolonged sick-leave, homestay and strongly limited activities of daily life. In this narrative review, we focus on the symptoms and signs of post-COVID-19 condition in adults - particularly those associated with cardiovascular and respiratory systems, such as postural orthostatic tachycardia syndrome or airway disorders - and explore the evidence for chronic autonomic dysfunction as a potential underlying mechanism. The most plausible hypotheses regarding cellular and molecular mechanisms behind the wide spectrum of observed symptoms - such as lingering viruses, persistent inflammation, impairment in oxygen sensing systems and circulating antibodies directed to blood pressure regulatory components - are discussed. In addition, an overview of currently available pharmacological and non-pharmacological treatment options is presented.

The neuromuscular evaluation of postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is a diagnosis with a wide spectrum of symptomatology and a variety of clinicopathological associations, including hereditary, autoimmune, and infectious associations. There is little consensus regarding the appropriate diagnostic approach to the condition. The aim of this work was to provide guidance on the initial diagnosis and when and how to expand diagnostic testing. We define the "typical" POTS patient as younger, female, and with a normal examination apart from joint hyperextensibility. Red flags for "atypical" POTS would be older age at onset, male, prominent syncope, review of systems suggestive of specific alternative diagnoses, examination abnormalities other than joint hyperextensibility, or disease refractory to nonpharmacological and other first-line treatments. Although a limited evaluation is appropriate in POTS with typical features, we recommend an expanded and individualized workup in atypical cases, including additional cardiac testing, autonomic testing, neuropathy workup, and/or autoimmune workup (including consideration of Guillain-Barré syndrome), depending on clinical presentation. We emphasize the importance of shared decision-making in this condition for which treatment remains primarily symptomatic regardless of etiology.

Clinical standards for diagnosis, treatment and prevention of post-COVID-19 lung disease

BACKGROUND: The aim of these clinical standards is to provide guidance on 'best practice' care for the diagnosis, treatment and prevention of post-COVID-19 lung disease.METHODS: A panel of international experts representing scientific societies, associations and groups active in post-COVID-19 lung disease was identified; 45 completed a Delphi process. A 5-point Likert scale indicated level of agreement with the draft standards. The final version was approved by consensus (with 100% agreement).RESULTS: Four clinical standards were agreed for patients with a previous history of COVID-19: Standard 1, Patients with sequelae not explained by an alternative diagnosis should be evaluated for possible post-COVID-19 lung disease; Standard 2, Patients with lung function impairment, reduced exercise tolerance, reduced quality of life (QoL) or other relevant signs or ongoing symptoms ≥4 weeks after the onset of first symptoms should be evaluated for treatment and pulmonary rehabilitation (PR); Standard 3, The PR programme should be based on feasibility, effectiveness and cost-effectiveness criteria, organised according to local health services and tailored to an individual patient's needs; and Standard 4, Each patient undergoing and completing PR should be evaluated to determine its effectiveness and have access to a counselling/health education session.CONCLUSION: This is the first consensus-based set of clinical standards for the diagnosis, treatment and prevention of post-COVID-19 lung disease. Our aim is to improve patient care and QoL by guiding clinicians, programme managers and public health officers in planning and implementing a PR programme to manage post-COVID-19 lung disease.

Long COVID-19 Pathophysiology: What Do We Know So Far?

Long COVID-19 is a recognized entity that affects millions of people worldwide. Its broad clinical symptoms include thrombotic events, brain fog, myocarditis, shortness of breath, fatigue, muscle pains, and others. Due to the binding of the virus with ACE-2 receptors, expressed in many organs, it can potentially affect any system; however, it most often affects the cardiovascular, central nervous, respiratory, and immune systems. Age, high body mass index, female sex, previous hospitalization, and smoking are some of its risk factors. Despite great efforts to define its pathophysiology, gaps remain to be explained. The main mechanisms described in the literature involve viral persistence, hypercoagulopathy, immune dysregulation, autoimmunity, hyperinflammation, or a combination of these. The exact mechanisms may differ from system to system, but some share the same pathways. This review aims to describe the most prevalent pathophysiological pathways explaining this syndrome.

Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome - a case-control study

PURPOSE

Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls.

METHODS

Thirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction.

RESULTS

LCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups.

CONCLUSIONS

LCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome.

Low-Dose Naltrexone Use in Postural Orthostatic Tachycardia Syndrome: A Case Series

Introduction In recent years, low-dose naltrexone has emerged as a novel off-label therapy for many chronic conditions including postural orthostatic tachycardia syndrome (POTS), however, there is little evidence for its efficacy. Methods In this institutional review board (IRB)-approved case series, the charts of six tilt table-confirmed patients with POTS who underwent a trial of low-dose naltrexone (LDN) at our institution were reviewed. Medical history, subjective description of symptom severity, the continuation of therapy, tolerability, and scores on patient-reported outcome measures (Patient-Reported Outcomes Measurement Information System {PROMIS} Fatigue, PROMIS physical and mental health, Generalized Anxiety Disorder Assessment {GAD}-7, Patient Health Questionnaire {PHQ}-9, and Composite Autonomic Symptom Score {COMPASS}) were collected at therapy initiation and six to 12 months after the start of LDN. Results Three out of six reviewed patients reported an improvement in their POTS after the initiation of LDN. Two patients discontinued the therapy due to a lack of perceived benefit. No side effects or adverse outcomes were reported. The patient-reported outcome measures of PROMIS Fatigue, PROMIS physical and mental health, GAD-7, PHQ-9, and COMPASS showed inconsistent changes over the course of therapy, with some patients showing improvement or stability and others showing worsening. The small sample size and incomplete response rate did not allow for extensive statistical analysis. Conclusion As seen in its use in other conditions, LDN appears to have a favorable safety and side effect profile in patients with POTS but has little evidence for efficacy. Although some patients noted benefit, patient-reported outcome measures show a variable response profile. High-quality randomized controlled trials are needed to determine if the treatment is efficacious and should be used outside of a trial basis.

Cognitive functioning in postural orthostatic tachycardia syndrome among different body positions: a prospective pilot study (POTSKog study)

PURPOSE

Approximately 96% of patients with postural orthostatic tachycardia syndrome (PoTS) report cognitive complaints. We investigated whether cognitive function is impaired during sitting and active standing in 30 patients with PoTS compared with 30 healthy controls (HCs) and whether it will improve with the counter manoeuvre of leg crossing.

METHODS

In this prospective pilot study, patients with PoTS were compared to HCs matched for age, sex, and educational level. Baseline data included norepinephrine plasma levels, autonomic testing and baseline cognitive function in a seated position [the Montreal Cognitive Assessment, the Leistungsprüfsystem (LPS) subtests 1 and 2, and the Test of Attentional Performance (TAP)]. Cognitive functioning was examined in a randomized order in supine, upright and upright legs crossed position. The primary outcomes were the cognitive test scores between HCs and patients with PoTS at baseline testing, and among the different body positions.

RESULTS

Patients with PoTS had impaired attention (TAP median reaction time) in the seated position and impaired executive functioning (Stroop) while standing compared with HC. Stroop was influenced by position (supine versus upright versus upright legs crossed) only in the PoTS group. Leg crossing did not result in an improvement in executive function. In patients with PoTS, there was a negative correlation of Stroop with norepinephrine plasma levels while standing.

CONCLUSION

Compared with HCs, PoTS participants showed impaired cognitive attention and executive function in the upright position that did not improve in the legs crossed position. Data provide further evidence for orthostatic cognitive deterioration in patients with PoTS.

TRIAL REGISTRATION INFORMATION

The study was registered at ClinicalTrials.gov (NCT03681080).

A Clinical Qualification Protocol Highlights Overlapping Genomic Influences and Neuro-Autonomic Mechanisms in Ehlers-Danlos and Long COVID-19 Syndromes

A substantial fraction of the 15% with double-jointedness or hypermobility have the traditionally ascertained joint-skeletal, cutaneous, and cardiovascular symptoms of connective tissue dysplasia and its particular manifestation as Ehlers-Danlos syndrome (EDS). The holistic ascertainment of 120 findings in 1261 EDS patients added neuro-autonomic symptoms like headaches, muscle weakness, brain fog, chronic fatigue, dyspnea, and bowel irregularity to those of arthralgia and skin laxity, 15 of these symptoms shared with those of post-infectious SARS-CoV-2 (long COVID-19). Underlying articulo-autonomic mechanisms guided a clinical qualification protocol that qualified DNA variants in 317 genes as having diagnostic utility for EDS, six of them identical (F2-LIFR-NLRP3-STAT1-T1CAM1-TNFRSF13B) and eighteen similar to those modifying COVID-19 severity/EDS, including ADAMTS13/ADAMTS2-C3/C1R-IKBKG/IKBKAP-PIK3C3/PIK3R1-POLD4/POLG-TMPRSS2/TMPRSS6-WNT3/WNT10A. Also, contributing to EDS and COVID-19 severity were forty and three genes, respectively, impacting mitochondrial functions as well as parts of an overlapping gene network, or entome, that are hypothesized to mediate the cognitive-behavioral, neuro-autonomic, and immune-inflammatory alterations of connective tissue in these conditions. The further characterization of long COVID-19 natural history and genetic predisposition will be necessary before these parallels to EDS can be carefully delineated and translated into therapies.

Evidence for Impaired Renin Activity in Postural Orthostatic Tachycardia Syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous condition predominantly affecting autonomic control of the cardiovascular system. Its extensive symptom diversity implies multi-organ involvement that interacts in ways still requiring full exploration. Current understanding of POTS pathophysiology suggests alterations in the renin-angiotensin-aldosterone system as a possible contributing factor. Therefore, we investigated the relationship between the activity of the renin-angiotensin-aldosterone system and hemodynamic parameters in a cohort of POTS patients and controls recruited at a tertiary referral center.

METHODS

The case-control study included 46 patients with POTS (27 ± 9 years), and 48 healthy controls (30 ± 9 years) without orthostatic intolerance. Plasma renin activity, expressed as angiotensin I generation, and plasma aldosterone were measured by enzyme-linked immunosorbent assay and were correlated with hemodynamic parameters obtained during active standing tests.

RESULTS

Renin activity was significantly downregulated in POTS patients compared to healthy individuals (median, 3406 ng/mL vs. 9949 ng/mL, p < 0.001), whereas aldosterone concentration did not differ between POTS and healthy controls (median, 218 pmol/L vs. 218 pmol/L, p = 0.26). A significant inverse correlation between renin activity and supine and orthostatic blood pressure levels was observed in healthy individuals (p < 0.05 for all), but not in POTS patients.

CONCLUSIONS

Renin activity, but not aldosterone concentration, is downregulated in patients with POTS. Moreover, renin activity in POTS is dissociated from supine and standing blood pressure levels in contrast to healthy individuals. These findings suggest impaired renin function in POTS, which may direct future therapeutic approaches.

Predicting Therapeutic Efficacy of Pharmacological Treatments in Children with Postural Orthostatic Tachycardia Syndrome: A Mini-Review

Postural orthostatic tachycardia syndrome (POTS) is common in children, with an excessive increment in heart rate when moving from the supine to upright position. It has significant negative impacts on the daily life of pediatric patients. The pathogenesis of POTS includes peripheral vascular dysfunction, central hypovolemia, abnormal autonomic function, a high-adrenergic state, impaired skeletal-muscle pump function, the abnormal release of vasoactive factors, and autoimmune abnormalities. Therefore, the empirical use of pharmacological treatments has limited therapeutic efficacy due to the diversity of its mechanisms. A crucial aspect of managing POTS is the selection of appropriate treatment targeting the specific pathogenesis. This review summarizes the commonly used pharmacological interventions, with a focus on their predictive indicators for treatment response. Factors such as heart rate variability, plasma biomarkers, and cardiac-function parameters are discussed as potential predictors of therapeutic efficacy, enabling the implementation of individualized treatment to improve therapeutic effectiveness. This review consolidates the current knowledge on POTS, encompassing its clinical characteristics, epidemiological patterns, underlying pathogenic mechanisms, and predictive indicators for treatment response. Further research is warranted to enhance the understanding of POTS and facilitate the development of more effective therapeutic approaches for this challenging syndrome.

Postural Orthostatic Tachycardia Syndrome in Spinal Cord Injury

Spinal cord injury (SCI), in addition to motor and sensory problems, may also lead to autonomic dysfunction. Postural orthostatic tachycardia syndrome (POTS) is one of them and has often been reported in traumatic brain injuries, multiple sclerosis, and other spinal cord pathologies. However, there is not much data on POTS in SCI even in extensive databases. We present a case of an adolescent female with paraplegia due to traumatic SCI. During her tilt table training, she started having episodes of sinus tachycardia associated with fatigue, dizziness, headache, palpitations, and presyncope with no orthostatic hypotension, after achieving 60 degrees of head tilt. After ruling out the common causes of tachycardia and syncope, a diagnosis of POTS was established. With pharmacologic and non-pharmacological measures, including metoprolol, increased fluid intake, and compression stockings, her symptoms resolved, and she was able to continue rehabilitation.

Comparison of a 20 degree and 70 degree tilt test in adolescent myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients

Introduction

During a standard 70-degree head-up tilt test, 90% of adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develop an abnormal reduction in cerebral blood flow (CBF). A 70-degree test might not be tolerated by young ME/CFS patients because of the high incidence of syncopal spells. This study examined whether a test at 20 degrees would be sufficient to provoke important reductions in CBF in young ME/CFS patients.

Methods

We analyzed 83 studies of adolescent ME/CFS patients. We assessed CBF using extracranial Doppler measurements of the internal carotid and vertebral arteries supine and during the tilt. We studied 42 adolescents during a 20 degree and 41 during a 70 degree test.

Results

At 20 degrees, no patients developed postural orthostatic tachycardia (POTS), compared to 32% at 70 degrees (p = 0.0002). The CBF reduction during the 20 degree tilt of -27(6)% was slightly less than during the reduction during a 70 degree test [-31(7)%; p = 0.003]. Seventeen adolescents had CBF measurements at both 20 and 70 degrees. The CBF reduction in these patients with both a 20 and 70 degrees test was significantly larger at 70 degrees than at 20 degrees (p < 0.0001).

Conclusions

A 20 degree tilt in young ME/CFS patients resulted in a CBF reduction comparable to that in adult patients during a 70 degree test. The lower tilt angle provoked less POTS, emphasizing the importance of using the 70 degree angle for that diagnosis. Further study is needed to explore whether CBF measurements during tilt provide an improved standard for classifying orthostatic intolerance.

Choices and Challenges With Drug Therapy in Postural Orthostatic Tachycardia Syndrome: A Systematic Review

The literature on pharmacologic treatments for postural orthostatic tachycardia syndrome (POTS) is inconsistent and unstandardized. Therefore, we aimed to evaluate choices in pharmacologic treatment options for POTS and the challenges encountered in the studies. We searched numerous databases like PubMed, Scopus, Embase, Web of Science, and Google Scholar for literature published before April 8, 2023. The search was done to retrieve potential peer-reviewed articles that explored drug therapy in POTS. Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were used to conduct the systematic review. Of the 421 potential articles assessed, 17 met the inclusion criteria. Results demonstrated that pharmacologic treatment options for POTS were effective in reducing symptoms of POTS, but most of the studies were underpowered. Several were terminated due to various reasons. Midodrine ivabradine, bisoprolol, fludrocortisone, droxidopa, desmopressin, propranolol, modafinil, methylphenidate, and melatonin have been studied with positive impact but sample sizes that were low in the range of 10-50 subjects. Therefore, we concluded the treatment options effectively improve symptoms of POTS and increase orthostatic tolerance, but more evidence is needed as most studies had a low sample size and thus are underpowered.