Palmitoylation regulates norepinephrine transporter uptake, surface localization, and total expression with pathogenic implications in postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) is an adrenergic signaling disorder characterized by excessive plasma norepinephrine, postural tachycardia, and syncope. The norepinephrine transporter (NET) modulates adrenergic homeostasis via the reuptake of extracellular catecholamines and is implicated in the pathogenesis of adrenergic and neurological disorders. In this study, we reveal NET is palmitoylated in male Sprague-Dawley rats and Lilly Laboratory Cell Porcine Kidney (LLC-PK1) cells. S-palmitoylation, or the addition of a 16-carbon saturated fatty acid, is a reversible post-translational modification responsible for the regulation of numerous biological mechanisms. We found that LLC-PK1 NET is dynamically palmitoylated, and that inhibition with the palmitoyl acyltransferase (DHHC) inhibitor, 2-bromopalmitate (2BP) results in decreased NET palmitoylation within 90 min of treatment. This result was followed closely by a reduction in transport capacity, cell surface, and total cellular NET expression after 120 min of treatment. Increasing 2BP concentrations and treatment time revealed a nearly complete loss of total NET protein. Co-expression with individual DHHCs revealed a single DHHC enzyme, DHHC1, promoted wild-type (WT) hNET palmitoylation and elevated NET protein levels. The POTS-associated NET mutant, A457P, exhibits dramatically decreased transport capacity and cell surface levels which we have confirmed in the current study. In an attempt to recover A457P NET expression, we co-expressed the A457P variant with DHHC1 to drive expression as seen with the WT protein but instead saw an increase in NET N-terminal immuno-detectable forms and fragments. Elimination of a potential palmitoylation site at cysteine 44 in the N-terminal tail of hNET resulted in a low expression phenotype mimicking the A457P hNET variant. Further investigation of A457P NET palmitoylation and surface expression is necessary, but our preliminary novel findings reveal palmitoylation as a mechanism of NET regulation and suggest that dysregulation of this process may contribute to the pathogenesis of adrenergic disorders like POTS.

Cardiovascular dysautonomia in postacute sequelae of SARS-CoV-2 infection.

Coronavirus disease 2019 (COVID-19) has led to a worldwide pandemic that continues to transform but will not go away. Cardiovascular dysautonomia in postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection has led to persistent symptoms in a large number of patients. Here, we define the condition and its associated symptoms as well as potential mechanisms responsible. We provide a careful and complete overview of the topic addressing novel studies and a generalized approach to the management of individuals with this complex and potentially debilitating problem. We also discuss future research directions and the important knowledge gaps to be addressed in ongoing and planned studies.

CURRENT CONCEPTS IN LONG-COVID BRAIN FOG AND POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME.

Neurologic complications of long-COVID syndrome are one of the leading causes of global disability. In particular, post-COVID cognitive dysfunction and dysautonomia in the form of postural orthostatic tachycardia syndrome (POTS) markedly affect patient quality of life and ability to return to work. The underlying pathophysiology of postCOVID neurologic complications is unknown but is likely multifactorial with immune dysregulation and microvascular dysfunction playing central roles. Specific pathogenic factors with supportive evidence to date include cytokine-mediated inflammation, autoantibodies, immune exhaustion, disruption of the renin-angiotensin system, reduced serotonin levels and microglial activation. The prevalence of post-COVID cognitive dysfunction ranges from 10% to 88% and is affected by viral variant and hospitalization status among other factors, while that of long-COVID POTS is unknown due to referral bias and varying definitions. Treatment is largely supportive and often incorporates combined modalities. Marginal benefits with cognitive behavioral therapy, hyperbaric oxygen therapy and supplements have been shown for post-COVID brain fog, while established POTS therapies aimed at improving venous return and reducing heart rate may reduce symptoms of long-COVID POTS. Although significant recovery has been noted for many cases of post-COVID brain fog and POTS, prospective studies have demonstrated evidence of persistent symptoms and neurologic deficits a year after infection in some patients. Further studies that provide insight into the underlying pathophysiology of long-COVID are needed for development of target directed therapy.

Gastrointestinal manifestations seen in pediatric patients diagnosed with small fiber neuropathy.

OBJECTIVES: Small fiber neuropathy (SFN) affects the fibers involved in cutaneous and visceral pain and temperature sensation and are a crucial part of the autonomic nervous system. Autonomic dysfunction secondary to SFN and autoimmune receptor antibodies is being increasingly recognized, and gastrointestinal (GI) manifestations include constipation, early satiety, nausea, vomiting, and diarrhea. Enteric nervous system involvement may be a possible explanation of abnormal GI motility patterns seen in these patients. METHODS: Children suspected to have SFN based on symptoms underwent skin biopsy at the Child Neurology clinic at Arnold Palmer Hospital for Children, which was processed at Therapath™ Neuropathology. SFN was diagnosed using epidermal nerve fiber density values that were below 5th percentile from the left distal leg (calf) as reported per Therapath™ laboratory. RESULTS: Twenty-six patients were diagnosed with SFN. Retrospective chart review was performed, including demographic data, clinical characteristics, and evaluation. A majority of patients were white adolescent females. Autonomic dysfunction, including orthostasis and temperature dysregulation were seen in 61.5% of patients (p = 0.124). Somatosensory symptoms, including pain or numbness were seen in 85% of patients (p < 0.001). GI symptoms were present in 85% of patients (p < 0.001) with constipation being the most common symptom seen in 50% of patients. This correlated with the motility testing results. CONCLUSIONS: Pediatric patients with SFN commonly have GI symptoms, which may be the main presenting symptom. It is important to recognize and look for symptoms of small fiber neuropathy in children with refractory GI symptoms that may explain multisystemic complaints often seen in these patients.

Randomized controlled trial of intravenous immunoglobulin for autoimmune postural orthostatic tachycardia syndrome (iSTAND).

OBJECTIVE: This study assesses response to intravenous immunoglobulin (IVIG) in presumed autoimmune postural orthostatic tachycardia syndrome (POTS). BACKGROUND: POTS may be associated with autoimmune disorders, serum autoantibodies, or recent infection. Uncontrolled case studies suggest that IVIG is beneficial for treating autoimmune POTS. No previous randomized controlled trials have been conducted. METHODS: This single-site randomized controlled trial compared IVIG with intravenous albumin infusions. Albumin comparator ensured blinding and control for effects of volume expansion. Eligible patients with POTS had COMPASS-31 total weighted score ≥ 40 and met predetermined criteria suggesting autoimmunity. Over 12 weeks, participants received eight infusions (0.4 gm/kg each). Four infusions were given weekly followed by four infusions every other week. Primary outcome measure was improvement in COMPASS-31 2 weeks after final infusion. RESULTS: A total of 50 participants consented; 30 met inclusion criteria and received study drug (16 IVIG and 14 albumin; 29 female). Group baseline characteristics were well matched; 27 participants completed treatment protocol. Change in COMPASS-31 did not differ between groups (median change [IQR]; IVIG: -5.5 [-23.3, 2.5] versus albumin: -10.6 [-14.1, -4.7]; p-value = 0.629). The IVIG group had a higher response rate (46.7% versus 38.5%), but this was not statistically significant. Adverse events were common but usually mild and did not differ between treatment groups. CONCLUSIONS: This small randomized controlled trial of IVIG in POTS found no statistical difference in response compared with albumin infusion. Both groups showed improvement possibly related to volume expansion or other effects obscuring group differences. These findings inform development of future immunomodulatory clinical trials in POTS.

Postural orthostatic tachycardia syndrome in a Thai male patient.

Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous autonomic disorder. All patients have exaggerated tachycardia upon standing, but the pathophysiology may be diverse. We present a young adult Thai male with a chief complaint of palpitations while in an upright posture since childhood. The patient underwent a modified Ewing test battery which included standing test, deep breathing, and Valsalva maneuver. His heart rate increased more than 30 beats per minute (bpm) during repeated active stand tests (65 to 110 bpm and 77 to 108 bpm), while upright diastolic blood pressure increased more than 10 mmHg. Normal Valsalva ratio (2.01 and 1.86) and baseline heart rate variability (HFRRI = 4030.24 ms2 and 643.92 ms2) indicated intact vagal function. High low-frequency systolic blood pressure variability (LFSBP = 20.93 mmHg2), increased systolic blood pressure overshoot in phase IV of Valsalva (42 mmHg), and increased upright diastolic blood pressure indicated a hyperadrenergic state. In conclusion, the overall autonomic profile was compatible with hyperadrenergic POTS. Thus, we confirmed the first male POTS case reported in Thailand. We demonstrated the importance of autonomic function testing with continuous measurements to confirm POTS. There is a need for further research in POTS in Thailand.

Complication Avoidance in Chiari Malformation Surgery.

Posterior fossa decompression for symptomatic Chiari malformation is an effective and frequently performed procedure, but it does carry risks of significant complications including cerebrospinal fluid leak and craniocervical instability. Patients sometimes do not improve or worsen after decompression, which may discourage neurosurgeons from performing Chiari decompression surgery. In this chapter, management strategies and surgical approaches are discussed that minimize the risks of complications and maximize favorable outcomes in Chiari malformation surgery.

Bridging the gap in BASCULE syndrome: A retrospective case series of a recently described clinical entity.

BACKGROUND: Bier anemic spots, cyanosis with urticaria-like eruption (BASCULE) syndrome is a recently described entity with episodic urticarial lesions and white anemic halos on a background of erythrocyanosis, commonly affecting the lower extremities. Possible association with autonomic dysfunction remains poorly understood. Existing publications are limited, but the condition is suggested as highly underrecognized. OBJECTIVE: To further characterize clinical and epidemiologic data for BASCULE syndrome. METHODS: We performed an IRB-approved retrospective chart review on patients with BASCULE syndrome evaluated at Mayo Clinic from April 2021 to November 2022. RESULTS: A total of 17 patients were identified (13 female, 4 male). Median age of onset was 12 years (range 9-17). Lower extremities were involved in all patients (17). Most patients were symptomatic with pruritus (8) or burning pain (8); three were asymptomatic. Triggers were standing (11), hot showers or hot environments (7), or no clear trigger (4). Autonomic dysfunction was present in 10 patients. Treatment responses were observed from propranolol (3) and high-dose cetirizine (1). CONCLUSION: Novel epidemiologic data from 17 pediatric and young adult patients with BASCULE syndrome further supports an association with autonomic dysfunction and suggests a higher prevalence than previously acknowledged.

Stress-Related Chronic Fatigue Syndrome: A Case Report with a Positive Response to Alpha-Methyl-P-Tyrosine (AMPT) Treatment.

Chronic fatigue syndrome (CFS) is a heterogeneous disorder with a genetically associated vulnerability of the catecholamine metabolism (e.g., catechol O-methyltransferase polymorphisms), in which environmental factors have an important impact. Alpha-methyl-p-tyrosine (AMPT; also referred to as metyrosine) is an approved medication for the treatment of pheochromocytoma. As a tyrosine hydroxylase inhibitor, AMPT may be a potential candidate for the treatment of diseases involving catecholamine alterations. However, only small-scale clinical trials have tested AMPT repurposing in a few other illnesses. The current case report compiles genetic and longitudinal biochemical data for over a year of follow-up of a male patient sequentially diagnosed with sustained overstress, neurasthenia, CFS (diagnosed in 2012 as per the Center for Disease Control (CDC/Fukuda)), and postural orthostatic tachycardia syndrome (POTS) over a 10-year period and reports the patient's symptom improvement in response to low-medium doses of AMPT. This case was recognized as a stress-related CFS case. Data are reported from medical records provided by the patient to allow a detailed response to treatment targeting the hyperadrenergic state presented by the patient. We highlight the lack of a positive response to classical approaches to treating CFS, reflecting the limitations of CFS diagnosis and available treatments to alleviate patients' symptoms. The current pathomechanism hypothesis emphasizes monoamine alterations (hyperadrenergic state) in the DA/adrenergic system and a dysfunctional autonomic nervous system resulting from sympathetic overactivity. The response of the patient to AMPT treatment highlights the relevance of pacing with regard to stressful situations and increased activity. Importantly, the results do not indicate causality between AMPT and its action on the monoamine system, and future studies should evaluate the implications of other targets.

Postural Orthostatic Tachycardia Syndrome Associated with COVID-19: A Narrative Review.

Postural orthostatic tachycardia syndrome (POTS) is a complex condition marked by an atypical autonomic response to standing, leading to orthostatic intolerance and significant tachycardia without accompanying hypotension. In recent studies, a considerable number of individuals recovering from COVID-19 have been reported to experience POTS within 6 to 8 months post-infection. Key symptoms of POTS include fatigue, difficulty with orthostatic tolerance, tachycardia, and cognitive challenges. The underlying causes of POTS following COVID-19 remain unknown, with various theories proposed such as renin-angiotensin-aldosterone system (RAAS) dysregulation, hyperadrenergic reaction, and direct viral infection. Healthcare professionals should be vigilant for POTS in patients who have recovered from COVID-19 and are experiencing signs of autonomic dysfunction and use diagnostic procedures such as the tilt-up table test for confirmation. COVID-19-related POTS should be approached with a holistic strategy. Although many patients show improvement with initial non-drug treatments, for subjects who do not respond and exhibit more severe symptoms, medication-based therapies may be necessary. The current understanding of COVID-19-related POTS is limited, underscoring the need for more research to increase knowledge and enhance treatment approaches.

Detection of G Protein-Coupled Receptor Autoantibodies in Postural Orthostatic Tachycardia Syndrome Using Standard Methodology.

BACKGROUND: Postural orthostatic tachycardia syndrome (POTS) is a disorder of orthostatic intolerance that primarily affects women of childbearing age. The underlying pathophysiology of POTS is not fully understood, but it has been suggested that autoimmunity may play a role. The aim of this study was to compare concentrations of autoantibodies to cardiovascular G protein-coupled receptors between patients with POTS and healthy controls. METHODS: Sera were collected from 116 patients with POTS (91% female; medium age, 29 years) and 81 healthy controls (84% female; medium age, 27 years) from Calgary, Canada, and Malmö, Sweden. Samples were evaluated for autoantibodies to 11 receptors (adrenergic, muscarinic, angiotensin II, and endothelin) using a commercially available enzyme-linked immunosorbent assay. RESULTS: Autoantibody concentrations against all of the receptors tested were not significantly different between controls and patients with POTS. The majority of patients with POTS (98.3%) and all controls (100%) had α1 adrenergic receptor autoantibody concentrations above the seropositive threshold provided by the manufacturer (7 units/mL). The proportion of patients with POTS versus healthy controls who fell above the diagnostic thresholds was not different for any tested autoantibodies. Receiver operating characteristic curves showed a poor ability to discriminate between patients with POTS and controls. CONCLUSIONS: Patients with POTS and healthy controls do not differ in their enzyme-linked immunosorbent assay-derived autoantibody concentrations to cardiovascular G protein-coupled receptors. These findings suggest that these tests are not useful for establishing the role of autoimmunity in POTS.

Clinical presentation and management strategies of cardiovascular autonomic dysfunction following a COVID-19 infection - A systematic review.

BACKGROUND: Cardiovascular autonomic dysfunction may reportedly occur after a coronavirus-disease-2019 (COVID-19) infection, but the available evidence is scattered. Here we sought to understand the acute and mid-term effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on cardiovascular autonomic function. METHODS: We performed a systematic PubMed, Embase, Web of Science, medRxiv, and bioRxiv search for cases of cardiovascular autonomic dysfunction during an acute SARS-CoV-2 infection or post-COVID-19 condition. The clinical-demographic characteristics of individuals in the acute versus post-COVID-19 phase were compared. RESULTS: We screened 6470 titles and abstracts. Fifty-four full-length articles were included in the data synthesis. One-hundred and thirty-four cases were identified: 81 during the acute SARS-CoV-2 infection (24 thereof diagnosed by history) and 53 in the post-COVID-19 phase. Post-COVID-19 cases were younger than those with cardiovascular autonomic disturbances in the acute SARS-CoV-2 phase (42 vs. 51 years old, p = 0.002) and were more frequently women (68% vs. 49%, p = 0.034). Reflex syncope was the most common cardiovascular autonomic disorder in the acute phase (p = 0.008) and postural orthostatic tachycardia syndrome (POTS) the most frequent diagnosis in individuals with post-COVID-19 orthostatic complaints (p < 0.001). Full recovery was more frequent in individuals with acute versus post-COVID-19 onset of cardiovascular autonomic disturbances (43% vs. 15%, p = 0.002). CONCLUSIONS: There is evidence from the scientific literature about different types of cardiovascular autonomic dysfunction developing during and after COVID-19. More data about the prevalence of autonomic disorders associated with a SARS-CoV-2 infection are needed to quantify its impact on human health.

Impact of the COVID-19 pandemic on clinical autonomic practice in Europe A survey of the European Academy of Neurology (EAN) and the European Federation of Autonomic Societies (EFAS).

OBJECTIVE: To investigate the impact of the coronavirus-disease-2019 (COVID-19) pandemic on European clinical autonomic practice. METHODS: Eighty-four neurology-driven or interdisciplinary autonomic centers in 22 European countries were invited to fill in a web-based survey between September and November 2021. RESULTS: Forty-six centers completed the survey (55%). During the first pandemic year, the number of performed tilt-table tests, autonomic outpatient and inpatient visits decreased respectively by 50%, 45% and 53%, and every-third center reported major adverse events due to postponed examinations or visits. The most frequent newly-diagnosed or worsened cardiovascular autonomic disorders after COVID-19 infection included postural orthostatic tachycardia syndrome (POTS), orthostatic hypotension, and recurrent vasovagal syncope, deemed likely related to the infection by ≥50% of the responders. Forty-seven percent of the responders also reported about people with new-onset of orthostatic intolerance, but negative tilt-table findings, and 16% about people with psychogenic pseudosyncope after COVID-19. Most patients were treated non-pharmacologically and symptomatic recovery at follow-up was observed in ≥45% of cases. By contrast, low frequencies of newly-diagnosed cardiovascular autonomic disorders following COVID-19 vaccination were reported, most frequently POTS and recurrent vasovagal syncope, and most of the responders judged a causal association unlikely. Non-pharmacological measures were the preferred treatment choice, with 50-100% recovery rates at follow-up. CONCLUSIONS: Cardiovascular autonomic disorders may develop or worsen following a COVID-19 infection, while the association with COVID-19 vaccines remains controversial. Despite the severe pandemic impact on European clinical autonomic practice, a specialized diagnostic work-up was pivotal to identify non-autonomic disorders in people with post-COVID-19 orthostatic complaints.

Symptoms of postural orthostatic tachycardia syndrome in pregnancy: a cross-sectional, community-based survey.

OBJECTIVE: To evaluate the relationship between postural orthostatic tachycardia syndrome (POTS) and pregnancy. DESIGN: Cross-sectional survey. SETTING: International. SAMPLE: A total of 8941 female patients with a diagnosis of POTS. METHODS: Data from the survey were analysed using descriptive measures and stratified for comparisons. MAIN OUTCOME MEASURES: Symptom course of POTS during pregnancy. Secondary outcomes included pregnancy loss, POTS onset during pregnancy and the impacts of a comorbid diagnosis of Ehlers-Danlos syndrome or an autoimmune disorder on symptoms during pregnancy. RESULTS: Overall, 40.8% (n = 3652) of participants reported one or more pregnancies. Most participants experienced worsening of symptoms in the first (62.6%) and third (58.9%) trimesters and 3 months after pregnancy (58.7%), and 81.1% experienced worsening symptoms at any point in their pregnancy. Most participants with worsening symptoms in the first trimester also experienced worsening symptoms in the second (61.6%) and third (68.1%) trimesters, but if they improved in the first trimester then this improvement persisted in the second and third trimesters. Of participants who reported that POTS was triggered by a specific event (41.3%), 8.1% reported pregnancy as the trigger for the onset. CONCLUSIONS: Postural orthostatic tachycardia syndrome symptoms in the first trimester of pregnancy may help predict symptom course throughout the duration of pregnancy. Some individuals may experience an initial onset of POTS during pregnancy. This novel information may guide clinicians in counselling patients with POTS who are planning pregnancy.

Autonomic Manifestations of Long-COVID Syndrome.

PURPOSE OF REVIEW: Long-COVID is a novel condition emerging from the COVID-19 pandemic. Long-COVID is characterized by symptoms commonly seen in autonomic disorders including fatigue, brain fog, light-headedness, and palpitations. This article will critically evaluate recent findings and studies on Long-COVID and its physiological autonomic manifestations. RECENT FINDINGS: Studies have reported on the prevalence of different symptoms and autonomic disorders in Long-COVID cohorts. Autonomic nervous system function, including both the parasympathetic and sympathetic limbs, has been studied using different testing techniques in Long-COVID patients. While numerous mechanisms may contribute to Long-COVID autonomic pathophysiology, it is currently unclear which ones lead to a Long-COVID presentation. To date, studies have not tested treatment options for autonomic disorders in Long-COVID patients. Long-COVID is associated with autonomic abnormalities. There is a high prevalence of clinical autonomic disorders among Long-COVID patients, with limited knowledge of the underlying mechanisms and the effectiveness of treatment options.

Dysautonomia, Hypermobility Spectrum Disorders and Mast Cell Activation Syndrome as Migraine Comorbidities.

PURPOSE OF REVIEW: Dysautonomia refers to the dysfunction of the autonomic nervous system and encompasses a wide variety of autonomic symptoms and disorders. The most common autonomic disorders are postural orthostatic tachycardia syndrome (POTS), neurocardiogenic syncope (NCS), and orthostatic hypotension (OH), which may be encountered in clinical practice as part of a triad of dysautonomia, hypermobility spectrum disorders (HSD), and mast cell activation syndrome (MCAS). Migraine is one of the most common comorbidities of POTS, HSD, and MCAS; conversely, these conditions are also prevalent in patients with migraine, especially in those with multiple systemic symptoms, such as chronic dizziness, lightheadedness, orthostatic intolerance, joint pain, and allergic symptoms. Diagnostic criteria, pathophysiologic mechanisms, and therapeutic considerations in patients with migraine and comorbid dysautonomia, HSD, and MCAS are reviewed. RECENT FINDINGS: Numerous studies indicate a significant overlap and shared pathophysiology in migraine, dysautonomia, HSD, and MCAS. In clinical setting, dysautonomia, HSD, and MCAS may present a diagnostic and therapeutic challenge in patients with migraine and require a high index of suspicion on the part of the neurologist. Diagnosis and treatment of these complex disorders in patients with migraine is essential to comprehensive patient-centric care, reduced symptom burden, and improved functional impairment secondary to both migraine and comorbidities.

Augmented ocular vestibular-evoked myogenic potentials in postural orthostatic tachycardia syndrome.

PURPOSE: To delineate the association between otolith function and changes in mean orthostatic blood pressure (BP) and heart rate (HR) in patients with postural orthostatic tachycardia syndrome (POTS). METHODS: Forty-nine patients with POTS were prospectively recruited. We analyzed the results of ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPs), as well as head-up tilt table tests using a Finometer. The oVEMP and cVEMP responses were obtained using tapping stimuli and 110 dB tone-burst sounds, respectively. We measured maximal changes in 5-s averaged systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) within 15 s and during 10 min after tilting. We compared the results with those of 20 age- and sex-matched healthy participants. RESULTS: The n1-p1 amplitude of oVEMPs was larger in patients with POTS than in healthy participants (p = 0.001), whereas the n1 latency (p = 0.280) and interaural difference (p = 0.199) did not differ between the two. The n1-p1 amplitude was a positive predictor for POTS (odds ratio 1.07, 95% confidence interval 1.01-1.13, p = 0.025). Body weight (p = 0.007) and n1-p1 amplitude of oVEMP (p = 0.019) were positive predictors for ΔSBP15s in POTS, whereas aging was a negative predictor (p = 0.005). These findings were not observed in healthy participants. CONCLUSIONS: Augmented utricular inputs may be associated with a relative predominance of sympathetic over vagal control of BP and HR, especially for an early response during orthostasis in patients with POTS. Overt sympathoexcitation due to exaggerated utricular input and lack of readaptation may be associated with the pathomechanism of POTS.

Poor health-related quality of life in postural orthostatic tachycardia syndrome in comparison with a sex- and age-matched normative population.

PURPOSE: The effect of postural orthostatic tachycardia syndrome (POTS) on health-related quality of life (HrQoL) remains poorly studied. Here, we sought to compare the HrQoL in individuals with POTS to a normative age-/sex-matched population. METHODS: Participants enrolled in the Australian POTS registry between 5 August 2021 and 30 June 2022 were compared with propensity-matched local normative population data from the South Australian Health Omnibus Survey. The EQ-5D-5L instrument was used to assess HrQoL across the five domains (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) with global health rating assessed with a visual analog scale (EQ-VAS). A population-based scoring algorithm was applied to the EQ-5D-5L data to calculate utility scores. Hierarchical multiple regression analyses were undertaken to explore predictors of low utility scores. RESULTS: A total of 404 participants (n = 202 POTS; n = 202 normative population; median age 28 years, 90.6% females) were included. Compared with the normative population, the POTS cohort demonstrated significantly higher burden of impairment across all EQ-5D-5L domains (all P < 0.001), lower median EQ-VAS (p < 0.001), and lower utility scores (p < .001). The lower EQ-VAS and utility scores in the POTS cohort were universal in all age groups. Severity of orthostatic intolerance symptoms, female sex, fatigue scores, and comorbid diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome were independent predictors of reduced HrQoL in POTS. The disutility in those with POTS was lower than many chronic health conditions. CONCLUSIONS: This is the first study to demonstrate significant impairment across all subdomains of EQ-5D-5L HrQoL in the POTS cohort as compared with a normative population. TRIAL REGISTRATION: ACTRN12621001034820.

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).

Pre-pandemic autonomic function as a predictor of the COVID clinical course in young adults.

Long coronavirus disease (COVID) is emerging as a common clinical entity in the current era. Autonomic dysfunction is one of the frequently reported post-COVID complications. We hypothesize a bi-directional relationship between the autonomic function and the COVID course. This postulation has been inadequately addressed in the literature. A retrospective cohort (pre and post-comparison) study was conducted on 30 young adults whose pre-COVID autonomic function test results were available. They were divided into case and control groups based on whether they tested reverse transcription polymerase chain reaction positive for COVID-19. Autonomic function tests were performed in both the case and control groups. COVID infection in healthy young adults shifts the sympatho-vagal balance from the pre-disease state. Postural orthostatic tachycardia syndrome was present in 35% of the COVID-affected group. COVID course parameters were found to be associated with parasympathetic reactivity and the baroreflex function. Baseline autonomic function (parasympathetic reactivity represented by Δ heart rate changes during deep breathing and 30:15 ratio during lying-to-standing test) was also associated with the COVID course, the post-COVID symptoms and the post-COVID autonomic function profile. Additionally, multiple regression analysis found that the baseline parasympathetic reactivity was a very important determinant of the clinical course of COVID, the post-COVID symptoms and the post-COVID autonomic profile. Sympatho-vagal balance shifts to parasympathetic withdrawal with sympathetic predominance due to COVID infection in healthy young adults. There is a bi-directional relationship between the autonomic function and the COVID course.