Neurologic complications of long COVID-19 syndrome are one of the leading causes of global disability. In particular, post-COVID-19 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 post-COVID-19 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-19 cognitive dysfunction ranges from 10% to 88% and is affected by viral variant and hospitalization status among other factors, whereas that of long COVID-19 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 found for post-COVID-19 brain fog, whereas established POTS therapies aimed at improving venous return and reducing heart rate may reduce symptoms of long COVID-19 POTS. Although significant recovery has been noted for many cases of post-COVID-19 brain fog and POTS, prospective studies have revealed 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-19 are needed for development of target directed therapy.

Postural orthostatic tachycardia syndrome (POTS) is a poorly understood chronic disorder characterized by an unexplained excessive increase in heartbeat upon standing. The aim of this study was to investigate psychosocial and physiological correlates and predictors of symptom severity over time in patients presenting with POTS-like symptoms. Longitudinal cohort study of patients under investigation for POTS ( n = 149). Patients completed questionnaires at 1 month preclinic appointment and 6 months later. Diagnosis, blood pressure (BP), and heart rate (HR) measures were collected from medical records. Data were analyzed using hierarchical linear multiple regression. Orthostatic and small fiber neuropathy (SFN) symptoms remained stable over time and were significantly correlated with distress, cardiac anxiety, threatening views of the illness, and cognitive-behavioral responses to symptoms, but not with emotional reactivity or social support. Baseline psychosocial factors collectively explained 48% ( F = 5.37, p < .001) of the variance in orthostatic symptoms, and 35% ( F = 3.49, p < .001) of the variance of SFN symptoms at baseline, but a nonsignificant amount of variance in symptoms at 6 months when controlling for baseline symptoms. Hemodynamic measures explained a significant 4% ( F = 3.37, p = .026) of variance of orthostatic symptoms at 6 months. Symptom burden in patients with suspected POTS remained high over 6 months. Psychosocial factors explained a large amount of the variance in symptoms at baseline. As symptoms did not change/improve over time, baseline symptoms accounted for most of the variance in symptoms at 6 months. An integrated approach addressing psychosocial factors alongside medical treatments may promote adjustment to the condition and lessen symptom burden for this group.

Evidence for the pathogenesis and treatment of postacute coronavirus disease 2019 (COVID-19) (long COVID) is lacking. As long COVID symptoms are predicted to have an impact on the global economy, clarification of the pathogenesis is urgently needed. Our experiences indicated that some symptoms were complicated by diseases established before the COVID-19 pandemic. Using a retrospective, cross-sectional study, we aimed to evaluate the diseases complicating long COVID. Using the medical records of patients with confirmed COVID-19 exhibiting residual symptoms lasting ≥60 days postinfection who visited our clinic in January 2021-February 2023, we investigated the symptoms and diseases observed. We identified diseases that occurred after COVID-19 and excluded those that were exacerbations of existing diseases. During the first visit, the most common symptoms reported in a total of 798 patients were fatigue (523 patients), anxiety (349 patients), and lack of motivation (344 patients). Complicating diseases were observed in 452 patients (57%). There were 115, 65, and 60 patients with postural tachycardia syndrome, postural syndrome without tachycardia, and mood disorders, respectively. Some diseases requiring immediate treatment included pulmonary thromboembolism, purulent shoulder arthritis, cerebellopontine angle tumors, myasthenia gravis, and cervical myelopathy. Not all symptoms that occur after COVID-19 should be treated as long COVID. Similar to normal medical treatment, a list of differential diagnoses should be maintained based on symptoms to obtain definitive diagnoses.

Postural orthostatic tachycardia syndrome (POTS) presents excessive orthostatic tachycardia and orthostatic intolerance. POTS is a common and therapeutically challenging condition affecting numerous people worldwide. As many disease entities can be confused with POTS, it becomes critical to identify this syndrome. Moreover, unbalanced autonomic nervous activity can induce cardiovascular diseases and influence the bio-feedback mechanism: Baroreflex (BR) and cerebral autoregulation (CA). BR and CA are important bio-mechanisms that maintain a stable circulatory system via the autonomic nervous system. Therefore, an impaired autonomic nervous system would lead to imbalanced BRS and CA. Consequently, we propose an advanced cross-correlation function (ACCF) time-domain approach to analyze baroreflex and cerebral autoregulation using physiological signals. This study assesses relation changes in BR and CA using ACCF in POTS for early clinical detection and diagnosis. The ACCF analysis results has thresholds that reveal that the BR of healthy and POTS groups present significantly different maximum CCF values (p < 0.05). The complete CCF index shows that the BR phase changes significantly into phase lag in the POTS group. Although CA analysis using the maximum CCF index was mildly weak, it did not differ in the POTS group. Thus, POTS only affects BR. An increasing sympathetic activity might induce an unbalanced baroreflex effect and increase cerebral vasomotor tone with CA. Maximum CCF value correlation coefficients between BR and CA indicated positive in POTS groups and negative in the healthy group. It could be speculated that the sympathetic nervous system compensates to improve BR function, which remains CA function. The advantage of this ACCF algorithm is that it helps observe BR and CA for early detection.

Dysautonomia is an abnormal clinical state with multiple etiologies, including autoimmunity. Antiphospholipid antibodies (aPL) are among the autoantibodies that have been associated with autonomic dysfunction. We have observed that an elevated total serum IgM appears to be associated with the presence of aPL in dysautonomia patients. This is a retrospective study analyzing the clinical characteristics of 45 consecutive patients with cardiac autonomic dysfunction and a persistently elevated total serum IgM. 93% of patients were female with a mean age of 32.7 years. Most patients had severely disabling disease, with a mean Karnofsky-like functional ability score of 42% (normal 100%). 93% of patients tested persistently positive for one or more aPL and all patients tested persistently positive for aPL and/or Sjogren's antibodies. No patient had lupus specific antibodies. One third of patients experienced one or more thrombotic events and 58% of patients attempting pregnancy experienced pregnancy morbidity. Lastly, 78% of aPL-positive patients treated with antithrombotic therapy experienced 50 to 100% improvement in one or more symptoms (e.g., migraine, cognitive dysfunction) recognized to be responsive to antithrombotic therapy in a subset of aPL-positive patients and 73% of patients treated with and tolerating immune modulatory therapy experienced a positive response. We propose total serum IgM as a reliable and inexpensive test that can be used to identify dysautonomia patients at risk for persistent aPL-positivity. These patients are important to identify as they have a significant risk for thrombosis and pregnancy morbidity and often experience significant symptomatic improvement with antithrombotic therapy and/or immune modulatory therapy.

Postural orthostatic tachycardia syndrome (POTS) often manifests following an acute infection. This case study reports a post-malarial onset of POTS in a young female medical student who presented with tachycardia, dizziness, presyncope, several episodes of syncope, and dysautonomic symptoms. The diagnosis of POTS was established only four years later by a tilt table test. The patient made a remarkable functional recovery from POTS, as she responded well to pharmacotherapy, primarily beta-blockers, along with lifestyle modifications. Although mild dysautonomic symptoms such as lack of thermoregulation and decreased perspiration have persisted throughout her life, the patient has managed to cope with these symptoms and function well in her daily life. To our knowledge, this is probably the first reported case of post-malarial POTS, and we recommend that the non-viral etiology of POTS, particularly the post-malarial cases, be studied in detail to understand the pathophysiology and management of this disorder.

Cervicogenic dizziness (CGD) is a disorder in which dizziness arises from cervical spine dysfunction and is diagnosed after excluding other conditions. We present a case of a 27-year-old woman with a six-year history of dizziness, neck and cervicothoracic pain, and occipital-temporal-orbital headaches. The patient also experienced occasional severe, incapacitating episodes of dizziness with vomiting. Previous evaluations, including advanced imaging, had helped rule out central, otolithic, and psychogenic causes of dizziness. Dynamic radiographs revealed signs of lateral instability of C1 while tilt table testing revealed postural orthostatic tachycardia syndrome (POTS). Over eight months, the patient underwent a regimen of gentle manual therapies and cervical stability exercises. The patient's dizziness substantially improved, as measured by the Dizziness Handicap Inventory (DHI), with scores reducing from 50 (moderate handicap) to 10 (less than mild handicap). This case highlights the importance of considering cervical spine dysfunction and associated conditions like POTS in the differential diagnosis of chronic dizziness. While conservative management including manual therapy appeared effective in this case for CGD with underlying upper cervical instability and POTS, additional research is needed on this topic.

Postural orthostatic tachycardia syndrome (POTS) is a chronic illness with unknown mortality and high morbidity, often diagnosed in the adolescent years. Published literature regarding POTS primarily focuses on the adult population, and guidance on treatment in pediatrics is sparse. The purpose of this clinical review is to evaluate the current literature on the management of POTS in pediatric patients. A search was conducted using the Cochrane database, Google Scholar, and PubMed. Studies were included if they evaluated the management of POTS, primarily in pediatric patients. Case reports and series were excluded. Eight published studies met the inclusion and exclusion criteria. To date, there are no US Food and Drug Administration-approved agents for the treatment of POTS. However, select pharmacological therapies have shown positive outcomes by addressing symptom origins, such as providing heart rate control, peripheral autonomic modulation, and targeting hypovolemia. Targeted pharmacological therapies studied in children and young adults include ivabradine, metoprolol, midodrine, pyridostigmine, intravenous crystalloid fluids, and fludrocortisone. Before adding pharmacotherapeutic interventions, non-pharmacologic interventions such as patient education, avoidance of symptom-triggering environments and medications, dietary fluid and sodium supplementation, exercise, and use of compression garments should be first attempted. Although the body of evidence for the management of POTS is expanding, additional research is needed to determine safe and efficacious dosing and establish clear guidelines for POTS in the pediatric population.

The risk of cardiovascular complications due to SARS-CoV-2 are significantly increased within the first 6 months of the infection. Patients with COVID-19 have an increased risk of death, and there is evidence that many may experience a wide range of post-acute cardiovascular complications. Our work aims to provide an update on current clinical aspects of diagnosis and treatment of cardiovascular manifestations during acute and long-term COVID-19. SARS-CoV-2 has been shown to be associated with increased incidence of cardiovascular complications such as myocardial injury, heart failure, and dysrhythmias, as well as coagulation abnormalities not only during the acute phase but also beyond the first 30 days of the infection, associated with high mortality and poor outcomes. Cardiovascular complications during long-COVID-19 were found regardless of comorbidities such as age, hypertension, and diabetes; nevertheless, these populations remain at high risk for the worst outcomes during post-acute COVID-19. Emphasis should be given to the management of these patients. Treatment with low-dose oral propranolol, a beta blocker, for heart rate management may be considered, since it was found to significantly attenuate tachycardia and improve symptoms in postural tachycardia syndrome, while for patients on ACE inhibitors or angiotensin-receptor blockers (ARBs), under no circumstances should these medications be withdrawn. In addition, in patients at high risk after hospitalization due to COVID-19, thromboprophylaxis with rivaroxaban 10 mg/day for 35 days improved clinical outcomes compared with no extended thromboprophylaxis. In this work we provide a comprehensive review on acute and post-acute COVID-19 cardiovascular complications, symptomatology, and pathophysiology mechanisms. We also discuss therapeutic strategies for these patients during acute and long-term care and highlight populations at risk. Our findings suggest that older patients with risk factors such as hypertension, diabetes, and medical history of vascular disease have worse outcomes during acute SARS-CoV-2 infection and are more likely to develop cardiovascular complications during long-COVID-19.

This study investigated the effects of deep abdominal breathing on cardiovascular parameters and symptoms in patients with postural orthostatic tachycardia syndrome (POTS) during head-up tilt-table (HUT) challenge. Thirty POTS patients completed two consecutive rounds of 10-min HUT in a crossover design. One round was HUT without intervention, and one round combined the HUT with deep breathing at a rate of 6 breaths/min. Cardiovascular parameters, including mean blood pressure and maximum and mean heart rate (HR), were measured supine and standing. Symptoms were assessed using the Vanderbilt Orthostatic Symptom Score (VOSS). During the breathing technique, the mean HR increase was -7.35 bpm (95% confidence interval [CI] = -11.71 to -2.98), and the maximum HR increase was -6.27 bpm (95% CI = -11.85 to -0.68, p = 0.041), significantly lower compared to normal breathing. Additionally, improvements were observed in all absolute cardiovascular parameters during standing, with VOSS symptoms simultaneously and significantly decreasing by -5.38 (95% CI = -10.43 to -0.36). Slow deep abdominal breathing can act as a simple technique to reduce the standing HR increase upon HUT in patients with POTS. This suggests that modulation of the cardiopulmonary neurocircuits and the respiratory pump may reduce HR increase and symptoms in patients with POTS. The findings of this study highlight the use of a safe, zero-cost, and simple behavioral tool to suggest to POTS patients for symptom relief apart from standard treatment. The observed improvements in cardiovascular parameters and symptoms offer a promising therapeutic approach for patients in times of inadequate treatment options.

Chronic fatigue syndrome (CFS), fibromyalgia (FM), silicone breast implants (SBI), Coronavirus-19 infectious disease (COVID), COVID-19 vaccination (post-COVIDvac-syndrome), Long-COVID syndrome (PCS), sick-building syndrome (SBS), post-orthostatic tachycardia syndrome (PoTS), and autoimmune/ inflammatory syndrome induced by adjuvants (ASIA) are a cluster of poorly understood medical conditions that have in common a group of ill-defined symptoms and dysautonomic features. Most of the clinical findings of this group of diseases are unspecific, such as fatigue, diffuse pain, cognitive impairment, paresthesia, tachycardia, anxiety, and depression. Hearing disturbances and vertigo have also been described in this context, the underlying pathophysiologic process for these conditions might rely on autonomic autoimmune dysbalance. The authors procced a literature review regarding to hearing and labyrinthic disturbances in CSF, FM, SBI, COVID, post-COVIDvac-syndrome, PCS, SBS, POTS, and ASIA. The PRISMA guidelines were followed, and the literature reviewed encompassed papers from January 1990 to January 2024. After the initial evaluation of the articles found in the search through Pubmed, Scielo and Embase, a total of 172 articles were read and included in this review. The prevalence of hearing loss, dizziness, vertigo and tinnitus was described and correlated with the diseases investigated in this study. There are great variability in the frequencies of symptoms found, but cochlear complaints are the most frequent in most studies. Vestibular symptoms are less reported. The main pathophysiological mechanisms are discussed. Direct effects of the virus in the inner ear or nervous pathways, impaired vascular perfusion, cross-reaction or autoimmune immunoreactivity, oxidative stress, DNA methylation, epigenetic modifications and gene activation were implicated in the generation of the investigated symptoms. In clinical practice, all patients with these autoimmune conditions who have any audiological complaint an ENT consultation followed by an audiometry are needed.

Postural orthostatic tachycardia syndrome is a debilitating disorder. We compared paediatric patients with this dysautonomia presenting with and without peak upright heart rate > 100 beats per minute. Subjects were drawn from the Postural Orthostatic Tachycardia Syndrome Program database of the Children's Hospital of Philadelphia diagnosed between 2007 and 2018. Subjects were aged 12-18 years at diagnosis with demographic data, supine and peak heart rate from 10-minute stand, symptoms, and family history. Patients were divided into "low heart rate" (peak less than 100 beats/minute) and "high heart rate" (peak at least 100 beats/minute) groups. In total, 729 subjects were included (low heart rate group: 131 patients, high heart rate group: 598 patients). The low heart rate group had later age at diagnosis (16.1 versus 15.7, p = 0.0027). Median heart rate increase was 32 beats/minute in the low heart rate group versus 40 beats/minute in the high heart rate group (p < 0.00001). Excluding palpitations and tachypalpitations, there were no differences in symptom type or frequency between groups. Paediatric patients meeting heart rate criteria for postural orthostatic tachycardia syndrome but without peak heart rate > 100 demonstrate no difference in symptom type or frequency versus those who meet both criteria. Differences observed reached statistical significance due to population size but are not clinically meaningful. This suggests that increased heart rate, but not necessarily tachycardia, is seen in these patients, supporting previous findings suggesting maximal heart rate is not a major determinant of symptom prevalence in paediatric postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) affects children and adolescents-normally fit and well and yet troubled by a myriad of everyday symptoms. Understanding the pathophysiology of this not uncommon disorder together with a review of the clinical features may well assist the attending clinicians to arrive at a clear diagnosis without the need for extensive testing and multiple investigations. Simple lifestyle measures such as increasing fluid intake, electrolyte and/or salt supplements, adequate sleep, not missing out on meals and instituting an exercise programme to improve muscle tone and strength may avoid the need of pharmacological management. These simple measures may benefit symptoms which generally improve as adulthood approaches. In addition, it is important to recognise the comorbidities that may be associated with POTS, each of which may require specific management strategies. This paper reviews the pathophysiology, clinical features and recommended treatment in the management of POTS.

The protracted form of COVID-19 known as 'long covid' was first described in 2020. Its symptoms, course and prognosis vary widely; some patients have a multi-system, disabling and prolonged illness. In 2021, ring-fenced funding was provided to establish 90 long covid clinics in England; some clinics were also established in Scotland and Wales. The NIHR-funded LOCOMOTION project implemented a UK-wide quality improvement collaborative involving ten of these clinics, which ran from 2021 to 2023. At regular online meetings held approximately 8-weekly, participants prioritised topics, discussed research evidence and guidelines, and presented exemplar case histories and clinic audits. A patient advisory group also held a priority-setting exercise, participated in quality meetings and undertook a service evaluation audit. The goal of successive quality improvement cycles aimed at changing practice to align with evidence was sometimes hard to achieve because definitive evidence did not yet exist in this new condition; many patients had comorbidities; and clinics were practically constrained in various ways. Nevertheless, much progress was made and a series of 'best practice' guides was produced, covering general assessment and management; breathing difficulties; orthostatic tachycardia and other autonomic symptoms; fatigue and cognitive impairment; and vocational rehabilitation. This paper summarises key findings with the frontline clinician in mind.

Postural orthostatic tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance characterized by various symptoms such as dizziness, lightheadedness, and increased heart rate. Conflicting reports exist regarding the prevalence of anxiety and depression in adults with POTS, while data on pediatric POTS remains scarce. A retrospective analysis of pediatric patients aged 11-17 years with POTS, who underwent autonomic testing at Nemours Children's Hospital in Orlando, Florida, was conducted. The patients were screened for anxiety, using the Severity Measure for Generalized Anxiety Disorder-Child Age 11-17 years (GAD-7) questionnaire, and depression, using PHQ-9 Modified for Adolescence (PHQ-A) for depression. The prevalence rates of anxiety and depression in the study cohort were compared to historical data from similar age groups in the existing literature. The study was approved by the Nemours Children's Hospital Institutional Review Board. The cohort comprised 27 children with POTS (26 females, age 15.8±1.6 years). Overall, 74% exhibited moderate-to-severe anxiety, depression, or both, with 44% having comorbid anxiety and depression. In total, 4/27 (14%) had pure depression and 4/27 (14%) had pure anxiety. Six patients had no depression or anxiety. On average, POTS symptoms began 1.9±1.3 years before diagnosis. Eleven patients took stable doses of psychotropic medications. After a follow-up period of 5.1±1.7 months of POTS therapy, seven patients had follow-up questionnaires. In 4/7 patients, the depression severity improved, and in 3/7 patients, the anxiety severity improved. Patients were not actively treated for depression and anxiety during this time. Anxiety and depression are prevalent among pediatric patients with POTS. While preliminary data suggests POTS therapy may alleviate these psychological symptoms, further longitudinal studies are warranted to explore the therapeutic impact in greater detail.

The objective of this study was to examine the utility of the acceleration index observed in an electrocardiogram (ECG) for the prediction of the effectiveness of orthostatic training in pediatric patients diagnosed with postural orthostatic tachycardia syndrome (POTS). This investigation focused on children diagnosed with POTS and undergoing orthostatic training at the Department of Pediatrics of Peking University First Hospital from January 2012 to October 2022. Specifically, patients hospitalized from January 2012 to December 2019 were included in the training set (54 cases), while those hospitalized from January 2020 to October 2022 were included in the external validation set (37 cases). All children received a 3-month orthostatic training, and the baseline symptom score (SS) was calculated in agreement with the pretreatment orthostatic intolerance symptom frequency. Additionally, we determined post-treatment SS during follow-up via telephone after the 3-month treatment. Children with a decrease in post-treatment SS by ≥ 50% of the baseline were considered as responders; otherwise, they were considered as non-responders. Demographic data (age, sex, and body mass index), hemodynamic parameters (supine blood pressure, time to achieve a positive standing test, maximum increase in heart rate during the standing test, maximal heart rate reached during the standing test, and blood pressure at the point of maximal heart rate during the standing test), and electrocardiographic parameters (RR interval in the supine position, shortest RR interval in the upright position, and acceleration index) were collected from all the children prior to treatment. Univariate and multivariate regression analysis were conducted to investigate factors associated with the efficacy of orthostatic training. The predictive value of these indicators for the therapeutic effectiveness of orthostatic training in children with POTS was evaluated using receiver operating characteristic (ROC) analysis, and the indicators were validated using the validation set. Among the 54 children in the training set, 28 responded to orthostatic training, and 26 were nonresponsive. Compared with the non-responders, the responders demonstrated a significant reduction in acceleration index (P < 0.01). The ROC curve for the predictive value of the acceleration index exhibited an area under the curve = 0.81 (95% confidence interval: 0.685-0.926). With the acceleration index threshold < 27.93%, the sensitivity and specificity in the prediction of orthostatic training efficacy among children with POTS were 85.7% and 69.2%, respectively. The external validation results demonstrated that using acceleration index < 27.93% as the threshold, the sensitivity, specificity, and accuracy of predicting orthostatic training efficacy among children with POTS were 89.5%, 77.8%, and 83.8%, respectively. Electrocardiographic acceleration index can be used to predict the effectiveness of orthostatic training in treating children with POTS. • Postural orthostatic tachycardia syndrome (POTS) is a chronic orthostatic intolerance involving multiple mechanisms. Autonomic dysfunction is one of the main mechanisms of POTS in children and could be treated with orthostatic training. • In order to improve the efficacy of orthostatic training in children with POTS, it is particularly important to identify the patients with autonomic dysfunction as the main mechanism before the treatment. • We found acceleration index of the electrocardiogram (ECG) can be used as a satisfactory index to predict the efficacy of orthostatic training in the treatment of POTS in children. • Using the acceleration index to predict the efficacy of orthostatic training on POTS in children is easy to be popularized in hospitals at all levels because it is non-invasive, convenient, and not expensive.

Heart rate (HR) stands as a prognostic indicator of cardiovascular disease and a modifiable risk factor in heart failure (HF). Medication intolerance can curtail the application of conventional HR-lowering β-blockers to the optimum target dose. Ivabradine (IVA), a specific negative-chronotropic agent, selectively inhibits I f current in pacemaker cells of the sinoatrial node without depressing myocardial contractility or comprising hemodynamics. This review summarized ivabradine's clinical labeled and off-label uses and mechanism of action focusing on the clinical outcomes. PubMed was searched up to January 2024 using the main keywords of IVA, coronary artery disease (CAD), HF, postural tachycardia syndrome (POTS), and tachyarrhythmia. To comprehensively review IVA's clinical indications, mechanisms, and therapeutic effects, all studies investigating treatment with IVA in humans were included, comprising different types of studies such as randomized controlled trials and longitudinal prospective observational studies. After screening, 141 studies were included in our review. A large number of reviewed articles were allocated to heart failure with reduced ejection fraction and CAD, suggesting IVA as an alternative to β-blockers in case of contraindications or intolerance. The beneficial effects of IVA as premedication for coronary computed tomography angiography, HR lowering in POTS, and inappropriate sinus tachycardia constituted most studies among off-label uses. The promising results have been reported on the efficacy of IVA in controlling HR, especially in patients with inappropriate sinus tachycardia or POTS. Owing to the unique mechanism of action, IVA has the potential to be used more frequently in future clinical practice.

Dizziness is a frequent complaint encountered in neurology clinics. Dizziness can be spontaneous or triggered, which includes orthostatic dizziness. Orthostatic dizziness can be acute (reflex/vasovagal syncope), chronic (orthostatic hypotension (OH), or postural orthostatic tachycardia syndrome (POTS). Since dizziness has numerous causes, these patients undergo extensive investigations before a diagnosis is made. Here, we describe five patients who presented with dizziness and were diagnosed to have POTS on evaluation. We conducted a retrospective study of patients who presented to the Department of Neurology from August 2020 to November 2021 with the complaint of dizziness and were diagnosed with POTS. The clinical history, neurological examination, treatment response, routine blood investigations, magnetic resonance imaging (MRI) brain, and autonomic function tests (AFTs) of the patients were reviewed from patients' clinical records. Patients with dizziness and with diagnosis other than POTS were excluded from the study. Among the five patients, males were predominant with a male to female ratio of 3:2. All the patients were in their early fourth decade with a mean age of 35.4 years. The presenting symptom was dizziness, and the key associated symptoms were anxiety and headache. Due to the orthostatic nature of symptoms and absence of orthostatic fall in blood pressure (BP), a detailed AFT was carried out, leading to the diagnosis of POTS. Patients were assessed at 3-6 months after treatment and there was a moderate response in one and no response in the remaining four patients. POTS should be considered a possible etiology when patients present with orthostatic dizziness in the absence of orthostatic fall in BP. Anxiety and headache may be associated with this type of dizziness.

Postural orthostatic tachycardia syndrome (POTS) occurs in approximately 30% of people with highly symptomatic post-COVID-19 condition (PCC). It involves several symptoms that limit physical and psychological functions and cause reduced quality of life. Evidence for different treatments of POTS and PCC is limited, and this study aimed to evaluate the feasibility of individually tailored physical exercise. The secondary aim of the study was to evaluate the preliminary effectiveness of this intervention. Twenty-six participants (81% female, median age 41 years) were enrolled and performed individually tailored endurance and strength training, with progression, for twelve weeks. During the intervention period, the participants had weekly support from a physiotherapist. Feasibility was evaluated with good compliance, with 76% adherence to exercise prescription and 96% completing the study protocol. The treatment was safe, and the evaluation methods (questionnaires, physical assessments, and accelerometer monitoring) were judged to be feasible. After the intervention, improvements in symptom burden as well as in psychological and physical functions were observed. In conclusion, future randomized controlled trials can be performed with only minor adjustments and could include questionnaires, physical assessment and accelerometer monitoring, which were demonstrated as feasible by this study.

Postural Orthostatic Tachycardia Syndrome (POTS) affects up to 1% of the US population, predominantly women, and is characterized by a complex, elusive etiology and heterogeneous phenotypes. This review delves into the intricate physiology and etiology of POTS, decoding the roles of the sinoatrial node, the autonomic nervous system, fluid dynamics, and the interplay between the immune and endocrine systems. It further examines key contributing factors such as dysautonomia, thoracic hypovolemia, autonomic neuropathies, sympathetic denervation, autoimmune responses, and associations with conditions such as small-fiber neuropathy and mast cell activation syndrome. Given the numerous mysteries surrounding POTS, we also cautiously bring attention to sinoatrial node and myocardial function, particularly in how the heart responds to stress despite exhibiting a normal cardiac phenotype at rest. The potential of genomic research in elucidating the underlying mechanisms of POTS is emphasized, suggesting this as a valuable approach that is likely to improve our understanding of the genetic underpinnings of POTS. The review introduces a tentative classification system for the etiological factors in POTS, which seeks to capture the condition's diverse aspects by categorizing various etiological factors and acknowledging co-occurring conditions. This classification, while aiming to enhance understanding and optimize treatment targets, is presented as a preliminary model needing further study and refinement. This review underscores the ongoing need for research to unravel the complexities of POTS and to develop targeted therapies that can improve patient outcomes.

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.

An increasing number of reports suggest an association between a newly recognized disease cluster and significant and often disabling gastrointestinal (GI) symptoms. This cluster is composed of diagnoses of hypermobility spectrum disorders (HSDs) such as joint hypermobility and hypermobile variant Ehlers-Danlos syndrome (hEDS), postural orthostatic tachycardia syndrome (POTS), and mast cell activation syndrome (MCAS). The diagnosis of these entities remains a challenge, as the pathophysiology of each has not been completely elucidated and the diagnostic criteria continue to evolve. This article describes a cohort of young adult females who shared similar GI symptoms, with intractable nausea and vomiting being most prominent and gastroesophageal reflux disease and constipation also occurring. Most strikingly, these females also exhibited or reported a history of HSD, hEDS, POTS, and/or MCAS. The clinical course of their GI symptoms was remarkable for considerable challenges in management, and artificial nutritional support proved necessary for some. This article describes the clinical features and outcomes of their GI manifestations, examines how these manifestations might be linked to their systemic syndromes, and discusses whether a shared pathophysiology exists. Pending the definition of a common thread between these conditions, this article seeks to raise awareness of their clinical definitions and foster research that will hopefully improve outcomes for these patients.

Postural hyperventilation has been implicated as a cause of postural orthostatic tachycardia syndrome (POTS), yet the precise mechanisms underlying the heightened breathing response remain unclear. This study challenges current hypotheses by revealing that exaggerated peripheral chemoreceptor activity is not the primary driver of postural hyperventilation. Instead, significant contributions from reduced stroke volume and compromised brain perfusion during orthostatic stress were identified. These findings shed light on our understanding of POTS pathophysiology, emphasizing the critical roles of systemic hemodynamic status. Further research should explore interventions targeting stroke volume and brain perfusion for more effective clinical management of POTS.

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 (HF = 4030.24 ms and 643.92 ms) indicated intact vagal function. High low-frequency systolic blood pressure variability (LF = 20.93 mmHg), 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.

Orthostatic intolerance (OI) is a key symptom of long COVID; however, the pathophysiology remains unknown. Among 688 long COVID patients who visited our clinic during the period from February 2021 to April 2023, 86 patients who were suspected of having OI and who underwent an active standing test (ST) were investigated to elucidate the clinical characteristics of OI in patients with long COVID. Of the 86 patients, 33 patients (38%) were ST-positive. Nausea and tachycardia in daily life were frequent complaints in the ST-positive group. The increase in heart rate (HR) during the ST was significantly greater during a 10-min period after standing in the ST-positive group (+ 30 bpm) than in the ST-negative group (+ 16 bpm). The initial increase in diastolic blood pressure (DBP) just after standing was significantly greater in the ST-positive group (+ 14 mmHg) than in the ST-negative group (+ 9 mmHg). Serum cortisol levels in the ST-positive patients aged over 20 years were higher and growth hormone levels in the patients under 20 years of age were lower than those in the ST-negative group. Autonomous nervous symptoms, transient DBP rise with increasing HR after standing, and endocrine dysfunctions are helpful for detecting OI related to long COVID.