COVID-19 Dysautonomia

Low-dose naltrexone for post-COVID fatigue syndrome: a study protocol for a double-blind, randomised trial in British Columbia

INTRODUCTION

A significant proportion of individuals suffering from post COVID-19 condition (PCC, also known as long COVID) can present with persistent, disabling fatigue similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-viral fatigue syndromes. There remains no clear pharmacological therapy for patients with this subtype of PCC, which can be referred to as post-COVID fatigue syndrome (PCFS). A low dose of the opioid antagonist naltrexone (ie, low-dose naltrexone (LDN)) has emerged as an off-label treatment for treating fatigue and other symptoms in PCC. However, only small, non-controlled studies have assessed LDN in PCC, so randomised trials are urgently required.

METHODS AND ANALYSIS

A prospective, randomised, double-blind, parallel arm, placebo-controlled phase II trial will be performed to assess the efficacy of LDN for improving fatigue in PCFS. The trial will be decentralised and open to eligible individuals throughout the Canadian province of British Columbia (BC). Participants will be recruited through the province-wide Post-COVID-19 Interdisciplinary Clinical Care Network (PC-ICCN) and research volunteer platform (REACH BC). Eligible participants will be 19-69 years old, have had a confirmed or physician-suspected SARS-CoV-2 infection at least 3 months prior and meet clinical criteria for PCFS adapted from the Institute of Medicine ME/CFS criteria. Individuals who are taking opioid medications, have a history of ME/CFS prior to COVID-19 or history of significant liver disease will be excluded. Participants will be randomised to an LDN intervention arm (n=80) or placebo arm (n=80). Participants in each arm will be prescribed identical capsules starting at 1 mg daily and follow a prespecified schedule for up-titration to 4.5 mg daily or the maximum tolerated dose. The trial will be conducted over 16 weeks, with assessments at baseline, 6, 12 and 16 weeks. The primary outcome will be fatigue severity at 16 weeks evaluated by the Fatigue Severity Scale. Secondary outcomes will include pain Visual Analogue Scale score, overall symptom severity as measured by the Patient Phenotyping Questionnaire Short Form, 7-day step count and health-related quality of life measured by the EuroQol 5-Dimension questionnaire.

ETHICS AND DISSEMINATION

The trial has been authorised by Health Canada and approved by The University of British Columbia/Children's and Women's Health Centre of British Columbia Research Ethics Board. On completion, findings will be disseminated to patients, caregivers and clinicians through engagement activities within existing PCC and ME/CFS networks. Results will be published in academic journals and presented at conferences.

TRIAL REGISTRATION NUMBER

NCT05430152.

Autonomic cardiac function in children and adolescents with long COVID: a case-controlled study

Although the mechanisms underlying the pathophysiology of long COVID condition are still debated, there is growing evidence that autonomic dysfunction may play a role in the long-term complications or persisting symptoms observed in a significant proportion of patients after SARS-CoV-2 infection. However, studies focused on autonomic dysfunction have primarily been conducted in adults, while autonomic function has not yet been investigated in pediatric subjects. In this study, for the first time, we assessed whether pediatric patients with long COVID present abnormalities in autonomic cardiac function. Fifty-six long COVID pediatric patients (mean age 10.3 ± 3.8 y) and 27 age-, sex-, and body surface area-matched healthy controls (mean age 10.4 ± 4.5y) underwent a standard 12-lead electrocardiography (ECG) and 24-h ECG Holter monitoring. Autonomic cardiac function was assessed by time-domain and frequency-domain heart rate variability parameters. A comprehensive echocardiographic study was also obtained by two-dimensional echocardiography and tissue Doppler imaging. Data analysis showed that pediatric patients with long COVID had significant changes in HRV variables compared to healthy controls: significantly lower r-MSSD (root mean square of successive RR interval differences, 47.4 ± 16.9 versus 60.4 ± 29.1, p = 0.02), significant higher values VLF (very low frequency, 2077.8 ± 1023.3 versus 494.3 ± 1015.5 ms, p = 0.000), LF (low frequency, 1340.3 ± 635.6 versus 354.6 ± 816.8 ms, p = 0.000), and HF (high frequency, 895.7 ± 575.8 versus 278.9 ± 616.7 ms, p = 0.000). No significant differences were observed between the two groups both in systolic and diastolic parameters by echocardiography.  Conclusion: These findings suggest that pediatric patients with long COVID have an imbalance of cardiac autonomic function toward a relative predominance of parasympathetic tone, as already reported in adult patients with long COVID. Further studies are needed to clarify the clinical significance of this autonomic dysfunction and demonstrate its role as a pathophysiological mechanism of long COVID, paving the way for effective therapeutic and preventive strategies. What is Known: • Long Covid in children has been described globally, but studies have mostly focused on collecting the temporal evolution of persisting symptoms. What is New: • Cardiac autonomic imbalance toward a relative predominance of parasympathetic tone is a mechanism underlying Long Covid in children, as also described in adults.

Postural Tachycardia Syndrome and COVID-19: Focus on Ivabradine Therapy

In this article we discuss the association of postural orthostatic tachycardia syndrome (POTS) with coronavirus-19 (COVID-19), ivabradine's unique mechanism of action, and its use in POTS patients. We highlight the pathophysiology and common etiologies of POTS, including preceding viral infections, vaccines, trauma, surgeries, and other stressors. COVID-19, a viral illness, has been associated with POTS through a variety of mechanisms that are not yet well understood. The initial management strategy for POTS is largely nonpharmacological, focusing on increasing venous return to the heart through physical therapy or other exercise activities. Ivabradine is a selective inhibitor of the funny sodium channels within the sinoatrial node. This unique mechanism of action allows for the reduction of heart rate without any effect on the heart's ionotropic activity. With an increase in the number of POTS cases, especially during the COVID pandemic, the importance of utilizing new medications and management strategies for POTS becomes imperative. Though ivabradine is currently only approved for the management of patients with coronary artery disease and heart failure by the Food and Drug Administration (FDA), it has also proven to be effective at reducing symptoms among patients with refractory POTS, and thus, should be considered for the management of patients who do not respond to initial treatment strategies.

Elevated Arterial Blood Pressure as a Delayed Complication Following COVID-19-A Narrative Review

Arterial hypertension is one of the most common and significant cardiovascular risk factors. There are many well-known and identified risk factors for its development. In recent times, there has been growing concern about the potential impact of COVID-19 on the cardiovascular system and its relation to arterial hypertension. Various theories have been developed that suggest a connection between COVID-19 and elevated blood pressure. However, the precise link between SARS-CoV-2 infection and the long-term risk of developing hypertension remains insufficiently explored. Therefore, the primary objective of our study was to investigate the influence of COVID-19 infection on blood pressure elevation and the subsequent risk of developing arterial hypertension over an extended period. To accomplish this, we conducted a thorough search review of relevant papers in the PubMed and SCOPUS databases up to 3 September 2023. Our analysis encompassed a total of 30 eligible articles. Out of the 30 papers we reviewed, 19 of them provided substantial evidence showing a heightened risk of developing arterial hypertension following COVID-19 infection. Eight of the studies showed that blood pressure values increased after the infection, while three of the qualified studies did not report any notable impact of COVID-19 on blood pressure levels. The precise mechanism behind the development of hypertension after COVID-19 remains unclear, but it is suggested that endothelial injury and dysfunction of the renin-angiotensin-aldosterone system may be contributory. Additionally, changes in blood pressure following COVID-19 infection could be linked to lifestyle alterations that often occur alongside the illness. Our findings emphasize the pressing requirement for thorough research into the relationship between COVID-19 and hypertension. These insights are essential for the development of effective prevention and management approaches for individuals who have experienced COVID-19 infection.

Postural orthostatic tachycardia syndrome and other related dysautonomic disorders after SARS-CoV-2 infection and after COVID-19 messenger RNA vaccination

The COVID-19 pandemic has caused a challenge for our society due to the post-acute sequelae of the disease. Persistent symptoms and long-term multiorgan complications, known as post-acute COVID-19 syndrome, can occur beyond 4 weeks from the onset of the COVID-19 infection. Postural orthostatic tachycardia syndrome (POTS) is considered a variety of dysautonomia, which is characterized by chronic symptoms that occur with standing and a sustained increase in heart rate, without orthostatic hypotension. POTS can lead to debilitating symptoms, significant disability, and impaired quality of life. In this narrative review, the etiopathogenic basis, epidemiology, clinical manifestations, diagnosis, treatment, prognosis, and socioeconomic impact of POTS, as well as other related dysautonomic disorders, after COVID-19 infection and SARS-CoV-2 postvaccination, were discussed. After a search conducted in March 2023, a total of 89 relevant articles were selected from the PubMed, Google Scholar, and Web of Science databases. The review highlights the importance of recognizing and managing POTS after COVID-19 infection and vaccination, and the approach to autonomic disorders should be known by all specialists in different medical areas. The diagnosis of POTS requires a comprehensive clinical assessment, including a detailed medical history, physical examination, orthostatic vital signs, and autonomic function tests. The treatment of POTS after COVID-19 infection or vaccination is mainly focused on lifestyle modifications, such as increased fluid and salt intake, exercise, and graduated compression stockings. Pharmacotherapy, such as beta-blockers, fludrocortisone, midodrine, and ivabradine, may also be used in selected cases. Further research is needed to understand the underlying mechanisms, risk factors, and optimal treatment strategies for this complication.

Assessment and Therapeutic Modulation of Heart Rate Variability: Potential Implications in Patients with COVID-19

Cardiac damage has been attributed to SARS-CoV-2-related pathology contributing to increased risk of vascular events. Heart rate variability (HRV) is a parameter of functional neurocardiac integrity with low HRV constituting an independent predictor of cardiovascular mortality. Whether structural cardiac damage translates into neurocardiac dysfunction in patients infected with SARS-CoV-2 remains poorly understood. Hypothesized mechanisms of possible neurocardiac dysfunction in COVID-19 comprise direct systemic neuroinvasion of autonomic control centers, ascending virus propagation along cranial nerves and cardiac autonomic neuropathy. While the relationship between the autonomic nervous system and the cytokine cascade in general has been studied extensively, the interplay between the inflammatory response caused by SARS-CoV-2 and autonomic cardiovascular regulation remains largely unclear. We reviewed the current literature on the potential diagnostic and prognostic value of autonomic neurocardiac function assessment via analysis of HRV including time domain and spectral analysis techniques in patients with COVID-19. Furthermore, we discuss potential therapeutic targets of modulating neurocardiac function in this high-risk population including HRV biofeedback and the impact of long COVID on HRV as well as the approaches of clinical management. These topics might be of particular interest with respect to multimodal pandemic preparedness concepts.

Postural Orthostatic Tachycardia Syndrome After COVID-19: A Systematic Review of Therapeutic Interventions

ABSTRACT

Postural orthostatic tachycardia syndrome (POTS) is a clinical syndrome of inappropriate increase in heart rate on standing that has been recently also associated with Coronavirus Disease 2019 (COVID-19) as part of the postacute sequelae of COVID-19 (PASC) or long-COVID. We herein aimed to systematically review reported cases of POTS after COVID-19 and determine the characteristics of the subjects, the diagnostic approach used, and the treatment strategies. We searched the literature according to the following criteria: (1) diagnosis of POTS according to standard definition; (2) timely association with a probable or definite diagnosis of COVID-19; and (3) a description of the individual subject(s). We identified 21 reports meeting criteria between March 2020 and September 2022, including 68 subjects (51 females and 17 males, 3:1 ratio) with a mean age of 34 ± 12 years, with reports deriving from the United States, Norway, Sweden, Israel, Ireland, United Kingdom, Singapore, and Japan. Most cases had mild COVID-19 symptoms. The most common POTS symptoms were palpitations, chest pain, lightheadedness, and debilitating fatigue. The diagnosis was established by means of head-up tilt table or active stand test. Nonpharmacologic treatments (fluids, sodium intake, and compression stockings) were virtually always used, but largely ineffective. Subjects received different treatments, the most common being beta-adrenergic blockers (ie, propranolol), mineral corticosteroids (ie, fludrocortisone), midodrine, and ivabradine. Symptoms tended to improve over time, but most patients remained symptomatic for several months. In conclusion, POTS after COVID-19 is a clinical condition affecting young individuals, and disproportionately young women, occurring as part of PASC-long-COVID, often debilitating, which can be easily diagnosed with a thorough clinical assessment and measuring changes in orthostatic heart rate and blood pressure. POTS after COVID-19 seems to be poorly responsive to nonpharmacological treatments but with symptoms improving with pharmacological interventions. Given the limited data available, additional research is urgently needed with respect to its epidemiology, pathophysiology, and treatments.

High incidence of autonomic dysfunction and postural orthostatic tachycardia syndrome in patients with long-COVID: Implications for management and healthcare planning

BACKGROUND

Autonomic dysfunction including postural orthostatic tachycardia syndrome (POTS) has been reported in individuals with post-acute sequelae of Covid-19 (PASC). However, the degree of dysautonomia in PASC has not been compared to those with POTS and healthy controls.

METHODS

All participants were prospectively enrolled between 5^th August 2021 and 31^st October 2022. Autonomic testing included beat-to-beat hemodynamic monitoring to assess respiratory sinus arrhythmia, Valsalva ratio and orthostatic changes during a 10-minute active standing test as well as Sudomotor assessment. The Composite Autonomic Symptom Score (COMPASS-31) was used to assess symptoms and the Euroquol 5-Dimension survey (EQ-5D-5L) was used to assess health-related quality of life (HrQoL) measures.

RESULTS

A total of 99 participants (n=33 PASC, n=33 POTS and n=33 healthy controls; median age 32 [18], 85.9% females) were included. Compared to healthy controls, the PASC and POTS cohorts demonstrated significantly reduced respiratory sinus arrhythmia (p<0.001), greater heart rate increase during 10-minute active standing test (p<0.001), greater burden of autonomic dysfunction evidenced by higher COMPASS-31 scores across all subdomains (all p<0.001) and poor HrQoL across all EQ-5D-5L domains (all p<0.001), lower median EQ-VAS (p<0.001) and lower utility scores (p<0.001). The majority (79%) of those with PASC met the internationally established criteria for POTS.

CONCLUSION

The prevalence of autonomic symptomology or POTS was high in those with PASC, leading to poor HrQoL and high health disutility. Autonomic testing should be routinely undertaken in those with PASC to aid diagnosis and direct appropriate management to improve health outcomes.

TRIAL REGISTRATION

ANZCTR 12621000476831.

Cognitive impairment in post-acute sequelae of COVID-19 and short duration myalgic encephalomyelitis patients is mediated by orthostatic hemodynamic changes

Introduction

Cognitive impairment is experienced by people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-acute sequelae of COVID-19 (PASC). Patients report difficulty remembering, concentrating, and making decisions. Our objective was to determine whether orthostatic hemodynamic changes were causally linked to cognitive impairment in these diseases.

Methods

This prospective, observational cohort study enrolled PASC, ME/CFS, and healthy controls. All participants underwent clinical evaluation and assessment that included brief cognitive testing before and after an orthostatic challenge. Cognitive testing measured cognitive efficiency which is defined as the speed and accuracy of subject's total correct responses per minute. General linear mixed models were used to analyze hemodynamics and cognitive efficiency during the orthostatic challenge. Additionally, mediation analysis was used to determine if hemodynamic instability induced during the orthostatic challenge mediated the relationship between disease status and cognitive impairment.

Results

Of the 276 participants enrolled, 256 were included in this study (34 PASC, 71 < 4 year duration ME/CFS, 69 > 10 year ME/CFS duration, and 82 healthy controls). Compared to healthy controls, the disease cohorts had significantly lower cognitive efficiency scores immediately following the orthostatic challenge. Cognitive efficiency remained low for the >10 year ME/CFS 2 and 7 days after orthostatic challenge. Narrow pulse pressure less than 25% of systolic pressure occurred at 4 and 5 min into the orthostatic challenge for the PASC and ME/CFS cohorts, respectively. Abnormally narrow pulse pressure was associated with slowed information processing in PASC patients compared to healthy controls (-1.5, p = 0.04). Furthermore, increased heart rate during the orthostatic challenge was associated with a decreased procedural reaction time in PASC and < 4 year ME/CFS patients who were 40 to 65 years of age.

Discussion

For PASC patients, both their disease state and hemodynamic changes during orthostatic challenge were associated with slower reaction time and decreased response accuracy during cognitive testing. Reduced cognitive efficiency in <4 year ME/CFS patients was associated with higher heart rate in response to orthostatic stress. Hemodynamic changes did not correlate with cognitive impairment for >10 year ME/CFS patients, but cognitive impairment remained. These findings underscore the need for early diagnosis to mitigate direct hemodynamic and other physiological effects on symptoms of cognitive impairment.

Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients

Several disabling symptoms potentially related to dysautonomia have been reported in "long-COVID" patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31-43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0-16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

Neurorecovery after Critical COVID-19 Illness

With the hundreds of millions of people worldwide who have been, and continue to be, affected by pandemic coronavirus disease (COVID-19) and its chronic sequelae, strategies to improve recovery and rehabilitation from COVID-19 are critical global public health priorities. Neurologic complications have been associated with acute COVID-19 infection, usually in the setting of critical COVID-19 illness. Neurologic complications are also a core feature of the symptom constellation of long COVID and portend poor outcomes. In this article, we review neurologic complications and their mechanisms in critical COVID-19 illness and long COVID. We focus on parallels with neurologic disease associated with non-COVID critical systemic illness. We conclude with a discussion of how recent findings can guide both neurologists working in post-acute neurologic rehabilitation facilities and policy makers who influence neurologic resource allocation.

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

OBJECTIVE

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

RESEARCH DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

COVID-19 Induced Postural Orthostatic Tachycardia Syndrome (POTS): A Review

POTS (Postural Orthostatic Tachycardia Syndrome) is a multisystem disorder characterized by the abnormal autonomic response to an upright posture, causing orthostatic intolerance and excessive tachycardia without hypotension. Recent reports suggest that a significant percentage of COVID-19 survivors develop POTS within 6 to 8 months of infection. Prominent symptoms of POTS include fatigue, orthostatic intolerance, tachycardia, and cognitive impairment. The exact mechanisms of post-COVID-19 POTS are unclear. Still, different hypotheses have been given, including autoantibody production against autonomic nerve fibers, direct toxic effects of SARS-CoV-2, or sympathetic nervous system stimulation secondary to infection. Physicians should have a high suspicion of POTS in COVID-19 survival when presented with symptoms of autonomic dysfunction and should conduct diagnostic tests like the Tilt table and others to confirm it. The management of COVID-19-related POTS requires a comprehensive approach. Most patients respond to initial non-pharmacological options, but when the symptoms become more severe and they do not respond to the non-pharmacological approach, pharmacological options are considered. We have limited understanding and knowledge of post-COVID-19 POTS, and further research is warranted to improve our understanding and formulate a better management plan.

Prognosis value of pupillometry in COVID-19 patients admitted in intensive care unit

INTRODUCTION

ICU patients with SARS-CoV-2-related pneumonia are at risk to develop a central dysautonomia which can contribute to mortality and respiratory failure. The pupillary size and its reactivity to light are controlled by the autonomic nervous system. Pupillometry parameters (PP) allow to predict outcomes in various acute brain injuries. We aim at assessing the most predictive PP of in-hospital mortality and the need for invasive mechanical ventilation (IV).

MATERIAL AND METHODS

We led a prospective, two centers, observational study. We recruited adult patients admitted to ICU for a severe SARS-CoV-2 related pneumonia between April and August 2020. The pupillometry was performed at admission including the measurement of baseline pupillary diameter (PD), PD variations (PDV), pupillary constriction velocity (PCV) and latency (PDL).

RESULTS

Fifty patients, 90 % males, aged 66 (60-70) years were included. Seven (14 %) patients died in hospital. The baseline PD (4.1 mm [3.5; 4.8] vs 2.6 mm [2.4; 4.0], P = 0.009), PDV (33 % [27; 39] vs 25 % [15; 36], P = 0.03) and PCV (3.5 mm.s^-1 [2.8; 4.4] vs 2.0 mm.s^-1 [1.9; 3.8], P = 0.02) were significantly lower in patients who will die. A PD value <2.75 mm was the most predictive parameter of in-hospital mortality, with an AUC = 0.81, CI 95 % [0.63; 0.99]. Twenty-four (48 %) patients required IV. PD and PDV were significantly lower in patients who were intubated (3.5 mm [2.8; 4.4] vs 4.2 mm [3.9; 5.2], P = 0.03; 28 % [25; 36 %] vs 35 % [32; 40], P = 0.049, respectively).

CONCLUSIONS

A reduced baseline PD is associated with bad outcomes in COVID-19 patients admitted in ICU. It is likely to reflect a brainstem autonomic dysfunction.

Long COVID and hypertension-related disorders: a report from the Japanese Society of Hypertension Project Team on COVID-19

The coronavirus disease 2019 (COVID-19) affects infected patients even after the acute phase and impairs their health and quality of life by causing a wide variety of symptoms, referred to as long COVID. Although the evidence is still insufficient, hypertension is suspected to be a potential risk factor for long COVID, and the occurrence of cardiovascular diseases seems to be a key facet of multiple conditions observed in long COVID. Nonetheless, there are few reports that comprehensively review the impacts of long COVID on hypertension and related disorders. As a sequel to our previous report in 2020 which reviewed the association of COVID-19 and hypertension, we summarize the possible influences of long COVID on hypertension-related organs, including the cardiovascular system, kidney, and endocrine system, as well as the pathophysiological mechanisms associated with the disorders in this review. Given that the clinical course of COVID-19 is highly affected by age and sex, we also review the impacts of these factors on long COVID. Lastly, we discuss areas of uncertainty and future directions, which may lead to better understanding and improved prognosis of clinical problems associated with COVID-19.

European Working Group on SARS-CoV-2: Current Understanding, Unknowns, and Recommendations on the Neurological Complications of COVID-19

The emergence of COVID-19 was rapidly followed by infection and the deaths of millions of people across the globe. With much of the research and scientific advancement rightly focused on reducing the burden of severe and critical acute COVID-19 infection, the long-term effects endured by those who survived the acute infection has been previously overlooked. Now, an appreciation for the post-COVID-19 condition, including its neurological manifestations, is growing, although there remain many unknowns regarding the aetiology and risk factors of the condition, as well as how to effectively diagnose and treat it. Here, drawing upon the experiences and expertise of the clinicians and academics of the European working group on COVID-19, we have reviewed the current literature to provide a comprehensive overview of the neurological sequalae of the post-COVID-19 condition. In this review, we provide a summary of the neurological symptoms associated with the post-COVID-19 condition, before discussing the possible mechanisms which may underly and manifest these symptoms. Following this, we explore the risk factors for developing neurological symptoms as a result of COVID-19 and the post-COVID-19 condition, as well as how COVID-19 infection may itself be a risk factor for the development of neurological disease in the future. Lastly, we evaluate how the post-COVID condition could be accurately diagnosed and effectively treated, including examples of the current guidelines, clinical outcomes and tools that have been developed to aid in this process, as well as addressing the protection provided by COVID-19 vaccines against post-COVID-19 condition. Overall, this review provides a comprehensive overview of the neurological sequalae of the post-COVID-19 condition.

Autonomic Nerve Involvement in Post-Acute Sequelae of SARS-CoV-2 Syndrome (PASC)

The novel SARS-CoV-2 virus and resulting COVID-19 global pandemic emerged in 2019 and continues into 2022. While mortality from COVID-19 is slowly declining, a subset of patients have developed chronic, debilitating symptoms following complete recovery from acute infection with COVID-19. Termed as post-acute sequelae of SARS-CoV-2 syndrome (PASC), the underlying pathophysiology of PASC is still not well understood. Given the similarity between the clinical phenotypes of PASC and postural orthostatic tachycardia syndrome (POTS), it has been postulated that dysautonomia may play a role in the pathophysiology of PASC. However, there have been only a few studies that have examined autonomic function in PASC. In this retrospective study, we performed an analysis of autonomic nerve function testing in PASC patients and compared the results with those of POTS patients and healthy controls. Our results suggest that a significant number of PASC patients have abnormal autonomic function tests, and their clinical features are indistinguishable from POTS.

Cardiac Manifestations of Post-Acute COVID-19 Infection

PURPOSE OF REVIEW

There is emerging evidence that the post-acute and chronic phases of COVID-19 infection are associated with various significant cardiovascular sequelae.

RECENT FINDINGS

Long COVID has been shown to be associated with multiple cardiovascular sequelae including direct myocardial injury, arrhythmias, and cardiomyopathies. Hypotheses on the mechanism of myocardial injury include direct viral infiltration and autoimmune dysregulation. Long COVID is associated with persistent cardiac ischemia in patients with no previous history of coronary disease, atrial and ventricular arrhythmias, and the development of new-onset heart failure in previously healthy patients. Onset of long COVID may be related to severity of the initial SARS-CoV2 infection. Cardiac MRI is a valuable tool in assessing myocarditis and the development of cardiomyopathies in the setting of long COVID. Both patients with and without pre-existing cardiovascular disease are at risk of developing myocardial injury in the setting of long COVID. Future studies will elucidate both cardiovascular mortality and cardiac rehabilitation in the post-acute and chronic phases of COVID-19.

Potential Therapeutic Benefits of Metformin Alone and in Combination with Sitagliptin in the Management of Type 2 Diabetes Patients with COVID-19

Type 2 diabetes mellitus (T2DM) is a potential risk factor for the development of COVID-19 and is associated with higher severity and mortality rates. T2DM patients are commonly treated with metformin monotherapy or metformin plus sitagliptin. In the present case-control, single-center cohort study, a total number of 112 T2DM patients suffering from COVID-19 and aged 44−62 years old were compared with 78 T2DM patients without COVID-19 and aged 42−56 years old. Both the patient group and the control group were allocated into four groups. Group A: T2DM patients with COVID-19 on metformin treatments plus standard therapy (n = 60); group B: T2DM patients with COVID-19 on metformin plus sitagliptin plus standard therapy (n = 52); group C: T2DM patients without COVID-19 on metformin treatments (n = 40); and group D: T2DM patients without COVID-19 on metformin plus sitagliptin (n = 38). The investigation duration was 2−3 weeks. Anthropometric measurements, serological and biochemical investigations, pulmonary radiological findings, and clinical outcomes were evaluated. Only 101 T2DM patients with COVID-19 continued the study, 71 (70.29%) with mild-moderate COVID-19 and 30 (29.7%) with severe COVID-19 were compared with 78 T2DM patients as a control. Inflammatory biomarkers (C reactive protein, ferritin, and procalcitonin), a lung injury biomarker (lactate dehydrogenase), and a coagulopathy biomarker (D-dimer) were elevated in severe COVID-19 patients compared with mild-moderate COVID-19 (p < 0.05) and T2DM patients (p < 0.05). However, metformin plus sitagliptin was more effective than metformin monotherapy in T2DM patients with COVID-19, as evidenced by the mitigation of oxidative stress, CT scan score, and clinical outcomes. The present study confirmed the protective effects of this combination against the development of COVID-19 severity, as most T2DM COVID-19 patients develop mild-moderate forms. Herein, the combination of metformin and sitagliptin may lead to more beneficial effects than metformin monotherapy.

Central Effects of Ivermectin in Alleviation of Covid-19-induced Dysauto-nomia

Covid-19 may be associated with various neurological disorders, including dysautonomia, a dysfunction of the autonomic nervous system (ANS). In Covid-19, hypoxia, immunoinflammatory abnormality, and deregulation of the renin-angiotensin system (RAS) may increase sympathetic discharge with dysautonomia development. Direct SARS-CoV-2 cytopathic effects and associated inflammatory reaction may lead to neuroinflammation, affecting different parts of the central nervous system (CNS), including the autonomic center in the hypothalamus, causing dysautonomia. High circulating AngII, hypoxia, oxidative stress, high pro-inflammatory cytokines, and emotional stress can also provoke autonomic deregulation and high sympathetic outflow with the development of the sympathetic storm. During SARS-CoV-2 infection with neuro-invasion, GABA-ergic neurons and nicotinic acetylcholine receptor (nAChR) are inhibited in the hypothalamic pre-sympathetic neurons leading to sympathetic storm and dysautonomia. Different therapeutic modalities are applied to treat SARS-CoV-2 infection, like antiviral and anti-inflammatory drugs. Ivermectin (IVM) is a robust repurposed drug widely used to prevent and manage mild-moderate Covid-19. IVM activates both GABA-ergic neurons and nAChRs to mitigate SARS-CoV-2 infection- induced dysautonomia. Therefore, in this brief report, we try to identify the potential role of IVM in managing Covid-19-induced dysautonomia.

COVID-19, cardiac involvement and cardiac rehabilitation: Insights from a rehabilitation perspective - State of the Art

Since the beginning of the pandemic, many novel coronavirus disease 2019 (COVID-19) patients have experienced multisystem involvement or become critically ill and treated in intensive care units, and even died. Among these systemic effects, cardiac involvement may have very important consequences for the patient’s prognosis and later life. Patients with COVID-19 may develop cardiac complications such as heart failure, myocarditis, pericarditis, vasculitis, acute coronary syndrome, and cardiac arrhythmias or trigger an accompanying cardiac disease. The ratio of COVID-19 cardiac involvement ranges between 7 and 28% in hospitalized patients with worse outcomes, longer stay in the intensive care unit, and a higher risk of death. Furthermore, deconditioning due to immobility and muscle involvement can be seen in post-COVID-19 patients and significant physical, cognitive and psychosocial impairments may be observed in some cases. Considering that the definition of health is “a state of complete physical, mental and social well-being”, individuals with heart involvement due to COVID-19 should be rehabilitated by evaluating all these aspects of the disease effect. In the light of the rehabilitation perspective and given the increasing number of patients with cardiac manifestations of COVID-19, in this review, we discuss the rehabilitation principles in this group of patients.

Understanding the Pivotal Role of the Vagus Nerve in Health from Pandemics

The COVID-19 pandemic seems endless with the regular emergence of new variants. Is the SARS-CoV-2 virus particularly evasive to the immune system, or is it merely disrupting communication between the body and the brain, thus pre-empting homeostasis? Retrospective analysis of the COVID-19 and AIDS pandemics, as well as prion disease, emphasizes the pivotal but little-known role of the 10th cranial nerve in health. Considering neuroimmunometabolism from the point of view of the vagus nerve, non-invasive bioengineering solutions aiming at monitoring and stimulating the vagal tone are subsequently discussed as the next optimal and global preventive treatments, far beyond pandemics.

Neuromuskuläre Manifestationen beim Long-COVID-Syndrom

Unter dem Long-COVID(„coronavirus disease“)-Syndrom werden Beschwerden zusammengefasst, die nach einer akuten SARS-CoV-2(„severe acute respiratory syndrome coronavirus type 2“)-Infektion auftreten, über einen Zeitraum von mehreren Wochen anhalten und nicht durch eine andere Diagnose erklärt werden können. Long-COVID wird als Multiorganmanifestation aufgefasst. In diesem Übersichtsartikel wird die Datenlage hinsichtlich neuromuskulärer Manifestationen des Long-COVID-Syndroms summiert und anhand von Kriterien wie Effektstärke, Plausibilität, Kohärenz und experimentelle Evidenz bewertet. Bisher sind vor allem Myalgien und eine autonome Dysfunktion (u. a. das posturale Tachykardiesyndrom) als neuromuskuläre Symptome von Long-COVID beschrieben worden. Die bisherige Evidenz ist allerdings gering: Neben einer sehr heterogenen Methodik und unterschiedlichen Definitionen in den klinischen Long-COVID-Studien fehlen schlüssige experimentelle Daten, die die beschriebenen Symptome als spezifische Langzeitfolge von COVID-19 belegen.

Pathological Features and Neuroinflammatory Mechanisms of SARS-CoV-2 in the Brain and Potential Therapeutic Approaches

The number of deaths has been increased due to COVID-19 infections and uncertain neurological complications associated with the central nervous system. Post-infections and neurological manifestations in neuronal tissues caused by COVID-19 are still unknown and there is a need to explore how brainstorming promoted congenital impairment, dementia, and Alzheimer’s disease. SARS-CoV-2 neuro-invasion studies in vivo are still rare, despite the fact that other beta-coronaviruses have shown similar properties. Neural (olfactory or vagal) and hematogenous (crossing the blood–brain barrier) pathways have been hypothesized in light of new evidence showing the existence of SARS-CoV-2 host cell entry receptors into the specific components of human nerve and vascular tissue. Spike proteins are the primary key and structural component of the COVID-19 that promotes the infection into brain cells. Neurological manifestations and serious neurodegeneration occur through the binding of spike proteins to ACE2 receptor. The emerging evidence reported that, due to the high rate in the immediate wake of viral infection, the olfactory bulb, thalamus, and brain stem are intensely infected through a trans-synaptic transfer of the virus. It also instructs the release of chemokines, cytokines, and inflammatory signals immensely to the blood–brain barrier and infects the astrocytes, which causes neuroinflammation and neuron death; and this induction of excessive inflammation and immune response developed in more neurodegeneration complications. The present review revealed the pathophysiological effects, molecular, and cellular mechanisms of possible entry routes into the brain, pathogenicity of autoantibodies and emerging immunotherapies against COVID-19.

Autonomic Dysfunction during Acute SARS-CoV-2 Infection: A Systematic Review

Although autonomic dysfunction (AD) after the recovery from Coronavirus disease 2019 (COVID-19) has been thoroughly described, few data are available regarding the involvement of the autonomic nervous system (ANS) during the acute phase of SARS-CoV-2 infection. The primary aim of this review was to summarize current knowledge regarding the AD occurring during acute COVID-19. Secondarily, we aimed to clarify the prognostic value of ANS involvement and the role of autonomic parameters in predicting SARS-CoV-2 infection. According to the PRISMA guidelines, we performed a systematic review across Scopus and PubMed databases, resulting in 1585 records. The records check and the analysis of included reports’ references allowed us to include 22 articles. The studies were widely heterogeneous for study population, dysautonomia assessment, and COVID-19 severity. Heart rate variability was the tool most frequently chosen to analyze autonomic parameters, followed by automated pupillometry. Most studies found ANS involvement during acute COVID-19, and AD was often related to a worse outcome. Further studies are needed to clarify the role of autonomic parameters in predicting SARS-CoV-2 infection. The evidence emerging from this review suggests that a complex autonomic nervous system imbalance is a prominent feature of acute COVID-19, often leading to a poor prognosis.

COVID-19 Vaccination Might Induce Postural Orthostatic Tachycardia Syndrome: A Case Report

We report a case of new-onset postural orthostatic tachycardia syndrome in a healthy 46-year-old female after a single dose of the BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 vaccine. There have been three prior reports of new-onset postural orthostatic tachycardia syndrome after COVID-19 vaccination. Predominant symptoms noted included fatigue, brain fog, headache, sinus tachycardia, and dizziness. Management includes noninvasive therapies, behavioral approaches, and pharmacologic regimens. Here, the patient presented with fatigue, palpitations, dizziness, and presyncope, with symptoms beginning 7 days after vaccination. Presenting vitals included temperature within normal limits, inappropriate tachycardia, up to 120 beats per minute, blood pressure of 128/87 mm of mercury, and 100% saturation in room air. Her management included lifestyle changes, dietary supplements, and ivabradine. Further studies are needed to evaluate prevalence, etiology, and optimal management.

Inflammatory reflex disruption in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China, in late 2019 and caused coronavirus disease 2019 (COVID-19), which is still a global pandemic. In most infected people, SARS-CoV-2 can only cause moderate symptoms, while in other patients, it leads to severe illness and eventually death. Although the main clinical manifestation of COVID-19 is often seen in the lungs, this disease affects almost all body organs. The excessive and prolonged release of inflammatory cytokines that may occur in COVID-19 patients, known as cytokine storms, stimulates undesired immune responses and can cause various tissues damage. In the current review article, we focus on the potential advantages of the intrinsic cholinergic anti-inflammatory pathway (CAP) as the efferent arm of inflammatory reflex in COVID-19 management. Considering this endogenous protective mechanism against chronic inflammation, we focused on the effects of SARS-CoV-2 in the destruction of this anti-inflammatory system. Several studies indicated the interaction of SARS-CoV-2 with the alpha7 subtype of the nicotinic acetylcholine receptor as the effector molecule of the inflammatory reflex. On the other hand, neurological manifestations have increasingly been identified as significant extrapulmonary manifestations of COVID-19. The rational connection between these findings and COVID-19 pathogenesis may be an important issue in both our understanding and dealing with this disease. COVID-19 is deeply rooted in our daily life and requires an urgent need for the establishment of effective therapeutic options, and all the possible treatments must be considered for the control of such inflammatory conditions.

Role of antibodies, inflammatory markers, and echocardiographic findings in post-acute cardiopulmonary symptoms after SARS-CoV-2 infection

Shortness of breath, chest pain, and palpitations occur as postacute sequelae of COVID-19, but whether symptoms are associated with echocardiographic abnormalities, cardiac biomarkers, or markers of systemic inflammation remains unknown. In a cross-sectional analysis, we assessed symptoms, performed echocardiograms, and measured biomarkers among adults more than 8 weeks after confirmed SARS-CoV-2 infection. We modeled associations between symptoms and baseline characteristics, echocardiographic findings, and biomarkers using logistic regression. We enrolled 102 participants at a median of 7.2 months following COVID-19 onset; 47 individuals reported dyspnea, chest pain, or palpitations. Median age was 52 years, and 41% of participants were women. Female sex, hospitalization, IgG antibody against SARS-CoV-2 receptor binding domain, and C-reactive protein were associated with symptoms. Regarding echocardiographic findings, 4 of 47 participants (9%) with symptoms had pericardial effusions compared with 0 of 55 participants without symptoms; those with effusions had a median of 4 symptoms compared with a median of 1 symptom in those without effusions. There was no strong evidence for a relationship between symptoms and echocardiographic functional parameters or other biomarkers. Among adults more than 8 weeks after SARS-CoV-2 infection, SARS-CoV-2 RBD antibodies, markers of inflammation, and, possibly, pericardial effusions are associated with cardiopulmonary symptoms. Investigation into inflammation as a mechanism underlying postacute sequelae of COVID-19 is warranted.

Possible Mechanisms Underlying Neurological Post-COVID Symptoms and Neurofeedback as a Potential Therapy

Theoretical considerations related to neurological post-COVID complications have become a serious issue in the COVID pandemic. We propose 3 theoretical hypotheses related to neurological post-COVID complications. First, pathophysiological processes responsible for long-term neurological complications caused by COVID-19 might have 2 phases: (1) Phase of acute Sars-CoV-2 infection linked with the pathogenesis responsible for the onset of COVID-19-related neurological complications and (2) the phase of post-acute Sars-CoV-2 infection linked with the pathogenesis responsible for long-lasting persistence of post-COVID neurological problems and/or exacerbation of another neurological pathologies. Second, post-COVID symptoms can be described and investigated from the perspective of dynamical system theory exploiting its fundamental concepts such as system parameters, attractors and criticality. Thirdly, neurofeedback may represent a promising therapy for neurological post-COVID complications. Based on the current knowledge related to neurofeedback and what is already known about neurological complications linked to acute COVID-19 and post-acute COVID-19 conditions, we propose that neurofeedback modalities, such as functional magnetic resonance-based neurofeedback, quantitative EEG-based neurofeedback, Othmer's method of rewarding individual optimal EEG frequency and heart rate variability-based biofeedback, represent a potential therapy for improvement of post-COVID symptoms.

Long-Term COVID 19 Sequelae in Adolescents: the Overlap with Orthostatic Intolerance and ME/CFS

Purpose of Review

To discuss emerging understandings of adolescent long COVID or post-COVID-19 conditions, including proposed clinical definitions, common symptoms, epidemiology, overlaps with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance, and preliminary guidance on management.

Recent Findings

The recent World Health Organization clinical case definition of post-COVID-19 condition requires a history of probable or confirmed SARS-CoV-2 infection, with symptoms starting within 3 months of the onset of COVID-19. Symptoms must last for at least 2 months and cannot be explained by an alternative diagnosis. Common symptoms of the post-COVID-19 condition include, but are not limited to, fatigue, shortness of breath, and cognitive dysfunction. These symptoms generally have an impact on everyday functioning. The incidence of prolonged symptoms following SARS-CoV-2 infection has proven challenging to define, but it is now clear that those with relatively mild initial infections, without severe initial respiratory disease or end-organ injury, can still develop chronic impairments, with symptoms that overlap with conditions like ME/CFS (profound fatigue, unrefreshing sleep, post-exertional malaise, cognitive dysfunction, and orthostatic intolerance).

Summary

We do not yet have a clear understanding of the mechanisms by which individuals develop post-COVID-19 conditions. There may be several distinct types of long COVID that require different treatments. At this point, there is no single pharmacologic agent to effectively treat all symptoms. Because some presentations of post-COVID-19 conditions mimic disorders such as ME/CFS, treatment guidelines for this and related conditions can be helpful for managing post-COVID-19 symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40124-022-00261-4.

Autonomic dysfunction in patients with COVID‑19

Purpose

Autonomic dysfunction in patients with viral infections has been described before. In this study, we aimed to evaluate autonomic functions in patients with the coronavirus infectious disease 2019 (COVİD-19).

Methods

In this cross-sectional study, we compared 112 patients who had recovered from COVID-19 and 106 healthy controls. Symptoms of autonomic dysfunction were assessed with the SCOPA-AUT scale.

Results

Pupillomotor, urinary and sudomotor subscores of SCOPA-AUT scale were significantly higher in the COVID-19 patient group (p = 0.03, p = 0,006, p = 0.0001, respectively). There were no significant difference in terms of gastrointestinal, cardiovascular, sexual subscores and total SCOPA-AUT scores between the patient and control groups. The presence of fatigue symptom in the acute phase of COVID-19 increased the total SCOPA-AUT score by 2.2 points (p = 0.04) whereas the presence of smell loss (OR = 5.82, p = 0.01) and dyspnea (OR = 5.8, p = 0.03) were significant risk factors for pupillomotor dysfunction. The urinary, cardiovascular, sexual subscores and the total score of SCOPA-AUT scale were positively correlated with the age of the patient group.

Conclusion

Our study suggests that many patients might have prolonged symptoms of autonomic dysfunction after the acute phase of COVID-19 that might worsen the clinical recovery.

Autonomic neuropathy as post-acute sequela of SARS-CoV-2 infection: a case report

Symptoms of autonomic dysfunction, particularly those of orthostatic intolerance, continue to represent a major component of the currently recognized post-acute sequelae of SARS-CoV-2 infections. Different pathophysiologic mechanisms can be involved in the development of orthostatic intolerance including hypovolemia due to gastrointestinal dysfunction, fatigue-associated deconditioning, and hyperadrenergic state due to pandemic-related anxiety. Additionally, there has been a well-established association of a common primary autonomic disorder like postural orthostatic tachycardia syndrome, a subtype of orthostatic intolerance, with antecedent viral infections. Here we report a case of neuropathic type postural orthostatic tachycardia syndrome as a form of autonomic neuropathy that developed following COVID-19 infection.

The autonomic aspects of the post-COVID19 syndrome

The SARS-CoV-2 outbreak, responsible for the widespread COVID-19, led to one of the most rogue pandemics in modern time, yet the major effects of the pandemic may still be ahead of us. SARS-CoV-2 had been found to possess autoimmune properties. Close to 20 distinct autoantibodies which target GPCR of the nervous system and renin-angiotensin system-related molecules were found significantly associated with the clinical severity of COVID-19. The new on-set of more than 10 various autoimmune disorders were documented as well. Additionally, clinical presentations of persisted symptoms were triggered in numerous recently recovered COVID-19 patients, which led to the formulation of the novel term “post-COVID19 syndrome”. Manifestations related to post-COVID-19 syndrome exist among approximately 50–80% of symptomatic COVID-19 patients who recovered, and among patients reported more than 50 different long-term effects of the SARS-CoV-2 infection. Many of the common symptoms of the post-COVID19 syndrome are not explained by the virus-related injury alone. Similarly to chronic fatigue syndrome and fibromyalgia, autoimmune-mediated autonomic nervous system dysfunction may play a significant part in the pathogenesis of such symptoms, including chronic fatigue, cognitive impairment, mood related disorders, and numerous more. Importantly, therapeutic options such as immunomodulatory and immunosuppressive therapy may favor some post-COVID19 patients, while plasmapheresis and IVIG could be considered in severe cases. Nevertheless, as physical exercise has been found to stabilize the autonomic nervous system, exercise therapy might be a safer and more effective remedy for the post-COVID19 syndrome.

A COVID Constellation: A Case of Transverse Myelitis and Acquired von Willebrand Syndrome

The coronavirus disease 2019 (COVID-19) pandemic revealed a myriad of postinfectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequelae, many of which remain poorly understood. We describe a rare presentation of a patient developing 2 simultaneous COVID-19 sequelae: transverse myelitis and acquired von Willebrand syndrome (AVWS). There have been numerous published case reports of patients developing transverse myelitis after a diagnosis of COVID-19. However, none have described AVWS as an observed complication from SARS-CoV-2 infection. To our knowledge, this case report is the first to describe AVWS as a result of COVID-19 infection, suggesting that patients with a prior diagnosis of COVID-19 are susceptible to developing this rare bleeding disorder.

Heart rate variability as a marker of cardiovascular dysautonomia in post-COVID-19 syndrome using artificial intelligence

Introduction

Cardiovascular dysautonomia comprising postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH) is one of the presentations in COVID-19 recovered subjects. We aim to determine the prevalence of cardiovascular dysautonomia in post COVID-19 patients and to evaluate an Artificial Intelligence (AI) model to identify time domain heart rate variability (HRV) measures most suitable for short term ECG in these subjects.

Methods

This observational study enrolled 92 recently COVID-19 recovered subjects who underwent measurement of heart rate and blood pressure response to standing up from supine position and a 12-lead ECG recording for 60 s period during supine paced breathing. Using feature extraction, ECG features including those of HRV (RMSSD and SDNN) were obtained. An AI model was constructed with ShAP AI interpretability to determine time domain HRV features representing post COVID-19 recovered state. In addition, 120 healthy volunteers were enrolled as controls.

Results

Cardiovascular dysautonomia was present in 15.21% (OH:13.04%; POTS:2.17%). Patients with OH had significantly lower HRV and higher inflammatory markers. HRV (RMSSD) was significantly lower in post COVID-19 patients compared to healthy controls (13.9 ± 11.8 ms vs 19.9 ± 19.5 ms; P = 0.01) with inverse correlation between HRV and inflammatory markers. Multiple perceptron was best performing AI model with HRV(RMSSD) being the top time domain HRV feature distinguishing between COVID-19 recovered patients and healthy controls.

Conclusion

Present study showed that cardiovascular dysautonomia is common in COVID-19 recovered subjects with a significantly lower HRV compared to healthy controls. The AI model was able to distinguish between COVID-19 recovered patients and healthy controls.

Long-COVID Syndrome and the Cardiovascular System: A Review of Neurocardiologic Effects on Multiple Systems

PURPOSE OF REVIEW

Long-COVID syndrome is a multi-organ disorder that persists beyond 12 weeks post-acute SARS-CoV-2 infection (COVID-19). Here, we provide a definition for this syndrome and discuss neuro-cardiology involvement due to the effects of (1) angiotensin-converting enzyme 2 receptors (the entry points for the virus), (2) inflammation, and (3) oxidative stress (the resultant effects of the virus).

RECENT FINDINGS

These effects may produce a spectrum of cardio-neuro effects (e.g., myocardial injury, primary arrhythmia, and cardiac symptoms due to autonomic dysfunction) which may affect all systems of the body. We discuss the symptoms and suggest therapies that target the underlying autonomic dysfunction to relieve the symptoms rather than merely treating symptoms. In addition to treating the autonomic dysfunction, the therapy also treats chronic inflammation and oxidative stress. Together with a full noninvasive cardiac workup, a full assessment of the autonomic nervous system, specifying parasympathetic and sympathetic (P&S) activity, both at rest and in response to challenges, is recommended. Cardiac symptoms must be treated directly. Cardiac treatment is often facilitated by treating the P&S dysfunction. Cardiac symptoms of dyspnea, chest pain, and palpitations, for example, need to be assessed objectively to differentiate cardiac from neural (autonomic) etiology. Long-term myocardial injury commonly involves P&S dysfunction. P&S assessment usually connects symptoms of Long-COVID to the documented autonomic dysfunction(s).

OUP accepted manuscript

This article provides an overview of the recommendations of the Aviation and Occupational Cardiology Task Force of the European Association of Preventive Cardiology on returning individuals to work in high-hazard occupations (such as flying, diving, and workplaces that are remote from healthcare facilities) following symptomatic Coronavirus Disease 2019 (COVID-19) infection. This process requires exclusion of significant underlying cardiopulmonary disease and this consensus statement (from experts across the field) outlines the appropriate screening and investigative processes that should be undertaken. The recommended response is based on simple screening in primary healthcare to determine those at risk, followed by first line investigations, including an exercise capacity assessment, to identify the small proportion of individuals who may have circulatory, pulmonary, or mixed disease. These individuals can then receive more advanced, targeted investigations. This statement provides a pragmatic, evidence-based approach for those (in all occupations) to assess employee health and capacity prior to a return to work following severe disease, or while continuing to experience significant post-COVID-19 symptoms (so-called ‘long-COVID’ or post-COVID-19 syndrome).

Acute and chronic neurological disorders in COVID-19: potential mechanisms of disease

Coronavirus disease 2019 (COVID-19) is a global pandemic caused by SARS-CoV-2 infection and is associated with both acute and chronic disorders affecting the nervous system. Acute neurological disorders affecting patients with COVID-19 range widely from anosmia, stroke, encephalopathy/encephalitis, and seizures to Guillain-Barré syndrome. Chronic neurological sequelae are less well defined although exercise intolerance, dysautonomia, pain, as well as neurocognitive and psychiatric dysfunctions are commonly reported. Molecular analyses of CSF and neuropathological studies highlight both vascular and immunologic perturbations. Low levels of viral RNA have been detected in the brains of few acutely ill individuals. Potential pathogenic mechanisms in the acute phase include coagulopathies with associated cerebral hypoxic-ischaemic injury, blood-brain barrier abnormalities with endotheliopathy and possibly viral neuroinvasion accompanied by neuro-immune responses. Established diagnostic tools are limited by a lack of clearly defined COVID-19 specific neurological syndromes. Future interventions will require delineation of specific neurological syndromes, diagnostic algorithm development and uncovering the underlying disease mechanisms that will guide effective therapies.

Proposed subtypes of post-COVID-19 syndrome (or long-COVID) and their respective potential therapies

The effects of coronavirus disease 2019 (COVID-19), a highly transmissible infectious respiratory disease that has initiated an ongoing pandemic since early 2020, do not always end in the acute phase. Depending on the study referred, about 10%-30% (or more) of COVID-19 survivors may develop long-COVID or post-COVID-19 syndrome (PCS), characterised by persistent symptoms (most commonly fatigue, dyspnoea, and cognitive impairments) lasting for 3 months or more after acute COVID-19. While the pathophysiological mechanisms of PCS have been extensively described elsewhere, the subtypes of PCS have not. Owing to its highly multifaceted nature, this review proposes and characterises six subtypes of PCS based on the existing literature. The subtypes are non-severe COVID-19 multi-organ sequelae (NSC-MOS), pulmonary fibrosis sequelae (PFS), myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), post-intensive care syndrome (PICS) and medical or clinical sequelae (MCS). Original studies supporting each of these subtypes are documented in this review, as well as their respective symptoms and potential interventions. Ultimately, the subtyping proposed herein aims to provide better clarity on the current understanding of PCS.

Post-COVID symptoms of potential peripheral nervous and muscular origin

Many patients report persistent symptoms attributable to dysfunction of the peripheral nervous and muscular systems after acute COVID-19. These symptoms may constitute part of the so-called post-acute COVID-19 syndrome (PACS), or may result from neuromuscular complications of hospitalisation in intensive care units (ICUs). This article provides an updated review of symptoms of potential neuromuscular origin in patients with PACS, differentiating symptoms according to muscle, peripheral nerve, or autonomic nervous system involvement, and analyses the forms of neuromuscular involvement in patients who were admitted to the ICU due to severe COVID-19.

Post-Acute Sequelae of COVID-19 and Cardiovascular Autonomic Dysfunction: What Do We Know?

Post-acute sequelae of SARS-CoV-2 (PASC), or long COVID syndrome, is emerging as a major health issue in patients with previous SARS-CoV-2 infection. Symptoms commonly experienced by patients include fatigue, palpitations, chest pain, dyspnea, reduced exercise tolerance, and “brain fog”. Additionally, symptoms of orthostatic intolerance and syncope suggest the involvement of the autonomic nervous system. Signs of cardiovascular autonomic dysfunction appear to be common in PASC and are similar to those observed in postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. In this review, we report on the epidemiology of PASC, discuss current evidence and possible mechanisms underpinning the dysregulation of the autonomic nervous system, and suggest nonpharmacological and pharmacological interventions to treat and relieve symptoms of PASC-associated dysautonomia.

Covid-19-Induced Dysautonomia: A Menace of Sympathetic Storm

Among the plethora of debilitating neurological disorders of COVID-19 syndrome in survivors, the scope of SARS-CoV-2-induced dysautonomia (DNS) is yet to be understood, though the implications are enormous. Herein, we present an inclusive mini-review of SARS-CoV-2-induced DNS and its associated complications. Although, the direct link between Covid-19 and DSN is still speculative, the hypothetical links are thought to be either a direct neuronal injury of the autonomic pathway or a para/post-infectious immune-induced mechanism. SARS-CoV-2 infection-induced stress may activate the sympathetic nervous system (SNS) leading to neuro-hormonal stimulation and activation of pro-inflammatory cytokines with further development of sympathetic storm. Sympathetic over-activation in Covid-19 is correlated with increase in capillary pulmonary leakage, alveolar damage, and development of acute respiratory distress syndrome. Furthermore, SARS-CoV-2 can spread through pulmonary mechanoreceptors and chemoreceptors to medullary respiratory center in a retrograde manner resulting in sudden respiratory failure. Taken together, DSN in Covid-19 is developed due to sympathetic storm and inhibition of Parasympathetic nervous system-mediated anti-inflammatory effect with development of cytokine storm. Therefore, sympathetic and cytokine storms together with activation of Renin-Angiotensin-System are the chief final pathway involved in the development of DSN in Covid-19.

Symptom Persistence Despite Improvement in Cardiopulmonary Health - Insights from longitudinal CMR, CPET and lung function testing post-COVID-19

BACKGROUND

The longitudinal trajectories of cardiopulmonary abnormalities and symptoms following infection with coronavirus disease (COVID-19) are unclear. We sought to describe their natural history in previously hospitalised patients, compare this with controls, and assess the relationship between symptoms and cardiopulmonary impairment at 6 months post-COVID-19.

METHODS

Fifty-eight patients and thirty matched controls (single visit), recruited between 14^th March - 25^th May 2020, underwent symptom-questionnaires, cardiac and lung magnetic resonance imaging (CMR), cardiopulmonary exercise test (CPET), and spirometry at 3 months following COVID-19. Of them, forty-six patients returned for follow-up assessments at 6 months.

FINDINGS

At 2-3 months, 83% of patients had at least one cardiopulmonary symptom versus 33% of controls. Patients and controls had comparable biventricular volumes and function. Native cardiac T₁ (marker of fibroinflammation) and late gadolinium enhancement (LGE, marker of focal fibrosis) were increased in patients at 2-3 months. Sixty percent of patients had lung parenchymal abnormalities on CMR and 55% had reduced peak oxygen consumption (pV̇O₂) on CPET. By 6 months, 52% of patients remained symptomatic. On CMR, indexed right ventricular (RV) end-diastolic volume (-4·3 mls/m², P=0·005) decreased and RV ejection fraction (+3·2%, P=0·0003) increased. Native T₁ and LGE improved and was comparable to controls. Lung parenchymal abnormalities and peak V̇O₂, although better, were abnormal in patients versus controls. 31% had reduced pV̇O₂ secondary to symptomatic limitation and muscular impairment. Cardiopulmonary symptoms in patients did not associate with CMR, lung function, or CPET measures.

INTERPRETATION

In patients, cardiopulmonary abnormalities improve over time, though some measures remain abnormal relative to controls. Persistent symptoms at 6 months post-COVID-19 did not associate with objective measures of cardiopulmonary health.

FUNDING

The authors' work was supported by the NIHR Oxford Biomedical Research Centre, Oxford British Heart Foundation (BHF) Centre of Research Excellence (RE/18/3/34214), United Kingdom Research Innovation and Wellcome Trust. This project is part of a tier 3 study (C-MORE) within the collaborative research programme entitled PHOSP-COVID Post-hospitalization COVID-19 study: a national consortium to understand and improve long-term health outcomes, funded by the Medical Research Council and Department of Health and Social Care/National Institute for Health Research Grant (MR/V027859/1) ISRCTN number 10980107.

Cardiovascular and Renal Risk Factors and Complications Associated With COVID-19

The current COVID-19 pandemic, caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) virus, represents the largest medical challenge in decades. It has exposed unexpected cardiovascular vulnerabilities at all stages of the disease (pre-infection, acute phase, and subsequent chronic phase). The major cardiometabolic drivers identified as having epidemiologic and mechanistic associations with COVID-19 are abnormal adiposity, dysglycemia, dyslipidemia, and hypertension. Hypertension is of particular interest, because components of the renin-angiotensin system (RAS), which are critically involved in the pathophysiology of hypertension, are also implicated in COVID-19. Specifically, angiotensin-converting enzyme-2 (ACE2), a multifunctional protein of the RAS, which is part of the protective axis of the RAS, is also the receptor through which SARS-CoV-2 enters host cells, causing viral infection. Cardiovascular and cardiometabolic comorbidities not only predispose people to COVID-19, but also are complications of SARS-CoV-2 infection. In addition, increasing evidence indicates that acute kidney injury is common in COVID-19, occurs early and in temporal association with respiratory failure, and is associated with poor prognosis, especially in the presence of cardiovascular risk factors. Here, we discuss cardiovascular and kidney disease in the context of COVID-19 and provide recent advances on putative pathophysiological mechanisms linking cardiovascular disease and COVID-19, focusing on the RAS and ACE2, as well as the immune system and inflammation. We provide up-to-date information on the relationships among hypertension, diabetes, and COVID-19 and emphasize the major cardiovascular diseases associated with COVID-19. We also briefly discuss emerging cardiovascular complications associated with long COVID-19, notably postural tachycardia syndrome (POTS).

Autonomic dysfunction in post-COVID patients with and witfhout neurological symptoms: a prospective multidomain observational study

The autonomic nervous system (ANS) can be affected by COVID-19, and dysautonomia may be a possible complication in post-COVID individuals. Orthostatic hypotension (OH) and postural tachycardia syndrome (POTS) have been suggested to be common after SARS-CoV-2 infection, but other components of ANS function may be also impaired. The Composite Autonomic Symptom Scale 31 (COMPASS-31) questionnaire is a simple and validated tool to assess dysautonomic symptoms. The aim of the present study was to administer the COMPASS-31 questionnaire to a sample of post-COVID patients with and without neurological complaints. Participants were recruited among the post-COVID ambulatory services for follow-up evaluation between 4 weeks and 9 months from COVID-19 symptoms onset. Participants were asked to complete the COMPASS-31 questionnaire referring to the period after COVID-19 disease. Heart rate and blood pressure were manually taken during an active stand test for OH and POTS diagnosis. One-hundred and eighty participants were included in the analysis (70.6% females, 51 ± 13 years), and OH was found in 13.8% of the subjects. Median COMPASS-31 score was 17.6 (6.9-31.4), with the most affected domains being orthostatic intolerance, sudomotor, gastrointestinal and pupillomotor dysfunction. A higher COMPASS-31 score was found in those with neurological symptoms (p < 0.01), due to more severe orthostatic intolerance symptoms (p < 0.01), although gastrointestinal (p < 0.01), urinary (p < 0.01), and pupillomotor (p < 0.01) domains were more represented in the non-neurological symptoms group. This study confirms the importance of monitoring ANS symptoms as a possible complication of COVID-19 disease that may persist in the post-acute period.

Post-covid-19 neurological syndromes

The article highlights the pathogenesis, clinical manifestations of lesions of the central and peripheral nervous system that have arisen or persist in patients in the postcoid period (Long-COVID-19). Their correct assessment, the use of effective methods of complex treatment, targeted neurorehabilitation contribute to the reversibility of functional disorders, prevention, reduction of disability, improvement of quality of life indicators, prevention of the progression of cognitive, emotional, behavioral disorders initiated by SARS-CoV-2.