Vagus Nerve Dysfunction in the Post-COVID-19 Condition

Abstract:

Background: The post-COVID-19 condition (PCC) is a disabling syndrome affecting 5-15% of subjects who survive COVID-19. SARS-CoV-2 mediated vagus nerve dysfunction could explain some of the PCC symptoms, including persistent dysphonia, dysphagia, dyspnea, dizziness, tachycardia, orthostatic hypotension, gastrointestinal disturbances or neurocognitive complaints.

Methods: We performed a cross-sectional pilot study in subjects with PCC with symptoms suggesting vagus nerve dysfunction (n=30) and compared them to subjects fully recovered from acute COVID-19 (n=14) and individuals never infected with SARS-CoV-2 (n=16), matched by age and sex. We evaluated the structure and function of the vagus nerve, including dysphonia, dysphagia, and dysautonomia tests, and evaluated the structure and function of respiratory muscles with vagus nerve innervation.

Findings: Participants were mostly (80%) women with median 44 years of age. Their most prevalent symptoms were cognitive dysfunction (83%), dyspnea (80%) and tachycardia (80%). Compared with COVID-19-recovered and uninfected controls, respectively, subjects with PCC were more likely to show thickening and hyperechogenic vagus nerve in neck ultrasounds (mean ± SD left vagus nerve cross-sectional area: 2.4 ± 0.97mm2 vs. 2 ± 0.52mm2 vs. 1.9 ± 0.73 mm2, p=0.080), flattened diaphragmatic curve (47% vs 6% vs 14%, p=0.007), reduced esophageal peristalsis (34% vs 0% vs 21%, p=0.020), gastroesophageal reflux (34% vs 19% vs 7%, p=0.130), hiatal hernia (25% vs 0% vs 7%, p=0.050) and reduced maximal inspiratory pressure in functional respiratory tests (62% vs. 6% vs. 17%, p ≤0.001).

Interpretation: Vagus nerve dysfunction has a central pathogenic role in the pathophysiology of the post-COVID condition.

Source: Lladós, Gemma and Massanella, Marta and Coll-Fernández, Roser and Rodríguez, Raúl and Hernández, Electra and Lucente, Giuseppe and López, Cristina and Loste, Cora and Santos, José Ramón and España-Cueto, Sergio and Nevot, Maria and Muñoz-López, Francisco and Arrieta, Sandra Silva and Brander, Christian and Durà, Maria José and Cuadras, Patricia and Bechini, Jordi and Tenesa, Montserrat and Martinez-Piñeiro, Alicia and Herrero, Cristina and Chamorro, Anna and Garcia, Anna and Grau, Eulalia and Clotet, Bonaventura and Paredes, Roger and Mateu, Lourdes and Unit, Germans Trias Long-COVID, Vagus Nerve Dysfunction in the Post-COVID-19 Condition. Available at SSRN: https://ssrn.com/abstract=4479598 or http://dx.doi.org/10.2139/ssrn.4479598

Clinical Features of Post-Covid Syndrome

Abstract:

There is no common understanding of the clinical picture of post-covid syndrome. The US regulator CDC proposes to highlight:

(A) persistent symptoms and conditions that begin during acute COVID-19 illness;

B) new onset late complications after asymptomatic disease or a period of acute symptomatic relief or remission;

(C) the evolution of symptoms and conditions that include some persistent symptoms (eg, shortness of breath) with the addition of new symptoms or conditions over time (eg, cognitive difficulties).

Some manifestations may resemble other postviral syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome, dysautonomia (eg, postural orthostatic tachycardia syndrome), or mast cell activation syndrome.

Source: Sayfulloyevich, P. S. ., & Musayevich, U. R. . (2023). Clinical Features of Post-Covid Syndrome. EUROPEAN JOURNAL OF INNOVATION IN NONFORMAL EDUCATION3(6), 34–36. Retrieved from http://inovatus.es/index.php/ejine/article/view/1786 http://inovatus.es/index.php/ejine/article/view/1786/1794 (Full text)

Diagnostic value of 24-h ECG recording in Long COVID patients with postural orthostatic tachycardia syndrome

Abstract:

Background: Cardiovascular autonomic dysfunction (CVAD) is a major complication for a large proportion of Long COVID (LC) patients. The main phenotype of CVAD is postural orthostatic tachycardia syndrome (POTS), commonly observed as a sequalae of COVID infection, thus defining a subset of LC patients. POTS is a cardiovascular autonomic disorder characterized by an excessive heart rate (HR) increase and symptoms of orthostatic intolerance when assuming upright posture, occurring predominantly in young and middle-aged women. Since the start of COVID-19 pandemic it has been observed that up to 30% of patients with post-COVID-19 syndrome develop POTS with such symptoms as tachycardia, orthostatic intolerance, fatigue, and cognitive impairment. The heterogeneity of POTS symptoms makes the diagnosis and appropriate management of POTS more difficult and one of the first steps for clinicians is to develop and test relevant diagnostic methods for POTS.
Methods: Patients with persistent symptoms, 3 months after an acute SARS-CoV-2 infection were referred to the multi-disciplinary LC unit at a hospital in Sweden. Consecutive patients seen at this unit from 2021 to 2022 underwent a 24-h ECG recording. LC patients with POTS verified by active standing test and/or head-up tilt testing were prospectively enrolled in the study database and were compared with LC patients without POTS according to 3 specific analyses based on 24-h ECG recording : (1) cardiac autonomic activity expressed by heart rate variability, HRV (SDNN and RMSSD in ms) parameters, (2) awakening HR increase (HR mean 10 min before vs. 30 min after awakening) and (3) HR spikes (number/h if at least over than 30 bpm and at least during 30 s). Control group consisted of healthy subjects from 24-h ECG recordings database (HRV analysis) of a hospital in France. Data were expressed as mean (± standard deviation, SD) and frequencies (%).
Results: A total of 120 LC patients (mean age: 42.7 +/-9.97 y, 88% women) and 100 healthy subjects (mean age: 46.4 +/-10.2 y, 82% women) were included. LC with POTS (42%) was associated with (1) a decrease in most HRV parameters (mean SDNN: 86.8 +/-24.3 vs. 108.7 +/-24.1 ms, p=0.03), and the most reduced components were those related to the parasympathetic tone (mean RMSSD: 34,5 +/-20.4 vs. 45.6 +/-22.1 ms, p=0.04), (2) an abrupt and sustained increase in HR during the first 30 min after awakening (+30%, p<0.05) and (3) a higher number of HR spikes per h (1.4 +/-0.8 vs. 0.8 +/-0.7/h, p<0.001) compared with healthy subjects (HRV) and LC patients without POTS (awakenings and HR peaks) respectively.
Conclusion: A triple analysis of 24-h ECG recordings revealed presence of autonomic dysfunction in LC patients with POTS compared with those without POTS. This novel analysis may be introduced in the clinic for screening and therapy monitoring.

Source: D Hupin and others, Diagnostic value of 24-h ECG recording in Long COVID patients with postural orthostatic tachycardia syndrome, EP Europace, Volume 25, Issue Supplement_1, June 2023, euad122.626, https://doi.org/10.1093/europace/euad122.626 (Full text available as PDF file)

Autonomic Nervous System Affection Due to Post Covid Syndrome

Identification of the Effects of Post Covid Syndrome on the Autonomic Nervous System With Heart Rate Variability

Post-Covid syndrome is defined as symptoms that develop in addition to respiratory symptoms in individuals who have had Covid-19 infection for more than 12 weeks. Symptoms such as fatigue, headache, cognitive impairment, dyspnea, heart palpitations, heat intolerance, digestive system disorders, sleep disorders, dermal problems, orthostatic intolerance come to the fore in individuals with post-Covid syndrome. It has been tried to be revealed in some studies that Covid-19 infection affects the autonomic nervous system (ANS) and the relationship between Post-Covid 19 syndrome and ANS dysfunction.
Heart rate variability (HRV) measurement method can be used to evaluate ANS activity. HRV is a non-invasive method and is a measure of the change in heart rate over a period of time. HRV is a scalar quantity that shows the time between two beats of the heart and defines the oscillations between the R-R intervals. In HRV measurements, time-dependent and frequency-dependent measurement results are obtained and from these measurements, time-dependent RMSSD (square root of the square of the difference of the R-R intervals) and frequency-dependent high-frequency (HF) and low frequency (LF) measurement components are used in relation to the sympathetic nervous system (CNS) and parasympathetic nervous system (PSS). HRV can be measured in short-term (5 minutes) in terms of measurement time.
The aim of this study is to clearly reveal the relationship between Post-Covid 19 syndrome and ANS dysfunction and to provide standardization related to HRV measurement method and sub-parameters.
Source: Ali Veysel Özden, M.D. Bahçeşehir University. Istanbul, Beşiktaş, Turkey, 34000. ICH GCP US Clinical Trials Registry, Clinical Trial NCT05502094 https://ichgcp.net/clinical-trials-registry/NCT05502094

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

Abstract:

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.

Source: Zanin, A., Amah, G., Chakroun, S. et al. Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of “long-COVID” patients. Sci Rep 13, 8251 (2023). https://doi.org/10.1038/s41598-023-35086-8 https://www.nature.com/articles/s41598-023-35086-8 (Full text)

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

Abstract:

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.

Source: González-Hermosillo G JA, Galarza EJ, Fermín OV, González JMN, Tostado LMFÁ, Lozano MAE, Rabasa CR, Martínez Alvarado MDR. Exaggerated blood pressure elevation in response to orthostatic challenge, a post-acute sequelae of SARS-CoV-2 infection (PASC) after hospitalization. Auton Neurosci. 2023 Apr 21;247:103094. doi: 10.1016/j.autneu.2023.103094. Epub ahead of print. PMID: 37137186; PMCID: PMC10121145. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10121145/ (Full text)

Autonomic Dysfunction related to Post-Acute SARS-CoV-2 Syndrome

Introduction:

The SARS-CoV-2 virus, a member of the coronavirus family, has been responsible for the Coronavirus Disease-19 (COVID-19) pandemic with an acute phase causing pneumonia and pulmonary disorders, but it has been shown to extrapulmonary manifestations including cardiovascular and neurological diseases. Moreover, residual symptoms have been reported to persist past the acute phase. In a cross-sectional study of SARS-CoV-2 positive patients, at 48 days post-discharge the most common persistent symptoms were fatigue, difficulty breathing, and psychological distress.
 In a cohort study of 1,733 COVID-19 patients from Wuhan, China, patients reported persistence of fatigue, muscle weakness, sleeping difficulties, palpitations, anxiety, or depression at 6 months after initial onset.
 Numerous other studies now indicate the presence of persistent symptoms following COVID-19 infection, with over 200 symptoms reported. This syndrome has been coined as the Post-Acute SARS-CoV-2 Syndrome (PASC) and has been defined as the persistence of symptoms or development of new symptoms after the time of infection, which can include fatigue, brain fog, palpitations, and a plethora of other manifestations.
Source: Justin Haloot, DO, MS, MS, Ratna Bhavaraju-Sanka, MD, Jayasree Pillarisetti, MD Msc, Monica Verduzco-Gutierrez, MD. Autonomic Dysfunction related to Post-Acute SARS-CoV-2 Syndrome. Physical Medicine and Rehabiliation Clinics. Published: April 18, 2023. DOI:https://doi.org/10.1016/j.pmr.2023.04.003 (Full text)

Exercise Intolerance Associated with Impaired Oxygen Extraction in Patients with Long COVID

Abstract:

Objective: Chronic mental and physical fatigue and post-exertional malaise are the more debilitating symptoms of long COVID-19. The study objective was to explore factors contributing to exercise intolerance in long COVID-19 to guide development of new therapies. Exercise capacity data of patients referred for a cardiopulmonary exercise test (CPET) and included in a COVID-19 Survivorship Registry at one urban health center were retrospectively analyzed.

Results: Most subjects did not meet normative criteria for a maximal test, consistent with suboptimal effort and early exercise termination. Mean O2 pulse peak % predicted (of 79 ± 12.9) was reduced, supporting impaired energy metabolism as a mechanism of exercise intolerance in long COVID, n=59. We further identified blunted rise in heart rate peak during maximal CPET. Our preliminary analyses support therapies that optimize bioenergetics and improve oxygen utilization for treating long COVID-19.

Source: Norweg A, Yao L, Barbuto S, Nordvig AS, Tarpey T, Collins E, Whiteson J, Sweeney G, Haas F, Leddy J. Exercise Intolerance Associated with Impaired Oxygen Extraction in Patients with Long COVID. Respir Physiol Neurobiol. 2023 Apr 17;313:104062. doi: 10.1016/j.resp.2023.104062. Epub ahead of print. PMID: 37076024; PMCID: PMC10108551. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10108551/ (Full text)

Five cluster classifications of long COVID and their background factors: A cross-sectional study in Japan

Abstract:

Purpose: The long-term symptoms of coronavirus disease 2019 (COVID-19), i.e., long COVID, have drawn research attention. Evaluating its subjective symptoms is difficult, and no established pathophysiology or treatment exists. Although there are several reports of long COVID classifications, there are no reports comparing classifications that include patient characteristics, such as autonomic dysfunction and work status. We aimed to classify patients into clusters based on their subjective symptoms during their first outpatient visit and evaluate their background for these clusters.

Methods: Included patients visited our outpatient clinic between January 18, 2021, and May 30, 2022. They were aged ≥ 15 years and confirmed to have SARS-CoV-2 infection and residual symptoms lasting at least 2 months post-infection. Patients were evaluated using a 3-point scale for 23 symptoms and classified into five clusters (1. fatigue only; 2. fatigue, dyspnea, chest pain, palpitations, and forgetfulness; 3. fatigue, headache, insomnia, anxiety, motivation loss, low mood, and forgetfulness; 4. hair loss; and 5. taste and smell disorders) using CLUSTER. For continuous variables, each cluster was compared using the Kruskal–Wallis test. Multiple comparison tests were performed using the Dunn’s test for significant results. For nominal variables, a Chi-square test was performed; for significant results, a residual analysis was conducted with the adjusted residuals.

Results: Compared to patients in other cluster categories, those in cluster categories 2 and 3 had higher proportions of autonomic nervous system disorders and leaves of absence, respectively.

Conclusions: Long COVID cluster classification provided an overall assessment of COVID-19. Different treatment strategies must be used based on physical and psychiatric symptoms and employment factors.

Source: Tsuchida, T., Yoshimura, N., Ishizuka, K. et al. Five cluster classifications of long COVID and their background factors: A cross-sectional study in Japan. Clin Exp Med (2023). https://doi.org/10.1007/s10238-023-01057-6 (Full text)

Cardiovascular Considerations in the Management of People with Suspected Long COVID

Abstract:

Approximately 15% of adult Canadians with SARS-CoV-2 infection develop lingering symptoms beyond 12 weeks post-acute infection, known as post-COVID condition or long COVID. Some of the commonly reported long COVID cardiovascular symptoms include fatigue, shortness of breath, chest pain, and palpitations. Suspected long-term cardiovascular complications of SARS-CoV-2 infection may present as a constellation of symptoms that can be challenging for clinicians to diagnose and treat.

When assessing patients with these symptoms, clinicians need to keep in mind Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), post-exertional malaise and post-exertional symptom exacerbation (PEM/PESE), cardiac dysautonomia such as Inappropriate Sinus Tachycardia (IST), and Postural Orthostatic Tachycardia Syndrome (POTS), and occasionally Mast Cell Activation Syndrome (MCAS).

This paper summarizes the globally evolving evidence around management of cardiac sequelae of long COVID. In addition, this review includes a Canadian perspective, consisting of a panel of expert opinions from experienced clinicians across Canada who have been involved in management of long COVID. The objective of this review is to offer some practical guidance to cardiologists and generalist clinicians regarding diagnostic and treatment approaches for adult patients with suspected long COVID who continue to experience unexplained cardiac symptoms.

Source: Quinn KL, Lam GY, Walsh JF, Bhéreur A, Brown AD, Chow CW, Christie Chung KY, Cowan J, Crampton N, Décary S, Falcone EL, Graves L, Gross DP, Hanneman K, Harvey PJ, Holmes S, Katz GM, Parhizgar P, Sharkawy A, Tran KC, Waserman S, Zannella VE, Cheung AM. Cardiovascular Considerations in the Management of People with Suspected Long COVID. Can J Cardiol. 2023 Apr 6:S0828-282X(23)00303-3. doi: 10.1016/j.cjca.2023.04.003. Epub ahead of print. PMID: 37030518. Quinn KL, Lam GY, Walsh JF, Bhéreur A, Brown AD, Chow CW, Christie Chung KY, Cowan J, Crampton N, Décary S, Falcone EL, Graves L, Gross DP, Hanneman K, Harvey PJ, Holmes S, Katz GM, Parhizgar P, Sharkawy A, Tran KC, Waserman S, Zannella VE, Cheung AM. Cardiovascular Considerations in the Management of People with Suspected Long COVID. Can J Cardiol. 2023 Apr 6:S0828-282X(23)00303-3. doi: 10.1016/j.cjca.2023.04.003. Epub ahead of print. PMID: 37030518. https://www.onlinecjc.ca/article/S0828-282X(23)00303-3/fulltext (Full text)