Exploring trajectory recovery curves of post-COVID cognitive symptoms in previously hospitalized COVID-19 survivors: the LONG-COVID-EXP-CM multicenter study

Dear Sirs,

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, responsible of causing coronavirus disease 2019 (COVID-19), primary affects the respiratory system; however, neurological symptoms (e.g., ageusia, anosmia, headache) and also other severe complication are commonly experienced at the acute phase []. Neurological symptoms presented at the acute COVID-19 phase such as headache [] or anosmia [] are likely present at a post-COVID phase; however, other neurological symptoms, e.g., cognitive disorders, are “de novo” developed in up to 22% of COVID-19 survivors []. A recent meta-analysis reported prevalence rates of 32%, 27% and 22% for post-COVID brain fog, memory loss, and attention/concentration problems the six months after respectively []. However, the presence of post-COVID cognitive symptoms are questioned by others [].

Interestingly, the recent definition of post-COVID includes cognitive dysfunction as one of the most common symptoms, after fatigue or dyspnoea []. The presence of post-COVID symptoms is overall associated with worse quality of life []. In fact, the presence of post-COVID cognitive symptoms represents a challenge for affected individuals since these symptoms affect daily life []. Although the presence of post-COVID cognitive symptoms is associated with nervous system changes [], it seems that these symptoms generally improve over time []. However, most studies investigating these symptoms have used cross-sectional designs. Therefore, understanding the longitudinal pattern of post-COVID cognitive symptoms may have significant implications in diagnosis, triaging, and management of post-COVID individuals.

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Source: Fernández-de-Las-Peñas C, Martín-Guerrero JD, Cancela-Cilleruelo I, Rodríguez-Jiménez J, Moro-López-Menchero P, Pellicer-Valero OJ. Exploring trajectory recovery curves of post-COVID cognitive symptoms in previously hospitalized COVID-19 survivors: the LONG-COVID-EXP-CM multicenter study. J Neurol. 2022 May 10:1–5. doi: 10.1007/s00415-022-11176-x. Epub ahead of print. PMID: 35538169; PMCID: PMC9090121. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9090121/ (Full text)

Post-COVID Condition in Adults and Children Living in the Same Household in Italy: A Prospective Cohort Study Using the ISARIC Global Follow-Up Protocol

Abstract:

Background: Emerging evidence shows that both adults and children may develop post-acute sequelae of SARS-CoV-2 infection (PASC). The aim of this study is to characterise and compare long-term post-SARS-CoV-2 infection outcomes in adults and children in a defined region in Italy.

Methods: A prospective cohort study including children (≤18 years old) with PCR-confirmed SARS-CoV-2 infection and their household members. Participants were assessed via telephone and face-to-face visits up to 12 months post-SARS-CoV-2 diagnosis of household index case, using the ISARIC COVID-19 follow-up survey.

Results: Of 507 participants from 201 households, 56.4% (286/507) were children, 43.6% (221/507) adults. SARS-CoV-2 positivity was 87% (249/286) in children, and 78% (172/221) in adults. The mean age of PCR positive children was 10.4 (SD = 4.5) and of PCR positive adults was 44.5 years (SD = 9.5), similar to the PCR negative control groups [children 10.5 years (SD = 3.24), adults 42.3 years (SD = 9.06)]. Median follow-up post-SARS-CoV-2 diagnosis was 77 days (IQR 47-169). A significantly higher proportion of adults compared to children reported at least one persistent symptom (67%, 68/101 vs. 32%, 57/179, p < 0.001) at the first follow up. Adults had more frequently coexistence of several symptom categories at both follow-up time-points. Female gender was identified as a risk factor for PASC in adults (p 0.02 at 1-3 months and p 0.01 at 6-9 months follow up), but not in children. We found no significant correlation between adults and children symptoms. In the paediatric group, there was a significant difference in persisting symptoms between those with confirmed SARS-CoV-2 infection compared to controls at 1-3 months follow up, but not at 6-9 months. Conversely, positive adults had a higher frequency of persisting symptoms at both follow-up assessments.

Conclusion: Our data highlights that children can experience persistent multisystemic symptoms months after diagnosis of mild acute SARS-CoV-2 infection, although less frequently and less severely than co-habitant adults. There was no correlation between symptoms experienced by adults and children living in the same household. Our data highlights an urgent need for studies to characterise PASC in whole populations and the wider impact on families.

Source: Buonsenso D, Munblit D, Pazukhina E, Ricchiuto A, Sinatti D, Zona M, De Matteis A, D’Ilario F, Gentili C, Lanni R, Rongai T, Del Balzo P, Fonte MT, Valente M, Zampino G, De Rose C, Sigfrid L, Valentini P; FIMP-Roma. Post-COVID Condition in Adults and Children Living in the Same Household in Italy: A Prospective Cohort Study Using the ISARIC Global Follow-Up Protocol. Front Pediatr. 2022 Apr 21;10:834875. doi: 10.3389/fped.2022.834875. PMID: 35529336; PMCID: PMC9070551.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9070551/ (Full text)

Long-Term Cardiovascular Effects of COVID-19: Emerging Data Relevant to the Cardiovascular Clinician

Abstract:

Purpose of review: COVID-19 is now a global pandemic and the illness affects multiple organ systems, including the cardiovascular system. Long-term cardiovascular consequences of COVID-19 are not yet fully characterized. This review seeks to consolidate available data on long-term cardiovascular complications of COVID-19 infection.

Recent findings: Acute cardiovascular complications of COVID-19 infection include myocarditis, pericarditis, acute coronary syndrome, heart failure, pulmonary hypertension, right ventricular dysfunction, and arrhythmia. Long-term follow-up shows increased incidence of arrhythmia, heart failure, acute coronary syndrome, right ventricular dysfunction, myocardial fibrosis, hypertension, and diabetes mellitus. There is increased mortality in COVID-19 patients after hospital discharge, and initial myocardial injury is associated with increased mortality. Emerging data demonstrates increased incidence of cardiovascular illness and structural changes in recovered COVID-19 patients. Future research will be important in understanding the clinical significance of these structural abnormalities, and to determine the effect of vaccines on preventing long-term cardiovascular complications.

Source: Tobler DL, Pruzansky AJ, Naderi S, Ambrosy AP, Slade JJ. Long-Term Cardiovascular Effects of COVID-19: Emerging Data Relevant to the Cardiovascular Clinician. Curr Atheroscler Rep. 2022 May 4:1–8. doi: 10.1007/s11883-022-01032-8. Epub ahead of print. PMID: 35507278; PMCID: PMC9065238. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9065238/ (Full text)

Clinical, radiological, and transbronchial biopsy findings in patients with long COVID-19: a case series

Abstract:

This brief communication demonstrates the correlation of persistent respiratory symptoms with functional, tomographic, and transbronchial pulmonary biopsy findings in patients with COVID-19 who had a long follow-up period. We report a series of six COVID-19 patients with pulmonary involvement who presented with persistent dyspnea within 4-15 months of discharge. We performed transbronchial biopsies, and the histopathological pattern consistently demonstrated peribronchial remodeling with interstitial pulmonary fibrosis. Therefore, lung biopsy may be useful in the approach of patients with long COVID-19, although the type of procedure, its precise indication, and the moment to perform it are yet to be clarified.

(Brazilian Registry of Clinical Trials-ReBEC; identifier: RBR-8j9kqy [http://www.ensaiosclinicos.gov.br]).

Source: Baldi BG, Fabro AT, Franco AC, Machado MHC, Prudente RA, Franco ET, Marrone SR, Vale SAD, Cezare TJ, Moraes MPT, Ferreira EVM, Albuquerque ALP, Sawamura MVY, Tanni SE. Clinical, radiological, and transbronchial biopsy findings in patients with long COVID-19: a case series. J Bras Pneumol. 2022 Apr 29;48(3):e20210438. doi: 10.36416/1806-3756/e20210438. PMID: 35508067; PMCID: PMC9064656. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9064656/  (Full text)

Long COVID and neuropsychiatric manifestations (Review)

Abstract:

There is accumulating evidence in the literature indicating that a number of patients with coronavirus disease 2019 (COVID-19) may experience a range of neuropsychiatric symptoms, persisting or even presenting following the resolution of acute COVID-19. Among the neuropsychiatric manifestations more frequently associated with ‘long COVID’ are depression, anxiety, post-traumatic stress disorder, sleep disturbances, fatigue and cognitive deficits, that can potentially be debilitating and negatively affect patients’ wellbeing, albeit in the majority of cases symptoms tend to improve over time.

Despite variations in results obtained from studies using different methodological approaches to define ‘long COVID’ syndrome, the most widely accepted factors associated with a higher risk of developing neuropsychiatric manifestations include the severity of foregoing COVID-19, the female sex, the presence of comorbidities, a history of mental health disease and an elevation in the levels of inflammatory markers, albeit further research is required to establish causal associations. To date, the pathophysiological mechanisms implicated in neuropsychiatric manifestations of ‘long COVID’ remain only partially elucidated, while the role of the indirect effects of the COVID-19 pandemic, such as social isolation and uncertainty concerning social, financial and health recovery post-COVID, have also been highlighted.

Given the alarming effects of ‘long-COVID’, interdisciplinary cooperation for the early identification of patients who are at a high risk of persistent neuropsychiatric presentations, beyond COVID-19 recovery, is crucial to ensure that appropriate integrated physical and mental health support is provided, with the aim of mitigating the risks of long-term disability at a societal and individual level.

Source: Efstathiou V, Stefanou MI, Demetriou M, Siafakas N, Makris M, Tsivgoulis G, Zoumpourlis V, Kympouropoulos SP, Tsoporis JN, Spandidos DA, Smyrnis N, Rizos E. Long COVID and neuropsychiatric manifestations (Review). Exp Ther Med. 2022 May;23(5):363. doi: 10.3892/etm.2022.11290. Epub 2022 Apr 1. PMID: 35493431; PMCID: PMC9019760. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9019760/ (Full text)

The incidence and characteristics of chronic pain and fatigue after 12 months later admitting with COVID-19; The Post- COVID 19 syndrome

Abstract:

Introduction: This study aimed to evaluate chronic pain and fatigue in patients 12 months after hospitalization for Covid-19.

Methods: We studied the COVID-19 patients discharged from Hospital, March 10 and April 20, 2020.

Results: A total of 157 patients were included in this study. Forty-three patients (27.4%) complained of chronic fatigue and muscle weakness in the last six months. The visual analog fatigue scale (VAFS) score of 3.84 ± 1.48 was obtained. Forty patients (25.5%) were suspected of Chronic Fatigue Syndrome (CFS).Twenty-four patients (15.3%) had severe chronic pain or exacerbation of previous chronic pain, most of which were reported in the lower back (70.8%) and lower extremities (66.7%). Pain intensity had a mean score of 2.33 ± 0.87 and was mainly described as “muscle cramps,” “persistent dull pain,” and “boring and numbing.” In women, chronic pain and fatigue, extended hospital stays, ICU admission, and depressed mood were common than in men.For these pain and fatigue, 37% used nonsteroidal anti-inflammatory drugs, and 16.3% used antidepressants. Only one person had applied for physiotherapy, and none of the patients had received psychotherapy.

Conclusion: Fatigue and chronic pain in patients recovering from COVID-19 are common complications, even after 12 months of illness.

Source: Janbazi L, Kazemian A, Mansouri K, Madani SP, Yousefi N, Vahedifard F, Raissi G. The incidence and characteristics of chronic pain and fatigue after 12 months later admitting with COVID-19; The Post- COVID 19 syndrome. Am J Phys Med Rehabil. 2022 Apr 13. doi: 10.1097/PHM.0000000000002030. Epub ahead of print. PMID: 35473921.  https://pubmed.ncbi.nlm.nih.gov/35473921/

Global Prevalence of Post COVID-19 Condition or Long COVID: A Meta-Analysis and Systematic Review

Abstract:

Introduction: This study aims to examine the worldwide prevalence of post COVID-19 condition, through a systematic review and meta-analysis.

Methods: PubMed, Embase, and iSearch were searched on July 5, 2021 with verification extending to March 13, 2022. Using a random effects framework with DerSimonian-Laird estimator, we meta-analyzed post COVID-19 condition prevalence at 28+ days from infection.

Results: 50 studies were included, and 41 were meta-analyzed. Global estimated pooled prevalence of post COVID-19 condition was 0.43 (95% CI: 0.39,0.46). Hospitalized and non-hospitalized patients have estimates of 0.54 (95% CI: 0.44,0.63) and 0.34 (95% CI: 0.25,0.46), respectively. Regional prevalence estimates were Asia- 0.51 (95% CI: 0.37,0.65), Europe- 0.44 (95% CI: 0.32,0.56), and North America- 0.31 (95% CI: 0.21,0.43). Global prevalence for 30, 60, 90, and 120 days after infection were estimated to be 0.37 (95% CI: 0.26,0.49), 0.25 (95% CI: 0.15,0.38), 0.32 (95% CI: 0.14,0.57) and 0.49 (95% CI: 0.40,0.59), respectively. Fatigue was the most common symptom reported with a prevalence of 0.23 (95% CI: 0.17,0.30), followed by memory problems (0.14 [95% CI: 0.10,0.19]).

Discussion: This study finds post COVID-19 condition prevalence is substantial; the health effects of COVID-19 appear to be prolonged and can exert stress on the healthcare system.

Source: Chen C, Haupert SR, Zimmermann L, Shi X, Fritsche LG, Mukherjee B. Global Prevalence of Post COVID-19 Condition or Long COVID: A Meta-Analysis and Systematic Review. J Infect Dis. 2022 Apr 16:jiac136. doi: 10.1093/infdis/jiac136. Epub ahead of print. PMID: 35429399. https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiac136/6569364?login=false (Full text available as PDF file)

The Relationship between Physical Activity and Long COVID: A Cross-Sectional Study

The relationship between Long Covid (LC) symptoms and physical activity (PA) levels are unclear. In this cross-sectional study, we examined this association, and the advice that individuals with LC received on PA. Adults with LC were recruited via social media. The New Zealand physical activity questionnaire short form (NZPAQ-SF) was adapted to capture current and pre-COVID-19 PA levels and activities of daily living (ADLs).
Participants reported how PA affected their symptoms, and what PA recommendations they had received from healthcare professionals and other resources; 477 participants completed the survey. Mean age (SD) was 45.69 (10.02) years, 89.1% female, 92.7% white, and median LC duration was 383.5 days (IQR: 168.25,427). Participants were less active than pre-COVID-19 (26.88 ± 74.85 vs. 361.68 ± 396.29 min per week, p < 0.001) and required more assistance with ADLs in a 7-day period compared to pre-COVID-19 (2.23 ± 2.83 vs. 0.11 ± 0.74 days requiring assistance, p < 0.001). No differences were found between the number of days of assistance required with ADLs, or the amount of PA, and the different durations of LC illness (p > 0.05).
Participants reported the effect of PA on LC symptoms as: worsened (74.84%), improved (0.84%), mixed effect (20.96%), or no effect (28.72%). Participants received contradictory advice on whether to be physically active in LC. LC is associated with a reduction in PA and a loss of independence, with most participants reporting PA worsened LC symptoms. PA level reduction is independent of duration of LC. Research is needed to understand how to safely return to PA without worsening LC symptoms.
Source: Wright J, Astill SL, Sivan M. The Relationship between Physical Activity and Long COVID: A Cross-Sectional Study. International Journal of Environmental Research and Public Health. 2022; 19(9):5093. https://doi.org/10.3390/ijerph19095093  https://www.mdpi.com/1660-4601/19/9/5093/htm (Full text)

Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study

Abstract:

Background: Fatigue is the most prevalent and debilitating long COVID symptom, however risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long COVID fatigue and explored its possible pathophysiology.

Methods: Nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long COVID fatigue.

Results: Total of 141 individuals were included. Mean age was 47 (SD 13) years; 115 (82%) were recovering from mild COVID-19. Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long COVID fatigue. They had significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness and long COVID symptoms, and of physical limitation in daily activities. Individuals with fatigue had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53), p=0.038] and oxygen consumption per Kg [27.69 (7.52) vs 30.71 (7.52), p=0.036] at peak exercise. The two independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (odds ratio [OR] 0.79 per 10 beats/minute, 95% confidence interval [CI] 0.65-0.96, p=0.019); and long COVID memory impairment (OR 3.76, 95% CI 1.57-9.01, p=0.003).

Conclusions: Long COVID fatigue may be related to autonomic dysfunction, impaired cognition and decreased mood. This may suggest a limbic-vagal pathophysiology. Clinical Trial registration: NCT04851561.

Source: Margalit I, Yelin D, Sagi M, Rahat MM, Sheena L, Mizrahi N, Gordin Y, Agmon H, Epstein NK, Atamna A, Tishler O, Daitch V, Babich T, Abecasis D, Yarom Y, Kazum S, Shitenberg D, Baltaxe E, Elkana O, Shapira-Lichter I, Leibovici L, Yahav D. Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study. Clin Infect Dis. 2022 Apr 11:ciac283. doi: 10.1093/cid/ciac283. Epub ahead of print. PMID: 35403679.  https://pubmed.ncbi.nlm.nih.gov/35403679/

Autonomic dysfunction and post-COVID-19 syndrome: A still elusive link

Editorial:

Infection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the long-lasting pandemic coronavirus disease 2019 (COVID-19), with dramatic clinical, social, and economic implications. Importantly, evolving experience consistently shows that, in addition to issues related to the acute phase, patients who recover from COVID-19 may present a wide variety of bothersome symptoms, which may be debilitating and significantly impair their quality of life. This condition, when it persists beyond 12 weeks after recovery, is defined as “post–COVID-19” or “long COVID-19” syndrome.

Some of the symptoms, including tachycardia/palpitations, chest pain, fatigue, and dyspnea with reduced effort tolerance, suggest a possible cardiovascular cause, whereas others (eg, muscle and/or joint pain, headache, memory loss, nausea, mood disturbances) suggest involvement of other systems. Symptoms may occur independently of the severity of COVID-19, although patients with more severe symptoms in the acute phase experience a higher rate of symptom persistence during follow-up. , 

Importantly, careful diagnostic assessment usually fails to identify specific causes of post–COVID-19 syndrome. However, it has been suggested that at least some post–COVID-19 symptoms, including those of potential cardiovascular origin, might be related to abnormalities of the autonomic nervous system (ANS). The pathophysiological mechanisms responsible for ANS impairment remain speculative and might include direct damage of the ANS (ganglia and/or nerve terminations) by the virus, a toxic effect of inflammatory cytokines released during the acute infection, and an immune-mediated response triggered by some viral component(s). ,  Independent of the mechanism, the possibility of ANS involvement in SARS-CoV-2 infection is supported by the frequent occurrence of neurologic symptoms (eg, anosmia, dysgeusia) as well as the sporadic occurrence of clinical conditions typically related to ANS dysfunction (eg, orthostatic hypotension, orthostatic tachycardia) in post–COVID-19 syndrome. Furthermore, patients with COVID-19, compared to healthy subjects, have been found to show reduced heart rate variability (HRV) parameters 20 weeks after recovery from the illness. However, a pathogenetic relationship between dysautonomia and post–COVID-19 syndrome remains to be demonstrated. Establishing such a relationship would be of importance because it might help guide the management of this clinical condition.

The study by Ladlow et al in this issue of Heart Rhythm Journal is welcome because it attempts to clarify whether any association exists between dysautonomia and symptoms, as well as objective evidence of exercise intolerance, in patients with post–COVID-19 syndrome. In their study, Ladlow et al enrolled 205 patients referred to a post–COVID-19 clinic who fulfilled specific eligibility criteria (hospitalization and desaturation ≤95% on a Harvard step test or chest pain with electrocardiographic [ECG] changes during acute illness and life-limiting symptoms persisting for >12 weeks). All patients underwent bicycle cardiopulmonary exercise testing (CPET) and were divided into 1 of 2 groups according to evidence or no evidence of dysautonomia.

Dysautonomia was diagnosed based on 3 heart rate (HR) parameters that Jouven et al found to be associated with total mortality and sudden death in a population of asymptomatic subjects: (1) resting HR >75 bpm; (2) increase in HR during exercise <89 bpm; and (3) HR reduction <25 bpm during the first minute of recovery from peak exercise. HRV was also assessed by calculating the root mean square of the squared differences of adjacent RR intervals (RMSSD) on a 1-minute 12-lead ECG at rest and on 30-second ECGs during the first 3 minutes of recovery after peak exercise.

Patients were studied 183 ± 77 days (∼6 months) from COVID-19 disease, and dysautonomia was found in 51 patients (25%). Per definition, these patients had higher HR at rest (95 ± 12 bpm vs 81 ± 12 bpm; P <.001) and lower HR increase during CPET (75 ± 12 bpm vs 96 ± 13 bpm; P <.001) and HR recovery after peak exercise (17 ± 4 bpm vs 31 ± 17 bpm; P <.001) compared to those without dysautonomia.

Patients with dysautonomia were older, had a higher body mass index (BMI) (P = .013) and waist circumference (WC) (P = .003), and had a lower basal RMSSD (P <.001). Furthermore, at rest, dysautonomic patients showed a higher breathing rate (P = .006) and lower forced vital capacity (P = .031), forced expiratory volume in 1 second (P = .036), and ventilatory efficiency (Ve/Vco 2) (P = .036).

When assessing symptoms that showed prevalence >25%, a significant association with dysautonomia was found for low mood (P = .007), headache (P = .026), and poor attention (P = .047). However, other symptoms, including some of potential cardiovascular origin (eg, shortness of breath, fatigue), showed no significant association with dysautonomia.

Patients with dysautonomia, however, showed a lower performance on CPET. In particular, HR at peak exercise (170 ± 13 bpm vs 177 ± 15 bpm; P = .003), maximal work rate (219 ± 37 W vs 253 ± 52 W; P <.001), and maximal oxygen consumption (VO2) (30.6 ± 5.5 mL/kg/min vs 35.8 ± 7.6 mL/kg/min; P <.001) all were significantly lower in patients with dysautonomia than in those without dysautonomia, suggesting a role of ANS dysfunction in their physical limitation.

Ladlow et al should be congratulated for performing this large study on post–COVID-19 syndrome. However, possible alternative interpretations of the data suggest caution in deriving definitive conclusions from their results.

Although the study shows the lack of significant relationship between dysautonomia and most post–COVID-19 symptoms, including, in particular, some symptoms of possible cardiovascular origin, the method applied to identify patients with an impairment of ANS function presents some limitations. Both higher HR at rest and lower HR recovery after exercise suggest an imbalance of sympathovagal tone toward adrenergic predominance in their patients with dysautonomia. However, rather than reflecting a primary impairment of the ANS, these findings simply might have been related to differences between the 2 groups with regard to some basal clinical characteristics, including higher BMI/WC, lower efficiency in respiratory function, and lower mood in dysautonomic patients. In addition, the lower increase in HR during maximal exercise in patients with dysautonomia might have been a mere consequence of their having a higher HR at rest and, given their older age, a lower maximal theoretical HR for age. The percent of predicted maximal HR for age achieved during CPET, in fact, did not differ between the 2 groups. The possibility that the differences in HR behavior might have not been related to a primary abnormality of the ANS is also suggested by the fact that, despite the basal difference, RMSSD values were similar during exercise recovery in the 2 groups of patients, suggesting a similar ANS response to exercise interruption in the 2 groups.

Future studies should clarify whether different results regarding the relationship between ANS dysfunction and post–COVID-19 symptoms might be obtained using more comprehensive and better validated methods for the diagnosis of ANS dysfunction, such as standard tests of autonomic function and HRV assessed from its multiple (short-term and long-term) components.

Of note, although the results of CPET in the study by Ladlow et al suggest lower performance by patients classified with dysautonomia, exercise tolerance was largely normal in these subjects, who achieved >100% of the predicted maximal oxygen consumption and an average maximal work rate of 219 W, with only small differences compared to patients without dysautonomia, possibly explained, again, and at least in part, by some demographic (age) and clinical (BMI, respiratory function) differences.

In conclusion, the study by Ladlow et al provides interesting data on the clinical characteristics and objective physical performance of patients with post–COVID-19 syndrome. However, the role of ANS in determining symptoms (particularly those of potential cardiovascular origin) and physical limitation in these patients still has not been fully elucidated by their data, making necessary further studies applying more comprehensive and valuable methods for the assessment of ANS function.

Source: Lanza GA. Autonomic dysfunction and post-COVID-19 syndrome: A still elusive link. Heart Rhythm. 2022 Apr;19(4):621-622. doi: 10.1016/j.hrthm.2021.12.027. Epub 2021 Dec 28. PMID: 34968741; PMCID: PMC8712711. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8712711/ (Full study)