Tag: heart rate variability

Wearable heart rate variability monitoring identifies autonomic dysfunction and thresholds for post-exertional malaise in Long COVID

Abstract:

Objectives Patients with Long COVID experience disabling fatigue, autonomic dysfunction, reduced exercise capacity, and post-exertional malaise (PEM). Heart rate variability (HRV) can evaluate autonomic function and monitor overexertion, potentially helping to mitigate PEM. This study aimed to use continuous multi-day HRV recordings to monitor overexertion and study autonomic function in Long COVID.

Method Heart rate and HRV were continuously measured in 127 patients with long COVID (43±11 years, 32% male) and 21 healthy controls (42±13 years, 48% male), and daily life activities tracked in a logbook. Participants underwent a (sub)maximal cardiopulmonary exercise test to determine heart rate at the first ventilatory threshold (VT1) to study HRV responses to exercise at different intensities.

Results HRV was lower in patients with long COVID compared to healthy controls during various daily activities and sleep (p<0.027). HRV remained lower for 24 hours after exercise below, at or above VT1 in patients, but not in healthy controls (p=0.010). Nighttime HRV decreased with intense exercise and longer durations in patients with long COVID (p=0.018), indicative of exercise-induced diurnal disturbances of the autonomic nervous system in long COVID.

Conclusion Heart rate variability, assessed by wearables, confirms autonomic dysfunction in patients with long COVID. The delayed recovery of the sympathovagal balance after exercise close and above to VT1 suggests that VT1 can be practically interpreted as a PEM threshold.

Application These results confirm the applicability of wearables to assess autonomic function and manage overexertion in long COVID patients.

What is already known on this topic Patients with long COVID often experience fatigue, autonomic dysfunction, and post-exertional malaise (PEM). HRV can be used as a non-invasive tool to measure autonomic function and recovery. Anecdotal evidence suggests lower HRV in patients with long COVID, but measurements are usually very short.

What this study adds This study demonstrates that continuous HRV monitoring through wearables can effectively identify overexertion and autonomic dysfunction during daily activities in patients with long COVID. Patients with long COVID have a lower heart rate variability during sleep and HRV remained significantly lower for a longer period after moderate-to-heavy exercise, that is generally associated with the induction of post-exertional malaise.

How this study might affect research, practice, or policy This study supports the use of wearables for assessing autonomic function and overexertion in daily life, helping patients with long COVID in pacing daily activities to mitigate symptoms of post-exertional malaise. HRV tracking after exercise shows that VT1 is a potential threshold for PEM. Sports physicians and physiotherapists can incorporate HRV biofeedback measures into pacing advice to patients. Additional research is needed to further investigate the effect of such an intervention.

Source: Twan Ruijgt, Anouk Slaghekke, Anneke Ellens, Kasper W. Janssen, Rob C.I. Wüst.. Wearable heart rate variability monitoring identifies autonomic dysfunction and thresholds for post-exertional malaise in Long COVID. medRxiv 2025.03.18.25320115; doi: https://doi.org/10.1101/2025.03.18.25320115 https://www.medrxiv.org/content/10.1101/2025.03.18.25320115v1.full-text (Full text)

Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: a pilot study

Abstract:

Post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are debilitating post-viral conditions with many symptomatic overlaps, including exercise intolerance and autonomic dysfunction. Both conditions are growing in prevalence, and effective safe treatment strategies must be investigated. We hypothesized that inspiratory muscle training (IMT) could be used in PASC and mild to moderate ME/CFS to mitigate symptoms, improve exercise capacity, and improve autonomic function.

We recruited healthy controls (n=12; 10 women), people with PASC (n=9; 8 women), and people with mild to moderate ME/CFS (n=12; 10 women) to complete 8 weeks of IMT. This project was registered as a clinical trial (NCT05196529) with clinicaltrials.gov.

After completion of IMT, all groups experienced improvements in inspiratory muscle pressure (p<0.001), 6-minute walk distance (p=0.002), resting heart rate (p=0.037), heart rate variability (p<0.05), and symptoms related to sleep (p=0.009). In the ME/CFS group only, after completion of IMT, there were additional improvements with regard to vascular function (p=0.001), secretomotor function (p=0.023), the total weighted score (p=0.005) of the COMPASS 31 autonomic questionnaire, and symptoms related to pain (p=0.016).

We found that after 8 weeks of IMT, people with PASC and/or ME/CFS could see some overall improvements in their autonomic function and symptomology.

Source: Edgell H, Pereira TJ, Kerr K, Bray R, Tabassum F, Sergio L, Badhwar S. Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: a pilot study. Respir Physiol Neurobiol. 2024 Oct 5:104360. doi: 10.1016/j.resp.2024.104360. Epub ahead of print. PMID: 39374820. https://www.sciencedirect.com/science/article/pii/S1569904824001538 (Full text)

A Case Report of Chronic Epipharyngitis With Chronic Fatigue Treated With Epipharyngeal Abrasive Therapy (EAT)

Abstract:

A case of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) with chronic epipharyngitis was treated with epipharyngeal abrasive therapy (EAT). The symptoms of ME/CFS improved along with the improvement of chronic epipharyngitis. The patient was followed up with endocrine and autonomic function tests.

Endocrine function tests included salivary cortisol and salivary α-amylase activity. Salivary α-amylase activity was stimulated by EAT. EAT improved the diurnal variability of salivary cortisol secretion. Autonomic function tests included heart rate variability analysis by orthostatic stress test. EAT normalized parasympathetic and sympathetic reflexes over time and regulated autonomic balance.

Based on the improvement of symptoms and test results, EAT was considered effective for ME/CFS. A literature review was conducted on the mechanism of the therapeutic effect of EAT on ME/CFS.

Source: Hirobumi I. A Case Report of Chronic Epipharyngitis With Chronic Fatigue Treated With Epipharyngeal Abrasive Therapy (EAT). Cureus. 2024 Feb 23;16(2):e54742. doi: 10.7759/cureus.54742. PMID: 38405656; PMCID: PMC10884883. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10884883/ (Full text)

Post-COVID Postural Orthostatic Tachycardia Syndrome and Inappropriate Sinus Tachycardia in the Pediatric Population

Abstract:

Purpose of Review: Long COVID, or post-COVID Condition, is increasingly recognized in children and adolescents, despite being less studied compared with the adult population. Recent studies are documenting that inappropriate sinus tachycardia (IST) or postural orthostatic tachycardia syndrome (POTS) may be key clinical problems in patients with long COVID, and preliminary findings have shown that these may be important features also in children. However, POTS and IST are poorly known among non-specialized pediatricians, and this gap may limit access to appropriate care for children and adolescents with long COVID or other post-viral fatigue syndromes. In this review, we critically evaluate the available literature investigating the burden of post-COVID-19 IST and POTS in children and young people, their pathogenesis, and available evidence for their management in the pediatric population.

Recent Findings: In line with adult studies, there is increasing evidence that also children with long COVID may suffer from IST and POTS. Case reports and case series, as well as pediatric experience from other conditions, suggest that IST and POTS can be treated also in the pediatric population

Summary: IST and POTS are under-recognized conditions in children. Clinical findings as well as diagnostics like 24-h ECG and heart rate variability are non-invasive tests to diagnose IST and POTS. If properly recognized, these conditions are treatable.

Source: Spera, F.R., Mistrulli, R., Salerno, L. et al. Post-COVID Postural Orthostatic Tachycardia Syndrome and Inappropriate Sinus Tachycardia in the Pediatric Population. Curr Clin Micro Rpt (2024). https://doi.org/10.1007/s40588-024-00217-w (Full text available as PDF file)

Analysis of the correlation between heart rate variability and palpitation symptoms in female patients with long COVID

Abstract:

Objectives: To analyze the correlation between heart rate variability (HRV) and palpitation symptoms in female patients with long COVID.

Methods: A total of 272 female healthcare workers who were infected with SARS-CoV-2 for the first time in December 2022 at Fuzhou First Hospital affiliated with Fujian Medical University, were selected as study subjects. These subjects were divided into three groups based on their symptoms: a group with palpitations (70 cases), a group without palpitations but with other symptoms (124 cases), and a group consisting of asymptomatic cases (78 cases). The study compared the general information, COMPASS-31 scores, quality of life scores, and HRV parameters among the three groups. Furthermore, it analyzed the factors influencing palpitation symptoms in female patients with long COVID.

Results: Compared to the other two groups, the HRV parameters SDNN, HRVIndex, LF, and TP were significantly reduced in the group with palpitations (p < 0.05). Multivariate analysis revealed that HRVIndex (p = 0.016; OR: 0.966, 95% CI: 0.940∼0.994) had a significant impact on palpitation symptoms in female patients with long COVID.

Conclusions: The symptoms of palpitations in female patients with long COVID were found to be related to HRV parameters. Autonomic dysfunction may be connected to the occurrence of palpitation symptoms in long COVID.

Source: Jiang Yu, Cheng Yan, Xiao Jingwen, Wang Yicheng, Chen Geng, Zhang Yan. Analysis of the correlation between heart rate variability and palpitation symptoms in female patients with long COVID. Frontiers in Cardiovascular Medicine, 10, 2023 DOI=10.3389/fcvm.2023.1273156 ISSN=2297-055X  https://www.frontiersin.org/articles/10.3389/fcvm.2023.1273156 (Full text)

Similar Patterns of Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue and Post-COVID-19 Syndromes

Abstract:

Background There is a considerable overlap between clinical presentation of post-COVID-19 condition (PCC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) . Many of their common symptoms can be linked to dysregulation of the autonomic nervous system (dysautonomia). This study aimed to objectively assess autonomic function in patients with PCC and in patients with ME/CFS whose disease was not related to COVID-19.

Methods Synchronous recordings of an electrocardiogram, continuous dynamics of blood pressure in the digital artery using the Penaz method and ultrasound pneumotachography with the spirography function were obtained with spiroarteriocardiorhythmography method in 34 patients diagnosed with ME/CFS, in whom the onset of the disease was not associated with COVID-19, 29 patients meeting PCC definition and 32 healthy controls. Heart rate variability (HRV), systolic and diastolic blood pressure variability (RV), respiration variability were assessed at rest and in tests with fixed respiratory rates. At rest, indicators of baroreflex regulation were additionally determined (baroreflex effectiveness index and baroreflex sensitivity).

Results The total power, power of very low frequency, low-frequency and high-frequency of RR interval variability at rest as well as baroreflex effectiveness index in up-ramps of arterial blood pressure and baroreflex sensitivity were significantly lower both in PCC and ME/CFS patients compared to HC. Several diagnostic prediction models for ME/CFS were developed based on HRV parameters. During slow breathing HRV parameters return to normal in PCC, but not in ME/CFS. Correlation analysis revealed a close relationship of HRV, RV parameters and baroreflex sensitivity with fatigue, but not with HADS depressive/anxiety symptoms in ME/CFS and PCC.

Conclusion A similar pattern of HRV and baroreflex failure with signs of a pathological acceleration of age-dependent dysautonomia was identified in ME/CFS and PCC. The clinical, diagnostic and therapeutic implications of these findings are discussed, in light of previously described relationship between inflammation, vascular pathology, atherosclerotic cardiovascular disease and autonomic dysfunction.

Source: Ryabkova, V.A.; Rubinskiy, A.V.; Marchenko, V.N.; Trofimov, V.I.; Churilov, L.P. Similar Patterns of Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue and Post-COVID-19 Syndromes. Preprints 2023, 2023111228. https://doi.org/10.20944/preprints202311.1228.v1 https://www.preprints.org/manuscript/202311.1228/v1 (Full text available as PDF file)

An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients

Abstract:

Our Master’s thesis falls within the research domain of Rehabilitation Sciences and Physiotherapy. In our study we investigated patients with chronic fatigue syndrome (CFS).

CFS is a complicated disorder of which the pathology is still poorly understood. Due to the significant prevalence, the socio-economic impact of the disorder is high. In addition to the physiological dysfunctions that are often reported in CFS literature, patients can also experience altered symptom perception. Patients for example show increased subjective responses to unpleasant somatic stimuli in comparison with healthy persons (Van den Houte et al., 2018). Therefore, this study project fits within the domain of pain, fatigue and somatically unexplained physical symptoms.

Despite a lot of articles reporting the role of altered symptom perception, they mainly focused on symptom perception in the lab. However, these laboratory measurements do not take day-to-day variability in symptoms into account.

We think that the lack of studies investigating the symptomatology in CFS patients via ecological momentary measurements is a gap in the literature. Therefore, in our study, we executed symptom assessments in the lab and in daily life.

In addition, we investigated the interactions between the reported symptoms and heart rate variability (HRV) in order to investigate, on a small scale, if psychological and physiological dysfunctions in patients do not work independently.

Extra information about the pathology of CFS is useful to all professionals in rehabilitation sciences and physical therapy who work with CFS patients. It will help professionals to understand the complex problem of CFS better and to tailor the care for these patients.

Our study is situated in a larger study project with the title “Identifying (psycho)physiology-based subgroups in chronic fatigue syndrome and their relevance for rehabilitation” and with study number S66452. The project is reimbursed by Fonds Wetenschappelijk Onderzoek. The project runs in collaboration with the Multidisciplinary Diagnostic Center of UZ Leuven, the Multidisciplinary Expertise Center Tumi Therapeutics, the Vlaams Instituut voor Biotechnologie KU Leuven Raes Lab and IMEC. All laboratory tasks were conducted in the University Hospital of Leuven.

The study is written in line with the central format. The study topics and research questions were determined in collaboration with Msc. Y. Dooms and Dr. Maaike Van Den Houte. Due to the fact that the study was a component of an ongoing research project, we were not involved in decisions about research design or methodology.

We carried out the academic writing procedure concerning this Master’s thesis. During the writing procedure, we received input from Msc. Y. Dooms. The thesis was written in close cooperation amongst both of us. We both independently contributed to the thesis, reviewed it, and wrote multiple sections together. The data-analysis was done in collaboration with Dr. Maaike Van Den Houte.

Source: Jentro Dest and Daan Grosemans.An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients. Master Thesis [University of Hasselt] https://documentserver.uhasselt.be/bitstream/1942/41042/1/1b9fa48e-2513-4665-8ba1-a6b1eb7f2056.pdf (Full text)

Autonomic dysregulation in long-term patients suffering from Post-COVID-19 Syndrome assessed by heart rate variability

Abstract:

Post-COVID-19 Syndrome (PCS) is a condition with multiple symptoms partly related to dysregulation of the autonomic nerve system. Assessment of heart rate variability (HRV) using 24 h Holter-ECG may serve as a surrogate to characterize cardiac autonomic activity. A prospective study including 103 PCS patients (time after infection = 252 days, age = 49.0 ± 11.3 years, 45.7% women) was performed and patients underwent detailed clinical screening, cardiopulmonary exercise testing, and 24 h Holter monitoring.

Data of PCS patients was compared to 103 CAD patients and a healthy control group (n = 90). After correction for age and sex, frequency-related variables differed in PCS patients compared to controls including LF/HFpower, LF/HFnu, and LF/HF ratio (24 h; p ≤ 0.001). By contrast, these variables were largely comparable between PCS and CAD patients, while sympathetic activation was highest in PCS patients during the 24 h period.

Overall, PCS patients showed disturbed diurnal adjustment of HRV, with impaired parasympathetic activity at night. Patients hospitalized during acute infection showed an even more pronounced overactivation of sympathetic activity compared to patients who underwent ambulant care.

Our data demonstrate persistent HRV alterations in PCS patients with long-term symptom duration, suggesting a sustained impairment of sympathovagal balance. Moreover, sympathetic overstimulation and diminished parasympathetic response in long-term PCS patients are comparable to findings in CAD patients. Whether HRV variables have a prognostic value in PCS and/or might serve as biomarkers indicating a successful interventional approach warrants further longitudinal studies.

Source: Mooren FC, Böckelmann I, Waranski M, Kotewitsch M, Teschler M, Schäfer H, Schmitz B. Autonomic dysregulation in long-term patients suffering from Post-COVID-19 Syndrome assessed by heart rate variability. Sci Rep. 2023 Sep 22;13(1):15814. doi: 10.1038/s41598-023-42615-y. PMID: 37739977; PMCID: PMC10516975. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10516975/ (Full text)

Ivabradine effects on COVID-19-associated postural orthostatic tachycardia syndrome: a single center prospective study

Abstract:

Background: A wide range of cardiac arrhythmias were reported in the setting of active infection or as a complication of COVID-19. The main pathophysiology can be attributed to dysautonomia or autonomic nervous system dysfunction. Postural orthostatic tachycardia syndrome (POTS) is a complex, multisystemic disorder affecting usually younger age with tachycardia at rest or with minimal effort being the main symptom. Data regarding the safety and efficacy of ivabradine in POTS treatment is limited to small studies and case reports.

Methods: This prospective observational study included a total of 55 COVID-19-associated POTS patients after the exclusion of other causes of tachycardia. Ivabradine 5 mg twice daily was initiated. Re-assessment of patients’ symptoms, heart rate, and heart rate variability (HRV) parameters’ changes after 3 days of ivabradine therapy was done.

Results: The mean age of the included patients was 30.5±6.9 years with 32 patients being males (58.2%). 43 of 55 (78%) of the included patients reported significant improvement of the symptoms within 7 days of ivabradine therapy. 24-hour heart rate (minimum, average, and maximum) was significantly lower (p-value < 0.0001*, = 0.001*, < 0.0001* consecutively) with a significant difference in HRV time-domain parameters (SDNN, rMSSD) (p-value < 0.0001*) after ivabradine therapy.

Conclusion: In a prospective study that evaluated the effects of ivabradine in post-COVID-19 POTS, patients treated with ivabradine reported improvement of their symptoms within 7 days of ivabradine treatment with a significant reduction of 24-hour average, minimum, and maximum heart rate, and improvement of HRV time domains parameters. Ivabradine might be a useful option to relieve symptoms of tachycardia in COVID-19 POTS. Further research is required to confirm the safety and efficacy of ivabradine in POTS treatment.

Source: Abdelnabi M, Saleh Y, Ahmed A, Benjanuwattra J, Leelaviwat N, Almaghraby A. Ivabradine effects on COVID-19-associated postural orthostatic tachycardia syndrome: a single center prospective study. Am J Cardiovasc Dis. 2023 Jun 25;13(3):162-167. PMID: 37469536; PMCID: PMC10352820. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10352820/ (Full text)

Evaluation of Outpatients in the Post-COVID-19 Period in Terms of Autonomic Dysfunction and Silent Ischemia

Abstract:

Introduction and objective: In this context, the objective of this study is to evaluate the 24-hour ambulatory electrocardiography (ECG) recordings, autonomous function with heart rate variability (HRV), and silent ischemia (SI) attacks with ST depression burden (SDB) and ST depression time (SDT) of post-COVID-19 patients. Materials and methods: The 24-hour ambulatory ECG recordings obtained >12 weeks after the diagnosis of COVID-19 were compared between 55 consecutive asymptomatic and 73 symptomatic post-COVID-19 patients who applied to the cardiology outpatient clinic with complaints of palpitation and chest pain in comparison with asymptomatic post-COVID-19 patients in Kars Harakani state hospital. SDB, SDT, and HRV parameters were analyzed. Patients who had been on medication that might affect HRV, had comorbidities that might have caused coronary ischemia, and were hospitalized with severe COVID-19 were excluded from the study.

Results: There was no significant difference between symptomatic and asymptomatic post-COVID-19 patients in autonomic function. On the other hand, SDB and SDT parameters were significantly higher in symptomatic post-COVID-19 patients than in asymptomatic post-COVID-19 patients. Multivariate analysis indicated that creatine kinase-myoglobin binding (CK-MB) (OR:1.382, 95% CI:1.043-1.831; p=0.024) and HRV index (OR: 1.033, 95% CI:1.005-1.061; p=0.019) were found as independent predictors of palpitation and chest pain symptoms in post-COVID-19 patients.

Conclusion: The findings of this study revealed that parasympathetic overtone and increased HRV were significantly higher in symptomatic patients with a history of COVID-19 compared to asymptomatic patients with a history of COVID-19 in the post-COVID-19 period. Additionally, 24-hour ambulatory ECG recordings and ST depression analysis data indicated that patients who experienced chest pain in the post-COVID-19 period experienced silent ischemia (SI) attacks.

Source: Karakayalı M, Artac I, Ilis D, Omar T, Rencuzogullari I, Karabag Y, Altunova M, Arslan A, Guzel E. Evaluation of Outpatients in the Post-COVID-19 Period in Terms of Autonomic Dysfunction and Silent Ischemia. Cureus. 2023 Jun 11;15(6):e40256. doi: 10.7759/cureus.40256. PMID: 37440812; PMCID: PMC10335598. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10335598/ (Full text)