Effects of Heart Rate Variability Biofeedback in Patients With Acute Ischemic Stroke: A Randomized Controlled Trial

Heart Rate Variability Applications in Medical Specialties: A Narrative Review

HRV is clinically considered to be a surrogate measure of the asymmetrical interplay of the sympathetic and parasympathetic nervous system. While HRV has become an increasingly measured variable through commercially-available wearable devices, HRV is not routinely monitored or utilized in healthcare settings at this time. The purpose of this narrative review is to discuss and evaluate the current research and potential future applications of HRV in several medical specialties, including critical care, cardiology, pulmonology, nephrology, gastroenterology, endocrinology, infectious disease, hematology and oncology, neurology and rehabilitation, sports medicine, surgery and anesthesiology, rheumatology and chronic pain, obstetrics and gynecology, pediatrics, and psychiatry/psychology. A narrative literature review was conducted with search terms including HRV and relevant terminology to the medical specialty in question. While HRV has demonstrated promise for some diagnoses as a non-invasive, easy to use, and cost-effective metric for early disease detection, prognosis and mortality prediction, disease monitoring, and biofeedback therapy, several issues plague the current literature. Substantial heterogeneity exists in the current HRV literature which limits its applicability in clinical practice. However, applications of HRV in psychiatry, critical care, and in specific chronic diseases demonstrate sufficient evidence to warrant clinical application regardless of the surmountable research issues. More data is needed to understand the exact impact of standardizing HRV monitoring and treatment protocols on patient outcomes in each of the clinical contexts discussed in this paper.

Autonomic dysfunction after stroke: an overview of recent clinical evidence and perspectives on therapeutic management

PURPOSE

Central autonomic dysfunction is common in acute stroke and is associated with cardiovascular complications and increased mortality. The aim of this review is to present novel diagnostic and therapeutic approaches to the management of this disorder and the latest data on its impact on the clinical outcome after stroke.

METHODS

We performed a narrative review of recent literature, with a particular focus on articles related to underlying pathophysiological mechanisms of cardiac autonomic dysregulation, the role of cardiac autonomic dysregulation in the activation of neuroinflammatory response and the development of cardiovascular, respiratory and metabolic complications in patients with ischemic and hemorrhagic stroke.

RESULTS

The assessment of central autonomic dysfunction by non-invasive diagnostic techniques, including heart rate variability and baroreflex sensitivity, has gained wide practical application in recent years, and they may have a predictive role for evaluating disease prognosis. The emerging evidence derived from recent trials demonstrates that the presence of autonomic imbalance may lead to increased mortality and have an adverse effect on post-stroke rehabilitation.

CONCLUSION

The early detection and treatment of central autonomic system dysfunction may lead to improved survival of patients with stroke. Among the available therapeutic approaches, neuromodulatory techniques and pharmacological interventions are promising strategies which may be implemented as part of standard acute stroke care to improve patient recovery. Future studies are warranted to address the long-term effects of potential therapeutic agents on the modulation of cardiovascular autonomic function in stroke survivors.

Reducing decision-making deficits in patients with brain injury: effect of slow-paced breathing

Impairments in decision-making have been reported in brain-damaged (stroke/traumatic brain injury) patients with a wide range of lesion sites. Here, we propose that the performances of patients in complex sequential decision-making (DM) tasks can be explained by their negative affectivity, leading to deliberative processing associated with poor DM performances. We assumed that a slow-paced breathing (SPB) training, by reducing negative affectivity would improve performances in a complex DM task. For 24 days, 34 brain-damaged patients (16 males and 18 females; 12 had a hemorrhagic stroke, 17 with an ischemic stroke and 5 with a TBI), practiced either daily SPB or sham trainings for five min, three times a day. Before and after training, we assessed their vagal tone (electrocardiogram-ECG), affectivity (Positive and Negative Affect Schedule-PANAS) and certainty level (Dimensional Ratings Questionnaire-DRQ) and their performance on the Iowa Gambling Task. All participants showed initial weak performance, which improved only for patients in the SPB training condition. These results suggest that DM disorders in brain-damaged patients can be the consequence of their poor information processing strategy rather than an impairment in their DM abilities. Second, we showed that SPB could be efficient to normalize DM processes in brain injury patients.

Heart rate variability biofeedback enhances cognitive, motor, psychological, and autonomic functions in post-stroke rehabilitation

Post-stroke patients often experience psychological distress and autonomic nervous system (ANS) dysregulation, impacting their well-being. This study evaluated the effectiveness of heart rate variability (HRV) biofeedback on cognitive, motor, psychological, and ANS functions in sixty-two ischemic stroke patients (43 males, mean age = 60.1) at a Medical Center in southern Taiwan. To prevent interaction, we allocated patients to the HRV biofeedback or control (usual care) group based on their assigned rehabilitation days, with 31 patients in each group. Assessments conducted at baseline, three, and six months included the Montreal Cognitive Assessment (MoCA), Fugl-Meyer Assessment for Upper Extremities (FMA-UE), Perceived Stress Scale, Hospital Anxiety and Depression Scales (HADS), and HRV indices. Mixed-effect models were used to analyze Group by Time interactions. The results revealed significant interactions across all functions. At 3 months, significant improvements in the HRV biofeedback group were observed only in MoCA, FMA-UE, and HADS-depression scores compared to the control group. By 6 months, all measured outcomes demonstrated significant improvements in the biofeedback group relative to the control group. These results suggest that HRV biofeedback may be an effective complementary intervention in post-stroke rehabilitation, warranting further validation.

Stroke Related Brain-Heart Crosstalk: Pathophysiology, Clinical Implications, and Underlying Mechanisms

The emergence of acute ischemic stroke (AIS) induced cardiovascular dysfunctions as a bidirectional interaction has gained paramount importance in understanding the intricate relationship between the brain and heart. Post AIS, the ensuing cardiovascular dysfunctions encompass a spectrum of complications, including heart attack, congestive heart failure, systolic or diastolic dysfunction, arrhythmias, electrocardiographic anomalies, hemodynamic instability, cardiac arrest, among others, all of which are correlated with adverse outcomes and mortality. Mounting evidence underscores the intimate crosstalk between the heart and the brain, facilitated by intricate physiological and neurohumoral complex networks. The primary pathophysiological mechanisms contributing to these severe cardiac complications involve the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic and parasympathetic hyperactivity, immune and inflammatory responses, and gut dysbiosis, collectively shaping the stroke-related brain-heart axis. Ongoing research endeavors are concentrated on devising strategies to prevent AIS-induced cardiovascular dysfunctions. Notably, labetalol, nicardipine, and nitroprusside are recommended for hypertension control, while β-blockers are employed to avert chronic remodeling and address arrhythmias. However, despite these therapeutic interventions, therapeutic targets remain elusive, necessitating further investigations into this complex challenge. This review aims to delineate the state-of-the-art pathophysiological mechanisms in AIS through preclinical and clinical research, unraveling their intricate interplay within the brain-heart axis, and offering pragmatic suggestions for managing AIS-induced cardiovascular dysfunctions.

Heart Rate Variability Biofeedback in Adults with a Spinal Cord Injury: A Laboratory Framework and Case Series

Heart rate variability biofeedback (HRV-F) is a neurocardiac self-regulation therapy that aims to regulate cardiac autonomic nervous system activity and improve cardiac balance. Despite benefits in various clinical populations, no study has reported the effects of HRV-F in adults with a spinal cord injury (SCI). This article provides an overview of a neuropsychophysiological laboratory framework and reports the impact of an HRV-F training program on two adults with chronic SCI (T1 AIS A and T3 AIS C) with different degrees of remaining cardiac autonomic function. The HRV-F intervention involved 10 weeks of face-to-face and telehealth sessions with daily HRV-F home practice. Physiological (HRV, blood pressure variability (BPV), baroreflex sensitivity (BRS)), and self-reported assessments (Fatigue Severity Scale, Generalised Anxiety Disorder Scale, Patient Health Questionnaire, Appraisal of Disability and Participation Scale, EuroQol Visual Analogue Scale) were conducted at baseline and 10 weeks. Participants also completed weekly diaries capturing mood, anxiety, pain, sleep quality, fatigue, and adverse events. Results showed some improvement in HRV, BPV, and BRS. Additionally, participants self-reported some improvements in mood, fatigue, pain, quality of life, and self-perception. A 10-week HRV-F intervention was feasible in two participants with chronic SCI, warranting further investigation into its autonomic and psychosocial effects.

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.

Exploring the Utility of Autonomic Nervous System Evaluation for Stroke Prognosis

Stroke is a major cause of functional disability and is increasing in frequency. Therefore, stroke prognosis must be both accurate and timely. Among other biomarkers, heart rate variability (HRV) is investigated in terms of prognostic accuracy within stroke patients. The literature research of two databases (MEDLINE and Scopus) is performed to trace all relevant studies published within the last decade addressing the potential utility of HRV for stroke prognosis. Only the full-text articles published in English are included. In total, forty-five articles have been traced and are included in the present review. The prognostic value of biomarkers of autonomic dysfunction (AD) in terms of mortality, neurological deterioration, and functional outcome appears to be within the range of known clinical variables, highlighting their utility as prognostic tools. Moreover, they may provide additional information regarding poststroke infections, depression, and cardiac adverse events. AD biomarkers have demonstrated their utility not only in the setting of acute ischemic stroke but also in transient ischemic attack, intracerebral hemorrhage, and traumatic brain injury, thus representing a promising prognostic tool whose clinical application may greatly facilitate individualized stroke care.

Heart rate variability as a predictor of stroke course, functional outcome, and medical complications: A systematic review

Background: Heart rate variability (HRV) is a non-invasive marker of autonomic nervous system function that is based on the analysis of length differences between subsequent RR intervals of the electrocardiogram. The aim of this systematic review was to assess the current knowledge gap in the utility of HRV parameters and their value as predictors of the acute stroke course. Methods: A systematic review was performed in accordance with the PRISMA guidelines. Relevant articles published between 1 January 2016 and 1 November 2022 available in the PubMed, Web of Science, Scopus, and Cochrane Library databases were obtained using a systematic search strategy. The following keywords were used to screen the publications: "heart rate variability" AND/OR "HRV" AND "stroke." The eligibility criteria that clearly identified and described outcomes and outlined restrictions on HRV measurement were pre-established by the authors. Articles assessing the relationship between HRV measured in the acute phase of stroke and at least one stroke outcome were considered. The observation period did not exceed 12 months. Studies that included patients with medical conditions influencing HRV with no established stroke etiology and non-human subjects were excluded from the analysis. To minimize the risk of bias, disagreements throughout the search and analysis were resolved by two independent supervisors. Results: Of the 1,305 records obtained from the systematic search based on keywords, 36 were included in the final review. These publications provided insight into the usability of linear and non-linear HRV analysis in predicting the course, complications, and mortality of stroke. Furthermore, some modern techniques, such as HRV biofeedback, for the improvement of cognition performance after a stroke are discussed. Discussion: The present study showed that HRV could be considered a promising biomarker of a stroke outcome and its complications. However, further research is needed to establish a methodology for appropriate quantification and interpretation of HRV-derived parameters.

Psychological Stress Management and Stress Reduction Strategies for Stroke Survivors: A Scoping Review

BACKGROUND

Stroke can be a life-changing event, with survivors frequently experiencing some level of disability, reduced independence, and an abrupt lifestyle change. Not surprisingly, many stroke survivors report elevated levels of stress during the recovery process, which has been associated with worse outcomes.

PURPOSE

Given the multiple roles of stress in the etiology of stroke recovery outcomes, we aimed to scope the existing literature on stress management interventions that have been trialed in stroke survivors.

METHODS

We performed a database search for intervention studies conducted in stroke survivors which reported the effects on stress, resilience, or coping outcome. Medline (OVID), Embase (OVID), CINAHL (EBSCO), Cochrane Library, and PsycInfo (OVID) were searched from database inception until March 11, 2019, and updated on September 1, 2020.

RESULTS

Twenty-four studies met the inclusion criteria. There was significant variation in the range of trialed interventions, as well as the outcome measures used to assess stress. Overall, just over half (13/24) of the included studies reported a benefit in terms of stress reduction. Acceptability and feasibility were considered in 71% (17/24) and costs were considered in 17% (4/24) of studies. The management of stress was rarely linked to the prevention of symptoms of stress-related disorders. The overall evidence base of included studies is weak. However, an increase in the number of studies over time suggests a growing interest in this subject.

CONCLUSIONS

Further research is required to identify optimum stress management interventions in stroke survivors, including whether the management of stress can ameliorate the negative impacts of stress on health.

Heart Rate Variability: A Measure of Cardiovascular Health and Possible Therapeutic Target in Dysautonomic Mental and Neurological Disorders

Mental illness such as depression and anxiety as well as cerebrovascular disease are linked to impairment of neurocardiac function mediated by changes to the autonomic nervous system with increased sympathetic and decreased parasympathetic activity. Autonomic neurocardiac function can be evaluated by computing heart rate variability (HRV). Over the past decades, research has demonstrated the diagnostic value of HRV as independent predictor of cardiovascular mortality and as disease marker in progressive autonomic nervous system disorders such as Parkinson’s disease. Here we summarize our studies on HRV and its therapeutic modulation in the context of psychopharmacology as well as psychiatric and neurological disorders to honor the life of Professor Evgeny Vaschillo, the true pioneer of HRV research who sadly passed away on November 21st, 2020.

Temporal effects of two interferential current applications on peripheral circulation in children with hemiplegic cerebral palsy

Objectives

To determine the short-term effects of sympathetic and peripheral stimulation of interferential current (IFC) on blood flow (BF) in children with hemiplegic cerebral palsy (CP).

Methods

Thirty children with hemiplegic CP, ranging from 8 to 12 years old, were randomly divided into three groups (10 children/group). The first group received sympathetic stimulation of IFC, the second group received peripheral stimulation of IFC, and the third group (control) received placebo peripheral stimulation of IFC. A frequency of 80–100 Hz at an intensity of 10–20 mA was applied for 20 min. Blood volume pulse (BVP) amplitude was measured before IFC application using a plethysmography sensor at the big toe immediately after and 15 min poststimulation. The data were statistically analyzed and compared.

Results

There were statistically significant differences in BVP amplitude among the three time intervals in both the sympathetic and peripheral groups (P < 0.05) with no difference in the control group (P = 0.995). There was a significant increase in BVP amplitude immediately after stimulation compared with before stimulation in both the sympathetic and peripheral groups (P = 0.0001). However, differences between the sympathetic and peripheral groups at the three measured periods were statistically nonsignificant (P > 0.05).

Conclusion

Both IFC applications had a proper effect on improving BF in children with hemiplegic CP with no difference in efficacy between sympathetic and peripheral stimulation.

The Application of the GP Model to Manage Controllable Risk Factors in Stroke Patients with Diabetes Can Effectively Improve the Prognosis and Reduce the Recurrence Rate

Objective

The aim of this study is to examine the impacts of general practice model (GP) on prognosis and recurrence of stroke patients with diabetes.

Methods

Ninety patients with stroke combined with diabetes mellitus admitted to our hospital from June 2019 to June 2020 were selected for the study and were randomly and equally divided into 45 cases each in the control and experimental groups for the prospective trial. The patients in the control group received routine treatment while those in the experimental group were treated with GP model. Comparison in treatment effects, patients satisfaction, psychological status, quality of life, glycosylated hemoglobin level, and stroke recurrence was carried out between the two groups.

Results

The experimental group showed markedly better treatment effects (P < 0.05), higher satisfaction degree (P < 0.05), higher HAD (P < 0.05), GQOLI-74 score (P < 0.05), and BI index (P < 0.05), lower level of glycosylated hemoglobin (P < 0.05), and much lower recurrence rate (P < 0.05), as compared to the control group.

Conclusion

The application of the GP model to manage controllable risk factors in stroke patients with diabetes can effectively improve the prognosis and reduce the recurrence rate, which is worthy of clinical application and promotion.

Elevated resting heart rates are a risk factor for mortality among patients with coronavirus disease 2019 in Wuhan, China

BACKGROUND

We evaluated the association between higher resting heart rates (RHRs) and adverse events in COVID-19 patients.

METHODS

One hundred and thirty-six patients with laboratory-confirmed COVID-19 were admitted. Outcomes of patients with different RHRs were compared.

RESULTS

Twenty-nine patients had RHRs of <80 bpm (beat per min), 85 had 80-99 bpm and 22 had ≥100 bpm as tachycardia. Those with higher RHRs had lower pulse oxygen saturation (SpO2) and higher temperatures, and there was a higher proportion of men upon admission (all P < 0.05). Patients with higher RHRs showed higher white blood cell counts and D-dimer, cardiac troponin I (TnI), N-terminal pro-B-type natriuretic peptide and hypersensitive C-reactive protein levels, but lower albumin levels (all P < 0.05) after admission. During follow-up, 26 patients died (mortality rate, 19.1%). The mortality rate was significantly higher among patients with tachycardia than among the moderate and low RHR groups (all P < 0.001). Kaplan-Meier survival curves showed that the risks of death and ventilation use increased for patients with tachycardia (P < 0.001). Elevated RHR as a continuous variable and a mean RHR as tachycardia were independent risk factors for mortality and ventilator use (all P < 0.05) in the multivariable adjusted Cox proportional hazards regression model.

CONCLUSIONS

Elevated average RHRs during the first 3 days of hospitalisation were associated with adverse outcomes in COVID-19 patients. Average RHRs as tachycardia can independently predict all-cause mortality.

Heart rate variability biofeedback in chronic disease management: A systematic review

BACKGROUND

Heart rate variability biofeedback (HRVB) is a non-pharmacological intervention used in the management of chronic diseases.

METHOD

A systematic search was performed according to eligibility criteria including adult chronic patients, HRVB as main treatment with or without control conditions, and psychophysiological outcomes as dependent variables.

RESULTS

In total, 29 articles were included. Reported results showed the feasibility of HRVB in chronic patients without adverse effects. Significant positive effects were found in various patient profiles on hypertension and cardiovascular prognosis, inflammatory state, asthma disorders, depression and anxiety, sleep disturbances, cognitive performance and pain, which could be associated with improved quality of life. Improvements in clinical outcomes co-occurred with improvements in heart rate variability, suggesting possible regulatory effect of HRVB on autonomic function.

CONCLUSIONS

HRVB could be effective in managing patients with chronic diseases. Further investigations are required to confirm these results and recommend the most effective method.

Randomized Sham-Controlled Pilot Study of Neurocardiac Function in Patients With Acute Ischaemic Stroke Undergoing Heart Rate Variability Biofeedback

Background: Neurocardiac dysfunction worsens clinical outcome and increases mortality in stroke survivors. We hypothesized that heart rate variability (HRV) biofeedback improves neurocardiac function by modulating autonomic nervous system activity after acute ischaemic stroke (AIS).

Methods: We randomly allocated (1:1) 48 acute ischaemic stroke patients to receive nine sessions of HRV- or sham biofeedback over 3 days in addition to comprehensive stroke unit care. Before and after the intervention patients were evaluated for HRV via standard deviation of normal-to-normal intervals (SDNN, primary outcome), root mean square of successive differences between normal heartbeats (RMSSD), a predominantly parasympathetic measure, and for sympathetic vasomotor and sudomotor function. Severity of autonomic symptoms was assessed via survey of autonomic symptom scale total impact score (TIS) at baseline and after 3 months.

Results: We included 48 patients with acute ischaemic stroke [19 females, ages 65 (4.4), median (interquartile range)]. Treatment with HRV biofeedback increased HRV post intervention [SDNN: 43.5 (79.0) ms vs. 34.1 (45.0) ms baseline, p = 0.015; RMSSD: 46.0 (140.6) ms vs. 29.1 (52.2) ms baseline, p = 0.015] and alleviated autonomic symptoms after 3 months [TIS 3.5 (8.0) vs. 7.5 (7.0) baseline, p = 0.029], which was not seen after sham biofeedback (SDNN: p = 0.63, RMSSD: p = 0.65, TIS: 0.06). There were no changes in sympathetic vasomotor and sudomotor function (p = ns).

Conclusions: Adding HRV biofeedback to standard stroke unit care led to improved neurocardiac function and sustained alleviation of autonomic symptoms after acute ischaemic stroke, which was likely mediated by a predominantly parasympathetic mechanism.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03865225.

A meta-analysis on heart rate variability biofeedback and depressive symptoms

Heart rate variability biofeedback (HRVB) has been used for a number of years to treat depressive symptoms, a common mental health issue, which is often comorbid with other psychopathological and medical conditions. The aim of the present meta-analysis is to test whether and to what extent HRVB is effective in reducing depressive symptoms in adult patients. We conducted a literature search on Pubmed, ProQuest, Ovid PsycInfo, and Embase up to October 2020, and identified 721 studies. Fourteen studies were included in the meta-analysis. Three meta-regressions were also performed to further test whether publication year, the questionnaire used to assess depressive symptoms, or the interval of time between T0 and T1 moderated the effect of HRVB. Overall, we analysed 14 RCTs with a total of 794 participants. The random effect analysis yielded a medium mean effect size g = 0.38 [95% CI = 0.16, 0.60; 95% PI =  - 0.19, 0.96], z = 3.44, p = 0.0006. The total heterogeneity was significant, QT = 23.49, p = 0.03, I2 = 45%, which suggested a moderate variance among the included studies. The year of publication (χ2(1) = 4.08, p = 0.04) and the questionnaire used to assess symptoms (χ2(4) = 12.65, p = 0.01) significantly moderated the effect of the interventions and reduced heterogeneity. Overall, results showed that HRVB improves depressive symptoms in several psychophysiological conditions in adult samples and should be considered as a valid technique to increase psychological well-being.

Respiratory therapy for the treatment of anxiety: Meta-analytic review and regression

OBJECTIVE

Respiratory abnormalities are a hallmark of anxiety symptomatology and may serve as clinically useful modifiers for alleviating anxiety symptoms. However, gold-standard anxiety treatments (e.g., cognitive-behavioral interventions) often do not directly address respiratory components despite their theoretical utility and clinical accessibility. This review examined the clinical effectiveness of respiratory interventions, interventions that directly target respiration abnormalities and processes, in treating trait anxiety symptoms.

METHODS

The final analysis included 40 randomized controlled trials including at least one measure of trait anxiety, a respiratory-focused intervention group, and a non-respiratory control-group (active or inactive treatment). Overall effects of respiratory focused interventions were examined, as well as the effect of hypothesized moderators.

RESULTS

Respiratory component interventions yielded significantly greater improvements (moderate to large effect) in anxiety symptoms than controls, with the stronger effects observed in comparison to inactive, rather than active, control conditions. Significant heterogeneity in findings suggests that variability in intervention design, population, and control comparison may obfuscate interpretation of findings.

CONCLUSIONS

Evidence supports the clinical utility of respiratory interventions as either an independent anxiety treatment, or as an adjunct to other interventions. Clinical and research implications of findings along with recommendations for ongoing investigations in this domain are discussed.