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Journal of Clinical Medicine Apr 2020Cardiac autonomic dysfunction has been reported in patients with cerebral palsy (CP). The aim of this study was to assess the existing literature on heart rate... (Review)
Review
Cardiac autonomic dysfunction has been reported in patients with cerebral palsy (CP). The aim of this study was to assess the existing literature on heart rate variability (HRV) in pediatric patients with CP and a special attention was paid to the compliance of the studies with the current HRV assessment and interpretation guidelines. A systematic review was performed in PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases searched for English language publications from 1996 to 2019 using Medical Subject Headings (MeSH) terms "heart rate variability" and "cerebral palsy" in conjunction with additional inclusion criteria: studies limited to humans in the age range of 0-18 years and empirical investigations. Out of 47 studies, 12 were included in the review. Pediatric patients with CP presented a significantly higher resting heart rate and reduced HRV, different autonomic responses to movement stimuli compared to children with normal development, but also reduced HRV parameters in the children dependent on adult assistance for mobility compared to those generally independent. None of the included studies contained the necessary details concerning RR intervals acquisition and HRV measurements as recommended by the guidelines. Authors of HRV studies should follow the methodological guidelines and recommendations on HRV measurement, because such an approach may allow a direct comparison of their results.
PubMed: 32316278
DOI: 10.3390/jcm9041141 -
Applied Psychophysiology and Biofeedback Sep 2023Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual's resonance... (Review)
Review
Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual's resonance frequency, which stimulates respiratory sinus arrhythmia (RSA) and the baroreflex. There is, however, no methodological consensus on how to apply HRVB, while details about the protocol used are often not well reported. Thus, the objectives of this systematic review are to describe the different HRVB protocols and detect methodological concerns. PsycINFO, CINALH, Medline and Web of Science were searched between 2000 and April 2021. Data extraction and quality assessment were based on PRISMA guidelines. A total of 143 studies were finally included from any scientific field and any type of sample. Three protocols for HRVB were found: (i) "Optimal RF" (n = 37), each participant breathes at their previously detected RF; (ii) "Individual RF" (n = 48), each participant follows a biofeedback device that shows the optimal breathing rate based on cardiovascular data in real time, and (iii) "Preset-pace RF" (n = 51), all participants breathe at the same rate rate, usually 6 breaths/minute. In addition, we found several methodological differences for applying HRVB in terms of number of weeks, duration of breathing or combination of laboratory and home sessions. Remarkably, almost 2/3 of the studies did not report enough information to replicate the HRVB protocol in terms of breathing duration, inhalation/exhalation ratio, breathing control or body position. Methodological guidelines and a checklist are proposed to enhance the methodological quality of future HRVB studies and increase the information reported.
Topics: Humans; Heart Rate; Biofeedback, Psychology; Exhalation; Respiratory Rate; Respiratory Sinus Arrhythmia
PubMed: 36917418
DOI: 10.1007/s10484-023-09582-6 -
Autonomic Neuroscience : Basic &... Nov 2023The autonomic nervous system interacts with the immune system via the inflammatory response. Heart rate variability (HRV), a marker of autonomic activity, is associated... (Review)
Review
PURPOSE
The autonomic nervous system interacts with the immune system via the inflammatory response. Heart rate variability (HRV), a marker of autonomic activity, is associated with inflammation, and nosocomial infections/sepsis, and has clinical implications for the monitoring of at-risk patients. Due to the vagal tone's influence on anti-inflammatory immune response, this association may predominately be reflected by vagally-mediated HRV indices. However, HRV's predictive significance on inflammation/infection remains unclear.
METHODS
843 studies examining the associations/prognostic value of HRV indices on inflammation, and nosocomial infection/sepsis were screened in this systematic review. According to inclusion and exclusion criteria, 68 associative studies and 14 prediction studies were included.
RESULTS
HRV and pro-inflammatory state were consistently associated in healthy subjects and patient groups. Pro-inflammatory state was related to reduced total power HRV including vagally- and non-vagally-mediated HRV indices. Similar, compared to controls, HRV reductions were observed during nosocomial infections/sepsis. Only limited evidence supports the predictive value of HRV in the development of nosocomial infections/sepsis. Reduced very low frequency power HRV showed the highest predictive value in adults, even with different clinical conditions. In neonates, an increased heart rate characteristic score, combining reduced total power HRV, decreased complexity, and vagally-dominated asymmetry, predicted sepsis.
CONCLUSIONS
Pro-inflammatory state is related to an overall reduction in HRV rather than a singular reduction in vagally-mediated HRV indices, reflecting the complex autonomic-regulatory changes occurring during inflammation. The potential benefit of using continuous HRV monitoring for detecting nosocomial infection-related states, and the implications for clinical outcome, need further clarification.
PubMed: 37651781
DOI: 10.1016/j.autneu.2023.103116 -
Medical Sciences (Basel, Switzerland) Apr 2023Atrial fibrillation (AF) is the most common pathological arrhythmia, and its complications lead to significant morbidity and mortality. However, patients with AF can... (Review)
Review
BACKGROUND
Atrial fibrillation (AF) is the most common pathological arrhythmia, and its complications lead to significant morbidity and mortality. However, patients with AF can often go undetected, especially if they are asymptomatic or have a low burden of paroxysms. Identification of those at high risk of AF development may help refine screening and management strategies.
METHODS
PubMed and Embase databases were systematically searched for studies looking at electrocardiographic predictors of AF from inception to August 2021.
RESULTS
A total of 115 studies were reported which examined a combination of atrial and ventricular parameters that could be electrocardiographic predictors of AF. Atrial predictors include conduction parameters, such as the PR interval, p-wave index and dispersion, and partial interatrial or advanced interatrial block, or morphological parameters, such as p-wave axis, amplitude and terminal force. Ventricular predictors include abnormalities in QRS amplitude, morphology or duration, QT interval duration, r-wave progression and ST segment, i.e., t-wave abnormalities.
CONCLUSIONS
There has been significant interest in electrocardiographic prediction of AF, especially in populations at high risk of atrial AF, such as those with an embolic stroke of undetermined source. This review highlights the breadth of possible predictive parameters, and possible pathological bases for the predictive role of each parameter are proposed.
Topics: Humans; Atrial Fibrillation; Electrocardiography; Heart Atria; Heart Rate; Heart Ventricles
PubMed: 37092499
DOI: 10.3390/medsci11020030 -
Sports Medicine (Auckland, N.Z.) Feb 2018Although the acquisition of heat acclimation (HA) is well-documented, less is known about HA decay (HAD) and heat re-acclimation (HRA). The available literature suggests... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Although the acquisition of heat acclimation (HA) is well-documented, less is known about HA decay (HAD) and heat re-acclimation (HRA). The available literature suggests 1 day of HA is lost following 2 days of HAD. Understanding this relationship has the potential to impact upon the manner in which athletes prepare for major competitions, as a HA regimen may be disruptive during final preparations (i.e., taper).
OBJECTIVE
The aim of this systematic review and meta-analysis was to determine the rate of HAD and HRA in three of the main physiological adaptations occurring during HA: heart rate (HR), core temperature (T ), and sweat rate (SR).
DATA SOURCES
Data for this systematic review were retrieved from Scopus and critical review of the cited references.
STUDY SELECTION
Studies were included when they met the following criteria: HA, HAD, and HRA (when available) were quantified in terms of exposure and duration. HA had to be for at least 5 days and HAD for at least 7 days for longitudinal studies. HR, T , or SR had to be monitored in human participants.
STUDY APPRAISAL
The level of bias in each study was assessed using the McMaster critical review form. Multiple linear regression techniques were used to determine the dependency of HAD in HR, T , and SR from the number of HA and HAD days, daily HA exposure duration, and intensity.
RESULTS
Twelve studies met the criteria and were systematically reviewed. HAD was quantified as a percentage change relative to HA (0% = HA, 100% = unacclimated state). Adaptations in end-exercise HR decreased by 2.3% (P < 0.001) for every day of HAD. For end-exercise T , the daily decrease was 2.6% (P < 0.01). The adaptations in T during the HA period were more sustainable when the daily heat exposure duration was increased and heat exposure intensity decreased. The decay in SR was not related to the number of decay days. However, protracted HA-regimens seem to induce longer-lasting adaptations in SR. High heat exposure intensities during HA seem to evoke more sustained adaptations in SR than lower heat stress. Only eight studies investigated HRA. HRA was 8-12 times faster than HAD at inducing adaptations in HR and T , but no differences could be established for SR.
LIMITATIONS
The available studies lacked standardization in the protocols for HA and HAD.
CONCLUSIONS
HAD and HRA differ considerably between physiological systems. Five or more HA days are sufficient to cause adaptations in HR and T ; however, extending the daily heat exposure duration enhances T adaptations. For every decay day, ~ 2.5% of the adaptations in HR and T are lost. For SR, longer HA periods are related to better adaptations. High heat exposure intensities seem beneficial for adaptations in SR, but not in T . HRA induces adaptations in HR and T at a faster rate than HA. HRA may thus provide a practical and less disruptive means of maintaining and optimizing HA prior to competition.
Topics: Acclimatization; Body Temperature Regulation; Cross-Sectional Studies; Exercise; Heart Rate; Heat Stress Disorders; Hot Temperature; Humans; Male; Oxygen Consumption; Physical Exertion
PubMed: 29129022
DOI: 10.1007/s40279-017-0808-x -
Seizure Feb 2018To estimate the incidence of pre-ictal heart rate (HR) manifestations and to identify clinical and study-related factors modulating the estimate. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To estimate the incidence of pre-ictal heart rate (HR) manifestations and to identify clinical and study-related factors modulating the estimate.
METHODS
We searched articles recording concurrent pre-ictal EEG and HR in adults and children with epilepsy. Pre-ictal HR changes were classified as HR reduction (HRR) or increase (HRI). Studies reporting the total number of seizures and the number of seizures with pre-ictal HR changes were included in a random-effects meta-analysis. A random-effects meta-regression was used to identify variables affecting study heterogeneity.
RESULTS
Thirty studies, including 1110 participants and 2957 seizures, were included. The meta-analysis showed a pooled incidence of pre-ictal HRI of 36/100 seizures (95% CI 22-50). The pre-ictal HRI incidence was 44/100 seizures (95% CI 33-55) in studies including temporal lobe epilepsy, 55/100 seizures (95% CI 41-68) in studies enrolling adults and 35/100 seizures (95% CI 16-58) when patients on antiepileptic drugs were included. The meta-regression showed that the age group, the length of the pre-ictal period, the incidence of ictal tachycardia and the time of onset of the pre-ictal HRI had a significant impact on estimates variability. The pooled incidence of pre-ictal HRR was 0/100 seizures (95% CI 0-1).
CONCLUSION
Review of bias evaluation and methods assessment disclosed several major limitations in the evidence-base. HR monitoring could be valuable to identify seizures prior to their apparent onset, opening the possibility to early interventions. Additional effort is necessary to delineate the target population who might benefit from its use and the mechanisms sustaining the pre-ictal cardiac changes.
Topics: Adult; Anticonvulsants; Child; Epilepsy, Temporal Lobe; Heart Rate; Humans; Seizures
PubMed: 29367145
DOI: 10.1016/j.seizure.2018.01.003 -
Frontiers in Neuroscience 2019Autonomic dysfunctions may precede the development of cognitive impairment, but the connection between these dimensions is unclear. This systematic review aims to... (Review)
Review
Autonomic dysfunctions may precede the development of cognitive impairment, but the connection between these dimensions is unclear. This systematic review aims to analyze the relationship between heart rate variability (HRV) and cognitive functions. The review process was conducted according to the PRISMA-Statement. Restrictions were made, selecting the studies in English and published in peer-review journals, including at least one cognitive measure and presenting the measurement of HRV. Studies that included participants with medical conditions, dementia, psychiatric disorders, strokes, and traumatic brain injury were excluded. Twenty studies were selected, with a total of 19,431 participants. The results were divided into different cognitive domains determined : global cognitive functioning, attention, processing speed, executive functions, memory, language and visuospatial skills. Both increased sympathetic activity and decreased parasympathetic activity seem to be associated with a worse performance in the cognitive domains considered, in the absence of dementia and severe cardiovascular diseases or other medical and psychiatric diseases. The results highlight the influence of the autonomic nervous system (ANS) in cognitive functioning. However, the marked interest facing toward a specific domain, i.e., the executive functions, and the relatively small number of the studies on this topic do not allow understanding better this relationship. Despite these limits, HRV could be considered a promising early biomarker of cognitive impairment in populations without dementia or stroke. This index should be evaluated within a preventative perspective to minimize the risk of developing cognitive impairment.
PubMed: 31354419
DOI: 10.3389/fnins.2019.00710 -
Medicina (Kaunas, Lithuania) Mar 2020Background and Objectives: Cirrhosis is a liver disease that causes about one million deaths annually worldwide. The estimated cirrhosis prevalence ranges from 4.5-9.5%...
Background and Objectives: Cirrhosis is a liver disease that causes about one million deaths annually worldwide. The estimated cirrhosis prevalence ranges from 4.5-9.5% in the general population. Up to 40% of cirrhotic patients are asymptomatic and may be diagnosed late. Studies have described the importance of the functions of the liver and autonomic nervous system (ANS) and their relationship. There is limited information available on non-alcoholic cirrhosis and heart rate variability (HRV), which is a measure of the ANS. This study aimed to evaluate cardiac autonomic modulation through HRV in non-alcoholic cirrhosis individuals reported in previous observational and clinical trial studies. We performed a systematic review according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement using the Medline, Scopus, and Web of Science electronic databases. Five studies were identified and reviewed. HRV was decreased in patients with non-alcoholic cirrhosis, even in the first stage. HRV could be used as a complementary method to improve both the diagnosis and prognosis of non-alcoholic cirrhosis.
Topics: Autonomic Nervous System; Female; Heart; Heart Rate; Humans; Liver Cirrhosis; Male
PubMed: 32151106
DOI: 10.3390/medicina56030116 -
A systematic review and meta-analysis of heart rate variability in epilepsy and antiepileptic drugs.Epilepsia Feb 2012Epilepsy is associated with near-fatal and fatal arrhythmias, and sudden unexpected death in epilepsy (SUDEP) is partly related to cardiac events. Dysfunction of the... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
Epilepsy is associated with near-fatal and fatal arrhythmias, and sudden unexpected death in epilepsy (SUDEP) is partly related to cardiac events. Dysfunction of the autonomous nervous system causes arrhythmias and, although previous studies have investigated the effects of epilepsy on the autonomic control of the heart, the results are still mixed regarding whether imbalance of sympathetic, vagal, or both systems is present in epilepsy, and also the importance of anticonvulsant treatment on the autonomic system. Therefore, we aimed to investigate epilepsy and its treatment impact on heart rate variability (HRV), assessed by sympathetic and parasympathetic activity expressed as low-frequency (LF) and high-frequency (HF) power spectrum, respectively.
METHOD
We performed a systematic review from the first date available to July 2011 in Medline and other databases; key search terms were "epilepsy"; "anticonvulsants"; "heart rate variability"; "vagal"; and "autonomous nervous system." Original studies that reported data and/or statistics of at least one HRV value were included, with data being extracted by two independent authors. We used a random-effects model with Hedges's g as the measurement of effect size to perform two main meta-analyses comparing LF and HF HRV values in (1) epilepsy patients versus controls; (2) patients receiving versus not receiving treatment; and (3) well-controlled versus refractory patients. Secondary analyses assessed other time- and frequency-domain measurements (nonlinear methods were not analyzed due to lack of sufficient data sets). Quality assessment of each study was verified and also meta-analytic techniques to identify and control bias. Meta-regression for age and gender was performed.
KEY FINDINGS
Initially, 366 references were identified. According to our eligibility criteria, 30 references (39 studies) were included in our analysis. Regarding HF, epilepsy patients presented lower values (g -0.69) than controls, with the 95% confidence interval (CI) ranging from -1.05 to -0.33. No significant differences were observed for LF (g -0.18; 95% CI -0.71 to 0.35). Patients receiving treatment presented HF values to those not receiving treatment (g -0.05; 95% CI -0.37 to 0.27), with a trend for having higher LF values (g 0.1; 95% CI -0.13 to 0.33), which was more pronounced in those receiving antiepileptic drugs (vs. vagus nerve stimulation). No differences were observed for well-controlled versus refractory patients, possibly due to the low number of studies. Regression for age and gender did not influence the results. Finally, secondary time-domain analyses also showed lower HRV and lower vagal activity in patients with epilepsy, as shown by the standard deviation of normal-to-normal interval (SDNN) and the root mean square of successive differences (RMSSD) indexes, respectively.
SIGNIFICANCE
We confirmed and extended the hypothesis of sympathovagal imbalance in epilepsy, as showed by lower HF, SDNN, and RMSSD values when compared to controls. In addition, there was a trend for higher LF values in patients receiving pharmacotherapy. As lower vagal (HF) and higher sympathetic (LF) tone are predictors of morbidity and mortality in cardiovascular samples, our findings highlight the importance of investigating autonomic function in patients with epilepsy in clinical practice. Assessing HRV might also be useful when planning therapeutic interventions, as some antiepileptic drugs can show hazardous effects in cardiac excitability, potentially leading to cardiac arrhythmia.
Topics: Anticonvulsants; Arrhythmias, Cardiac; Autonomic Nervous System; Death, Sudden; Epilepsy; Heart Rate; Humans
PubMed: 22221253
DOI: 10.1111/j.1528-1167.2011.03361.x -
Journal of Clinical Medicine Sep 2023Our aim was to determine the differences in short-term heart rate variability (HRV) between patients with metabolic syndrome (MS) and healthy controls. (Review)
Review
BACKGROUND
Our aim was to determine the differences in short-term heart rate variability (HRV) between patients with metabolic syndrome (MS) and healthy controls.
METHODS
We searched electronic databases for primary works with short-term HRV recordings (≤30 min) that made comparisons between individuals with MS versus healthy controls. This systematic review and meta-analysis (MA) was performed according to PRISMA guidelines and registered at PROSPERO (CRD42022358975).
RESULTS
Twenty-eight articles were included in the qualitative synthesis and nineteen met the criteria for the MA. Patients with MS showed decreased SDNN (-0.36 [-0.44, -0.28], < 0.001), rMSSD (-7.59 [-9.98, -5.19], < 0.001), HF (-0.36 [-0.51, -0.20], < 0.00001) and LF (-0.24 [-0.38, -0.1], = 0.001). In subsequent subanalyses, we found a decrease in SDNN (-0.99 (-1.45, -0.52], < 0.001), rMSSD (-10.18 [-16.85, -3.52], < 0.01) and HF (-1.04 [-1.97, -0.1] < 0.05) in women. In men, only LF showed a significant lower value (-0.26 [-0.5, -0.02], < 0.05). We could not perform MA for non-linear variables.
CONCLUSIONS
Patients with MS showed changes in time-domain analyses, with lower values in SDNN and rMSSD. Regarding frequency-domain analyses, MS patients showed a decrease in HF and LF When sex was used as a grouping variable, the MA was only possible in one of both sexes (men or women) in rMSSD and LF/HF. Lastly, when data for both men and women were available, subanalyses showed a different behavior compared to mixed analyses for SDNN, HF and LF, which might point towards a different impact of MS in men and women.
PubMed: 37762990
DOI: 10.3390/jcm12186051