Use Of Heart Rate Variability Research Articles

Heart Rate Variability in Type 2 Diabetes Mellitus

Heart rate variability (HRV) is a noninvasive measure of cardiac autonomic modulation. Time and frequency domain measures have primarily been examined in patients with type 2 diabetes mellitus (T2D). Not only do frequency domain HRV parameters tend to be reduced in T2D, but healthy individuals with low HRV are also more likely to develop T2D. Furthermore, patients with T2D with low HRV have an increased prevalence of complications and risk of mortality compared with those with normal autonomic function. These findings provide support for the use of HRV as a risk indicator in T2D. Exercise is considered an important component to T2D prevention and treatment strategies. To date, few studies have examined the changes in HRV with exercise in T2D. One study showed changes in resting HRV, two studies showed changes in HRV during or following acute stressors, and one study showed no changes in HRV but improvements in baroreflex sensitivity. The most pronounced changes in HRV were realized following the exercise intervention with the greatest frequency of supervised exercise sessions and with the greatest intensity and duration of exercise bouts. These findings suggest that exercise following current American College of Sports Medicine/American Diabetes Association guidelines may be important in the prevention and treatment of T2D to improve autonomic function and reduce the risk of complications and mortality.

Heart Rate Variability a Cardiac Indicator in Diabetic Autonomic Neuropathy: A Systematic Review

Background: Cardiac indicator Heart Rate variability ( HRV) is a significant sensitive and early predictor, which could be used for early deduction of complications among Diabetes Mellitus patients. Many studies have reported the usefulness of HRV as diagnostic method, however, there is a gap in the literature in the utilization of HRV in the clinical practice in planning, providing, and evaluating quality care for patients with diabetic autonomic neuropathy. Purpose: The purpose of this systematic review is was to review the cardiac indicators of diabetic autonomic neuropathy. Method: A Systematic Review of published clinical research articles from PUBMED data source was performed and the review is organized under method and result section. The research articles were selected for the review with inclusion criteria including clinical research studies, addressing concepts of HRV, diabetes mellitus, and autonomic neuropathy. Conclusion: The review concluded that existing literature support that the HRV is a sensitive cardiac indicator, which may help to predict the cardiac morbidity and mortality among diabetes mellitus patients. HRV may be used as a significant cardiac indicator to predict diabetic autonomic neuropathy. This finding may be useful in the early diagnosis and treatment of complications among patients with diabetes mellitus.

Development of a Rugged handheld Device for Real-Time Analysis of heart Rate: Entropy in Critically Ill Patients

The usefulness of heart rate variability (HRV) and heart rate complexity (HRC) analysis as a potential triage tool has been limited by the inability to perform real-time analysis on a portable, handheld monitoring platform. Through a multidisciplinary effort of academia and industry, we report on the development of a rugged, handheld and noninvasive device that provides HRV and HRC analysis in real-time in critically ill patients.After extensive re-engineering, real-time HRV and HRC analyses were incorporated into an existing, rugged, handheld monitoring platform. Following IRB approval, the prototype device was used to monitor 20 critically ill patients and 20 healthy controls to demonstrate real-world discriminatory potential. Patients were compared to healthy controls using a Student?s t test as well as repeated measures analysis. Receiver operator characteristic (ROC) curves were generated for HRV and HRC.Critically ill patients had a mean APACHE-2 score of 15, and over 50% were mechanically ventilated and requiring vasopressor support. HRV and HRC were both lower in the critically ill patients compared to healthy controls (p < 0.0001) and remained so after repeated measures analysis. The area under the ROC for HRV and HRC was 0.95 and 0.93, respectively.This is the first demonstration of real-time, handheld HRV and HRC analysis. This prototype device successfully discriminates critically ill patients from healthy controls. This may open up possibilities for real-world use as a trauma triage tool, particularly on the battlefield.

Interest of analyses of heart rate variability in the prevention of fatigue states in senior runners

The use of heart rate variability (HRV) in the management of sport training is a practice which tends to spread, especially in order to prevent the occurrence of fatigue states. To estimate the HRV parameters obtained using a heart rate recording, according to different exercise impacts, and to make the link with the appearance of subjective fatigue. Ten senior runners, aged 51±5 years, were each monitored over a period of 12 weeks in different conditions: (i) after a resting period, (ii) after a day with training, (iii) after a day of competition and (iv) after a rest day. They also completed three questionnaires, to assess fatigue (SFMS), profile of mood states (POMS) and quality of sleep. The HRV indices (heart rate, LF (n.u.), HF (n.u.) and LF/HF) were significantly altered with the competitive impact, shifting toward a sympathetic predominance. After rest and recovery nights, the LF (n.u.) increased significantly with the competitive impact (62.1±15.2 and 66.9±11.6 vs. 76.0±10.7; p<0.05 respectively) whereas the HF (n.u.) decreased significantly (37.9±15.2 and 33.1±11.6 vs. 24.0±10.7; p<0.05 respectively). Positive correlations were found between fatigue and frequency domain indices and between fatigue and training impact. Autonomic nervous system modulation-fatigue relationships were significant, suggesting the potential use of HRV in follow-up and control of training. Furthermore, the addition of questionnaires constitutes complementary tools that allow to achieve a greater relevance and accuracy of the athletes' fitness and results.

The Use of Heart Rate Variability in Assessing Precompetitive Stress in High-Standard Judo Athletes

The objective of this study is to examine the sensitivity to and changes in heart rate variability (HRV) in stressful situations before judo competitions and to observe the differences among judo athletes according to their competitive standards in both official and unofficial competitions. 24 (10 male and 14 female) national- and international-standard athletes were evaluated. Each participant answered the Revised Competitive State Anxiety Inventory (CSAI-2R) and their HRV was recorded both during an official and unofficial competition. The MANOVA showed significant main effects of the athlete's standard and the type of competition in CSAI-2R, in HRV time domain, in HRV frequency domain and in HRV nonlinear analysis (p<0.05). International-standard judo athletes have lower somatic anxiety, cognitive anxiety, heart rate and low-high frequency ratio than national-standard athletes (p<0.05). International-standard athletes have a higher confidence, mean RR interval, standard deviation of RR, square root of the mean squared difference of successive RR intervals, number of consecutive RR that differ by more than 5 ms, short-term variability, long-term variability, long-range scaling exponents and short-range scaling exponent than national-standard judo athletes. In conclusion, international-standard athletes show less pre-competitive anxiety than the national-standard athletes and HRV analysis is sensitive to changes in pre-competitive anxiety.

Autonomic nervous system dysfunction and their relationship with disease severity in children with atopic asthma

The involvement of autonomic imbalance has been reported in the pathogenesis of allergic diseases. The aim of this study was to investigate the association between the clinical severity of childhood asthma with autonomic nervous system (ANS) dysfunction and to define whether the severity of asthma correlates with ANS activity. In this case–control study, we evaluated the ANS activity by testing heart rate variability (HRV) and sympathetic skin response (SRR) in 77 asthmatic children, age 7–12 yrs, who had no co-morbidity and compared them with 40 gender- and age-matched control subjects. According to the severity of their asthma, study subjects were further divided into three groups: I (mild asthmatics), II (moderate asthmatics), and III (severe asthmatics). Inter-group ANS scale scores differed significantly (p<0.01) between Groups I and III and between Groups II and III. Combined use of HRV and SSR provides a higher degree of sensitivity for assessing disease severity in cases of pediatric asthma.

Heart rate variability reproducibility during exercise

The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined.

Who benefits from simulator training: Personality and heart rate variability in relation to situation awareness during navigation training

ObjectiveThis study tested the relationship between individual differences and Situation Awareness (SA) during training in a navigation simulator. BackgroundSimulators have become an important tool in the training and education of maritime personnel with a view to improving decisions and performance. There are a few, inconclusive empirical studies that have focused on mapping personality characteristics and their link to the ability to generate and maintain SA during simulator training. MethodThirty-six first-year students from the Royal Norwegian Navy Officer Candidate School participated in the study. SA was measured using both subjective and observer ratings. ResultsThe results indicated that low scores on Neuroticism and high scores on Extraversion and Conscientiousness (resilient personality type) predicted both subjective and observer-rated SA. Furthermore, participants with high SA were able to modulate their Heart Rate Variability (HRV), with suppression of HRV during navigation training as well showing recovery of HRV. ApplicationThe potential applications of this research include the assessment of personality differences as a tool in selecting navigators, and the use of HRV as an objective index of adaptability to environmental demands.

Significance and usefulness of heart rate variability in patients with multiple system atrophy

The purpose of this study was to investigate whether heart rate variability parameters can be useful for evaluating cardiac autonomic dysfunction in multiple system atrophy patients. Both the time and frequency domains of heart rate variability were investigated among 17 multiple system atrophy patients and 27 normal control subjects. All time- and frequency-domain measures, except the low- to high-frequency ratio, were significantly lower in multiple system atrophy patients than in controls. In multiple system atrophy patients, there were significant inverse correlations between heart rate variability parameters and disease duration, as well as disease severity, but heart rate variability parameters were not affected by other autonomic dysfunctions. The cardiac autonomic state of multiple system atrophy was characterized by decreases in both sympathetic and parasympathetic tones. Because heart rate variability parameters were not affected by other autonomic dysfunctions, this may be a useful method for evaluating cardiac autonomic dysfunction in multiple system atrophy.

Heart rate variability after heart transplantation: A 10-year longitudinal follow-up study

Cross-sectional studies suggest, by use of heart rate variability (HRV), that partial re-innervation of the sinus node may occur after heart transplantation (HTx). Our aim was to test this hypothesis by examining HRV in long-term longitudinal follow-up study of HTx recipients. 14 HTx recipients (11 men) were studied 1-48 (median 13) months (baseline) and 119-172 (median 141) months after HTx (follow-up). At baseline and follow-up, electrocardiographic RR interval was continuously recorded in the supine position for 20 min. The signals were analyzed in the time domain and in the frequency domain by means of power spectral analysis. RR-interval decreased significantly from baseline to follow-up (p<0.05). This was associated with an increase of total power (p<0.001), absolute low frequency (p<0.001), and high frequency power (p<0.001), but unchanged relative low frequency and high frequency power. The observed changes in HRV during long-term follow-up after HTx are compatible with partial re-innervation of the cardiac sinus node, as has been suggested by cross-sectional studies.

668 Clinical Utility of Heart Rate Variability (HRV) Analysis for the Assessment of Autonomic Reinnervation in Pediatric Heart Transplant Recipients

Following heart transplantation (HTx), loss of autonomic input to the allograft results in an elevated resting heart rate (HR) and decreased chronotropic reserve in response to exercise. Enhanced exercise capacity and HR recovery post exercise are suggestive of reinnervation and have been correlated with graft survival in adults. Heart rate variability (HRV), a non-invasive method for assessing autonomic control, was used to assess reinnervation and its functional correlates in a large cohort of pediatric patients following HTx.

Heart rate variability in childhood obstructive sleep apnea

The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24-hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short-term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea-hypopnea index (AHI) > 1.5/hr and non-OSA if AHI ≤ 1.5/hr. Continuous 1-hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy-four male and 17 female snoring subjects were included in this study. Fifty-one (56%) and 40 (44%) of them were classified as "non-OSA" and "OSA," respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non-OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1-hr study of HRV may be a feasible tool in identifying children with OSA.

Hemodynamic Monitoring Today

Hemodynamic monitoring has been part of the routine management of intensive care patients and high risk surgical patients since the advent of the pulmonary artery catheter (PAC) more than thirty years ago. The growing availability of new less invasive devices over the past decades has now made it possible to monitor cardiac output (CO) more often in the operating room, as well as in new clinical settings such as the emergency department. In this special issue papers have been arranged that discuss different aspects of hemodynamic monitoring, from technical issues to new clinical applications. The first paper titled “Perioperative intravascular fluid assessment and monitoring: a narrative review of established and emerging techniques” is a review on perioperative intravascular fluid assessment and monitoring. How cardiovascular physiology can be monitored is explained, and different technologies are presented. The second paper titled “Cardiac output assessed by invasive and minimally invasive techniques” is a review on all available technologies to monitor CO. The authors start from the PAC and carry on to present the more recent less invasive devices. The review covers technical aspects as well as clinical validation and use. The third paper titled “The effect of a hyperdynamic circulation on tissue Doppler values: a simulation in young adults during exercise” presents research done on healthy individuals undergoing strenuous exercise, using left ventricular tissue Doppler velocity (TDI), giving us new data on the use of TDI in hyperdynamic circulation. The fourth paper titled “The effect of airway pressure release ventilation on pulmonary catheter readings: specifically pulmonary capillary wedge pressure in a swine model” investigates the effect of the airway pressure release ventilation (APRV) on the PAC readings in an animal model. This papers gives new insights into the heart-lung interaction when using this new mode of ventilation. In the fifth paper titled “Clinical applications of heart rate variability in the triage and assessment of traumatically injured patients” heart rate variability (HRV) is explored. HRV represents a way of looking at the function of autonomic nervous system during stress conditions and has been studied in different areas as a predictor of morbidity and mortality. In this paper the authors focus on the use of HRV in trauma patients. The sixth paper titled “Recommendations for haemodynamic and neurological monitoring in repair of acute type A aortic dissection” gives a perspective on how hemodynamic monitoring should be used in conjunction with other clinical strategies. In this review the authors describe how hemodynamic monitoring can be combined with neurological monitoring in order to optimize the circulation guaranteeing adequate cerebral blood flow. The seventh paper titled “Assessing the left ventricular systolic function at the bedside: the role of transpulmonary thermodilution-derived indices” is a review on the use of transpulmonary thermodilution to measure CO and other derived variables. The authors focus on how these variables can be used to assess the left ventricular function in different clinical situations. Maurizio Cecconi Jamal A. Alhashemi Maxime Cannesson Christoph K. Hofer

Heart rate variability: Standardisation of methodology

Introduction: The use of heart rate variability (HRV) as a non-invasive indicator of cardiac function and autonomic nervous system (ANS) function in athletes and patients has increased exponentially. However, the availability of clinical acknowledged standards are spares and non-standardization in data collection methods produce inconsistent study results. The aim of this study was to determine the influence of (a) different tachogram lengths (3, 5, 7 and 10 min) and (b) to determine whether comparable HRV are obtained when calculated from various 3 min segments of a 10 min tachogram. Methodology: Healthy active volunteers (n = 150, age = 20.2 yrs, mass = 61.11 kg; height = 165.88 cm) participated. RR intervals were sampled for 10 min in the supine position and 10 min during an orthostatic stressor. HRV were quantified with time domain, frequency domain and the Poincaré analysis. The SAS procedure MIXED was used to determine the effect of the different time intervals on each of the HRV measurements. Results and conclusions: Results obtained in the supine position showed that the mean values of HRV indicators influenced by parasympathetic efferent activity (pNN50, RMSSD, SD1, and HFms2) did not differ (p > 0.05) when measured over different tachogram lengths. However, these indicators did show a tachogram length dependency during an orthostatic stressor. HRV indicators influenced by the sympathetic as well as the parasympathetic branches, (STDHR, STDRR, SD2 and LFms) showed significant (p < 0.05) tachogram length dependency in supine and standing positions. In the supine position the variability indicated by SD2, HFms and HFnu (p < 0.05) were influenced by the specific segment of the tachogram used. HRV values (RMSSD, pNN50, SD1, LFms2, SD2, HFms2 and LF/HF) determined during the initial period (0–3 min) of the orthostatic stressor were significant different from mean values determined during the second dataset (3–6 min standing) and third data set (6–9 min standing). These results indicate that, due to the activation and de-activation of normal homeostatic mechanisms for the maintenance of blood pressure, the starting time of the tachogram during a posture change is critical. This effect renders comparisons unreliable if recording times and periods are not standardised. This study proposes standardized tachogram lengths and starting times that could facilitate comparability between studies, thereby strengthening the use of HRV as a non-invasive probe of cardiac function and ANS.

S16 Detection of sleep-disordered breathing in chronic heart failure patients: utility of heart rate variability versus pulse oximetry?

Introduction and ObjectivesSleep-disordered breathing (SDB) is a frequent comorbidity in chronic heart failure (CHF). Patients are often asymptomatic and sleep studies may be required for SDB diagnosis. Our department has...

The impact of heart rate variability on subjective well-being is mediated by emotion regulation

Resting heart rate variability (HRV) can serve as an index of self-regulatory strength. In the present study we tested the hypotheses that HRV, indexing adaptive self-regulation, is associated with subjective well-being, and that this association is mediated by the habitual use of strategies of emotion regulation that involve executive functions. In addition to measuring heart rate at rest, subjective well-being – as indicated by positive habitual mood and satisfaction with life – and habitual emotion regulation were assessed via self-reports. The findings were largely consistent with our predictions. HRV was positively associated with cheerfulness and calmness, and these effects were mediated by executive emotion regulation. Mediated by these strategies, HRV was also associated with satisfaction with life. Together, the results support the use of HRV as an index of self-regulatory strength.

Oximetry, heart rate variability, and the diagnosis of mild-to-moderate acute mountain sickness

The clinical evaluation of acute mountain sickness (AMS) is often performed in remote settings with minimal equipment. The purpose of this study was to examine the utility of heart rate variability and other cardiovascular parameters in a high-altitude clinical setting. Forty-one participants were recruited from the patient population of the clinic, and from festivalgoers [those who attended the Janai Purnima festival held at Lake Gosainkunda (4380 m) in Langtang, Nepal] in the vicinity of the clinic. Twenty-one participants were diagnosed with AMS; remaining participants were free from altitude illness. Heart rate variability (both time and frequency domain measures), arterial oxygen saturation (SpO2), blood pressure and Lake Louise Score were evaluated in all the participants. Oxygen saturation and diastolic blood pressure were negatively and positively correlated with Lake Louise Score, respectively. Receiver operating characteristic analysis indicated that an SpO2 of 86% or greater was associated with a very low likelihood of AMS at this altitude. No heart rate variability parameters were different in the AMS group as compared with the control group. In conclusion, in patients with SpO2 of 86% or more at 4380 m or higher, the likelihood of AMS is low. Diastolic blood pressure correlated with AMS severity, whereas heart rate variability was not useful in the diagnosis of AMS.

Analyses of heart rate variability in young soccer players: The effects of sport activity

Background The use of heart rate variability (HRV) in the management of sport training is a practice which tends to spread, especially in order to prevent the occurrence of states of fatigue. Objective To estimate the HRV parameters obtained using a heart rate recording, according to different loads of sporting activities, and to make the possible link with the appearance of fatigue. Methods Eight young football players, aged 14.6 years ± 2 months, playing at league level in Rhône-Alpes, training for 10 to 20 h per week, were followed over a period of 5 months, allowing to obtain 54 recordings of HRV in three different conditions: (i) after rest (ii) after a day with training and (iii) after a day with a competitive match. Results Under the effect of a competitive match, the HRV temporal indicators (heart rate, RR interval, and pNN50) were significantly altered compared to the rest day. The analysis of the sympathovagal balance rose significantly as a result of the competitive constraint (0.72 ± 0.17 vs. 0.90 ± 0.20; p < 0.05). Conclusion The main results obtained show that the HRV is an objective and non-invasive monitoring of management of the training of young sportsmen. HRV analysis allowed to highlight any neurovegetative adjustments according to the physical loads. Thus, under the effect of an increase of physical and psychological constraints that a football match represents, the LF/HF ratio rises significantly; reflecting increased sympathetic stimulation, which beyond certain limits could be relevant to prevent the emergence of a state of fatigue.

Heart rate variability changes induced by auditory stimulation in persistent vegetative state

Previous studies, using neuroimaging and electrophysiology, have identified the presence of cerebral responses to auditory stimulation in clinically unresponsive persistent vegetative state (PVS) patients. In normal individuals, it has been shown that stimulation with emotional content has a strong influence on autonomic cardiovascular regu­lation tested by heart rate variability (HRV). In this paper, we assessed responses to auditory stimulation with emotion­al content in PVS and minimally conscious (MCS) cases by HRV. We found a pattern of changes induced by auditory stimulation in three of our patients (decreased heart rate, increased HRV, decrease power in the low and increased power in high frequencies) consistent with increased cardiovagal stimulation. Both time and frequency domain changes were more pronounced during affective than during non-affective auditory stimulation, suggesting that PVS patients are able to discriminate between stimuli of different content and are more reactive to emotional than non-emotional stimulation. Our results demonstrate (is a conclusion, should be in present) that auditory stimulation can induce recordable changes in HRV in some PVS cases, providing evidence that these patients retain some preserved cognitive function examined by cardiovascular correlates. The use of HRV to study residual cognitive functions could have practical implications for the management of PVS and MCS.

Heart Rate Variability and Length of Survival in Hospice Cancer Patients

We examined the association between heart rate variability (HRV) and survival duration to evaluate the usefulness of HRV as a prognostic factor for hospice cancer patients. In terminally ill cancer patients who visited the Hospice clinic, we checked demographic data, Karnofsky performance scale (KPS), HRV, dyspnea, anorexia, as well as fasting blood glucose and total cholesterol. After following up their duration of survival, we examined meaningful prognostic factors for predicting life expectancy through the survival analysis. A total of 68 patients were included in final analysis. As KPS was lower, or when combined with dyspnea or anorexia, the survival duration was much shorter. HRV parameters except heart rate were all impaired in most patients. In particular, the group with mean heart rate of 100 or more beats per minute and the group with standard deviations of normal-to-normal R-R intervals (SDNN) of 21.3 ms (75 percentile) or less showed significantly shorter survival duration. The final multivariate analysis adjusting for age, gender, fasting blood glucose, and total cholesterol showed that KPS, dyspnea, anorexia, and SDNN were significant prognostic factors in survival duration. For the first time, we report that SDNN is a prognostic factor in terminal cancer patients.