Role Of Heart Rate Variability Research Articles

Evaluating the role of heart rate variability in monitoring stress and sleep quality among nurses in the aftermath of the COVID-19 pandemic.

To assess heart rate variability (HRV) as a measure to assess job stress and sleep quality among nurses in the post-COVID-19 period. The COVID-19 pandemic significantly affected nurses, with heightened job stress and impaired sleep quality impacting their well-being and effectiveness in patient care. HRV could offer insights for supporting strategies in the pandemic aftermath. A quantitative cross-sectional study. This study involved 403 clinical nurses recruited from a teaching hospital in Taiwan. Data on job stress, work frustration, sleep quality and HRV were collected and analysed. Among the nurses surveyed during the COVID-19 pandemic, 72.7% reported poor sleep quality (PSQI = 9.369). Job stress emerged as a strong predictor of work frustration. High stress levels and poor sleep quality were correlated with significantly decreased HRV, indicating a potential physiological impact of stress on the nurses' health and well-being. HRV is a valuable and cost-effective measure for monitoring and managing nurses' well-being in the post-COVID-19 era. Targeted interventions can be implemented to support nurses' overall performance and promote their well-being by identifying those at high risk of job stress and poor sleep quality.

Role of Heart Rate Variability in the Association between Myocardial Infarction Severity and Post-Myocardial Infarction Distress.

Myocardial infarction (MI) results in mental health consequences, including depression and post-traumatic stress disorder (PTSD). The risk and protective factors of such mental consequences are not fully understood. This study examined the relation between MI severity and future mental health consequences and the moderating role of vagal nerve activity. In a reanalysis of data from the Myocardial Infarction-Stress Prevention Intervention (MI-SPRINT) study, 154 post-MI patients participated. MI severity was measured by the Killip Scale and by troponin levels. Depression and PTSD symptoms were assessed with valid questionnaires, both at 3 and 12 months. Vagal nerve activity was indexed by the heart rate variability (HRV) parameter of the root-mean square of successive R-R differences (RMSSD). Following multivariate analyses, the association between MI severity and distress was examined in patients with low and high HRV (RMSSD = 30 ms). In the full sample, the Killip index predicted post-MI distress only at 3 months, while troponin predicted distress at 3- and 12-months post-MI. However, HRV moderated the effects of the Killip classification; Killip significantly predicted symptoms of depression and PTSD at 3- and 12-months post-MI, but only in patients with low HRV. Such moderation was absent for troponin. MI severity (Killip classification) predicted post-MI depression and PTSD symptoms, but only in patients with low HRV, suggesting that the vagal nerve is a partial protective (moderating) factor in the relation between Killip score and post-MI distress.

The role of heart rate variability in predicting the response to beta blocker in patients with frequent premature ventricular contractions

Abstract Background Frequent premature ventricular contractions (PVCs) in patients with structurally normal heart are not uncommon. Beta blocker is generally used to reduce symptom and burden of PVCs, but the response to beta blockers vary from patient to patient. Purpose This study aimed to investigate whether the heart rate variability (HRV) values could predict the response to beta blockers in patients with frequent PVCs. Methods We analyzed the patients who underwent 24-hour Holter monitoring and had PVC burden >3% in baseline 24-hour Holter monitoring. Bisoprolol and nebivolol was used to reduce symptom and burden of PVCs. The response to beta blocker was defined as the reduction of PVCs burden more than 50% in follow-up Holter monitoring. Baseline HRV was measured by time domain and frequency domain methods using 24-hour Holter monitoring. Results A total of 125 patients (mean age, 52.1 ± 14.7 years; male, 38.3%) underwent repeated 24-hour Holter monitoring were finally analyzed. Mean follow-up duration between the Holter monitoring was 205 ± 200 days. Among 125 patients with frequent PVCs, 45 patients had response to beta blockers. The ratio of low-frequency (LF) and high-frequency (HF) was higher in response group than those with non-response to beta blocker (P=0.016). LF, HF, and other variables measured by time-domain method were not associated with response to beta blocker. Conclusion The HRV value, especially LF/HF ratio, could predict the response to beta blockers in patients with idiopathic frequent PVCs.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring.

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

Inhibition and Heart Rate Variability in Experimentally Induced Pain.

Pain is a complex experience that requires executive functions (EFs) to be processed. The autonomic outcome of the neural networks involved in the cognitive evaluation of pain is reflected by heart rate variability (HRV), an index of self-regulation abilities. Although some results suggest a relationship between HRV, EFs, and pain, studies focusing on this three-way relationship are still scarce. This study aims to investigate the relationship between pain, cognitive, and autonomic mechanisms, hypothesizing an association between resting HRV and both cognitive and motor inhibition as indices of executive functioning. This relationship was investigated after an experimental-induced pain. Seventy-six young adults were exposed to the Cold Pressure Arm Warp to induce experimental pain. HRV was collected, and cognitive tasks were administered to assess executive performance. The results showed that (1) HRV indices significantly increased during pain stimulation, (2) cognitive inhibition was positively correlated with vagal indices and with pain parameters, (3) both inhibition tasks significantly predicted pain threshold while the performance on the Stroop Task predicted pain tolerance. Results suggest a three-way relationship. Further research would focus on the role of HRV and cognitive strategies in pain management in chronic pain conditions.

Heart failure with preserved left ventricular ejection fraction in non-obstructive coronary artery disease: clinical utility of heart rate variability

Aim. To evaluate the role of heart rate variability in the pathogenesis of chronic heart failure with preserved ejection fraction (HFpEF) in patients with non-obstructive coronary artery disease (CAD).Materials and methods. The cross-sectional study included 65 patients (55.4% were males) with non-obstructive CAD. Non-obstructive CAD (stenosis < 50%) was confirmed by coronary computed tomography angiography. Heart rate variability (HRV) was evaluated by 24-hour Holter monitoring; parameters of time series and spectral analysis were analyzed.Results. Depending on the presence of HFpEF, the patients were divided into 2 groups: group 1 (n = 48) included patients with HFpEF, and group 2 (n = 17) encompassed patients without it. In patients with HFpEF, a statistically significant decrease in the total HRV and parasympathetic effects on the heart rate, mainly at night, as well as increased activity of cerebral ergotropic systems were revealed. In group 1, the values of the time series analysis of HRV and QT dispersion based on the study of RR interval duration (SDANN and SDNNidx) had a significant direct relationship with the level of myocardial stress in diastole, the value of vascular resistance, and the E / e’ ratio. The cut-off values of SDNNidx and pNN50 were identified, that may be used as markers for early diagnosis of HFpEF.Conclusion. In patients with non-obstructive CAD and HFpEF, it is advisable to perform 24-hour Holter monitoring and assess HRV parameters by the time series analysis, which, compared with the spectral analysis, has a closer relationship with the characteristics of left ventricular diastolic function and afterload.

Effects of fear of cancer recurrence on subjective physical and mental health in breast cancer patients: The intermediary role of heart rate variability.

Fear of cancer recurrence (FCR) and psychological distress are common psychological problems in breast cancer (BC) patients and ultimately affecting their health-related quality of life (HRQoL). Heart rate variability (HRV) can reflect the activity of the parasympathetic nervous system. However, the pathways through which HRV influences between FCR and HRQoL are unclear. This study preliminarily explored the intermediary role of HRV in FCR and HRQoL in BC patients. A total of 101 BC patients participated in this study. HRV parameters were measured by a 5-min dynamic electrocardiogram. FCR, psychological distress and HRQoL were evaluated by the Fear of disease progression simplified scale (FOP-Q-SF), Distress thermometer and SF-36 concise health survey. The intermediary effect model was established to test the intermediary effect of high frequency-HRV (HF-HRV) on FCR and HRQoL. FCR and psychological distress were negatively correlated with HRV in the time domain, negatively correlated with HF-HRV in the frequency domain, and positively correlated with low frequency/high frequency (LF/HF). HF-HRV had a partial mediating effect on the FCR and physical health and mental health, with effects of 30.23% and 9.53%, respectively. FCR and psychological distress are correlated with HRV parameters in the time domain and the frequency domain, and we preliminarily believe that parasympathetic nerves play an important intermediary role between FCR and subjective physical and mental health. This may provide intervention information for improving the HRQoL of BC patients.

Potential autonomic nervous system dysfunction in COVID-19 patients detected by heart rate variability is a sign of SARS-CoV-2 neurotropic features.

Increasing evidence strongly support that the newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to the development of COVID-19-associated central nervous system (CNS) manifestations. The presence of SARS-CoV-2 viral protein in the brainstem, which includes cardiovascular control centers, has been documented previously. Given the changes in autonomic nervous system function evaluated by heart rate variability (HRV) metrics, which are observed even prior to clinical signs, the potential effect of SARS-CoV-2 on the autonomic nervous system (ANS) center is likely. The integral parts of the brain renin-angiotensin system, as ACE2 enzyme, are highly expressed in the brainstem, which may also be involved in baroreflex sensitivity, playing an important role in HRV. SARS-CoV-2 may bind to ACE2 in order to enter the host brainstem cell and change baroreflex sensitivity due to the altered ratio of the concentration of angiotensin II (Ag II) to angiotensin (1-7). In this article, we discussed the information on the possibility that the SARS-CoV-2 viral particle by disrupting the homeostasis of the brain renin-angiotensin system even without brainstem neuropathological changes, may affect the function of the ANS center in the brainstem. SARS-CoV-2 could influence ANS function before affecting the immune system. It is possible that the altered HRV parameters imply the potential neurotropic characteristics of SARS-CoV-2. Therefore, this potential feature should be taken into account in diagnostic and therapeutic approaches for COVID-19 patients.

Heart Rate Variability May Predict the Severity of Appendicitis: A Cross-Sectional Study.

Objective:To evaluate the role of heart rate variability (HRV) in predicting pre-operative severity of appendicitis.Methods:In this cross-sectional study, 171 cases of acute appendicitis who underwent appendectomy were enrolled. Pre-anesthetic pulse rate of included patients were documented while the severity of appendicitis was determined by intra-operative evidences reported by two independent surgeons. Demographic characteristics, laboratory variables, and Alvarado criteria were recorded. Results:The mean age of patients was 28.75±4.21 years; 54% were men. HRV negatively associated the severity of appendix inflammation. A positive association was found between HRV and omental wrapping and Alvarado score (p<0.01). The receiver operating characteristic (ROC) curve analysis demonstrated that HRV could differentiate simple and complicated appendicitis with a sensitivity of 78.5% and specificity of 97.2%.Conclusion:The present findings revealed that HRV may predict the pre-operative severity of appendicitis and help differentiate simple and complicated appendicitis.

The role of heart rate variability and heart rate turbulence in diabetic retinopathy.

The aim of this study was to evaluate the cardiac autonomic functions of individuals with asymptomatic diabetic retinopathy (DR) and no obvious heart disease by heart rate turbulence (HRT) and heart rate variability (HRV) analysis. A total of 72 patients with type 2 diabetes mellitus: 20 non-retinopathic (NRDM), 26 non-proliferative retinopathic patients (NPDR) and 26 proliferative retinopathic patients (PDR) were enrolled in this cross-sectional study. The HRV parameters of Standard deviation of NN intervals (SDNN) (119.8±11.7, 101.1±20.2, 100.6±17.04), standard deviation of the average NN intervals (108.3±10.8, 91.2±17.5, 93.6±18.4), SDNN Index (49.5±5.1, 40.1±13.4, 38.6±12.7), Root mean square of successive RR interval differences (28.3±5.1, 22.3±7.5, 26±9.2) and Triangular index (34.4±4.3, 29.7±8.8, 27.3±6.7) were significantly lower in the NPDR and PDR groups than in the NRDM group (for all P<0.05). Also, there was a statistically significant higher Turbulence Onset (-1.80±0.7, -1.1±0.9, -0.43±0.81) and lower Turbulence Slope (8.05±2.59, 5.82±3.39, 4.53±2.07) in HRT parameters in patients in the NPDR and PDR groups than in the NRDM group (P<0.001). We found that HRV and HRT parameters had a significant deterioration in retinopathic individuals compared to the group without retinopathy. We think that HRV and HRT analysis can have an important role in the evaluation of these patients.

A Study Protocol on Assessment of Heart Rate Variability as a Prognostic Marker in Critically Ill Patients

Background: Calculation of heart rate variability (HRV) is the most popular approach of actual evaluation of autonomic nervous system (ANS) dysregulation, representing natural physiological changes. The natural changes take place in the interim among successive heart beats when sympathetic and parasympathetic expression is balanced on the heart's electrical conduction system. Numerous adult studies have shown that reductions in HRV predate clinical decline, indicate therapy response in correlation with results. Therefore, HRV can be functional as a measure of more accurate clinical perception. This study aims to determine role of heart rate variability and other risk factors as a prognostic marker for 90-day survival among patients admitted to critical care units.&#x0D; Methods: This will be an Observational Cross-sectional Study with Control Group and will include hypertension, diabetes mellitus, Myocardial Infarction, Stroke, Sepsis cases and control cases. The patients admitted in Medicine critical care unit will be included in the study and they will be evaluated for HRV and APACHE IV scoring. Patients demographic profile, anthropometric measurements and history of other comorbid conditions will be documented. Patients’ outcome indicators like duration of hospital stay, 90-day survival and mortality will be obtained .Data will be analyzed by appropriate statistical tests.&#x0D; Expected Results: Mixed effects models will demonstrate that the result of three HRV will be relatively lower from the start of day and night compared to the last day and night of MICU admission. The significant relationship between the variability of time from enrollment and log heart rate values is expected over the last day and night of MICU stay. Also, average HRV is expected to persist significantly higher as compared with that of the first day and night.

Heart Rate Variability-A Review

Information about the health can be obtained by measuring various physiological parameters such as Heart Rate, Heart Rate Variability (HRV), Nerve conduction, brain activity, blood oxygen saturation level etc. The useful information resulted from the systematic analysis of these physical parameters are helpful for clinicians to make better decisions. HRV reflects the state of the Autonomic Nervous System (ANS) defined as the variance in the time between successive heartbeats expressed in milliseconds. The various factors that affects HRV are diet, nutrition, age, alcohol, gender, cardiac rhythm, sleep habits, genetics etc. The analysis of HRV is helpful in stress assessment and also in identifying the diseases at the early stage. This paper discusses the fundamentals of HRV, analysis of HRV, and the role of HRV in stress detection.

Anxiety and Attentional Processes: The Role of Resting Heart Rate Variability

Individuals with high anxiety preferentially focus attention on emotional information. The autonomic nervous system (ANS) plays an important role in modulating both anxiety and attentional processes. Despite many studies having evaluated attentional bias in anxious people, few of them have investigated the change blindness phenomenon associated with the attentional response toward salient stimuli, considering the role of the ANS. This study aimed to examine the role of heart rate variability (HRV) in trait anxiety and top-down and bottom-up attentional processes toward emotional stimuli. Seventy-five healthy university students were divided into high (N = 39) and low (N = 36) trait anxiety groups and completed a change detection flicker task with neutral, positive, and negative stimuli. The results evidenced a different attentional pattern between people with high and low anxiety considering both the two attentional processes and the valence of the stimuli. Specifically, individuals with high anxiety showed a bias in elaborating emotional stimuli related to their salience (i.e., negative stimuli were faster elaborated than neutral and positive stimuli when top-down attentional mechanisms were involved, while slower performances were highlighted considering bottom-up attentional mechanisms in response to emotional stimuli compared to neutral stimuli). Moreover, an association between HRV, trait anxiety levels, and change blindness phenomenon was confirmed. These results underline the role of HRV as a possible predictor of the alteration of attentional mechanism in anxiety.

Depressed mood, brooding rumination and affective interference: The moderating role of heart rate variability

Facilitated processing of negative information might contribute to the etiopathogenesis and maintenance of depressive symptoms. Cardiac vagal tone, indexed by heart rate variability (HRV), is believed to represent a proxy of the functional integrity of the neural networks implicated in brooding rumination, affective interference and depression. The present study examined whether HRV may moderate the relation between brooding rumination, affective interference and depressive symptoms in a sample of healthy individuals (n = 68) with different degrees of depressed mood. Self-report measures of depression and brooding were collected, whereas the emotional Stroop task was employed to measure affective interference. Three-minute resting-state electrocardiogram was recorded to obtain time- and frequency-domain vagally mediated HRV parameters. Stepwise linear regression analyses revealed that HRV was a significant moderator of the positive association between depression and brooding rumination, but not of the association between depression and affective interference. An integrated model is supported, in which vagally mediated HRV appeared to potentiate the positive link between depressive symptoms and brooding rumination. Considering that HRV and brooding rumination were found to have an interacting role in determining the severity of depressive symptoms, they may represent potential clinical targets in the prevention and treatment of depressive symptoms.

Stress Analysis Among University Students Using Psychometric Scale and Heart Rate Variability Approach

Stress has become one of the major mental health problems in Malaysia. Most Malaysians underestimate and neglect this critical issue, not knowing what the consequences might be due to the lack of knowledge on stress analysis. Many researchers are trying to identify the causes and ways to overcome stress. With the help of advancing electronic systems engineering, primed heart rate biomarker has been earmarked as the tool to analyse stress. However, the relationship between heart rate variability approach and the quantification of stress is still an open research challenge. Therefore, the goal of this study is to explore the role of heart rate variability (HRV) and psychometric scale on stress and resilience analysis among university students and the effectiveness of interventions and Heart Rate Variability devices on improving resilience. 30 students, 15 males and 15 females aged 23 to 24 years old were picked as the subjects for this experiment according to their stress and resilience scores obtained from two questionnaires, Brief Resilience Scale (BRS) and Depression Anxiety Stress Scale-21 (DASS21). Their heart rate variability was measured using HeartMath EmWave device to observe the changes of their heart rhythm when a stimulus and an intervention is given. The data acquired from HeartMath EmWave were analyzed using Kubios HRV software, where it provides more in-depth analysis regarding the subjects’ heart rate during the experiment. According to the results, most of the subjects’ heart rate becomes incoherent during the stimulus phase. However, their heart rate changes into a coherence state due to the effectiveness of slow breathing techniques as an intervention. It helps the subjects to become calmer and synchronize their autonomic nervous system (ANS) with their brain and heart. Therefore, choosing the right intervention is vital to get a coherent heart rate, thus train how our body responds to stressors. The results also provide fruitful insight relating to how a human reacts when they are facing something difficult in their lives and indicates that heart rate variability biofeedback is important to achieve human wellness and validate the quantification of resilience and stress. This study concludes that the heart rate variability device and measurement are effective and have a vital impact to create stress awareness.

Heart rate variability as possible marker of brain damage in neonates with hypoxic ischemic encephalopathy: a systematic review.

Heart rate variability (HRV) is currently considered the most valuable non-invasive test to investigate the autonomic nervous system function, based on the fact that fast fluctuations might specifically reflect changes of sympathetic and vagal activity. An association between abnormal values of HRV and brain impairment has been reported in the perinatal period, although data are still fragmentary. Considering such association, HRV has been suggested as a possible marker of brain damage also in case of hypoxic-ischemic encephalopathy following perinatal asphyxia. The aim of the present manuscript was to review systematically the current knowledge about the use of HRV as marker of cerebral injury in neonates suffering from hypoxic-ischemic encephalopathy. Findings reported in this paper were based on qualitative analysis of the reviewed data.Conclusion: A growing body of research supports the use of HRV as non-invasive, bedside tool for the monitoring of hypoxic-ischemic encephalopathy. The currently available data about the role of HRV as prognostic tool in case of hypoxic ischemic encephalopathy are promising but require further validation by future studies.What is Known:• Heart rate variability (HRV) is a non-invasive monitoring technique to assess the autonomic nervous system activity.• A correlation between abnormal HRV and cerebral injury has been reported in the perinatal period, and HRV has been suggested as possible marker of brain damage in case of hypoxic-ischemic encephalopathy.What is New:• HRV might provide precocious information about the entity of brain injury in asphyxiated neonates and be of help to design early, specific, and personalized treatments according to severity.• Further investigations are required to confirm these preliminary data.

The Role of Heart Rate Variability in the Future of Remote Digital Biomarkers.

Heart rate variability (HRV) offers insights into humoral, neural and neurovisceral processes in health and disorders of brain, body and behavior but has yet to be fully potentiated in the digital age. Remote measurement technologies (RMTs), such as, smartphones, wearable sensors or home-based devices, can passively capture HRV as a nested parameter of neurovisceral integration and health during everyday life, providing insights across different contexts, such as activities of daily living, therapeutic interventions and behavioral tasks, to compliment ongoing clinical care. Many RMTs measure HRV, even consumer wearables and smartphones, which can be deployed as wearable sensors or digital cameras using photoplethysmography. RMTs that measure HRV provide the opportunity to identify digital biomarkers indicative of changes in health or disease status in disorders where neurovisceral processes are compromised. RMT-based HRV therefore has potential as an adjunct digital biomarker in neurovisceral digital phenotyping that can add continuously updated, objective and relevant data to existing clinical methodologies, aiding the evolution of current “diagnose and treat” care models to a more proactive and holistic approach that pairs established markers with advances in remote digital technology.

Unravelling the black box of machine learning for atrial fibrillation forecast: role of heart rate variability and of premature beats

Abstract Background The identification of patients still in sinus rhythm who will present one month later an atrial fibrillation episode is possible using machine learning (ML) techniques. However, these new ML algorithms do not provide any relevant information about the underlying pathophysiology. Purpose To compare the predictive performance for forecasting AF between a machine learning algorithm and other parameters whose pathophysiological mechanisms are known to play a role in the triggering of arrhythmias (i.e. the count of premature beats (PB) and heart rate variability (HRV) parameters) Material and methods We conducted a retrospective study from an outpatient clinic. 10484 Holter ECG recordings were screened. 250 analysable AF onsets were labelled. We developed a deep neural network model composed of convolutional neural network layers and bidirectional gated recurrent units as recurrent neural network layers that was trained for the forecast of paroxysmal AF episodes, using RR intervals variations. This model works like a black box. For comparison purposes, we used a “random forest” (RF) model of ML to obtain forecast results using HRV parameters with and without PB. This model allows the evaluation of the relevance of HRV parameters and of PB used for the forecast. We calculated the area under the curve of the receiving operating characteristic curve for the different time windows counted in RR intervals before the AF onset. Results As shown in the table, the forecasting value of the deep neural network model (ML) was not superior to the random forest algorithm. Prediction value of both decreased when analyzing the RR intervals further away from the onset of AF Conclusions These results suggest that HRV plays a predominant role in triggering AF episodes and that premature beats could add minor information. Moreover, the closer the window from AF onset, the better the accuracy, regardless of the method used. Such detection algorithms once implemented in pacemakers, might prove useful to prevent AF onset by changing pacing sequence while patients would still be in sinus rhythm, however this remains to be demonstrated Funding Acknowledgement Type of funding source: None

Translating GWAS-identified loci for cardiac rhythm and rate using an in vivo image- and CRISPR/Cas9-based approach

A meta-analysis of genome-wide association studies (GWAS) identified eight loci that are associated with heart rate variability (HRV), but candidate genes in these loci remain uncharacterized. We developed an image- and CRISPR/Cas9-based pipeline to systematically characterize candidate genes for HRV in live zebrafish embryos. Nine zebrafish orthologues of six human candidate genes were targeted simultaneously in eggs from fish that transgenically express GFP on smooth muscle cells (Tg[acta2:GFP]), to visualize the beating heart. An automated analysis of repeated 30 s recordings of beating atria in 381 live, intact zebrafish embryos at 2 and 5 days post-fertilization highlighted genes that influence HRV (hcn4 and si:dkey-65j6.2 [KIAA1755]); heart rate (rgs6 and hcn4); and the risk of sinoatrial pauses and arrests (hcn4). Exposure to 10 or 25 µM ivabradine—an open channel blocker of HCNs—for 24 h resulted in a dose-dependent higher HRV and lower heart rate at 5 days post-fertilization. Hence, our screen confirmed the role of established genes for heart rate and rhythm (RGS6 and HCN4); showed that ivabradine reduces heart rate and increases HRV in zebrafish embryos, as it does in humans; and highlighted a novel gene that plays a role in HRV (KIAA1755).

A narrative review of heart rate and variability in sepsis.

Clinicians face challenges in the timely diagnosis and management of pediatric sepsis. Pediatric heart rate has been incorporated into early warning systems and studied as a predictor for critical illness. We aim to review: (I) the role of heart rate in pediatric warning systems and (II) the role of heart rate variability (HRV) in adult and neonatal sepsis, with a focus on its potential applications in pediatrics. We conducted a literature search for papers published up to December 2019 on the utility of heart rate and HRV analysis in the diagnosis and management of sepsis, using four medical databases: PubMed, Google Scholar, EMBASE and Web of Science. This review demonstrates that the clinical utility of pediatric heart rate in predicting clinical deterioration is limited by the lack of consensus among warning systems, consensus-based guidelines, and evidence-based studies as to what constitutes abnormal heart rate in the pediatric age group. Current studies demonstrate that abnormal heart rate itself does not adequately discriminate children with sepsis from those without. HRV analysis provides a quick and non-invasive method of assessment and can provide more information than traditional heart rate. HRV analysis has the potential to add value in identification and prognostication of adult and neonatal sepsis. With further studies to explore its role, HRV analysis has the potential to add to current tools in the diagnosis and prognosis of pediatric sepsis.