Differences In Heart Rate Variability Parameters Research Articles

Heart rate variability and its association with symptoms of orthostatic hypotension in spinal cord injury

Context/objective To assess differences in autonomic function using heart rate variability (HRV) parameters between people with and without orthostatic hypotension (OH), and to determine symptoms of OH in people with spinal cord injury (SCI). Methods R-R interval and blood pressure (BP) data were recorded using Finometer PRO® in both the supine position and at a 60-degree tilt using a tilt table, each lasting for 6 minutes. R-R interval data were processed using the Kubios HRV analysis software to convert R-R interval into time and frequency domains for further analysis. Results Compared to the non-OH group, the SCI group with OH exhibited lower values for root mean square of the successive differences (RMSSD) and standard deviation of normal-to-normal interval (SDNN), along with an elevated heart rate during tilt-up. Participants with OH symptoms had a lower average heart rate in the supine and 60-degree positions compared to asymptomatic participants. Logistic regression analysis indicated that SDNN in the supine position correlated with the presence of OH, and that the mean heart rate in the 60-degree position was related to the presence of symptoms. Conclusions Differences in HRV parameters were observed in people with SCI and OH, suggesting a reduced parasympathetic activity in the supine position, likely as a response to maintain homeostasis in BP regulation. Despite the presence or absence of OH symptoms, there was no difference in HRV parameters. This finding suggests that autonomic function may not be the primary determinant of these symptoms, with other factors likely being more influential.

Comparison of autonomic dysfunction in patients with Parkinson's Disease, progressive supranuclear palsy, and multiple system atrophy.

To assess and compare autonomic nervous system (ANS) dysfunction, especially cardiovascular dysautonomia, in Parkinson's Disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and healthy controls. Assessment of ANS can be useful in differential diagnosis. Dysautonomia affects quality of life and can lead to potentially life-threatening complications. There is very little literature data regarding dysautonomia in PSP in relation to other parkinsonian syndromes. This study expands the knowledge about ANS dysfunction in parkinsonisms, especially PSP. Patients with PD, MSA and PSP were prospectively recruited to our study. Demographic data and information about clinical and neuropsychological assessment, medication and comorbidities was collected. SCOPA-AUT questionnaire, 5-minute tilt test, and 5-minute heart rate variability (HRV) analysis in time and frequency domains were used to assess ANS. Analysis was also performed in patients with PSP-RS and PSP-P phenotypes, and in a subgroup with eliminated confounding factors, including age and disease duration. 76 PD, 25 PSP, and 12 MSA patients, and 20 controls, were included. Symptoms of dysautonomia revealed by a SCOPA-AUT questionnaire were present in all groups of patients. Urinary dysfunction was more pronounced in atypical parkinsonisms, and cardiovascular symptoms in α-synucleinopathies. HRV was disrupted in all groups of patients. However, when PSP-P and PSP-RS phenotypes were considered, HRV was diminished in PSP-RS, but there were no differences in HRV parameters between PSP-P and controls. Neurogenic orthostatic hypotension was present in 25% of PD and 58% of MSA patients, but it was absent in PSP patients and the control group. 13 PD and nine PSP patients and 16 controls were included in subanalysis. This revealed that PSP, but not PD, patients had significantly more symptoms of dysautonomia and lower HRV indices compared to controls, and that orthostatic hypotension was even more common in PD than in controls. Our study suggests that dysautonomia is common in PD, MSA and PSP, even though it has different profiles in the different diseases. NOH is present in PD and MSA, but not in PSP.

Effects of posture on heart rate variability in non-frail and prefrail individuals: a cross-sectional study

BackgroundFrailty is an aging-related syndrome leading to high mortality in older adults. Without effective assessment and prevention of frailty, the incidence of frailty and relevant adverse outcomes will increase by 2050 as worldwide populations age. Although evidence suggested heart rate variability (HRV) is a potential measure of frailty, the role of HRV in frailty assessment remains unclear because of controversial findings. This study examined the effects of posture on HRV parameters in non-frail and prefrail individuals to understand the role of HRV in assessing frailty.MethodsForty-six participants aged ≥ 50 years were recruited between April and August 2022. Frailty was defined using Fried’s criteria. HRV was measured in standing, sitting, and lying postures, respectively, using a Polar Watch, and analyzed using Kubios HRV Standard 3.5.0 (Kubios). The five most commonly used parameters were examined, including standard deviations of all normal-to-normal intervals (SDNN), root mean square of the successive differences (RMSSD), low frequency (LF), high frequency (HF), and LF/HF. Independent t-tests and Mann–Whitney tests were used for inter-group comparisons. Friedman tests were used for intra-group comparisons across postures.ResultsThe non-frail group showed significant differences in HRV parameters across postures (all p < 0.05), whereas the prefrail group did not demonstrate any difference (all p > 0.05). The differences in the non-frail group included higher RMSSD and HF in the lying posture compared to those in the standing posture (29.54 vs 21.99 p = 0.003, 210.34 vs 96.34 p = 0.001, respectively), and higher LF and LF/HF in the sitting posture compared to those in the lying posture (248.40 vs 136.29 P = 0.024, 1.26 vs 0.77 p = 0.011, respectively).ConclusionsThe effects of posture on HRV were blunted in the prefrail group, which suggests an impaired cardiac autonomic functioning. Measuring the effects of posture on HRV parameters may contribute to frailty assessment. However, further evidence from larger cohorts and including additional HRV parameters is needed.

Altered Low Frequency Heart Rate Variability Associated with Agoraphobia in Panic Disorder: A Retrospective Study.

This study aimed to compare the clinical features of panic disorder (PD) with comorbid agoraphobia to those of PD alone. We focused on autonomic nervous system (ANS) alterations reflected in heart rate variability (HRV) and executive function deficits reflected in the Stroop test. We retrospectively compared psychometric features, Stroop test results, and resting-state HRV across three groups: a subclinical group with anxiety attack history, a PD group without agoraphobia, and a PD group with agoraphobia. The subclinical group included 10 male and 34 female, the PD without agoraphobia group included 17 male and 19 female, and the PD with agoraphobia group included 11 male and 18 female. The PD with agoraphobia group had higher Symptom Checklist-95 scores than the other groups. Both PD groups had longer reaction times in the Stroop test than the subclinical group. There were no significant differences in HRV parameters between the PD groups with and without agoraphobia. Compared with the subclinical group, the PD with agoraphobia group showed significantly lower values of the natural logarithm of low-frequency HRV. Our results do not support that executive function deficits and ANS alterations are more pronounced with comorbid agoraphobia among PD groups. However, PD with agoraphobia patients showed more complex and severe clinical symptoms in their self-reports. Compared with the subclinical group, PD patients with agoraphobia showed specific features in the natural logarithm of low-frequency HRV. Our findings suggest that agoraphobia comorbidity should be considered when evaluating or treating patients with PD.

HEART RATE VARIABILITY AND BASIC HEMODYNAMIC PARAMETERS IN MEDICAL STUDENTS IN SEASONS WITH DIFFERENT PHOTOPERIOD

One of the main external factors that contributes to the seasonal functional reorganization of the organism in the process of adaptation is seasonal photoperiodic variability. Day length is affecting not only visual function, but also all physiological and behavioural processes controlled by the circadian rhythm system. The person's ability to adapt to changes in external factors is especially important for medical students who experience significant mental overload in the process of studying at a university. The study goal was to investigate the features of the main hemodynamic parameters and heart rate variability in medical students in the spring and autumn periods, with taking into account gender differences. Materials and methods: A cross-sectional study of 304 students of the North-Ossetian State Medical Academy (Russia) comprising 233 female and 71 male subjects was performed during periods of elongation (spring) and shortening (autumn) of the photoperiod. Blood pressure (BP), pulse rate (HR), parameters of heart rate variability (HRV) were measured. Results: The students showed an increase in DBP and MBP rates within the normal range in autumn. Hemodynamic parameters of SBP, DBP, PBP, MBP in males were significantly higher than in females group, regardless of the season. Interseasonal differences in HRV parameters (LF, THF, PHF, PLF, LF/HF, IC) were revealed. From spring to autumn period, LF decreases from 980.22 (590.30; 1445.83) to 690.68 (438.81; 1170.15) ms2 against the background of a decrease in the dominant period of the high-frequency component of the spectrum (THF) from 5.40 (3 .77; 6.10) to 3.71 (3.08; 5.54) s. The contribution of the high-frequency component (PHF) to the total power of HRV fluctuations increases by 10.4%, and the low-frequency component (PLF) decreases by 6.45% as the photoperiod shortens. The centralization index (IC) also declines from 2.58 (1.42; 3.90) to 1.61 (0.97; 2.98); p=0.0076. Parameters of Mean, Mo, RMSSD, pNN50, SDNN, TP, HF, PHF in spring are lower in males in comparison with females, while parameters of HR, SI, PLF, LF/HF, VLF/HF, IC, PARS are higher in males. Conclusions: It was indicated that the change in the photoperiod trend is an important mediator of heart rate variability in the annual cycle. The lengthening of the photoperiod in the spring season is accompanied by a shift in the vegetative balance of students towards an increase in the tonus of the sympathetic division of the autonomic nervous system (ANS) together with the involvement of the central circuit of the heart rhythm regulation. In autumn, on the background of shorter daylight duration hours, parasympathetic influences are intensified and autonomic regulation circuit is most active. In the common trend of increased sympathetic activity of the ANS and activation of the central regulatory circuit in the spring, in young males these changes are indicated at greater extent.

Nutritional Biomarkers and Heart Rate Variability in Patients with Subacute Stroke.

Malnutrition and autonomic dysfunction are associated with poor outcomes, mortality, and psychological problems after stroke. Relevant laboratory biomarkers include serum albumin, prealbumin, and transferrin. Heart rate variability (HRV), a noninvasive measurement, can objectively measure autonomic nervous system (ANS) function. The relationship between HRV and nutritional biomarkers in stroke patients has not been studied. This study aimed to examine the relationship between nutritional biomarkers and HRV parameters in stroke patients. We retrospectively recruited 426 patients with subacute stroke who were examined for nutritional biomarkers, such as serum albumin, prealbumin, and transferrin, and underwent 24 h ambulatory Holter electrocardiography. Patients were divided into groups according to their nutritional biomarker status. Differences in HRV parameters between nutritional biomarker-deficient and normal groups were assessed. Pearson's correlation and multiple regression analyses were used to verify the relationship between HRV parameters and nutritional biomarkers. HRV parameters were significantly lower in the nutritional biomarker-deficient groups. In addition, there was a significant association between HRV parameters and nutritional biomarkers. Serum albumin, prealbumin, and transferrin levels were associated with ANS function, as measured by HRV, and their deficiency may be a predictive factor for the severity of ANS dysfunction in stroke patients.

Retrospective analysis of autonomic dysfunction in epilepsy patients from neurophysiological recordings

Autonomic dysfunction is often associated with seizures in patients with epilepsy. Autonomic dysfunction during seizures can cause serious events like cardiac arrest and sudden unexplained death. Early detection of autonomic dysfunction is crucial to avoid such medical emergencies. In our study, we analyzed the heart rate variability (HRV) in physiological recording during the preictal, ictal and postictal periods. A total of 142 seizures with various semiologies recorded from 49 epilepsy patients were included. Time-domain measurements including mean hear rate (HR), RR interval (RRI), root-mean-square of successive R-R interval differences (RMSSD), The standard deviation of N-N intervals (SDNN) and percentage of successive RR intervals that differ by more than 50 ms(pNN50) were analyzed at different time points, 20 minutes before the seizure, 1 minute before the seizure, during the seizure and 20 minutes after the seizure. We observed there was a significant difference in HRV parameters during and just before the seizure onset (RMSSD with p-value&lt;0.001 and SDNN with p-value&lt;0.001). We also observed that there was a suppression of parasympathetic activity and activation of sympathetic stimulation in the ictal and peri-ictal period, which was characterized by an elevation in the mean heart rate (HR), whereas the mean RRI showed an inversely proportional trend. There was a reduction in mean RMSSD, SDNN and pNN50 prior to seizure onset and was more pronounced in generalized seizures as compared to focal seizures with preserved or impaired awareness. There was a greater sympathetic activation and parasympathetic inhibition during an epileptic seizure in females as compared to male patients. These findings suggest that autonomic dysregulation was increased during a generalized seizure when compared to a focal seizure. HRV analysis can be used as a valid method for quantifying central influences on the autonomic nervous system and its cardiac control. A major advantage of electrocardiogram (ECG)-based seizure detection is that the ECG is an essentially easier signal to obtain, with a higher signal-to-noise ratio than EEG (electroencephalogram). Based on the inferences from this study future studies could be done to build machine learning models which could form the base for the development of wearable seizure prediction devices.

The role of revascularization on short-term Heart Rate Variability (HRV) and Signal Averaged Electrocardiogram (SAECG) in Stable Coronary Artery Disease (CAD)

Background: Revascularization in patients with stable coronary artery disease (SCAD) can reduce myocardial ischemia and improves the autonomic nervous system, which can be measured by heart rate variability (HRV) and signal-averaged electrocardiogram (SAECG). This study aimed to investigate the effect of revascularization on HRV and SAECG in patients with SCAD. Methods: This is a single-center prospective cohort study. Revascularization refers to percutaneous coronary intervention (PCI). The primary outcome of this study is the change in short-term HRV and SAECG from before revascularization to after revascularization. HRV and SAECG measurement was performed for 10 minutes before PCI and one-month post-PCI. Data were analyzed using SPSS version 23 for Windows. Results: There are 30 patients included in this study, and 46.7% underwent incomplete PCI. There was no significant difference in HRV parameters in the time domain method. In the frequency domain, only the LF/HF ratio changed significantly from 3.5±2.6 before PCI to 2.16±1.9 after PCI, with a 1.33 decrease in LF/HF (p=0.007). Subgroup analysis was performed for patients receiving complete and incomplete revascularization. In patients who received complete revascularization, there was a significant difference in LF/HF ratio change of 1.6±2.28 (p=0.013). In patients that receive incomplete revascularization, there is a significant increase in HF 37.8±57.3 (p=0,028). In terms of SAECG parameters, there is no significant difference between before and after PCI in both primary and subgroup analysis. Conclusion: Revascularization resulted in a significant reduction in LF/HF ratio assessed by short-term HRV. There was no benefit of revascularization in terms of SAECG parameters.

Does obstructive sleep apnoea modulate cardiac autonomic function in paroxysmal atrial fibrillation?

PurposeThe autonomic nervous system may mediate acute apnoea–induced atrial fibrillation (AF). We compared cardiac autonomic function in paroxysmal atrial fibrillation (PAF) patients with and without obstructive sleep apnoea (OSA).MethodsCase control study of 101 patients with PAF recruited at two tertiary centres. All patients underwent in-laboratory polysomnography. ECG signal demonstrating “steady state” sinus rhythm (i.e. with arrhythmic beats and respiratory events excluded) was included in the analysis. Cardiac autonomic function was assessed via measures of heart rate variability (HRV) and reported by sleep stage (REM vs Non-REM) for patients with and without OSA.ResultsSixty-five (66.3%) of patients were male, mean age 61.5 ± 11.6 years, mean BMI 27.1 ± 4.3 kg/m2. Global measures of HRV (triangular index, total power) did not differ between PAF patients with and without OSA in either REM or non-REM sleep. Frequency-domain analysis during non-REM sleep in PAF patients with OSA showed increased cardiac parasympathetic modulation (HF-nu: 39.1 ± 15.7 vs 48.0 ± 14.6, p = 0.008) and reduced cardiac sympathetic modulation (LF-nu 54.1 ± 19.7 vs 43.7 ± 18.0, p = 0.012, LF/HF ratio: 2.1 ± 2.0 vs 1.2 ± 1.0, p = 0.007). Results remained significant after adjusting for age, sex, and BMI (adjusted p values 0.024, 0.045 and 0.018 respectively). There were no differences in HRV parameters during REM sleep.ConclusionsThis is the first study of HRV in PAF patients with and without OSA. Our results indicate limited differences in HRV between groups. However, this work suggests a chronic increase in parasympathetic nervous modulation and relative reduction in sympathetic modulation in PAF patients with OSA during steady-state non-REM sleep.

Heart rate and heart rate variability in school dogs

The aim of this study was to examine whether the canine stress level was elevated during animal-assisted education by means of the Polar monitor V800 (Polar Electro Oy, Kempele, Finland), which recorded heart rate (HR) and heart rate variability (HRV). At 54 Bavarian schools with one working dog each, we attended one class for a single or double session. The dog was videotaped for subsequent behavior analysis, and real-time measurements of the RR intervals were transmitted by the Polar device to the data logger attached to the dog's collar.On average, the mean HR per dog was 87 ± standard deviation 19 beats per minute (bpm). When the dogs were grouped according to the behavior analysis, i.e., scores based on the occurrence of specified displacement behavior / appeasement behavior / signs of stress, inter alia, the "problematic" dogs (n = 25) showed significantly increased mean HR values compared to the "innocuous" dogs (n = 22). The highest mean HR values were recorded in the subgroup of "problematic" dogs during the first 10 min of the classes (107 ± 29 bpm, vs. "innocuous" dogs: 90 ± 22 bpm, p < 0.05). Moreover, HR and HRV were to be measured at rest for 5 min. The mean HR at rest was significantly reduced. With respect to HRV data, it turned out that only 18 dogs showed an artifact rate ≤ 5% and were thus suitable for analysis. Consequently, we performed a range of exploratory analyses - on the one hand to examine this subgroup of dogs, on the other hand to quantify the differences in HRV parameters and to compare certain canine features among the various rates of artifacts.The HR values were in line with the behavior analysis. This was also supported by the exploration of the subgroup with an artifact rate ≤ 5%. In conclusion, cardiac monitoring confirmed that the dogs classified as "problematic" were more stressed than the "innocuous" dogs. This study additionally provided insights into outliers in HRV data, so-called artifacts, underlining the need for standardized conditions.

Heart rate and heart rate variability in patients with chronic inflammatory joint disease: the role of pain duration and the insular cortex

BackgroundChronic inflammatory joint diseases (CIJD) have been linked to increased cardiovascular morbidity and mortality. A decisive reason could be a dysregulation of the autonomic nervous system, which is responsible for the control of cardiovascular function. So far, the cause of changes in autonomic nervous system functions remains elusive. In this study, we investigate the role of chronic pain and the insular cortex in autonomic control of cardiac functioning in patients with CIJD.MethodsWe studied the autonomic nervous system through the assessment of heart rate and heart rate variability (HRV) at rest and under cognitive stimulation. Furthermore, we investigated insular cortex volume by performing surface-based brain morphometry with FreeSurfer. For this study, 47 participants were recruited, 22 individual age- and sex-matched pairs for the magnetic resonance imaging analyses and 14 for the HRV analyses. All available patients’ data were used for analysis.ResultsPain duration was negatively correlated with the resting heart rate in patients with chronic inflammatory joint diseases (n = 20). In a multiple linear regression model including only CIJD patients with heart rate at rest as a dependent variable, we found a significant positive relationship between heart rate at rest and the volume of the left insular cortex and a significant negative relationship between heart rate at rest and the volume of the right insular cortex. However, we found no significant differences in HRV parameters or insular cortex volumes between both groups.ConclusionsIn this study we provide evidence to suggest insular cortex involvement in the process of ANS changes due to chronic pain in CIJD patients.The study was preregistered with the German Clinical Trials Register (https://www.drks.de; DRKS00012791; date of registration: 28 July 2017).

Study of the physiological effects of shift work using the HRV analysis method

Shift work in industry and services cannot be avoided, but the adverse health effects of shift work are well known. The results of workplace physiological measurements in the Hungarian solid mineral mining oil and gas extraction and processing industry was, carried out under the coordination of the Scientific Committee on Mining Health and Ergonomics of the Hungarian Academy of Sciences, The Committee studiedy the variations of age and life characteristics of the workers, the various working conditions and environment and the heart rate variability (HRV) parameters. Our workplace studies covered 8, 12 and 24-hour shift works alike during morning, afternoon and night shifts with 2, 5 or 7 days per shift. In the evaluation, the significant differences in HRV parameters reflecting different physiological conditions, working conditions and work environment are presented for the morning only (control group) and the shift work groups. Evaluation of the results of the measurements carried out at the workplaces adjusted to the actual work schedule using known methods of mathematical statistics made it possible to investigate the effects of different circumstances and conditions. Based on the reviewed research results regarding the health effects of shift work, IARC/WHO concluded in 2010 that shift work was probably carcinogenic to humans (category 2A) - a recommendation that was changed to night shift work in 2019, based on the research results revealed in the meantime. Our studies call attention to the potential for using the results of new methods developed through innovation and to the justification for their use in occupational health.

Autonomic Nervous System Function in Newly Diagnosed Multiple Sclerosis: Association With Lipid Levels and Insulin Resistance.

Autonomic nervous system (ANS) disorders are common in multiple sclerosis (MS). Previous studies showed differences in insulin resistance (IR) and lipoprotein levels in MS subjects compared to controls. Lipolysis caused by increased sympathetic activity could be one of the possible linking mechanisms leading to dyslipidemia in MS. Our study aimed to evaluate ANS activity in the context of glucose and lipid metabolism in people with MS. We prospectively measured short-term heart rate variability (HRV), fasting lipoprotein concentrations, and calculated IR indices based on plasma glucose and insulin levels during oral glucose tolerance test (oGTT) in 32 patients with MS and 29 healthy controls matched for age, sex and body mass index in our study. There was no significant difference in HRV parameters and lipoprotein levels between MS and controls. A significant positive correlation was found between low/high-frequency power ratio (LF/HF) and triglycerides (r=0.413, p=0.021) in MS subjects but not in controls. A significantly lower whole-body insulin sensitivity index (ISIMat) was found in patients with MS compared to the control group (7.3±3.7 vs. 9.8±5.6, p=0.041). No significant correlations were found between LF/HF and IR parameters. In MS subjects, the positive correlation of LF/HF with triglycerides could reflect the effects of sympathetic activity on lipolysis. Positive correlations of sympathetic activity with increased lipoprotein levels could rather reflect processes associated with immune system activation/inflammation, than processes involved in glucose homeostasis maintenance.

Similar Supine Heart Rate Variability Changes During 24-h Exposure to Normobaric vs. Hypobaric Hypoxia.

Purpose: This study aimed to investigate the differences between normobaric (NH) and hypobaric hypoxia (HH) on supine heart rate variability (HRV) during a 24-h exposure. We hypothesized a greater decrease in parasympathetic-related parameters in HH than in NH.Methods: A pooling of original data from forty-one healthy lowland trained men was analyzed. They were exposed to altitude either in NH (FIO2 = 15.7 ± 2.0%; PB = 698 ± 25 mmHg) or HH (FIO2 = 20.9%; PB = 534 ± 42 mmHg) in a randomized order. Pulse oximeter oxygen saturation (SpO2), heart rate (HR), and supine HRV were measured during a 7-min rest period three times: before (in normobaric normoxia, NN), after 12 (H12), and 24 h (H24) of either NH or HH exposure. HRV parameters were analyzed for time- and frequency-domains.Results: SpO2 was lower in both hypoxic conditions than in NN and was higher in NH than HH at H24. Subjects showed similarly higher HR during both hypoxic conditions than in NN. No difference in HRV parameters was found between NH and HH at any time. The natural logarithm of root mean square of the successive differences (LnRMSSD) and the high frequency spectral power (HF), which reflect parasympathetic activity, decreased similarly in NH and HH when compared to NN.Conclusion: Despite SpO2 differences, changes in supine HRV parameters during 24-h exposure were similar between NH and HH conditions indicating a similar decrease in parasympathetic activity. Therefore, HRV can be analyzed similarly in NH and HH conditions.

Heart rate variability in patients with refractory epilepsy: The influence of generalized convulsive seizures

ObjectivePatients with epilepsy, mainly drug-resistant, have reduced heart rate variability (HRV), linked to an increased risk of sudden death in various other diseases. In this context, it could play a role in SUDEP. Generalized convulsive seizures (GCS) are one of the most consensual risk factors for SUDEP. Our objective was to assess the influence of GCS in HRV parameters in patients with drug-resistant epilepsy. MethodsWe prospectively evaluated 121 patients with refractory epilepsy admitted to our Epilepsy Monitoring Unit. All patients underwent a 48-hour Holter recording. Only patients with GCS were included (n = 23), and we selected the first as the index seizure. We evaluated HRV (AVNN, SDNN, RMSSD, pNN50, LF, HF, and LF/HF) in 5-min epochs (diurnal and nocturnal baselines; preictal – 5 min before the seizure; ictal; postictal – 5 min after the seizure; and late postictal – >5 h after the seizure). These data were also compared with normative values from a healthy population (controlling for age and gender). ResultsWe included 23 patients, with a median age of 36 (min-max, 16–55) years and 65% were female. Thirty percent had cardiovascular risk factors, but no previously known cardiac disease. HRV parameters AVNN, RMSSD, pNN50, and HF were significantly lower in the diurnal than in the nocturnal baseline, whereas the opposite occurred with LF/HF and HR. Diurnal baseline parameters were inferior to the normative population values (which includes only diurnal values). We found significant differences in HRV parameters between the analyzed periods, especially during the postictal period. All parameters but LF/HF suffered a reduction in that period. LF/HF increased in that period but did not reach statistical significance. Visually, there was a tendency for a global reduction in our patients’ HRV parameters, namely AVNN, RMSSD, and pNN50, in each period, comparing with those from a normative healthy population. No significant differences were found in HRV between diurnal and nocturnal seizures, between temporal lobe and extra-temporal-lobe seizures, between seizures with and without postictal generalized EEG suppression, or between seizures of patients with and without cardiovascular risk factors. Significance/conclusionOur work reinforces the evidence of autonomic cardiac dysfunction in patients with refractory epilepsy, at baseline and mainly in the postictal phase of a GCS. Those changes may have a role in some SUDEP cases. By identifying patients with worse autonomic cardiac function, HRV could fill the gap of a lacking SUDEP risk biomarker.

Comparison of Heart Rate Variability among Young Malay Male Adult with Different BMI and Level of Adiposity

INTRODUCTION: Subclinical changes that occur in the heart at an early age may provide valuable information to outline prevention strategies for cardiovascular diseases. Heart rate variability (HRV) reflects regulation of autonomic balance, heart, and vascular tone, which are the determinants of blood pressure. Therefore, this study aimed to determine the difference in heart rate variability (HRV) of Malay male young adult with their BMI and adiposity level. MATERIALS AND METHODS: A total of 201 Malay male young adult aged between 19 to 24 years old were screened and their BMI and adiposity level were measured. Three non -invasive tests; Valsalva Manoeuvre, orthostatic response and 30/15 ratio of heart rate were performed. Short term HRV time and frequency domains were recorded. RESULTS: Despite few significant differences in HRV parameters of overweight/obese subjects, the result is inconclusive to conclude any reduced variability. However, those with high adiposity regardless of their BMI reported significantly lower mean of R -R SD in time domain and lower mean of LF/HF ratio in frequency domain. The orthostatic reflex results revealed that high adiposity subjects had significantly lower mean of LF and HF. A decrement of -0.28 ms2 HF/LF during Valsalva manoeuvre, -0.35 LF ms2 in orthostatic reflex and 0.33 ms2 in orthostatic reflex per 1% of body fat percentage were observed. CONCLUSION: HRV parameters were inversely proportional to the adiposity level which was suggestive of modulation of sympathetic function can occur at an early age.

Cardiac Autonomic Neuropathy Is Not Reversed by Euglycemia Following Islet Transplantation.

Cardiac autonomic neuropathy (CAN) is a significant cause of morbidity and mortality for people with type 1 (T1D) and type 2 (T2D) diabetes. Heart rate variability (HRV) has been shown to be a marker of CAN with 24-hour Holter monitoring being a robust modality to assess HRV. To investigate the impact of hypoglycemia on CAN and its potential reversibility with islet transplantation, we compared HRV assessment by 24-hour Holter monitor on a total of 109 subjects from 5 cohorts: (1) T1D with recurrent severe hypoglycemia and on waiting list for islet transplant, (2) T1D following islet cell transplantation (ICT), (3) T2D without hypoglycemia, (4) individuals with prediabetes, and (5) controls without diabetes. SD of the normal-normal interval, square root of the mean squared differences of successive normal-normal intervals (rMSSD) and total spectral power were analyzed. There was no significant difference in HRV parameters between T1D subjects and T1D post ICT suggesting CAN is not reversible at a median of 4 years postislet transplant. There was a significant difference in controls and T1D in rMSSD and between controls and T2D in total power. The differential effect on rMSSD in T1D and T2D suggests potential greater impact of hypoglycemia on rMSSD. Achieving euglycemia after ICT may not reverse CAN once established with no significant difference in HRV parameters at a median of 4 years postislet transplant. Differential effects of T1D as compared with T2D on CAN were identified.

Does empagliflozin modulate the autonomic nervous system among individuals with type 2 diabetes and coronary artery disease? The EMPA-HEART CardioLink-6 Holter analysis

ContextWe examined if empagliflozin was associated with modulation of cardiac autonomic tone among subjects with type 2 diabetes and stable coronary artery disease (CAD) relative to placebo. MethodsUsing ambulatory 24-h Holter electrocardiographic data prospectively collected from a randomized trial, we compared changes in heart rate variability (HRV) parameters between empagliflozin- and placebo-assigned subjects over a follow-up period of 6 months. Measured HRV domains included: standard deviation (SD) of NN intervals (SDNN), SD of average NN intervals per 5-min (SDANN), root mean square of successive RR interval differences (RMSSD), % successive NN intervals differing >50 ms (ms) (pNN50), low frequency (LF), high frequency (HF) and the LF/HF ratio (LF:HF). Differences in HRV parameters between the 2 groups were compared with analysis of covariance (ANCOVA). Statistical measures of significance were reported as adjusted differences between the 2 groups and their corresponding 95% confidence intervals. ResultsSixty-six subjects completed 24-h Holter monitoring at baseline and 6-months. Over 6 months, the change in HRV was similar between subjects treated with empagliflozin vs. placebo for the following parameters: RMSSD -1.2 ms (-6.0 to 3.6 ms); pNN50 0.5% (-2.6 to 3.6%); VLF -907.8 ms2 (-2388.8 to 573.1 ms2); LF -341 ms2 (-878.7 to 196.7 ms2); HF -33.8 ms2 (-111.1 to 43.5 ms2); LF:HF -0.1 (-0.4 to 0.2). Subjects who received placebo experienced an increase in SDNN 18.6 ms (2.8–34.3 ms) and SDANN 20.2 ms (3.2–37.3 ms) relative to those treated with empagliflozin. ConclusionCompared to placebo, empagliflozin did not result in changes in autonomic tone among individuals with type 2 diabetes and stable coronary artery disease.

Study on the relationship of National Institutes of Health Stroke Scale score with heart rate variability and cardiac complication in elderly patients with acute cerebral infarction

Objective To investigate the relationship of National Institute of Health Stroke Scale(NIHSS)with heart rate variability(HRV)and cardiac complication in elderly patients with acute cerebral infarction, and to clarify the effect of early drug intervention on the regulation of autonomic nerve function in patients with high NIHSS score. Methods One hundred twenty-six inpatients with first-onset acute cerebral infarction(ACI)(the cerebral infarction group)and 40 healthy subjects with no history of stroke(the control group)were retrospectively enrolled.All subjects underwent examinations of NIHSS and 24 h dynamic electrocardiogram.According to NIHSS score, patients in the cerebral infarction group were divided into 3 subgroups: NIHSS score 0-4 group(n=32), NIHSS score 5-15 group(n=66)and NIHSS score ≥ 15 group(n=28). The difference in HRV parameters were compared between ACI patients and the controls.Ninety-four ACI patients with NIHSS score ≥5 were randomly divided into 2 groups: (1)the traditional treatment group(n=44), taking routine drugs for cerebral infarction; (2)the special treatment group(n=42), taking metoprolol sustained release tablet and Shensonyangxin capsule as add-on to the routine drugs for cerebral infarction.The 24 h dynamic electrocardiogram examination were conducted 30 days after treatment.The differences in HRV parameters and cardiac complications were compared between the two treatment groups. Results In patients with acute cerebral infarction, the time-domain parameters of normal-to-normal intervals(NNI), standard deviation of normal-to-normal intervals(SDNN), square root of the mean squared successive differences between normal-to-normaI RR intervals(RMSSD), percentage of adjacent normal-to-normal intervals that differed more than 50 ms(PNN50), frequency domain parameters low-frequency(LF)power and high-frequency(HF)power were significantly reduced as compared with those in the control group(P<0.05). While, pulse rate and frequency domain parameters of sympathetic vagus balance index(LF/HF)were significantly increased(P<0.05). The time-domain parameters(NNI, SDNN, RMSSD and PNN50)and frequency domain parameters(LF, HF)were significantly reduced in the NIHSS score 5-15 group and NIHSS score ≥15 group as compared with the control group and the NIHSS score 0-4 group(P<0.05). The time-domain parameters(RMSSD and PNN50)and frequency domain parameters(LF and HF)were reduced(P<0.05), and the frequency domain parameters(LF/HF)were increased(P<0.05)in NIHSS score ≥15 group compared with in NIHSS score 5-15 group(P<0.05). Compared with pre-treatment, the special treatment group after treatment showed that the time domain parameters(NNI, SDNN, RMSSD and PNN50)and frequency domain parameters(LF and HF)were significantly increased(P<0.05), the frequency domain parameters(LF/HF)were significantly reduced(P<0.05)and the incidence of cardiac complication(total incidence of atrial arrhythmias and ventricular arrhythmias and cardiac complication)were significantly reduced(P<0.05). As compared with the traditional treatment group after treatment, the special treatment group after treatment showed that the time domain parameters(NNI, SDNN, RMSSD and PNN50)and frequency domain parameters(LF and HF)were significantly increased(P<0.05), frequency domain parameters(LF/HF)were significantly reduced(P<0.05)and the total incidence of cardiac complication were significantly reduced(18.4% or 7 cases vs.40.0% or 16 cases, P<0.05). Conclusions The HRV is decreased in patients with acute cerebral infarction.The reduction degree of HRV is more significant along with the higher NIHSS scores, which suggests that patients with high NIHSS scores are prone to an impairment of autonomic nerve function.For patients with high NIHSS scores after stroke, early drug intervention for regulating autonomic nerve function can effectively prevent the occurrence of cardiac emergencies and improve the prognosis of stroke. Key words: Cerebral infarction; Heart rate; Autonomic agents

Short term optimization of glycaemic control using insulin improves sympatho-vagal tone activities in patients with type 2 diabetes

IntroductionDiabetic cardiac autonomic neuropathy (CAN) is potentially life threatening and its severity might further be aggravated by poor glycaemic control. A decrease in Heart rate variability (HRV) is the earliest finding of CAN even at the sub clinical stage. While intensive glycaemic control prevents the development of CAN in patients with type 1 diabetes, it is not known whether the intensification of glycaemic control using insulin would improve cardiovascular autonomic functions in type 2 diabetes patients. This study aimed to determine the short term effects of optimizing glycaemic control using insulin on the HRV in type 2 diabetes patients. MethodsWe conducted a single arm open label clinical trial. Participants were poorly controlled non-insulin treated type 2 diabetes mellitus patients (HbA1c ≥ 7%). The intervention lasted 60 days and consisted in the intensification of glycaemic control through the initiation of a basal plus insulin regimen with titration of insulin to protocol defined glycaemic targets which were; fasting glycaemia: 0.70–1.30 g/L and post prandial glycaemia <1.80 g/L. Long term HRV measurement was done using a 24-h ambulatory electrocardiographic (ECG) recording on day 0 and day 60. Wilcoxon signed rank test was used to compare differences in HRV parameters before and after the intervention. ResultsA total of 29 (14 males and 15 females) consenting type 2 diabetes mellitus patients without clinical signs of CAN were enrolled and allocated to intervention (14 males and 15 females). The median age was 52 [43–59] years, and duration of diabetes 3.0 [0.6–6.7] years. The intervention induced a reduction in HbA1c from 10.1 [9.1–11.9]% to 6.7 [5.9–6.9]% (p < 0.001) without severe hypoglycaemic events. Concerning HRV parameters, there was a significant improvement in markers of the parasympathetic tone (PNN50: 5.7 [3.6–10.3]% to 8.1 [3.1–16.9]%, p = 0.008) and sympathetic tone (SDNN: 102.01 [90.45–111.05] ms to 122.40 [91.70–135.95] ms, p = 0.01). ConclusionThe optimization of glycaemic control using a basal plus insulin regimen while inducing a significant reduction in glycated hemoglobin, significantly improves 24-h ambulatory ECG derived sympathetic and parasympathetic activities. This suggests that tight glycaemic control using insulin may revert cardiac autonomic neuropathy in type 2 diabetes mellitus patients.