Heart Rate Variability Parameters Research Articles

Impact of COVID-19-associated Dysautonomia Phenotypes on the Effectiveness of Venovenous Extracorporeal Membrane Oxygenation

RELEVANCE. It is known that patients with severe cases of the novel coronavirus infection (COVID-19) are characterized by the development of COVID-19-associated dysautonomia (COVID-19-DA). At the moment, there are no studies examining the impact of this phenomenon on the course and outcomes of the disease in the most severe cohort of patients with COVID-19, namely those requiring venovenous extracorporeal membrane oxygenation (VV ECMO). AIM OF STUDY. The purpose of the presented work is to study the effect of different COVID-19-DA phenotypes on the performance parameters and effectiveness of VV ECMO, gas exchange and hemodynamics in patients with COVID-19. MATERIAL AND METHODS. The study included 20 patients, 12 (60%) women, 8 (40%) men, with COVID-19 who underwent VV ECMO. Patients underwent 24-hour Holter monitoring with assessment of the spectral parameters of heart rate variability (HRV): the low-frequency component (LF), the high-frequency component (HF), the ratio of the low-frequency component to the high frequency component (LF / HF) on days 1, 3, 5 of the VV ECMO. Patients were divided into three groups based on the identified COVID-19-DA phenotypes. The groups were compared in terms of gas exchange, hemodynamics, and VV ECMO performance parameters. RESULTS. The level of partial pressure of carbon dioxide in arterial blood (paCO2) in the phenotype with low sympathetic tone and high tone of the parasympathetic division of the autonomic nervous system (ANS) (lShP) was significantly higher than in the phenotype with normal sympathetic tone and high tone of the parasympathetic division of the ANS (nShP) with equal VV ECMO performance parameters. The heart rate (HR) in the nShP phenotype was significantly lower than in the lShP phenotype. A significant increase in respiratory dysfunction was revealed over time in the lShP phenotype. Weaning from VV ECMO in the nShP phenotype was successful in 50 %, whereas in the lShP phenotype, weaning from VV ECMO was observed in 7,2 % of patients. No significant differences in the mortality rate were obtained. The most common cause of death in both groups was septic shock. CONCLUSIONS. The COVID-19-DA phenotype, manifested by decreased tone of the sympathetic division and increased tone of the parasympathetic division of the ANS, leads to low efficiency of VV ECMO, resulting in a statistically significantly less frequent ECMO discontinuation in those patients.

Autonomic activity and cardiovascular system risk assessment in pediatric patients with hemolytic uremic syndrome.

In pediatric patients with hemolytic uremic syndrome (HUS), cardiac involvement and autonomic nervous system function can be evaluated by a non-invasive method called heart rate variability (HRV). This study aims to evaluate heart rate variability and electrocardiography findings in patients with HUS by comparing a healthy group. Patients who are diagnosed with HUS at a university hospital from December 2020 to June 2022 are screened by electrocardiography (ECG), echocardiography, and 24-h Holter ECG. A healthy control group, compatible in age and gender with the patient group, was selected from healthy subjects. HRV parameters, laboratory values, and ECG findings were analyzed and compared with the healthy group and each other. There were 25 patients with HUS and 51 participants in the healthy control group. Statistically significant differences were found in some HRV parameters: standard deviation of normal to normal intervals, the mean of the 5-min RR interval standard deviations, the standard deviation of 5-min RR interval means, the triangular interpolation of normal to normal interval, and very-low-frequency power. HUS patients had impaired and declined HRV values compared to the healthy group. There was a significant decrease in the PR distance, while a significant increase in the corrected QT and QT dispersion values was detected in the electrocardiographic findings of the patient group. HRV values impaired as renal failure parameters increased. Conclusion: Patients with HUS may have autonomic nervous system dysfunction. HRV measurement is a non-invasive method that can evaluate this. It can be thought that there may be an increased risk of cardiovascular events and arrhythmias in some patients with HUS. ECG should be also considered to detect arrhythmia. What is Known: • Hemolytic uremic syndrome (HUS) primarily effects the hematologic parameters and kidney. • Secondary cardiomyopathy with hypertension and renal failure could be observed in these patients. • Rhythm problems are not expected primarily in these patients. • There is very limited data in evaluating autonomic function and arrhythmia risk for these patients. What is New: • Patients with HUS may have autonomic nervous system dysfunction. • HRV measurement is a non-invasive method that can evaluate this. • Cardiovascular events and arrhythmias due to the deterioration of the balance between the sympathetic and parasympathetic systems could manifest in patients with HUS. • An ECG and screening patients for cardiac events, and monitoring them closely should be considered.

Essential Fatty Acid Associated with Heart Rate Variability in Highly Trained Male Cross-Country Skiers: A Pilot Study

Polyunsaturated fatty acid (PUFA) metabolites play important roles in the modulation of vascular tone, heart rate variability (HRV), and cardiovascular diseases. This study was undertaken to examine the relationship between HRV and the plasma levels of essential acids. Methods: Highly trained cross-country skiers participated in the study (n = 19). Time-domain and frequency-domain HRV analyses were performed. The plasma levels of fatty acids were determined using gas–liquid chromatography. Results: Plasma eicosapentaenoic acid and docosahexaenoic acid were found to be negatively correlated with resting heart rate (HR) (p = 0.026). The plasma levels of alpha-linolenic acid (ALA) were positively associated with the relative value of high-frequency power (rs = 0.465, p = 0.045) and negatively correlated with the sympathovagal balance ratio (rs = −0.493, p = 0.032) and the absolute and relative values of low-frequency power (rs = −0.490, p = 0.028). The plasma levels of arachidonic acid (ARA) were positively associated with the relative value of high-frequency power (rs = 0.59, p = 0.006) and negatively correlated with the sympathovagal balance ratio (rs = −0.54, p = 0.017) and the relative values of low-frequency power (rs = −0.52, p = 0.022). No correlation was found between n6/n3 and HRV parameters except for HR and pNN50. Conclusions: n-3 PUFAs and ARA play an important role in the autonomic regulation of heart rate in highly trained skiers. Athletes with substantial deficiencies in plasma ALA and excess levels of ARA had increased sympathetic and decreased parasympathetic activity.

Correlation between pupillary size and heart rate variability parameters among medical students

Autonomic nervous system controls and balances sympathetic and parasympathetic system to maintain homeostasis without conscious control. The sympathetic nervous system controls the dilation of the pupil or mydriasis. HR variation (HRV) analysis is a popular non-invasive tool for assessing functions of autonomic nervous system. Medical students are under constant cognitive load, it is required to follow-up on status on their autonomic control during their education phase. The objective of this study was to observe any correlation between pupillary size and heart rate.Total of 30 students participated in the study. Anthropometric measurements and vitals like pulse, blood pressure was recorded. Pupillary size of the participants was measured using the pupillometer in the illuminated. HRV recording was done by placing electrodes for standard Lead II ECG. HRV reports were generated using Kubios HRV 3.5 software standard version. The pupillary size Right and Left are negatively correlated with the SDNN, RMSSD, PNN50, HF, SDI and SD2. However, LF, LF/HF and SD2/SD1 ratio are positively correlated. These findings support the notion that pupillary size can serve as a non-invasive indicator of autonomic nervous system activity.

Time-domain heart rate dynamics in the prognosis of progressive atherosclerosis

Background and aimThe regular uptake of a high-fat diet (HFD) with changing lifestyle causes atherosclerosis leading to cardiovascular diseases and autonomic dysfunction. Therefore, the current study aimed to investigate the correlation of autonomic activity to lipid and atherosclerosis markers. Further, the study proposes a support vector machine (SVM) based model in the prediction of atherosclerosis severity. Methods and resultsThe Lead-II electrocardiogram and blood markers were measured from both the control and the experiment subjects each week for nine consecutive weeks. The time-domain heart rate variability (HRV) parameters were derived, and the significance level was tested using a one-way Analysis of Variance. The correlation analysis was performed to determine the relation between autonomic parameters and lipid and atherosclerosis markers. The statistically significant time-domain values were used as features of the SVM. The observed results demonstrated the reduced time domain HRV parameters with the increase in lipid and atherosclerosis index markers with the progressive atherosclerosis severity. The correlation analysis revealed a negative association between time-domain HRV parameters with lipid and atherosclerosis parameters. The percentage accuracy increases from 86.58% to 98.71% with the increase in atherosclerosis severity with regular consumption of HFD. ConclusionsAtherosclerosis causes autonomic dysfunction with reduced HRV. The negative correlation between autonomic parameters and lipid profile and atherosclerosis indexes marker revealed the potential role of vagal activity in the prognosis of atherosclerosis progression. The support vector machine presented a respectable accuracy in the prediction of atherosclerosis severity from the control group.

Acute cardiovascular effects of 4th generation electronic cigarettes and combusted cigarettes: implications for harm reduction.

The health consequences associated with using electronic cigarettes (ECs) are of great public interest because of their potential role in smoking cessation. In 110 participants, including 41 nonusers, 34 people who exclusively use ECs (EC group), and 35 people who smoke tobacco cigarettes (TCs) including 12 dual users (collectively called the TC-D group), the heart rate (HR), blood pressure (BP), and heart rate variability (HRV) were compared at baseline. People in the EC or the TC-D groups were also compared after using a 4th generation EC with or without nicotine, a TC with or without nicotine (TC-D group only), and a straw-control. Baseline HR, BP, and HRV parameters were not different among the EC, the TC-D, and nonuser groups. In people who exclusively use ECs, acute nicotine-EC use increased HR and BP, and produced changes in HRV patterns suggestive of increased cardiac sympathetic influence. In people in the TC-D group, BP increased similarly after acutely smoking a nicotine-TC or a nicotine-EC. However, the increase in HR was significantly greater after smoking a TC compared with the nicotine-EC despite similar acute increases in plasma nicotine. Overall, all exposures containing nicotine significantly increased HR and BP in both cohorts when compared with non-nicotine exposures. Since acute EC use 1) produces an abnormal HRV pattern associated with increased cardiac sympathetic tone in people who chronically use ECs, and 2) similar hemodynamic increases compared with acute TC smoking in people who chronically smoke TCs including dual users, the role of ECs as part of a harm reduction strategy is questioned.NEW & NOTEWORTHY We found that nicotine, not the non-nicotine constituents in tobacco cigarette (TC) or electronic cigarette (EC) emissions, may be the instigator of the acute, potentially adverse, changes in hemodynamics and heart rate variability (HRV) that were recorded several minutes after tobacco product use. Furthermore, acute EC use produced an abnormal HRV pattern associated with increased cardiac risk in people who chronically smoke ECs and produced similar hemodynamic increases compared with acute TC use in people who chronically smoke TCs, including people who are dual users.

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly.

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly. This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)). Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV. In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

Insulin pump treatment vs. multiple daily insulin injections in patients with poorly controlled Type 2 diabetes mellitus: a comparison of cardiovascular effects

AimsBoth hyperglycaemia and large glycaemic variability are associated with worse outcomes in patients with Type 2 diabetes mellitus (T2DM), possibly causing sympatho-vagal imbalance and endothelial dysfunction. Continuous subcutaneous insulin injection (CSII) improves glycemic control compared to multiple daily insulin injections (MDI). We aimed to assess whether CSII may improve cardiac autonomic and vascular dilation function compared to MDI.MethodsWe enrolled T2DM patients without cardiovascular disease with poor glycaemic control, despite optimized MDI therapy. Patients were randomized to continue MDI (with multiple daily peripheral glucose measurements) or CSII; insulin dose was adjusted to achieve optimal target ranges of blood glucose levels. Patients were studied at baseline and after 6 months by: 1) flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of the brachial artery; 2) heart rate variability (HRV) by 24-hour ECG Holter monitoring (HM). 7-day continuous glucose monitoring (CGM) was performed in 9 and 8 patients of Group 1 and 2, respectively.ResultsOverall, 21 patients were enrolled, 12 randomized to CSII (Group 1) and 9 to MDI (Group 2). The daily dose of insulin and Hb1AC did not differ significantly between the 2 groups, both at baseline and at follow-up. Glucose variability showed some significant improvement at follow-up in the whole population, but no differences were observed between the 2 groups. Both FMD and NMD, as well as HRV parameters, showed no significant differences between the 2 groups at 6-month follow-up.ConclusionsIn this randomized small study we show that, in T2DM patients, CSII achieves a similar medium-term glycemic control compared to MDI, without any adverse effect on the cardiovascular system.

Comparisons of heart rate variability responses to head-up tilt with and without abdominal and lower-extremity compression in healthy young individuals: a randomized crossover study.

Introduction: Abdominal and lower-extremity compression techniques can help reduce orthostatic heart rate increases. However, the effects of body compression on the cardiac autonomic systems, which control heart rate, remain unclear. The primary objective of this study was to compare heart rate variability, a reflection of cardiac autonomic regulation, during a head-up tilt test with and without abdominal and lower-extremity compression in healthy young individuals. The secondary objective was to conduct a subgroup analysis, considering participant sex, and compare heart rate and heart rate variability responses to head-up tilt with and without compression therapy. Methods: In a randomized crossover design, 39 healthy volunteers (20 females, aged 20.9 ± 1.2years) underwent two head-up tilt tests with and without abdominal and lower-extremity compression. Heart rate and heart rate variability parameters were measured during the head-up tilt tests, including the Stress Index, root mean square of successive differences between adjacent R-R intervals, low- and high-frequency components, and low-to-high frequency ratio. Results: Abdominal and lower-extremity compression reduced the orthostatic increase in heart rate (p < 0.001). The tilt-induced changes in heart rate variability parameters, except for the low-frequency component, were smaller in the compression condition than in the no-compression condition (p < 0.001). These results were consistent regardless of sex. Additionally, multiple regression analysis with potentially confounding variables revealed that the compression-induced reduction in Stress Index during the head-up tilt position was a significant independent variable for the compression-induced reduction in heart rate in the head-up tilt position (coefficient = 0.411, p = 0.025). Conclusion: Comparative analyses revealed that abdominal and lower-extremity compression has a notable impact on the compensatory sympathetic activation and vagal withdrawal typically observed during orthostasis, resulting in a reduction of the increase in heart rate. Furthermore, this decrease in heart rate was primarily attributed to the attenuation of cardiac sympathetic activity associated with compression. Our findings could contribute to the appropriate application of compression therapy for preventing orthostatic tachycardia. This study is registered with UMIN000045179.

Similar Patterns of Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue and Post-COVID-19 Syndromes.

There is a considerable overlap between the clinical presentation of post-COVID-19 condition (PCC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Many of their common symptoms can be linked to dysregulation of the autonomic nervous system (dysautonomia). This study aimed to objectively assess autonomic function in a general group of patients with PCC and in a group of patients with ME/CFS whose disease was not related to COVID-19. We hypothesize that the similarity in the chronic symptoms of patients with PCC and ME/CFS extends to objective autonomic nervous system abnormalities. Synchronous recordings of an electrocardiogram and continuous dynamics of blood pressure in the digital artery using the Penaz method were obtained using the spiroarteriocardiorhythmography method in 34 patients diagnosed with ME/CFS, in whom the onset of the disease was not associated with COVID-19, 29 patients meeting the PCC definition and 32 healthy controls. Heart rate variability (HRV) and systolic and diastolic blood pressure variability (BPV) were assessed at rest and in tests with fixed respiratory rates. Indicators of baroreflex regulation (baroreflex effectiveness index and baroreflex sensitivity) were additionally determined at rest. The total power and power of low-frequency and high-frequency of RR interval variability at rest as well as baroreflex sensitivity were significantly lower both in PCC and ME/CFS patients compared to healthy controls. Several diagnostic prediction models for ME/CFS were developed based on HRV parameters. During slow breathing, the HRV parameters returned to normal in PCC but not in ME/CFS patients. The correlation analysis revealed a close relationship of HRV, BPV parameters and baroreflex sensitivity with fatigue, but not with HADS depressive/anxiety symptoms in the ME/CFS and PCC patients. A similar pattern of HRV and baroreflex failure with signs of a pathological acceleration of age-dependent dysautonomia was identified in the ME/CFS and PCC patients. The clinical, diagnostic and therapeutic implications of these findings are discussed, in light of previously described relationships between inflammation, vascular pathology, atherosclerotic cardiovascular disease and autonomic dysfunction.

Exercise-induced changes in plasma S-Klotho levels are associated with the obtained enhancements of heart rate variability in sedentary middle-aged adults: the FIT-AGEING study.

The shed form of the Klotho protein (S-Klotho) is considered a biomarker of longevity, but it is still unknown whether the levels are related to heart rate (HR) and heart rate variability (HRV); both of them greatly influenced by the ageing process, physical fitness, exercise, and health status. This study aimed (i) to investigate the association between S-Klotho plasma levels with HR and HRV parameters and (ii) to examine the association of exercise-induced changes in S-Klotho and those obtained in HR and HRV parameters after a 12-week exercise intervention in sedentary middle-aged adults. Sixty-six sedentary middle-aged adults participated in this study (50% women; 45-65 years old). Participants were randomized into 4 groups: (a) a control group (no exercise), (b) a physical activity recommendation from the World Health Organization group, (c) a high-intensity interval training group, and (d) a high-intensity interval training group adding whole-body electromyostimulation. S-Klotho plasma levels, HR, and HRV parameters (SDNN, RMSSD, high frequency, stress score, and sympathetic/parasympathetic ratio) were measured. At baseline, S-Klotho plasma levels were not related to HR and HRV parameters. After the intervention, exercise-induced changes in S-Klotho plasma levels were positively associated with changes in SDNN (β=0.261; R2=0.102; p=0.014) and negatively related to changes in stress score and sympathetic/parasympathetic ratio (all β=-0.257; R2 ranges between 0.092 and 0.131; all p<0.020). Our study suggests that higher S-Klotho plasma levels are related to increased vagal influence and reduced sympathetic tone in the autonomic nervous system in sedentary middle-aged adults after different training programs. ClinicalTrials.gov identifier: CT03334357.

CORRELATION OF POINCARE PLOT DERIVED STRESS SCORE AND HEART RATE VARIABILITY PARAMETERS IN THE ASSESSMENT OF CORONARY ARTERY DISEASE

Atherosclerosis-generated coronary artery disease (CAD) causes the anomaly of autonomic activity. The assessment of autonomic balance under disease conditions is of clinical interest. Thus, this work aimed to evaluate the CAD using Poincare-derived stress score (SS) and sympathetic/sympathetic-parasympathetic (S/PS). A total of 60 male (50–55 years) volunteers including CAD ([Formula: see text]=30) and control ([Formula: see text]=30) participated in this work. Digital lead-II electrocardiogram (ECG) was recorded for 10 min in a supine position and filtered to remove noises. A total of 10 tachogram samples were computed from each subject for a 5 min ECG signal duration with a shift of 30 s on the processed signal using Acqknowledge 4.0 (Biopac Systems Inc., USA). The heart rate variability (HRV) parameters were computed from the obtained tachogram. The computed Poincare plot parameters were used to derive the SS and S/PS ratios. The regression model was employed to observe the correlation of SS and S/PS to the HRV parameters. The obtained results revealed reduced HRV with higher sympathetic and reduced parasympathetic activity under CAD than the control subjects. The autonomic dysfunction was observed with significantly higher values of SS and S/PS in CAD than in the control subjects. The S/PS was observed to be positively associated with LF/HF and SD2/SD1 parameters. While SS was found to be positively correlated to the LF and LF/HF parameters in CAD and control subjects. The obtained linear strong correlation of SS and S/PS with control and CAD subjects suggested the use of SS and S/PS as excellent sympathetic activity and sympathovagal balance markers.

The value of circadian heart rate variability for the estimation of obstructive sleep apnea severity in adult males.

Heart rate variability (HRV) is becoming more prevalent as a measurable parameter in wearable sleep-monitoring devices, which are simple and effective instruments for illness evaluation. Currently, most studies on investigating OSA severity and HRV have measured heart rates during wakefulness or sleep. Therefore, the objective of this study was to investigate the circadian rhythm of HRV in male patients with OSA and its value for the estimation of OSA severity using group-based trajectory modeling. Patients with complaints of snoring were enrolled from the Sleep Center of Shandong Qianfoshan Hospital. Patients were divided into 3 groups according to apnea hypopnea index (AHI inevents/h), as follows: (<15, 15≤AHI<30, and ≥30). HRV parameters were calculated using 24 h Holter monitoring, which included time-domain and frequency-domain indices. Circadian differences in the standard deviation of normal to normal (SDNN) were evaluated for OSA severity using analysis of variance, trajectory analysis, and multinomial logistic regression. A total of 228 patients were enrolled, 47 with mild OSA, 48 moderate, and 133 severe.Patients with severe OSA exhibited reduced triangular index and higher very low frequency than those in the other groups. Circadian HRV showed that nocturnal SDNN was considerably higher than daytime SDNN in patients with severe OSA. The difference among the OSA groups was significant at 23, 24, 2, and 3 o'clock sharp between the severe and moderate OSA groups (all P<0.05). The heterogeneity of circadian HRV trajectories in OSA was strongly associated with OSA severity, including sleep structure and hypoxia-related parameters. Among the low-to-low, low-to-high, high-to-low, and high-to-high groups, OSA severity in the low-to-high group was the most severe, especially compared with the low-to-low and high-to-low SDNN groups, respectively. Circadian HRV in patients with OSA emerged as low daytime and high nocturnal in SDNN, particularly in men with severe OSA. The heterogeneity of circadian HRV revealed that trajectories with low daytime and significantly high nighttime were more strongly associated with severe OSA. Thus, circadian HRV trajectories may be useful to identify the severity of OSA.

Behavioral observations, heart rate and cortisol monitoring in horses following multiple oral administrations of a cannabidiol containing paste (part 2/2).

As a remedy against stress and anxiety, cannabidiol (CBD) products are of increasing interest in veterinary medicine. Limited data is available describing the actual effectiveness of CBD in horses. The aim of this study (part 2 of 2) was to analyze stress parameters via behavioral observation, heart rate monitoring and assessment of blood and saliva cortisol levels in healthy horses treated repeatedly with a CBD containing paste. Twelve horses were randomly assigned to a treatment or a control group. Two pastes were orally administered in a double-blinded study design, one paste containing CBD and one paste without active ingredient. Both pastes were administered twice daily over 15 days (dose: 3 mg CBD/kg). Behavioral observations were conducted daily using a sedation score and a rating of facial expressions, based on the previously described facial sedation scale for horses (FaceSed) and the Horse Grimace Scale. Blood and saliva samples were obtained regularly to determine cortisol levels throughout the study. Cortisol levels were analyzed by means of liquid chromatography/tandem mass spectrometry (LC/MS/MS). Behavioral observations and cortisol levels were compared between groups. Prior to paste administration, a novel object test was performed and the horses' reaction to loading on a trailer was recorded. Both tests were repeated after 13 days of paste application. Movement patterns such as different gaits during the novel object test were evaluated and an ethogram was designed to assess exhibited behavioral traits. Cardiac beat-to-beat (R-R) intervals were recorded throughout and evaluated using heart rate (HR) and heart rate variability (HRV) parameters. Blood and saliva samples for cortisol analysis were taken before and after the tests. Daily behavioral observations and cortisol levels did not differ between the treatment and the control group. Similarly, analysis of movement patterns, HR, HRV and cortisol levels during the novel object test and trailer test did not identify significant differences between the groups. Regularly administered oral CBD (3 mg/kg BID over 15 days) had no statistically significant effect on behavioral observations, cortisol levels, HR and HRV in horses. Further research is required to establish adequate doses and indications for the use of CBD in horses.

The effects of anesthetic drug choice on heart rate variability and echocardiography parameters in cats

Heart rate variability (HRV) is one of the assessments of cardiovascular risk during general anesthesia. This study aimed to assess the effects of an anesthetic drug on HRV in cats and to provide information for clinical applications. Twenty-four healthy client-owned cats of various breeds, 12 females and 12 males scheduled for elective surgery, were enrolled in this study. The cats were premedicated and induced with 4 protocols: protocol 1, diazepam (0.3 mg/kg) and propofol (2–4 mg/kg) IV; protocol 2, diazepam (0.3 mg/kg) and alfaxalone (1–3 mg/kg) IV; protocol 3, diazepam (0.3 mg/kg) and ketamine (3–5 mg/kg) IV; and protocol 4, xylazine (1 mg/kg) and tiletamine/zolazepam (Zoletil) (5 mg/kg) IM. The heart rate and HRV of the 24 cats were collected before and at least 1 h after administering the anesthetic drugs. Echocardiography was performed to evaluate heart function. Oscillometric blood pressure monitoring was used to obtain the mean blood pressure. After anesthetic drug administration, higher heart rates were found in cats premedicated and induced with alfaxalone (p = 0.045) than in the other protocols. The lowest heart rate (HR) values were found in cats in protocol 4 using xylazine and Zoletil. The HRV low frequency (LF) and high frequency (HF) power ratios increased in all protocols except for cats premedicated and intubated with propofol. The standard deviation of the regular sinus beats (SDNN) was higher in cats premedicated and induced with ketamine than in other anesthetic protocols (p = 0.015). An increase in sympathetic activity and reduced HRV is associated with high blood pressure and left atrial dimension. The percentage of fractional shortening (FS) decreased in cats premedicated with ketamine. The results showed that the anesthesia method using diazepam and propofol caused the least disturbance of HRV compared with other anesthesia methods that were used in this study.

Cerebrovascular and cardiovascular autonomic regulation in sickle cell patients with white matter lesions.

White matter lesions (WMLs) are frequent in sickle cell disease (SCD), with a prevalence described to be as high as 53% by age 30. Cerebrovascular regulation and cardiovascular autonomic regulation, more specifically the sympatho-vagal balance, can be altered in SCD. In this study the association between WMLs, cerebrovascular regulation and sympatho-vagal balance was assessed in SCD patients. Sickle cell disease patients with no history of stroke were prospectively evaluated for cerebrovascular reactivity using the breath-holding test (BHT), the sympatho-vagal balance (ratio low frequency/high frequency [HF]) using heart rate variability parameters and cerebral autoregulation in the time domain using correlation index Mx, and arterial cerebral compliance based on continuous assessment of cerebral blood flow velocities using transcranial Doppler ultrasound and arterial blood pressure with photo-plethysmography. WMLs were assessed with magnetic resonance imaging using Fazekas score grading and the presence of lacunes. Forty-one patients (F/M 25/16) were included. Median age was 37.5 years (19-65). Twenty-nine (70.7%) patients had SS genotype. Eleven patients had WMLs (26.8%). Patients with WMLs were significantly older (p < 0.001), had a lower HF (p < 0.005) and an impaired cerebral arterial compliance (p < 0.014). The receiver operating curve for the regression model including age and HF showed a higher area under the curve compared to age alone (0.946 vs. 0.876). BHT and Mx did not significantly differ between the two groups. Lower parasympathetic activity and impaired cerebral arterial compliance were associated with WMLs in adults with SCD. This could potentially yield to a better understanding of pathophysiological parameters leading to premature cerebrovascular ageing in SCD.

Assessment of heart rate variability among healthy 1st year medical students in a Government Medical College of Kolkata: A cross-sectional observational study

Background: Heart rate variability (HRV) means the beat-to-beat variations of cardiac rhythm which is influenced by the interplay of sympathetic and parasympathetic nerves. At present, cardiovascular morbidity and mortality have become a matter of great concern in the young population. Such complications may arise from cardiac dysautonomia. HRV analysis may be considered an efficient tool to detect this derangement as early as possible. Moreover, normative data on HRV should be established among the young population of India considering other demographic parameters such as gender, height, weight, and BMI. Aim and Objective: Our study intends to establish normative data for short-term HRV parameters among medical students of a tertiary care hospital in West Bengal. Materials and Methods: After obtaining approval from the Institutional Ethics Committee, 250 apparently healthy medical students were assessed and HRV parameters such as mean RR, mean HR, SDNN, NN50, pNN50, root mean square of successive differences (RMSSD), high frequency (HF), low frequency (LF), and LF/HF ratio were recorded. Results: In time domain parameters, values were significantly higher in males for mean HR and significantly higher in females for mean RR, NN50, and pNN50. In frequency domain parameters, significantly higher values were found for LF and LF/HF ratio in males and HF in females. Conclusion: We have established gender-based normative values of HRV parameters in the young population.

Comparison of behavioral and physiological changes in postpartum healthy and inflammatory diseased cows.

During parturition, cows often experience intense pain and stress, which increases the risk of inflammatory diseases. This study aimed to compare the postpartum health status between healthy cows and those diagnoses with inflammatory diseases by examining behavioral and heart rate (HR) variability (HRV) changes, to provide information before the onset of disease. Eight Holstein cows were used in this study. HR, parameters of HRV (low-frequency power: LF; high-frequency power: HF; LF/HF ratio, and total power) and time budget of individual maintenance behaviors (standing, recumbency, feeding, rumination while standing and lying, and sleep) were continuously recorded from 0 to 168 h postpartum. Milk and blood samples were collected daily. Cows were categorized as diseases based on the positive result of California mastitis test and/or serum haptoglobin concentration that exceeded 50 μg/ml after all blood samples have been collected. Compared to healthy individuals (n = 3), diseased cows (n = 5) exhibited higher HR, LF/HF, and lower total power (p < 0.05), suggesting the dominance of the sympathetic nervous system in cows with inflammatory diseases. Additionally, diseased cows showed an increased standing time budget and reduced recumbency (p < 0.05), which may be a behavioral strategy in response to discomfort from inflammation.

Heart rate variability in acute pancreatitis: a narrative review.

Acute pancreatitis (AP) is a complex inflammatory disorder with potential systemic repercussions including sepsis, multiple organ failure and mortality. As such, the development of a prognostic tool to assess the complications and severity of AP is critical as urgent medical intervention is warranted in cases of severe AP to prevent complications and reduce mortality. Despite the plethora of scoring systems such as the Acute Physiology and Chronic Health Evaluation II (APACHE II) score available for prognostication of AP, they often require manual invasive blood testing and lack the ability to monitor the dynamic progression of the disease. To this end, heart rate variability (HRV), a measure of the autonomic nervous system's modulation on cardiac activity, has emerged as a promising tool. Having been previously posited as a tool to monitor the progression of cardiovascular and neurological conditions, the use of HRV as a risk stratification tool for AP is highly plausible. Therefore, this study aims to synthesize the existing literature regarding the usage of HRV as a tool for the prognostication and monitoring of AP. A comprehensive literature search was conducted in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus and Embase from inception to December 2023. Articles with mentions of AP and HRV were reviewed, and the complications of AP and its effects on HRV parameters were analyzed. Early studies on the use of HRV in AP have revealed the association of decreased HRV parameters with the development of subsequent complications, reflecting the suppression of sympathetic activity as a predominant driving force. In addition, HRV has also been shown to outperform other established scoring systems in predicting outcomes of the complications of AP, but more studies are needed to validate its accuracy. Preliminary studies have shown that certain parameters of HRV may be used to predict the severity of AP and prognosticate outcomes. Although HRV monitoring demonstrates potential to be superior to existing scoring systems in AP, more research is needed to validate its use as a prognostic tool. Nevertheless, the prospective utility of HRV monitoring in predicting the onset and outcomes of AP and its complications remains optimistic.

Long Sudarshan Kriya Yoga enhances cardiovascular and respiratory synchronization: An observational study

BackgroundSudarshan Kriya Yoga (SKY – a rhythmic cyclic breathing) is known to produce several physiological changes in human body. Earlier it has been reported that SKY improves cardiovascular modulations, namely increase in heart rate variability. ObjectiveTo observe the synchronization in oscillatory modulations in cardiac autonomic tone and ventilatory exchange during Long Sudarshan Kriya Yoga (LSKY). LSKY is a sequential combination of pranayama in ujjayi breath, bhastrika, and cyclic rhythmic breathing followed by yog-nidra. MethodsRegular LSKY practitioners from the Art of Living community with more than two years of experience participated in the study (n = 22; age 40.09 ± 12.68). The Electrocardiogram (ECG), respiration, oxygen saturation, and concentrations of oxygen and carbon-di-oxide from exhaled air were recorded before and during LSKY. The time domain parameters of heart rate variability (HRV) were calculated from ECG. All parameters were compared and correlated at each stage of LSKY. ResultsHighly significant reciprocal correlation was found between HRV parameters and respiration rate during LSKY. Both O2 consumption and CO2 production increased significantly during three stages of pranayama and decreased towards the end of cyclic breathing. We also saw increased SPO2 simultaneously. ConclusionThe autonomic parameters exhibited reciprocal response to respiratory rate and correlated well to the ventilatory parameters. Further during LSKY we observed enhanced synchronization. In conclusion the LSKY has a potential to influence cardiorespiratory parameters for improving the performance of both systems. LSKY - enhances oscillations in HRV that resets the autonomic system, indicative of better cardiac health and prepares body for better metabolic response. Such changes are capable of inducing resilience along with physiological, psychological relaxation and emotional well-being.