Heart rate variability in type 2 diabetes mellitus: A systematic review and meta-analysis

The effect of heart rate variability on the choroidal vascularity of the optical coherence tomography and angiography in central serous chorioretinopathy

PURPOSE

To investigate the correlation between the autonomic nervous system and choroidal vascularity in patients with central serous chorioretinopathy (CSC), using heart rate variability (HRV) analysis, optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

We retrospectively analyzed data of 25 patients with unilateral CSC (50 eyes, including the unaffected fellow eyes) and 25 healthy controls. The assessment involved a 5-minute HRV analysis encompassing both frequency and time domains, especially low frequency (LF), high frequency (HF), and LF/HF ratio. In OCT (12 × 9 mm) and en-face OCTA (3 × 3 mm) scans, we measured parameters including choroidal vascularity index (CVI), choroidal vessel density in the middle and deep layers, and choriocapillaris flow void. Regression analysis was conducted to elucidate the associations between HRV parameters and OCT/OCTA measurements.

RESULTS

Normalized LF(LFnorm) and LF/HF ratios were higher in patients with CSC than in healthy controls. LFnorm and the log-transformed ratio of LF to HF [log(LF/HF)] demonstrated a significant and borderline correlation with CVI in the linear regression analysis (P = 0.040, R2 = 0.171, and P = 0.059, R2 = 0.147, respectively). Both CVI and deep choroid vessel density showed a more significant association with LFnorm and log (LF/HF) in the non-linear quadratic regression analysis than in the linear analysis (all, P < 0.04, R2 > 0.25).

CONCLUSION

The frequency-domain parameters of HRV, including LFnorm and log (LF/HF), demonstrated a significant association with indicators reflective of large choroidal vessel luminal area on macular OCT/OCTA scans. This observation implies complicated modulation of choroidal blood flow by the autonomic nervous system in CSC.

Cardiopulmonary and metabolic responses during a 2-day CPET in myalgic encephalomyelitis/chronic fatigue syndrome: translating reduced oxygen consumption to impairment status to treatment considerations

BACKGROUND

Post-exertional malaise (PEM), the hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), represents a constellation of abnormal responses to physical, cognitive, and/or emotional exertion including profound fatigue, cognitive dysfunction, and exertion intolerance, among numerous other maladies. Two sequential cardiopulmonary exercise tests (2-d CPET) provide objective evidence of abnormal responses to exertion in ME/CFS but validated only in studies with small sample sizes. Further, translation of results to impairment status and approaches to symptom reduction are lacking.

METHODS

Participants with ME/CFS (Canadian Criteria; n = 84) and sedentary controls (CTL; n = 71) completed two CPETs on a cycle ergometer separated by 24 h. Two-way repeated measures ANOVA compared CPET measures at rest, ventilatory/anaerobic threshold (VAT), and peak effort between phenotypes and CPETs. Intraclass correlations described stability of CPET measures across tests, and relevant objective CPET data indicated impairment status. A subset of case-control pairs (n = 55) matched for aerobic capacity, age, and sex, were also analyzed.

RESULTS

Unlike CTL, ME/CFS failed to reproduce CPET-1 measures during CPET-2 with significant declines at peak exertion in work, exercise time, V ˙ e, V ˙ O2, V ˙ CO2, V ˙ T, HR, O2pulse, DBP, and RPP. Likewise, CPET-2 declines were observed at VAT for V ˙ e/ V ˙ CO2, PetCO2, O2pulse, work, V ˙ O2 and SBP. Perception of effort (RPE) exceeded maximum effort criteria for ME/CFS and CTL on both CPETs. Results were similar in matched pairs. Intraclass correlations revealed greater stability in CPET variables across test days in CTL compared to ME/CFS owing to CPET-2 declines in ME/CFS. Lastly, CPET-2 data signaled more severe impairment status for ME/CFS compared to CPET-1.

CONCLUSIONS

Presently, this is the largest 2-d CPET study of ME/CFS to substantiate impaired recovery in ME/CFS following an exertional stressor. Abnormal post-exertional CPET responses persisted compared to CTL matched for aerobic capacity, indicating that fitness level does not predispose to exertion intolerance in ME/CFS. Moreover, contributions to exertion intolerance in ME/CFS by disrupted cardiac, pulmonary, and metabolic factors implicates autonomic nervous system dysregulation of blood flow and oxygen delivery for energy metabolism. The observable declines in post-exertional energy metabolism translate notably to a worsening of impairment status. Treatment considerations to address tangible reductions in physiological function are proffered.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, retrospectively registered, ID# NCT04026425, date of registration: 2019-07-17.

Autonomic Nerve Function Predicts Risk of Early Death after Discharge in Acute Medical Disease

BACKGROUND

Heart rate variability, a marker of autonomic function, has shown promising prognostic results in specific populations, but has not been tested in a general medical population. We hypothesized that heart rate variability identifies high-risk medical patients early after admission to the hospital.

METHODS

This was a single-center prospective cohort study of acutely admitted medical patients aged ≥18 years with a life expectancy ≥3 months, included between 2019-2023. Unstable patients needing direct admission to the intensive care unit were excluded. Heart rate variability was recorded within 24 hours of admission for 10 minutes. The standard deviation of normal-normal beats (SDNN) was the primary heart rate variability marker. Low SDNN was defined as the lowest tertile (≤22 ms). The primary outcome was 30-day all-cause mortality. The secondary outcome was 30-day readmission or mortality.

RESULTS

Among 721 patients included, low SDNN carried an 8-fold greater risk of 30-day mortality in univariate analysis (hazard ratio [HR] 8.3; P = .001); in multivariate analyses a 4-fold greater risk (HR 3.8; P = .037). Low SDNN was associated with the combined outcome of 30-day mortality or readmission (HR 1.5; P = .03) in multivariate analysis. In receiver operating characteristics analyses, low SDNN improved the predictive accuracy of early warning score for 30-day mortality or readmission from 0.63 to 0.71 (P = .008) but did not improve the accuracy for 30-day mortality alone.

CONCLUSIONS

In patients admitted due to acute medical illness, low heart rate variability predicted 30-day mortality and readmission, suggesting heart rate variability as a tool to identify patients at high and low risk of relevant endpoints.

Exercise Effects on Autonomic Nervous System Activity in Type 2 Diabetes Mellitus Patients over Time: A Meta-Regression Study

BACKGROUND

Diabetic autonomic neuropathy is a common complication of type 2 diabetes mellitus (T2DM), especially in patients with long-term, poorly controlled diabetes. This study investigates the effects of exercise on autonomic nervous system activity in T2DM patients over time.

METHODS

A literature review using MEDLINE, Embase, Cochrane Library, Scopus, and PubMed identified studies assessed via heart rate variability. Papers were categorized into three groups: immediate effects (within 60 min), short-term effects (2-3 months), and long-term effects (over 4 months).

RESULTS

Nine articles with 161 T2DM patients were included in the meta-analysis. RMSSD changes after exercise were -4.3 (p = 0.227), 8.14 (p < 0.001), and 4.17 (p = 0.002) for the immediate, short-term, and long-term groups, respectively. LF/HF ratio changes were 0.21 (p = 0.264), -3.04 (p = 0.102), and -0.05 (p = 0.006) for the respective groups. Meta-regression indicated age, male gender, and exercise duration were associated with increased RMSSD, with coefficients of 2.36 (p = 0.001), 13.76 (p = 0.008), and 1.50 (p = 0.007), respectively. Age positively correlated with the LF/HF ratio, with a coefficient of 0.049 (p = 0.048).

CONCLUSIONS

Regular exercise (≥3 times per week) for over 2 months increases parasympathetic activity in T2DM patients, while sympathetic activity decreases significantly after 4 months. Further study is needed to validate these findings.

Cardiac electrophysiology, structure and diastolic function in patients with diabetic foot versus those without diabetic foot

AIMS/INTRODUCTION

To evaluate the differences in cardiac autonomic function, cardiac structure and diastolic function between individuals with diabetic foot (DF) and those with diabetes but without DF.

MATERIALS AND METHODS

A total of 413 individuals with DF and 437 without DF who underwent a 24-h electrocardiogram Holter and a Doppler echocardiogram were included. The heart rate variability parameters to evaluate cardiac autonomic function, and the indices for the assessment of cardiac structure and left ventricular (LV) diastolic function, including left atrium, LV posterior wall thickness, interventricular septum and E/e' ratio, were measured or calculated. Propensity score matching was used for the sensitivity analysis to minimize potential imbalance.

RESULTS

In both the crude and propensity score matching analyses, significant differences were observed in heart rate variability between individuals with and without DF, as evidenced by lower standard deviation of the normal sinus interval, lower low-frequency power/high-frequency power ratio, lower standard deviation of the 5-min average RR intervals, lower low-frequency power, lower percentage of normal adjacent RR interval difference >50 ms, lower root mean square of successive RR interval differences and lower high-frequency power (all P < 0.05). In multivariate analysis, DF showed an independent negative correlation with the aforementioned indices of heart rate variability (all P < 0.05). Individuals with DF showed higher left atrium, LV posterior wall thickness, interventricular septum and a higher E/e' ratio than those without DF in the crude analysis (all P < 0.05), whereas these indices were no longer associated with DF in the multivariate analysis and the propensity score matching analyses.

CONCLUSIONS

Cardiac autonomic modulation was more severely impaired in individuals with DF than in their counterparts without DF. There has been insufficient evidence to demonstrate the independent association of DF and LV diastolic dysfunction.

Practical strategies to manage obesity in type 2 diabetes

The rising phenomenon of obesity, a major risk factor for the development and progression of type 2 diabetes, is a complex and multifaceted issue that requires a comprehensive and coordinated approach to be prevented and managed. Although novel pharmacological measures to combat obesity have achieved unprecedented efficacy, a healthy lifestyle remains essential for the long-term success of any therapeutic intervention. However, this requires a high level of intrinsic motivation and continued behavioural changes in the face of multiple metabolic, psychological and environmental factors promoting weight gain, particularly in the context of type 2 diabetes. This review is intended to provide practical recommendations in the context of a holistic, person-centred approach to weight management, including evidence-based and expert recommendations addressing supportive communication, shared decision-making, as well as nutritional and pharmacological therapeutic approaches to achieve sustained weight loss.

The role of heart rate variability in predicting delirium: A systematic review and meta-analysis

Brain and heart interact through multiple ways. Heart rate variability, a non-invasive measurement is studied extensively as a predicting model for various health conditions including subarachnoid hemorrhage, cancer, and diabetes. There is limited evidence to predict delirium, an acute fluctuating disorder of brain dysfunction, as it poses a significant challenge in the intensive care unit (ICU) and post-operative setting. In this systematic review of 9 articles, heart rate variability indices were used to investigate the occurrence of post-operative and ICU delirium. This systematic review and meta-analysis reveal evidence of a strong predilection between postoperative and intensive care unit delirium and alterations in the heart rate variability, measured by mean differences for standard deviation of NN-intervals. Other heart rate variability indices [root mean squares of successive differences, low-frequency (LF), high-frequency (HF), and LF:HF ratio] showed lack of or very weak association. A non-invasive tool of brain and heart interaction may refine diagnostic predictions for acute brain dysfunctions like delirium in such population and would be an important step in delirium research.

Cardiovascular Autonomic Dysfunction in Hospitalized Patients with a Bacterial Infection: A Longitudinal Observational Pilot Study in the UK

PURPOSE

A temporal reduction in the cardiovascular autonomic responses predisposes patients to cardiovascular instability after a viral infection and therefore increases the risk of associated complications. These findings have not been replicated in a bacterial infection. This pilot study will explore the prevalence of cardiovascular autonomic dysfunction (CAD) in hospitalized patients with a bacterial infection.

METHODS

A longitudinal observational pilot study was conducted. Fifty participants were included: 13 and 37 participants in the infection group and healthy group, respectively. Recruitment and data collection were carried out during a two-year period. Participants were followed up for 6 weeks: all participants' cardiovascular function was assessed at baseline (week 1) and reassessed subsequently at week 6 so that the progression of the autonomic function could be evaluated over that period of time. The collected data were thereafter analyzed using STATA/SE version 16.1 (StataCorp). The Fisher Exact test, McNemar exact test, Mann-Whitney test and Wilcoxon test were used for data analysis.

RESULTS

32.4% of the participants in the healthy group were males (n = 12) and 67.6% were females (n = 25). Participants' age ranged from 33 years old to 76 years old with the majority being 40-60 years of age (62.1%) (Mean age 52.4 SD = 11.4). Heart rate variability (HRV) in response to Valsalva Maneuver, metronome breathing, standing and sustained handgrip in the infection group was lower than in the healthy group throughout the weeks. Moreover, both the HRV in response to metronome breathing and standing up showed a statistically significant difference when the mean values were compared between both groups in week 1 (p = 0.03 and p = 0.013). The prevalence of CAD was significantly higher in the infection group compared to healthy volunteers, both at the beginning of the study (p = 0.018) and at the end of follow up (p = 0.057), when all patients had been discharged.

CONCLUSIONS

CAD, as assessed by the HRV, is a common finding during the recovery period of a bacterial infection, even after 6 weeks post-hospital admission. This may increase the risk of complications and cardiovascular instability. It may therefore be of value to conduct a wider scale study to further evaluate this aspect so recommendations can be made for the cardiovascular autonomic assessment of patients while they are recovering from a bacterial infectious process.

Direct and indirect effects of adiposity on markers of autonomic nervous system activity in older adults

Several cardiovascular disease (CVD) risk factors (e.g., hypertension, poor glycemic control) can affect and be affected by autonomic nervous system (ANS) activity. Since excess adiposity can influence CVD development through its effect on hypertension and diabetes mellitus, it is important to determine how adiposity and altered ANS activity are related. The present study employed structural equation modeling to investigate the relation between adiposity and ANS activity both directly and indirectly through biological variables typically associated with glycemic impairment and cardiac stress in older adults. Utilizing the Atherosclerosis Risk in Communities (ARIC) dataset, 1,145 non-smoking adults (74±4.8 yrs, 62.8% female) free from known CVD, hypertension, and diabetes and not currently taking beta-blockers were evaluated for fasting blood glucose (FBG), insulin, and HbA1c concentrations, waist circumference (WC), blood pressure (BP), and markers of ANS activity. WC was recorded just above the iliac crest and was used to reflect central adiposity. Resting 2-minute electrocardiograph recordings, pulse wave velocity, and ankle-brachial index data were used to assess the root mean square of successive differences in RR intervals (RMSSD) and the pre-ejection period (PEP), markers of parasympathetic and sympathetic activity, respectively. FBG, insulin, and HbA1c inferred a latent variable termed glycemic impairment (GI), whereas heart rate and diastolic BP inferred a latent variable termed cardiac stress (CS). The structural equation model fit was acceptable [root mean square error of approximation = 0.050 (90% CI = .036, .066), comparative fit index = .970, Tucker Lewis Index = 0.929], with adiposity having both significant direct (β = 0.208, p = 0.018) and indirect (β = -.217, p = .041) effects on PEP through GI. Adiposity displayed no significant direct effect on RMSSD. CS displayed a significant pathway (β = -0.524, p = 0.035) on RMSSD, but the indirect effect of WC on RMSSD through CS did not reach statistical significance (β = -0.094, p = 0.137). These results suggest that adiposity's relation to ANS activity is multifaceted, as increased central adiposity had opposing direct and indirect effects on markers of sympathetic activity in this population of older adults.

Lipid profile, inflammatory biomarkers, endothelial dysfunction, and heart rate variability in adolescents with type 1 diabetes. A case-control study among UAE population

Background

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the chronic inflammation and cause of endothelial dysfunction (ED). Heart rate variability (HRV) is a marker of sympathetic and parasympathetic autonomic nervous system dysfunction. We investigated the association of lipid profile, inflammatory biomarkers, endothelial dysfunction, and heart rate variability in adolescents with T1DM among UAE population.

Method

In this case-control study we recruited 126 adolescents (13-22 years) from Abu Dhabi, UAE (United Arab Emirates). Demographic, anthropometric, blood and urine samples were collected after an overnight fasting. HRV measurements were determined per Task Force recommendations. Independent t-test or Mann-Whitney U test and Pearson's Chi-squared test were used to compare groups. Adjusted conditional logistic regression model was used to identify the determinants independently associated with T1DM.

Results

The mean ages in control (n = 47) and patient (n = 79) groups were 17.5 ± 4.6 and 18.6 ± 4.8 years, respectively. A family history of diabetes and waist and hip circumferences significantly differed between the groups (p = 0.030 and 0.010). The patients with T1DM exhibited significantly higher levels of atherogenic markers than control. Endothelial dysfunction biomarkers such as levels of sICAM-1 (p < 0.001), adiponectin (p < 0.001) and 25-hydroxyvitamin D (p < 0.001) were significantly different in the control group compared with those in the T1DM group. There was a significant difference in SDNN intervals, NN50, pNN50, and SD1/SD2 among the two groups. In adjusted analysis, total cholesterol (adjusted Odds Ratio (aOR): 2.78, 95 % CI:1.37-5.64; p = 0.005), LDL (2.66, 95%CI:1.19-5.92; p = 0.017), and triglycerides (5.51, 95%CI:1.57-19.41; p = 0.008) were significantly associated with developing T1DM. The HRV indicators were significantly associated with decrease odds of T1DM after controlling for SBP, BMI, and family history of DM.

Conclusion

In this study, adolescents with T1DM showed a significant association with lipid profile, ED, and HRV compared with controls. Thus, an early attention to diabetes control is required to reduce the risk of cardiac autonomic neuropathy leading to various cardiovascular diseases.

Guideline for the application of heart rate and heart rate variability in occupational medicine and occupational health science

This updated guideline replaces the "Guideline for the application of heart rate and heart rate variability in occupational medicine and occupational health science" first published in 2014. Based on the older version of the guideline, the authors have reviewed and evaluated the findings on the use of heart rate (HR) and heart rate variability (HRV) that have been published in the meantime and incorporated them into a new version of this guideline.This guideline was developed for application in clinical practice and research purposes in the fields of occupational medicine and occupational science to complement evaluation procedures with respect to exposure and risk assessment at the workplace by the use of objective physiological workload indicators. In addition, HRV is also suitable for assessing the state of health and for monitoring the progress of illnesses and preventive medical measures. It gives an overview of factors influencing the regulation of the HR and HRV at rest and during work. It further illustrates methods for measuring and analyzing these parameters under standardized laboratory and real workload conditions, areas of application as well as the quality control procedures to be followed during the recording and evaluation of HR and HRV.

Genetic markers of cardiac autonomic neuropathy in the Kazakh population

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a complication of diabetes mellitus (DM) that increases the risk of morbidity and mortality by disrupting cardiac innervation. Recent evidence suggests that CAN may manifest even before the onset of DM, with prediabetes and metabolic syndrome potentially serving as precursors. This study aims to identify genetic markers associated with CAN development in the Kazakh population by investigating the SNPs of specific genes.

MATERIALS AND METHODS

A case-control study involved 82 patients with CAN (cases) and 100 patients without CAN (controls). A total of 182 individuals of Kazakh nationality were enrolled from a hospital affiliated with the RSE "Medical Center Hospital of the President's Affairs Administration of the Republic of Kazakhstan". 7 SNPs of genes FTO, PPARG, SNCA, XRCC1, FLACC1/CASP8 were studied. Statistical analysis was performed using Chi-square methods, calculation of odds ratios (OR) with 95% confidence intervals (CI), and logistic regression in SPSS 26.0.

RESULTS

Among the SNCA gene polymorphisms, rs2737029 was significantly associated with CAN, almost doubling the risk of CAN (OR 2.03(1.09-3.77), p = 0.03). However, no statistically significant association with CAN was detected with the rs2736990 of the SNCA gene (OR 1.00 CI (0.63-1.59), p = 0.99). rs12149832 of the FTO gene increased the risk of CAN threefold (OR 3.22(1.04-9.95), p = 0.04), while rs1801282 of the PPARG gene and rs13016963 of the FLACC1 gene increased the risk twofold (OR 2.56(1.19-5.49), p = 0.02) and (OR 2.34(1.00-5.46), p = 0.05) respectively. rs1108775 and rs1799782 of the XRCC1 gene were associated with reduced chances of developing CAN both before and after adjustment (OR 0.24, CI (0.09-0.68), p = 0.007, and OR 0.43, CI (0.22-0.84), p = 0.02, respectively).

CONCLUSION

The study suggests that rs2737029 (SNCA gene), rs12149832 (FTO gene), rs1801282 (PPARG gene), and rs13016963 (FLACC1 gene) may be predisposing factors for CAN development. Additionally, SNPs rs1108775 and rs1799782 (XRCC1 gene) may confer resistance to CAN. Only one polymorphism rs2736990 of the SNCA gene was not associated with CAN.

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.

Heart Rate Variability, Deceleration Capacity of Heart Rate, and Death: A Veteran Twins Study

BACKGROUND

Autonomic function can be measured noninvasively using heart rate variability (HRV), which indexes overall sympathovagal balance. Deceleration capacity (DC) of heart rate is a more specific metric of vagal modulation. Higher values of these measures have been associated with reduced mortality risk primarily in patients with cardiovascular disease, but their significance in community samples is less clear.

METHODS AND RESULTS

This prospective twin study followed 501 members from the VET (Vietnam Era Twin) registry. At baseline, frequency domain HRV and DC were measured from 24-hour Holter ECGs. During an average 12-year follow-up, all-cause death was assessed via the National Death Index. Multivariable Cox frailty models with random effect for twin pair were used to examine the hazard ratios of death per 1-SD increase in log-transformed autonomic metrics. Both in the overall sample and comparing twins within pairs, higher values of low-frequency HRV and DC were significantly associated with lower hazards of all-cause death. In within-pair analysis, after adjusting for baseline factors, there was a 22% and 27% lower hazard of death per 1-SD increment in low-frequency HRV and DC, respectively. Higher low-frequency HRV and DC, measured during both daytime and nighttime, were associated with decreased hazard of death, but daytime measures showed numerically stronger associations. Results did not substantially vary by zygosity.

CONCLUSIONS

Autonomic inflexibility, and especially vagal withdrawal, are important mechanistic pathways of general mortality risk, independent of familial and genetic factors.

The Effect of Intra-abdominal Pressure on Heart Rate Variability and Hemodynamics During Laparoscopic Cholecystectomy: A Prospective Observational Study

Introduction This study aimed to evaluate hemodynamic changes using heart rate variability (HRV) measurements in diabetic and nondiabetic patients who will undergo laparoscopic cholecystectomy and to provide our preoperative measurements to guide us for better perioperative anesthesia management. Materials and methods The study included 143 patients aged 40 years and older who would undergo elective laparoscopic surgery, did not have any comorbidities other than diabetes mellitus (DM) type II, and were in the American Society of Anesthesiologists (ASA) class I-III risk group. Patients were divided into two groups: the control group (n = 77) and the DM group (n = 66). The preoperative glycated hemoglobin (HbA1C) level was measured. Peripheral oxygen saturation (SpO2) and hemodynamic parameters such as systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), and HRV parameters were measured preoperatively, perioperatively, and postoperatively. Intra-abdominal pressure (IAP) was administered at 10-12 mmHg. Results Even though SAP, DAP, MAP, and HR decreased with induction, they increased with insufflation, and an overall decrease was seen at the postoperative 24th hour for all parameters. When the groups were evaluated, no difference was observed except that the DAP was significantly lower in the DM group (p = 0.029) at insufflation and the HR was higher in the DM group at induction, and the difference was significant (p = 0.001). Preoperative HRV parameters were significantly lower in the DM group. According to the HRV parameters, although a decrease was observed after induction and insufflation, conversely, an increase was observed postoperatively. When the postoperative and preoperative values were compared, the standard deviation of the NN (R-R) intervals (SDNN), SDNN index, high frequency (HF), low frequency (LF), and LF/HF parameters were found to be significantly lower in the DM group than in the control group. Conclusion Diabetic patients are more sensitive to increased intra-abdominal pressure (IAP) in laparoscopic surgery, and the effects on cardiac autonomic functions can be determined by HRV measurements without clinically reflecting on hemodynamic data. Additionally, in diabetic patients with preoperative LF and/or HF values less than 100, we believe that careful follow-up in terms of autonomic neuropathy complications and anesthesia management should be done more meticulously in these patients.

Impaired Cardiovagal Activity as a Link Between Hyperglycemia and Arterial Stiffness in Adults With Type 2 Diabetes Mellitus Among an Eastern Indian Population: A Cross-sectional Study

OBJECTIVES

Cardiac autonomic neuropathy (CAN) is one of the most common yet overlooked complications of type 2 diabetes mellitus (T2DM). Individuals with T2DM with CAN have a 5-fold higher rate of cardiovascular morbidity and mortality. The presence of CAN in T2DM could potentially lead to arterial stiffness. However, only sparse data are available suggesting any association between autonomic dysfunction and arterial stiffness in T2DM.

METHODS

We recruited 80 people with T2DM and 74 healthy controls for our study. Heart rate variability (HRV) testing was performed to assess autonomic function. Assessment of arterial stiffness was done by measuring the brachial pulse wave velocity (baPWV) and augmentation index (AI).

RESULTS

The time-domain parameters were significantly decreased (p<0.001) and frequency-domain parameters, such as total power and high-frequency band expressed as a normalized unit, were found to be significantly reduced in people with T2DM (p<0.001). Both baPWV and AI were significantly higher in people with T2DM compared with healthy controls (p<0.001). We observed a moderate correlation between standard deviation of normal to normal interval (SDNN) and baPWV (r=-0.437, p=0.002) and AI (r=-0.403, p=0.002). A multiple linear regression model showed an association between SDNN and arterial stiffness parameters, such as baPWV and AI, which were statistically significant (p<0.05) in a fully adjusted model that included the conventional risk factors for atherosclerosis.

CONCLUSIONS

Impaired cardiovagal activity is an independent risk factor for the development of arterial stiffness. Incorporation of HRV testing into the diabetes management protocol would have potential benefits for identifying individuals at high risk of developing cardiovascular events. Hence, preventive measures can be taken as early as possible to improve patient outcomes.

Comparative Analysis of the Hemodynamic Effects of Remimazolam and Propofol During General Anesthesia: A Retrospective Study

PURPOSE

Hypotension is common during anesthesia induction. However, minimal hemodynamic effects of remimazolam anesthesia have been reported. We hypothesized that remimazolam would have weaker hemodynamic effects than would propofol. To test this, we simultaneously evaluated the hemodynamics using the estimated continuous cardiac output (esCCO) system and heart rate variability (HRV) during anesthesia induction.

METHODS

This was a single-center, observational, retrospective study of patients undergoing dental surgery under general anesthesia between 2020 and 2022. Seventy patients were divided into two groups: remimazolam (R group; n=34) and propofol (P group; n=36). The information obtained from the anesthesia records, patient information, esCCO system parameters, and HRV were integrated and analyzed. The percentages of various parameters were set to 100% for the pre-induction phase as the baseline.

RESULTS

The %MAP (noninvasive mean arterial blood pressure) decreased over a narrower range in the R compared to the P group (-17.8% (-26.3%, -11.9%) vs. -22.6% (-32.9%, -17.0%); P=0.039). The %HR (heart rate) increased significantly in the R group and decreased in the P group (+10.7% (+6.5%, +18.6%) vs. -6.5% (-14.5%, +8.4%); P<0.01). The %SVesCCO (stroke volume calculated using the esCCO system) decreased significantly in both groups, but the R group showed a smaller difference compared to the P group (- 5.1% (-7.7%, -2.1%) vs. -10.0% (-13.8%, -5.6%); P<0.01). The rates of change in %LF nu (normalized unit of low frequency) and %HF nu (normalized unit of high frequency) were lower for the R than for the P group, although the difference was not significant (+6.8% (-14.5%, 32.4%) vs. +9.2% (-7.2%, +59.7%), P=0.30; +7.9% (-51.0%, +66.9%) vs. +22.8% (-26.1%, +61.6%), P=0.57).

CONCLUSION

Remimazolam demonstrated a lower MAP reduction rate than propofol. A compensatory increase in HR occurred with a decrease in stroke volume. However, the HR increase was not attributable to the autonomic nervous system.

Analysis of Sinus Variability in a Group of Cameroonian Athletes

Background

Heart rate variability (HRV) analysis is a useful method for assessing the heart's ability to adapt to endogenous and exogenous loads. Data from African population on HRV are scarce and even more so in sports populations. This study aimed to compare cardiac autonomic modulation response in Cameroonian athletes and sedentary. Methodology. We conducted a prospective and analytical study in sports teams in the city of Yaoundé, Cameroon. The participants in our study were divided in three groups; people who practiced little or no sporting activity (sedentary as group 1) or who were regularly physically active as part of a sports team (footballers or handballers as second and third groups). They had to be aged 18 or over and have given their informed consent. Heart rate (HR) was continuously recorded at rest for ten minutes and then transferred to a computer equipped with Kubios HRV Standard software for analysis. Means ± mean standard errors were compared using the one-way ANOVA test, followed by Tukey's post-test. The significance threshold was set at 0.05.

Results

Of the 60 people selected to participate to our study, 75.0% were sportsmen (40.0% handball players and 35.0% footballers). The resting HR of sedentary people was higher (p < 0.001) than that of footballers and handball players. The SDNN, RMSSD, and pNN50 of sedentary people (16.22 ± 1.04; 9.97 ± 0.46; and 0.16 ± 0.06) were lower than those of footballers (30.13 ± 2.93; 20.61 ± 2.46; and 2.99 ± 0.63, with p < 0.001) and handball players (29.00 ± 1.86; 16.44 ± 1.16; and 2.15 ± 0.38, with p < 0.001 and p < 0.05 respectively). Absolute and relative very-low-frequency (VLF) power, absolute low and high-frequency (LF and HF) power, as well as total power (TP) were lower in sedentary people (3.66 ± 0.08 and 16.21 ± 0.64; 5.04 ± 0.15 and 2.50 ± 0.16 and 246.40 ± 18.04) compared to footballers (5.09 ± 0.24 and 26.87 ± 1.76; 5.85 ± 0.32 and 3.92 ± 0.22 and 836.10 ± 103.70, with p < 0.001, p < 0.01, and p < 0.001) and handball players (4.86 ± 0.16 and 30.82 ± 2.67; 6.03 ± 0.19 and 3.46 ± 0.16 and 927.30 ± 94.12, with p < 0.001, p < 0.05, p < 0.01, and p < 0.001). The LF/HF ratio was 12.1% and 20.1% lower in sedentary people (7.55 ± 0.58) compared with footballers (8.46 ± 0.50) and handball players (9.07 ± 0.60), respectively.

Conclusion

Sportsmen showed greater parasympathetic and global modulation when compared to sedentary people.

Autonomic Nervous System Activity and Dental Anxiety in the Northern Finland Birth Cohort (NFBC1966) Population

Autonomic nervous system (ANS) activity may be associated with dental anxiety; however, no studies exist on the topic. The aim of this study was to assess if ANS activity and dental anxiety are associated. Data were collected as part of a Northern Finland Birth Cohort Study, NFBC1966, at the age of 46 years with eligible data on 1905 participants. Dental anxiety was measured using the Modified Dental Anxiety Scale (MDAS) categorized as follows: 19-25 = high, 10-18 = moderate, 5-9 = no to low dental anxiety. Heart rate variability (HRV) data were collected using an HR monitor and a standard lead-II electrocardiogram (ECG). Baroreflex sensitivity (BRS) was calculated from continuous ECG and blood pressure signals. Participants were categorized into three groups as follows: Low = the lowest 20th percentile, Mid = medium 21-79th percentile, and High = the highest 20th percentile according to their ANS variables. The associations between the MDAS and ANS activity parameters were evaluated using unordered multinomial logit models adjusted for comorbidities, β-blockers, BMI, smoking, and education. High heart rate, reduced HRV, low cardiac vagal modulation, and poor BRS were associated with moderate dental anxiety, and high cardiac vagal modulation and good BRS were associated with no to low dental anxiety. Poorer ANS activity might predispose some to dental anxiety, and better ANS activity might protect from dental anxiety.

Healthy lifestyle and essential metals attenuated association of polycyclic aromatic hydrocarbons with heart rate variability in coke oven workers

Whether adopting healthy lifestyles and maintaining moderate levels of essential metals could attenuate the reduction of heart rate variability (HRV) related to polycyclic aromatic hydrocarbons (PAHs) exposure are largely unknown. In this study, we measured urinary metals and PAHs as well as HRV, and constructed a healthy lifestyle score in 1267 coke oven workers. Linear regression models were used to explore the association of healthy lifestyle score and essential metals with HRV, and interaction analysis was performed to investigate the potential interaction between healthy lifestyle score, essential metals, and PAHs on HRV. Mean age of the participants was 41.9 years (84.5% male). Per one point higher healthy lifestyle score was associated with a 2.5% (95% CI, 1.0%-3.9%) higher standard deviation of all normal to normal intervals (SDNN), 2.1% (95% CI, 0.5%-3.6%) higher root mean square of successive differences in adjacent NN intervals (r-MSSD), 4.3% (95% CI, 0.4%-8.2%) higher low frequency, 4.4% (95% CI, 0.2%-8.5%) higher high frequency, and 4.4% (95% CI, 1.2%-7.6%) higher total power, respectively. Urinary level of chromium was positively associated with HRV indices, with the corresponding β (95% CI) (%) was 5.17 (2.84, 7.50) for SDNN, 4.29 (1.74, 6.84) for r-MSSD, 12.26 (6.08, 18.45) for low frequency, 12.61 (5.87, 19.36) for high frequency, and 11.31 (6.19, 16.43) for total power. Additionally, a significant interaction was found between healthy lifestyle score and urinary total hydroxynaphthalene on SDNN (Pinteraction = 0.04), and higher level of urinary chromium could attenuate the adverse effect of total hydroxynaphthalene level on HRV (all Pinteraction <0.05). Findings of our study suggest adopting healthy lifestyle and maintaining a relatively high level of chromium might attenuate the reduction of HRV related to total hydroxynaphthalene exposure.

Correlations of cardiovascular autonomic neuropathy with urinary albumin excretion rate and cardiac function in patients with type 2 diabetes mellitus

BACKGROUND

The associations of cardiovascular autonomic neuropathy (CAN) with diabetic nephropathy and heart disease remain elusive. The aim of this study was to explore the correlations of CAN with urinary albumin excretion rate (UAER) and cardiac function in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 225 T2DM patients were assigned into CAN and non-CAN groups using cardiovascular reflex tests (CARTs). They were divided into macroalbuminuria, microalbuminuria and normoalbuminuria groups according to urinary albumin/creatinine ratio (UACR), or left ventricular diastolic dysfunction and normal groups based on left ventricular peak E/A velocity ratio (E/A). The correlations of CAN with albuminuria and left ventricular diastolic dysfunction, and the predictive values of UACR and E/A were analyzed.

RESULTS

Compared with non-CAN group, CAN group had older age, longer T2DM duration, higher serum urine acid (SUA) level, UACR, systolic and diastolic pressure differences between supine and standing positions, and lower other CARTs parameters and E/A (P<0.001). Macroalbuminuria group had largest positional systolic and diastolic pressure differences, and lowest other CARTs parameters (P<0.001). Compared with normal group, left ventricular diastolic dysfunction group had larger positional systolic and diastolic pressure differences, and lower other CARTs parameters (P<0.001). CAN in T2DM patients was positively correlated with albuminuria and left ventricular diastolic dysfunction (P<0.001). Age, SUA, UACR and E/A were independent predictive factors (P=0.031, P=0.005, P<0.001, P<0.001). UACR and E/A had high predictive values.

CONCLUSIONS

In T2DM patients, CAN is positively correlated with declined UAER and cardiac function. UACR and E/A have high predictive values.

High Resting Coronary Flow Velocity by Echocardiography Is Associated With Worse Survival in Patients With Chronic Coronary Syndromes

BACKGROUND

Resting coronary flow velocity (CFV) in the mid-distal left anterior descending coronary artery can be easily assessed with transthoracic echocardiography. In this observational study, the authors sought to assess the relationship between resting CFV, CFV reserve (CFVR), and outcome in patients with chronic coronary syndromes.

METHODS AND RESULTS

In a prospective multicenter study design, the authors retrospectively analyzed 7576 patients (age, 66±11 years; 4312 men) with chronic coronary syndromes and left ventricular ejection fraction ≥50% referred for dipyridamole stress echocardiography. Recruitment (years 2003-2021) involved 7 accredited laboratories, with interobserver variability <10% for CFV measurement at study entry. Baseline peak diastolic CFV was obtained by pulsed-wave Doppler in the mid-distal left anterior descending coronary artery. CFVR (abnormal value ≤2.0) was assessed with dipyridamole. All-cause death was the only end point. The mean CFV of the left anterior descending coronary artery was 31±12 cm/s. The mean CFVR was 2.32±0.60. During a median follow-up of 5.9±4.3 years, 1121 (15%) patients died. At multivariable analysis, resting CFV ≥32 cm/s was identified by a receiver operating curve as the best cutoff and was independently associated with mortality (hazard ratio [HR], 1.24 [95% CI, 1.10-1.40]; P<0.0001) together with CFVR ≤2.0 (HR, 1.78 [95% CI, 1.57-2.02]; P<0.0001), age, diabetes, history of coronary surgery, and left ventricular ejection fraction. When both CFV and CFVR were considered, the mortality rate was highest in patients with resting CFV ≥32 cm/s and CFVR ≤2.0 and lowest in patients with resting CFV <32 cm/s and CFVR >2.0.

CONCLUSIONS

High resting CFV is associated with worse survival in patients with chronic coronary syndromes and left ventricular ejection fraction ≥50%. The value is independent and additive to CFVR. The combination of high resting CFV and low CFVR is associated with the worst survival.

Harmony in Chaos: Deciphering the Influence of Ischemic Cardiomyopathy and Non-Cardiac Comorbidities on Holter ECG Parameters in Chronic Heart Failure Patients: A Pilot Study

Background and Objective: In the landscape of heart failure, non-cardiac comorbidities represent a formidable challenge, imparting adverse prognostic implications. Holter ECG monitoring assumes a supplementary role in delineating myocardial susceptibility and autonomic nervous system dynamics. This study aims to explore the potential correlation between Holter ECG parameters and comorbidities in individuals with ischemic cardiomyopathy experiencing heart failure (HF), with a particular focus on the primary utility of these parameters as prognostic indicators. Materials and Methods: In this prospective inquiry, a cohort of 60 individuals diagnosed with heart failure underwent stratification into subgroups based on the presence of comorbidities, including diabetes, chronic kidney disease, obesity, or hyperuricemia. Upon admission, a thorough evaluation of all participants encompassed echocardiography, laboratory panel analysis, and 24 h Holter monitoring. Results: Significant associations were uncovered between diabetes and unconventional physiological indicators, specifically the Triangular index (p = 0.035) and deceleration capacity (p = 0.002). Pertaining to creatinine clearance, notable correlations surfaced with RMSSD (p = 0.026), PNN50 (p = 0.013), and high-frequency power (p = 0.026). An examination of uric acid levels and distinctive Holter ECG patterns unveiled statistical significance, particularly regarding the deceleration capacity (p = 0.045). Nevertheless, in the evaluation of the Body Mass Index, no statistically significant findings emerged concerning Holter ECG parameters. Conclusions: The identified statistical correlations between non-cardiac comorbidities and patterns elucidated in Holter ECG recordings underscore the heightened diagnostic utility of this investigative modality in the comprehensive evaluation of individuals grappling with HF. Furthermore, we underscore the critical importance of the thorough analysis of Holter ECG recordings, particularly with regard to subtle and emerging parameters that may be overlooked or insufficiently acknowledged.

Glucose metabolism and autonomic function in healthy individuals and patients with type 2 diabetes mellitus at rest and during exercise

Autonomic dysfunction is a common complication of type 2 diabetes mellitus (T2DM). However, the character of dysfunction varies in different reports. Differences in measurement methodology and complications might have influenced the inconsistent results. We sought to evaluate comprehensively the relationship between abnormal glucose metabolism and autonomic function at rest and the response to exercise in healthy individuals and T2DM patients. We hypothesized that both sympathetic and parasympathetic indices would decrease with the progression of abnormal glucose metabolism in individuals with few complications related to high sympathetic tone. Twenty healthy individuals and 11 T2DM patients without clinically evident cardiovascular disease other than controlled hypertension were examined. Resting muscle sympathetic nerve activity (MSNA), heart rate variability, spontaneous cardiovagal baroreflex sensitivity (CBRS), sympathetic baroreflex sensitivity and the MSNA response to handgrip exercise were measured. Resting MSNA was lower in patients with T2DM than in healthy control subjects (P = 0.011). Resting MSNA was negatively correlated with haemoglobin A1c in all subjects (R = -0.45, P = 0.024). The parasympathetic components of heart rate variability and CBRS were negatively correlated with glycaemic/insulin indices in all subjects and even in the control group only (all, P < 0.05). In all subjects, the MSNA response to exercise was positively correlated with fasting blood glucose (R = 0.69, P < 0.001). Resting sympathetic activity and parasympathetic modulation of heart rate were decreased in relationship to abnormal glucose metabolism. Meanwhile, the sympathetic responses to handgrip were preserved in diabetics. The responses were correlated with glucose/insulin parameters throughout diabetic and control subjects. These results suggest the importance of a comprehensive assessment of autonomic function in T2DM.

Heart rate variability, interoceptive accuracy and functional connectivity in middle-aged and older patients with depression

BACKGROUND AND OBJECTIVE

Major depressive disorder (MDD) is associated with increased cardiac morbidity. Reduced heart rate variability (HRV) as well as lower interoceptive accuracy (IAc) have been observed in MDD as possible sympathomimetic mechanisms related to insula activity. The salience network (SN) anchored by the insula has been posited as a crucial functional network for cardiac sensations and the default mode network (DMN) for MDD. This study aimed to investigate the relation between insula-centered and depression-related brain networks, IAc and HRV in patients with depression as a possible mechanism by which MDD increases cardiac morbidity.

METHODS

30 depressed inpatients and 30 healthy subjects (derived from the population-based "Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression" cohort study, STAAB) all over 50 years were examined. HRV and IAc were assessed via electrocardiogram and a heartbeat perception task prior to a 3 T resting-state functional magnetic resonance imaging. Seed-to-voxel resting-state functional connectivity (FC) analysis was conducted with six seeds in the insula and two seeds in the DMN.

RESULTS

Depressed patients on the one hand showed decreased FC between insula cortex and frontal as well occipital cortical brain regions compared to controls. Depressed patients on the other hand exhibited higher FC between the medial prefrontal cortex and the insula cortex compared to controls. However, depressed patients did not differ in HRV nor in IAc compared to controls.

CONCLUSION

Thus, differences in insula-related brain networks in depression in our study were not mirrored by differences in HRV and IAc. Future research is needed to define the mechanism by which depression increases cardiac morbidity.

Respiratory sinus arrhythmia (RSA), vagal tone and biobehavioral integration: Beyond parasympathetic function

Linchpin to the entire area of psychophysiological research and discussion of the vagus is the respiratory and cardiovascular phenomenon known as respiratory sinus arrhythmia (RSA; often synonymous with high-frequency heart-rate variability when it is specifically linked to respiratory frequency), i.e. rhythmic fluctuations in heart rate synchronized to inspiration and expiration. This article aims 1) to clarify concepts, terms and measures commonly employed during the last half century in the scientific literature, which relate vagal function to psychological processes and general aspects of health; and 2) to expand upon an earlier theoretical model, emphasizing the importance of RSA well beyond the current focus upon parasympathetic mechanisms. A close examination of RSA and its relations to the vagus may 1) dispel certain commonly held beliefs about associations between psychological functioning, RSA and the parasympathetic nervous system (for which the vagus nerve plays a major role), and 2) offer fresh perspectives about the likely functions and adaptive significance of RSA, as well as RSA's relationship to vagal control. RSA is neither an invariably reliable index of cardiac vagal tone nor of central vagal outflow to the heart. The model here presented posits that RSA represents an evolutionarily entrenched, cardiovascular and respiratory phenomenon that significantly contributes to meeting continuously changing metabolic, energy and behavioral demands.

Prognostic Implications of Type 2 Diabetes Mellitus in Heart Failure with Mildly Reduced Ejection Fraction

BACKGROUND

Data regarding the characterization and outcomes of diabetics with heart failure with a mildly reduced ejection fraction (HFmrEF) is scarce. This study investigates the prevalence and prognostic impact of type 2 diabetes in patients with HFmrEF.

METHODS

Consecutive patients with HFmrEF (i.e., left ventricular ejection fraction 41-49% and signs and/or symptoms of HF) were retrospectively included at one institution from 2016 to 2022. Patients with type 2 diabetes (dia-betics) were compared to patients without (i.e., non-diabetics). The primary endpoint was all-cause mortality at 30 months. Statistical analyses included Kaplan-Meier, multivariable Cox regression analyses and propensity score matching.

RESULTS

A total of 2169 patients with HFmrEF were included. The overall prevalence of type 2 diabetes was 36%. Diabetics had an increased risk of 30-months all-cause mortality (35.8% vs. 28.6%; HR = 1.273; 95% CI 1.092-1.483; p = 0.002), which was confirmed after multivariable adjustment (HR = 1.234; 95% CI 1.030-1.479; p = 0.022) and propensity score matching (HR = 1.265; 95% CI 1.018-1.572; p = 0.034). Diabetics had a higher risk of HF-related rehospitalization (17.8% vs. 10.7%; HR = 1.714; 95% CI 1.355-2.169; p = 0.001). Finally, the risk of all-cause mortality was increased in diabetics treated with insulin (40.7% vs. 33.1%; log-rank p = 0.029), whereas other anti-diabetic pharmacotherapies had no prognostic impact in HFmrEF.

CONCLUSIONS

Type 2 diabetes is common and independently associated with adverse long-term prognosis in patients with HFmrEF.

Analysis of cardiovascular function in diabetic patients using EEMD-ICA fusion multi-scale percussion entropy

BACKGROUND

Diabetes is a chronic disease that can lead to a variety of complications and even cause death. The signal characteristics of the photoplethysmography signals (PPG) and electrocardiogram signals (ECG) can reflect the autonomic and vascular aspects of the effects of diabetes on the body.

OBJECTIVE

Based on the complex mechanism of interaction between PPG and ECG, a set of ensemble empirical mode decomposition-independent component analysis (EEMD-ICA) fusion multi-scale percussion entropy index (MSPEI) method was proposed to analyze cardiovascular function in diabetic patients.

METHODS

Firstly, the original signal was decomposed into multiple Intrinsic Mode Function (IMFs) by ensemble empirical mode decomposition EEMD, principal components of IMF were extracted by independent component analysis (ICA), then the extracted principal components were reconstructed to eliminate the complex high and low frequency noise of physiological signals. In addition, the MSPEI was calculated for the ECG R-R interval and PPG amplitude sequence.(RRI and Amp) The results showed that, compared with EEMD method, the SNR of EEMD-ICA method increases from 2.1551 to 11.3642, and the root mean square error (RMSE) decreases from 0.0556 to 0.0067. This algorithm can improve the performance of denoising and retain more feature information. The large and small scale entropy of MSPEI (RRI,Amp) was significantly different between healthy and diabetic patients (p< 0.01).

RESULTS

Compared with arteriosclerosis index (AI) and multi-scale cross-approximate entropy (MCAE): MSPEISS (RRI,Amp) indicated that diabetes can affect the activity of human autonomic nervous system, while MSPEILS (RRI,Amp) indicated that diabetes can cause or worsen arteriosclerosis.

CONCLUSION

Multi-scale Percussion Entropy algorithm has more advantages in analyzing the influence of diabetes on human cardiovascular and autonomic nervous function.

Heart rate variability in adults with chronic musculoskeletal pain: A systematic review

PURPOSE

The aim of this review was to compare the heart rate variability (HRV) responses at rest of adults with chronic musculoskeletal pain against healthy controls.

METHODS

The PubMed, Scopus, Web of Science (Science and Social Science Citation Index), and CINAHL databases were searched, with no date restrictions. Two independent reviewers selected observational studies that characterized the HRV responses at rest in adults with chronic musculoskeletal pain compared with those of healthy controls. Methodological quality was assessed using the Downs and Black checklist.

RESULTS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. HRV in adults with chronic musculoskeletal pain was evaluated systematically. Of the 4893 studies screened, 20 of poor-to-moderate quality met the inclusion criteria. Most studies used electrocardiography and at least one time and/or frequency domain index. Studies were found that investigated HRV in adults with temporomandibular disorders, neck pain, whiplash, low back pain, and fibromyalgia. The heterogeneity of the studies in relation to painful conditions, parameters or position for HRV analysis precluded a meta-analysis. In general, these studies seem to show increased sympathetic and decreased parasympathetic modulation in adults with musculoskeletal pain when compared to controls.

CONCLUSIONS

Adults with musculoskeletal pain exhibited a decline in HRV compared to controls. However, definitive conclusions cannot be drawn since the evidence is heterogeneous and of moderate quality. Further high-quality research with standardized measurements is needed.

[Wearable devices: Perspectives on assessing and monitoring human physiological status]

This review article aims to explore the major challenges that the healthcare system is currently facing and propose a new paradigm shift that harnesses the potential of wearable devices and novel theoretical frameworks on health and disease. Lifestyle-induced diseases currently account for a significant portion of all healthcare spending, with this proportion projected to increase with population aging. Wearable devices have emerged as a key technology for implementing large-scale healthcare systems focused on disease prevention and management. Advancements in miniaturized sensors, system integration, the Internet of Things, artificial intelligence, 5G, and other technologies have enabled wearable devices to perform high-quality measurements comparable to medical devices. Through various physical, chemical, and biological sensors, wearable devices can continuously monitor physiological status information in a non-invasive or minimally invasive way, including electrocardiography, electroencephalography, respiration, blood oxygen, blood pressure, blood glucose, activity, and more. Furthermore, by combining concepts and methods from complex systems and nonlinear dynamics, we developed a novel theory of continuous dynamic physiological signal analysis-dynamical complexity. The results of dynamic signal analyses can provide crucial information for disease prevention, diagnosis, treatment, and management. Wearable devices can also serve as an important bridge connecting doctors and patients by tracking, storing, and sharing patient data with medical institutions, enabling remote or real-time health assessments of patients, and providing a basis for precision medicine and personalized treatment. Wearable devices have a promising future in the healthcare field and will be an important driving force for the transformation of the healthcare system, while also improving the health experience for individuals.

Autonomic modulation and the risk of dementia in a middle-aged cohort: A 17-year follow-up study

BACKGROUND

Altered autonomic modulation, measured by heart rate variability (HRV), has been found to be associated with dementia risk in the elderly. However, long-term follow-up study evaluating the association between autonomic modulation from middle-age and the incidence of dementia has been limited.

METHODS

This retrospective cohort analyzed data from Taiwan's National Health Insurance Database covering the period from 2001 to 2017, with a linkage to citywide health examinations conducted by Tainan Metropolitan City, Taiwan. We included subjects aged 45-64 years. The mean follow-up period was 15.75 ± 3.40 years. The measurements of HRV included resting heart rate, high frequency (HF), low frequency (LF), standard deviation of normal-to-normal R-R intervals (SDNN), ratio between the 30th and 15th R-R interval after standing up from the supine position (30/15 ratio), ratio between the R-R intervals during expiration and inspiration, and the ratio between the high- and low-frequency components (LF/HF). The main study outcome was the incidence of dementia. We performed multivariable Cox proportional hazard regression models to compare the risk of dementia among different HRV subgroups.

RESULTS

We included 565 participants with a mean age of 53 (SD: 6) years, of whom 44% were male. The risk of dementia was significantly increased in association with lower parasympathetic HRV modulation, including SDNN (HR: 3.23, 95% CI: 1.55-6.73) and 30/15 ratio (HR: 3.52, 95%CI: 1.67-7.42). Moreover, the risk of dementia was increased in subjects with higher LF/HF ratios (HR: 2.05, 95% CI: 1.12-3.72).

CONCLUSIONS

Lower parasympathetic activity and higher sympathetic-vagal imbalance in middle-age were associated with dementia risk.

Assessment of the relationship of systemic vascular dysfunction and cardiac autonomic neuropathy (CAN) with diabetic retinopathy

Context

Diabetic retinopathy, a form of microvasculopathy, is the leading cause of the visual abnormality. However, there is no conclusive evidence of the relationship of systemic vascular dysfunction with retinal microvasculopathy. In addition, diabetes-associated cardiac autonomic neuropathy may also compromise vascular function.

Aims

The present study intends to correlate arterial stiffness, endothelial function, and heart rate variability (HRV) as a standardized measure of cardiac autonomic neuropathy with diabetic retinopathy.

Settings and Design

The present cross-sectional, observational study was conducted in the Department of Physiology.

Materials and Methods

Twenty subjects were recruited in group 1 (T2DM, type 2 diabetes mellitus patients, without retinopathy) and group 2 (T2DM with retinopathy). The vascular parameters such as heart rate, peripheral and central blood pressure, augmentation index [AIx (%)], brachial -ankle pulse wave velocity (baPWV), and reactive hyperaemia index (RHI) were recorded.

Statistical Analysis Used

Independent sample t-test (for parametric data) and Mann-Whitney U test (for non-parametric data) were employed to compare the variables of two groups. Spearman correlation was used to examine the relationship among the parameters. Linear regression analysis was performed to examine the important vascular predictor for diabetic retinopathy.

Results

baPWV was significantly higher in group 2 than in group 1 and positively associated with group 2. RHI was significantly less in group 2 than group 1 and negatively associated with group 2. Among HRV metrics, standard deviation of successive differences (SDSD), root mean square of successive differences between normal heartbeats (RMSSD), and high frequency (HF) power were significantly decreased in group 2 than in group 1. SDSD, RMSSD, and HF power were negatively associated with group 2. RHI emerged as a significant predictor of diabetic retinopathy following linear regression.

Conclusions

Overall, the result of the present study indicates that metabolic dysregulation of glucose may affect the normal functioning of the autonomic nervous system and vascular function. Therefore, screening of vascular function and cardiac autonomic tone may be advocated in diabetic patients in routine clinics to examine the existence of any comorbid condition, such as diabetic retinopathy, as systemic vascular changes may also affect ophthalmic vasculature.

Real-time heart rate variability according to ambulatory glucose profile in patients with diabetes mellitus

Background

Autonomic neuropathy commonly occurs as a long-term complication of diabetes mellitus (DM) and can be diagnosed based on heart rate variability (HRV), calculated from electrocardiogram (ECG) recordings. There are limited data on HRV using real-time ECG and ambulatory glucose monitoring in patients with DM. The aim of this study was to investigate real-time HRV according to ambulatory glucose levels in patients with DM.

Methods

A total of 43 patients (66.3 ± 7.5 years) with DM underwent continuous real-time ECG monitoring (225.7 ± 107.3 h) for HRV and ambulatory glucose monitoring using a remote monitoring system. We compared the HRV according to the ambulatory glucose profile. Data were analyzed according to the target in glucose range (TIR).

Results

There were no significant differences in the baseline characteristics of the patients according to the TIR. During monitoring, we checked ECG and ambulatory glucose levels (a total of 15,090 times) simultaneously for all patients. Both time- and frequency-domain HRVs were lower when the patients had poorly controlled glucose levels (TIR < 70%) compared with well controlled glucose levels (TIR > 70%). In addition, heart and respiratory rates increased with real-time glucose levels (P < 0.001).

Conclusions

Poorly controlled glucose levels were independently associated with lower HRV in patients with DM. This was further substantiated by the independent continuous association between real-time measurements of hyperglycemia and lower HRV. These data strongly suggest that cardiac autonomic dysfunction is caused by elevated blood sugar levels.

Anthracycline's Effects on Heart Rate Variability in Children with Acute Lymphoblastic Leukemia: Early Toxicity Signs-Pilot Study

Anthracycline treatments are known to cause cardiotoxic long-term side effects in cancer survivors. Recently, a decrease in heart rate variability (HRV) has been identified in these patients, signaling autonomic dysfunction and altered cardiac fitness. This study aimed at evaluating changes in HRV in children treated with anthracyclines. A total of 35 pediatric patients with acute lymphoblastic leukemia were evaluated by means of a 24 h Holter ECG, at baseline and after reaching half the total cumulative dose of doxorubicin equivalent (120 mg/m2). Parameters of HRV were assessed, as well as any arrhythmic episodes, bradycardia and tachycardia percentages. The results showed a significant decrease in both time-domain and frequency-domain HRV parameters, following anthracycline treatment. The low-frequency (LF) to high-frequency (HF) parameters' ratio also displayed a significant difference (p = 0.035), suggestive of early cardiac autonomic dysfunction. Of note, none of the patients presented symptoms of heart disease or elevated troponins, and only two patients presented echocardiographic signs of diastolic dysfunction. The present study showed that cardiac autonomic nervous system regulation is compromised in children treated with anthracyclines even before reaching the total cumulative dose. Therefore, HRV parameters could be the first indicators of subclinical cardiac toxicity, making Holter ECG monitoring of the oncological patient a necessity.

Inter- and intrarater reliability of short-term measurement of heart rate variability on rest in chronic obstructive pulmonary disease (COPD)

BACKGROUND

Individuals with COPD have an imbalance of cardiac autonomic control. In this context, HRV is considered an important tool for assessing cardiac sympathetic and parasympathetic balance, however it is a dependent evaluator measure and subject to methodological biases that may compromise the interpretation of results.

OBJECTIVE

This study examines the inter- and intrarater reliability of HRV parameters derived from short-term recordings in individuals with COPD.

METHODOLOGY

Fifty-one individuals of both genders with COPD clinical diagnosis confirmed by the pulmonary function test and aged ≥50 years were included. The RR interval (RRi) were recorded during a 10 min period on supine position using a portable heart rate monitor (Polar® H10 model). The data were transferred into Kubios® HRV Standard analysis software and analyzed within the stable sessions containing 256 sequential RRi.

RESULTS

The intraclass correlation coefficient (ICC) ranged from 0.942 to 1.000 according to the intrarater analysis by Researcher 01 and 0.915 to 0.998 to the intrarater by Researcher 02. The interrater ICC ranged from 0.921 to 0.998. The coefficient of variation was up to 8.28 for Researcher 01 intrarater analysis, 9.06 for Researcher 02 intrarater analysis and 13.07 for interrater analysis.

CONCLUSION

The measurement of HRV using a portable heart rate device in individuals with COPD present acceptable values of intra- and interrater reliability, supporting the use of HRV in the clinical and scientific scenario. Furthermore, it is important that the data analysis be performed by the same experienced evaluator.

Age and Gender Impact on Heart Rate Variability towards Noninvasive Glucose Measurement

Heart rate variability (HRV) parameters can reveal the performance of the autonomic nervous system and possibly estimate the type of its malfunction, such as that of detecting the blood glucose level. Therefore, we aim to find the impact of other factors on the proper calculation of HRV. In this paper, we research the relation between HRV and the age and gender of the patient to adjust the threshold correspondingly to the noninvasive glucose estimator that we are developing and improve its performance. While most of the literature research so far addresses healthy patients and only short- or long-term HRV, we apply a more holistic approach by including both healthy patients and patients with arrhythmia and different lengths of HRV measurements (short, middle, and long). The methods necessary to determine the correlation are (i) point biserial correlation, (ii) Pearson correlation, and (iii) Spearman rank correlation. We developed a mathematical model of a linear or monotonic dependence function and a machine learning and deep learning model, building a classification detector and level estimator. We used electrocardiogram (ECG) data from 4 different datasets consisting of 284 subjects. Age and gender influence HRV with a moderate correlation value of 0.58. This work elucidates the intricate interplay between individual input and output parameters compared with previous efforts, where correlations were found between HRV and blood glucose levels using deep learning techniques. It can successfully detect the influence of each input.

Implicit HbA1c Achieving 87% Accuracy within 90 Days in Non-Invasive Fasting Blood Glucose Measurements Using Photoplethysmography

To reduce the error induced by overfitting or underfitting in predicting non-invasive fasting blood glucose (NIBG) levels using photoplethysmography (PPG) data alone, we previously demonstrated that incorporating HbA1c led to a notable 10% improvement in NIBG prediction accuracy (the ratio in zone A of Clarke's error grid). However, this enhancement came at the cost of requiring an additional HbA1c measurement, thus being unfriendly to users. In this study, the enhanced HbA1c NIBG deep learning model (blood glucose level predicted from PPG and HbA1c) was trained with 1494 measurements, and we replaced the HbA1c measurement (explicit HbA1c) with "implicit HbA1c" which is reversely derived from pretested PPG and finger-pricked blood glucose levels. The implicit HbA1c is then evaluated across intervals up to 90 days since the pretest, achieving an impressive 87% accuracy, while the remaining 13% falls near the CEG zone A boundary. The implicit HbA1c approach exhibits a remarkable 16% improvement over the explicit HbA1c method by covering personal correction items automatically. This improvement not only refines the accuracy of the model but also enhances the practicality of the previously proposed model that relied on an HbA1c input. The nonparametric Wilcoxon paired test conducted on the percentage error of implicit and explicit HbA1c prediction results reveals a substantial difference, with a p-value of 2.75 × 10-7.

Hyperglycemia: A determinant of cardiac autonomic dysfunction in youth with obesity across the spectrum of glycemic regulation

OBJECTIVES

To characterize the determinants of heart rate variability (HRV) in youth with obesity across the glycemia spectrum.

METHODS

A total of 94 adolescents, 15 ± 2.1 years (21 with normal weight, 23 with overweight-normal glucose tolerance, 26 with prediabetes and 24 with type 2 diabetes [T2D]) underwent an assessment of body composition (dual-energy x-ray absorptiometry), 2-h oral glucose tolerance test with the calculation of indices of glycemia and insulin sensitivity (IS), inflammatory markers (high-sensitivity C-reactive protein [hs-CRP] and tumour necrosis factor-α [TNF-α]), and HRV by peripheral arterial tonometry.

RESULTS

The HRV frequency-domain index (low-frequency to high-frequency ratio [LF/HF]), an estimate of the ratio between sympathetic and parasympathetic activity, increased across the glycemic spectrum, and was highest in T2D compared with the other three groups (p = 0.004). LF/HF correlated with %body fat (r = 0.22, p = 0.04); fasting (r = 0.39, p < 0.001), 2-h (r = 0.31, p = 0.004), and area under the curve glucose (r = 0.32, p = 0.003); hs-CRP (r = 0.33, p = 0.002) and TNF-α (r = 0.38, p = 0.006). In a linear regression model, fasting glucose (β = 0.39, p = 0.003) and hs-CRP (β = 0.21, p = 0.09) contributed to the variance in Ln LF/HF independent of IS, %body fat, age, sex, race-ethnicity and Tanner stage (R2  = 0.23, p = 0.013).

CONCLUSIONS

Youth with impaired glucose regulation have evidence of cardiac autonomic dysfunction with decreased HRV, and sympathetic overdrive (increased LF/HF). This dysfunction is mainly related to glycemia and systemic inflammation.

Dose and time-response effect of photobiomodulation therapy on glycemic control in type 2 diabetic patients combined or not with hypoglycemic medicine: A randomized, crossover, double-blind, sham-controlled trial

Photobiomodulation therapy (PBMt) combined or not with oral hypoglycemic medication has not been investigated in type 2 diabetes (T2DM) patients. All 10 T2DM patients were assessed randomly at 6 different occasions (3 with and 3 without regular oral hypoglycemic medication). Capillary glycemia was assessed after overnight fast (pre-prandial), 1 h postprandially (standardized meal, 338 kcal), and 30 min, 3 h, 6 h, 12 h post-PBMt (830 nm; 25 arrays of LEDs, 80 mW/array). Three doses (0 J-sham, 100 J, 240 J per site) were applied bilaterally on quadriceps femoris muscles, hamstrings, triceps surae, ventral upper arm and forearm; and randomly combined or not with oral hypoglicemic medication, totaling six different therapies applied for all 10 TDM2 patients (PBMt sham, PBMt 100 J, PBMt 240 J, PBMt sham + medication, PBMt 100 J + medication, PBMt 240 J + medication). Cardiac autonomic control was assessed by heart rate variability (HRV) indices. Without medication, there was reduction in glycemia after all PBMt doses, with 100 J as the best dose that persisted until 12 h and presented lower area under the curve (AUC). With medication, glycemia decreased similarly among doses. No differences between 100 J and sham + medication, but AUC was significantly lower after 100 J, suggesting better glycemic control. Low frequency component of HRV increased after sham + medication and 100 J, suggesting higher sympathetic activation. PBMt showed time- and dose-response effect to reduce glycemia in T2DM patients. Effects on HRV were consistent with glycemic control.

Integrating Genome-wide information and Wearable Device Data to Explore the Link of Anxiety and Antidepressants with Heart Rate Variability

Background

Anxiety disorders are associated with decreased heart rate variability (HRV), but the underlying mechanisms remain elusive.

Methods

We selected individuals with whole-genome sequencing, Fitbit, and electronic health record data (N=920; 61,333 data points) from the All of Us Research Program. Anxiety PRS were derived with PRS-CS after meta-analyzing anxiety genome-wide association studies from three major cohorts-UK Biobank, FinnGen, and the Million Veterans Program (N Total =364,550). The standard deviation of average RR intervals (SDANN) was calculated using five-minute average RR intervals over full 24-hour heart rate measurements. Antidepressant exposure was defined as an active antidepressant prescription at the time of the HRV measurement in the EHR. The associations of daily SDANN measurements with the anxiety PRS, antidepressant classes, and antidepressant substances were tested. Participants with lifetime diagnoses of cardiovascular disorders, diabetes mellitus, and major depression were excluded in sensitivity analyses. One-sample Mendelian randomization (MR) was employed to assess potential causal effect of anxiety on SDANN.

Results

Anxiety PRS was independently associated with reduced SDANN (beta=-0.08; p=0.003). Of the eight antidepressant medications and four classes tested, venlafaxine (beta=-0.12, p=0.002) and bupropion (beta=-0.071, p=0.01), tricyclic antidepressants (beta=-0.177, p=0.0008), selective serotonin reuptake inhibitors (beta=-0.069; p=0.0008) and serotonin and norepinephrine reuptake inhibitors (beta=-0.16; p=2×10 -6 ) were associated with decreased SDANN. One-sample MR indicated an inverse effect of anxiety on SDANN (beta=-2.22, p=0.03).

Conclusions

Anxiety and antidepressants are independently associated with decreased HRV, and anxiety appears to exert a causal effect on HRV. Our observational findings provide novel insights into the impact of anxiety on HRV.

Interventional metabology: A review of bariatric arterial embolization and endovascular denervation for treating metabolic disorders

The rising prevalence of metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM) poses a major challenge to global health. Existing therapeutic approaches have limitations, and there is a need for new, safe, and less invasive treatments. Interventional metabolic therapy is a new addition to the treatment arsenal for metabolic disorders. This review focuses on two interventional techniques: bariatric arterial embolization (BAE) and endovascular denervation (EDN). BAE involves embolizing specific arteries feeding ghrelin-producing cells to suppress appetite and promote weight loss. EDN targets nerves that regulate metabolic organs to improve glycemic control in T2DM patients. We describe the current state of these techniques, their mechanisms of action, and the available safety and effectiveness data. We also propose a new territory called "Interventional Metabology" to encompass these and other interventional approaches to treating metabolic disorders.

Heart rate variability between hormone phases of the menstrual and oral contraceptive pill cycles of young women

INTRODUCTION

The interplay between the sympathetic and parasympathetic branches of the autonomic nervous system contribute to adequate hemodynamic responses to stressors, reflected by the variation in intervals between heart beats, known as heart rate variability. The sex hormones estrogen and progesterone have been shown to affect autonomic function. The extent to which autonomic function may vary between different hormone phases of the natural menstrual cycle and how this relationship may differ in women taking oral contraceptives has yet to be fully elucidated.

PURPOSE

To investigate differences in heart rate variability between the early follicular and early luteal phases of the menstrual cycle in naturally menstruating women and in oral contraceptive pill users.

METHODS

Twenty-two young (22 ± 3 years), healthy women who were naturally menstruating or taking oral contraceptive pills participated in this study. Heart rate variability was measured at rest and during two sympathomimetic stressors: isometric handgrip exercise and cold pressor test.

RESULTS

The proportion of successive NN intervals that differ by more than 50 ms was higher in oral contraceptive pill users during the placebo pill phase. Absolute high-frequency power was higher in the naturally menstruating women during the early luteal phase, relative to the early follicular phase. Other indices of vagal modulation were not different at rest or during sympathetic activation between hormone phases or groups.

CONCLUSIONS

Vagal modulation may be increased in the early luteal menstrual cycle phase. Further,oral contraceptive use does not appear to adversely affect this modulation in young, healthy women.

Adynamic response to cold pain reflects dysautonomia in type 1 diabetes and polyneuropathy

Cardiac autonomic neuropathy (CAN), widely assessed by heart rate variability (HRV), is a common complication of long-term diabetes. We hypothesized that HRV dynamics during tonic cold pain in individuals with type 1 diabetes mellitus (T1DM) could potentially demask CAN. Forty-eight individuals with long-term T1DM and distal symmetrical polyneuropathy and 21 healthy controls were included. HRV measures were retrieved from 24-h electrocardiograms. Moreover, ultra-short-term HRV recordings were used to assess the dynamic response to the immersion of the hand into 2 °C cold water for 120 s. Compared to healthy, the T1DM group had expectedly lower 24-h HRV measures for most components (p < 0.01), indicating dysautonomia. In the T1DM group, exposure to cold pain caused diminished sympathetic (p < 0.001) and adynamic parasympathetic (p < 0.01) HRV responses. Furthermore, compared to healthy, cold pain exposure caused lower parasympathetic (RMSSD: 4% vs. 20%; p = 0.002) and sympathetic responses (LF: 11% vs. 73%; p = 0.044) in the T1MD group. QRISK3-scores are negatively correlated with HRV measures in 24-h and ultra-short-term recordings. In T1DM, an attenuated sympathovagal response was shown as convincingly adynamic parasympathetic responses and diminished sympathetic adaptability, causing chronometric heart rhythm and rigid neurocardiac regulation threatening homeostasis. The findings associate with an increased risk of cardiovascular disease, emphasizing clinical relevance.

Heart rate variability: reference values and role for clinical profile and mortality in individuals with heart failure

AIMS

To establish reference values and clinically relevant determinants for measures of heart rate variability (HRV) and to assess their relevance for clinical outcome prediction in individuals with heart failure.

METHODS

Data from the MyoVasc study (NCT04064450; N = 3289), a prospective cohort on chronic heart failure with a highly standardized, 5 h examination, and Holter ECG recording were investigated. HRV markers were selected using a systematic literature screen and a data-driven approach. Reference values were determined from a healthy subsample. Clinical determinants of HRV were investigated via multivariable linear regression analyses, while their relationship with mortality was investigated by multivariable Cox regression analyses.

RESULTS

Holter ECG recordings were available for analysis in 1001 study participants (mean age 64.5 ± 10.5 years; female sex 35.4%). While the most frequently reported HRV markers in literature were from time and frequency domains, the data-driven approach revealed predominantly non-linear HRV measures. Age, sex, dyslipidemia, family history of myocardial infarction or stroke, peripheral artery disease, and heart failure were strongly related to HRV in multivariable models. In a follow-up period of 6.5 years, acceleration capacity [HR_perSD 1.53 (95% CI 1.21/1.93), p = 0.0004], deceleration capacity [HR_perSD: 0.70 (95% CI 0.55/0.88), p = 0.002], and time lag [HR_perSD 1.22 (95% CI 1.03/1.44), p = 0.018] were the strongest predictors of all-cause mortality in individuals with heart failure independently of cardiovascular risk factors, comorbidities, and medication.

CONCLUSION

HRV markers are associated with the cardiovascular clinical profile and are strong and independent predictors of survival in heart failure. This underscores clinical relevance and interventional potential for individuals with heart failure.

CLINICALTRIALS

GOV IDENTIFIER

NCT04064450.

The Vagal Nerve, Inflammation, and Diabetes-A Holy Triangle

Type 2 diabetic mellitus (T2DM) is a common chronic disease and a substantial risk factor of other fatal illnesses. At its core is insulin resistance, where chronic low-level inflammation is among its main causes. Thus, it is crucial to modulate this inflammation. This review paper provides scientific neuroimmunological evidence on the protective roles of the vagal nerve in T2DM. First, the vagus inhibits inflammation in a reflexive manner via neuroendocrine and neuroimmunological routes. This may also occur at the level of brain networks. Second, studies have shown that vagal activity, as indexed by heart-rate variability (HRV), is inversely related to diabetes and that low HRV is a predictor of T2DM. Finally, some emerging evidence shows that vagal nerve activation may reduce biomarkers and processes related to diabetes. Future randomized controlled trials are needed to test the effects of vagal nerve activation on T2DM and its underlying anti-inflammatory mechanisms.

Methods for analyzing infant heart rate variability: A preliminary study

Heart rate (HR) and heart rate variability (HRV) reflect autonomic development in infants. To better understand the autonomic response in infants, reliable HRV recordings are vital, yet no protocol exists. The purpose of this paper is to present reliability of a common procedure for analysis from two different file types. In the procedure, continuous electrocardiograph recordings of 5-10 min are obtained at rest in infants at 1 month of age by using a Hexoskin Shirt-Junior's (Carre Technologies Inc., Montreal, QC, Canada). Electrocardiograph (ECG; .wav) and R-R interval (RRi; .csv) files are extracted. The RRi of the ECG signal is generated by VivoSense (Great Lakes NeuroTechnologies, Independence, OH). Two MATLAB (The MathWorks, Inc., Natick, MA) scripts converted files for analysis with Kubios HRV Premium (Kubios Oy, Kuopio, Finland). A comparison was made between RRi and ECG files for HR and HRV parameters, and then tested with t tests and correlations via SPSS. There are significant differences in root mean squared successive differences between recording types, with only HR and low-frequency measures significantly correlated together. Recording with Hexoskin and analysis with MATLAB and Kubios enable infant HRV analysis. Differences in outcomes exist between procedures, and standard methodology for infant HR analysis is needed.

Continuous long-term heart rate variability and risk assessment in pulmonary hypertension

OBJECTIVE

Current multimodal risk assessment for pulmonary hypertension (PH) has been redefined with a simplified assessment for follow-up in the new European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines. Follow-up risk assessment parameters include WHO functional class, 6 min walk test and N-terminal pro-brain natriuretic peptide. Although these parameters have prognostic implications assessment reflect data relating to specific time points.

METHODS

Patients diagnosed with PH received an implantable loop recorder (ILR) to monitor daytime and night-time heart rate (HR), HR variability (HRV) and daily physical activity. Associations between the ILR measurements and established risk parameters were analysed using correlations, linear mixed models as well as logistical mixed models for addressing the ESC/ERS risk-score.

RESULTS

41 patients (median age: 56 years, range: 44-61.5 years) were included. Continuous monitoring had a median duration of 755 days (range: 343-1138 days), totalling 96 patient-years. In the linear mixed models, HRV and physical activity indexed by daytime HR (PAiHR) were significantly associated with the ERS/ERC risk parameters. In a logistical mixed model, HRV revealed a significant difference between 1-year mortality (<5% vs >5%) (p=0.027) with an OR of 0.82 for being in the group with 1-year mortality >5% for every increase by one HRV unit.

CONCLUSIONS

Risk assessment in PH can be refined with continuous monitoring of HRV and PAiHR. These markers were associated with the ESC/ERC parameters. Our study with continuous risk stratification in PH demonstrated that a lower HRV predict worse prognosis.

Induced Relaxation Enhances the Cardiorespiratory Dynamics in COVID-19 Survivors

Most COVID-19 survivors report experiencing at least one persistent symptom after recovery, including sympathovagal imbalance. Relaxation techniques based on slow-paced breathing have proven to be beneficial for cardiovascular and respiratory dynamics in healthy subjects and patients with various diseases. Therefore, the present study aimed to explore the cardiorespiratory dynamics by linear and nonlinear analysis of photoplethysmographic and respiratory time series on COVID-19 survivors under a psychophysiological assessment that includes slow-paced breathing. We analyzed photoplethysmographic and respiratory signals of 49 COVID-19 survivors to assess breathing rate variability (BRV), pulse rate variability (PRV), and pulse-respiration quotient (PRQ) during a psychophysiological assessment. Additionally, a comorbidity-based analysis was conducted to evaluate group changes. Our results indicate that all BRV indices significantly differed when performing slow-paced breathing. Nonlinear parameters of PRV were more appropriate for identifying changes in breathing patterns than linear indices. Furthermore, the mean and standard deviation of PRQ exhibited a significant increase while sample and fuzzy entropies decreased during diaphragmatic breathing. Thus, our findings suggest that slow-paced breathing may improve the cardiorespiratory dynamics of COVID-19 survivors in the short term by enhancing cardiorespiratory coupling via increased vagal activity.

FABP3, FABP4, and heart rate variability among patients with chronic schizophrenia

Introduction

The prevalence of cardiovascular disease (CVD) and CVD-related deaths in patients with schizophrenia is high. An elevated risk of CVD has been associated with low heart rate variability (HRV). There is increasing evidence that fatty acid-binding protein (FABP)3 and FABP4 play roles in the development and progression of CVD. This study aimed to explore the association of circulating FABP3/FABP4 levels with HRV in patients with chronic schizophrenia.

Methods

We included 265 consecutive patients with chronic schizophrenia who attended a disease management program. We used an enzyme-linked immunosorbent assay for the measurement of plasma concentrations of FABP3 and FABP4. Standard HRV was recorded at baseline following a standard protocol. Mean high- and low-frequency (HF/LF) HRV values were analyzed by tertile of FABP3 and FABP4 using one-way analysis of variance, and linear regression analysis was performed to assess trends.

Results

A positive association between FABP3 and creatinine was found in multiple regression analysis. In addition, negative associations between levels of hematocrit, hemoglobin, HF HRV, and estimated glomerular filtration rate (eGFR) with FABP3 were also found. Moreover, positive associations between FABP4 with body mass index, diabetes mellitus, hypertension, systolic blood pressure, low-density lipoprotein-cholesterol, triglycerides, creatinine, and FABP3 were found. Furthermore, negative associations between levels of high-density lipoprotein-cholesterol, eGFR, and HF HRV with FABP4 were found. We also found a significant inverse association between FABP3 and HF HRV (p for trend = 0.008), and significant inverse associations between FABP4 with HF and LF HRV (p for trend = 0.007 and 0.017, respectively).

Discussion

Together, this suggests that elevated levels of FABP3 and FABP4 may be linked to health problems related to CVD in patients with chronic schizophrenia.

Cardiorespiratory coupling as an early marker of cardiac autonomic dysfunction in type 2 diabetes mellitus patients

The aim of this study was to assess cardiorespiratory coupling (CRC) in type 2 diabetes mellitus patients (T2DM) and apparently healthy individuals, in order to test the hypothesis that this method can provide additional knowledge to the information obtained through the heart rate variability (HRV). A cross-sectional study was conducted in T2DM patients(T2DMG=32) and health controls (CON=32). For CRC analysis, the electrocardiogram, arterial pressure, and thoracic respiratory movement were recorded at rest in supine position and during active standing. Beat-to-beat series of heart period and systolic arterial pressure were analyzed with the respiratory movement signal via a traditional non-causal approach, such as squared coherence function. In this sample of T2DM, no differences in HRV were observed when compared to the CON, but the T2DMG showed a reduction in resting CRC. We conclude that in CRC in T2DM, reflected by the squared coherence may already be compromised even before HRV changes.