Evaluation of an association between maternal prenatal psychological stress and insulin resistance during pregnancy and postpartum

Objectives: Various physiological mechanisms counteract insulin resistance (IR) during normal pregnancy. Psychological stress is a known, independent risk factor for developing IR. Pregnancy-specific psychological stress may cause IR and increase the risk of overt diabetes. Hence, the study aims to evaluate maternal psychological stress using multiple stress markers and their association with changes in IR during pregnancy and postpartum. Materials and Methods: Anthropometric measurements such as height, weight and skinfold thickness were measured using standard techniques. The stress markers were assessed using perceived stress scales (K10 questionnaire), a physiological marker of stress (Heart rate variability [HRV] measures) and biochemical stress markers (Saliva, hair cortisol levels). IR was estimated using homeostasis model assessment-estimated IR (HOMA-IR). The association of stress markers with IR was studied among fifty healthy pregnant women during pregnancy and postpartum. Results: The psychological stress scores and saliva cortisol were significantly higher during pregnancy than postpartum (P = 0.000). A comparison of cardiac autonomic function as assessed by HRV measures shows that high frequency in normalised units (HFnu) was significantly higher during the postnatal period than in the prenatal period (P = 0.000). High frequency (HF) spectral power in absolute units was also significantly higher (P = 0.002) in the postpartum period (2612.30 ± 432.24) when compared with the prenatal period (1446.10 ± 299.15). Low frequency in normalised units (LFnu), low frequency (LF)/HF ratio was significantly higher during the prenatal period than in the postnatal period (P = 0.000). As assessed by HOMA-IR values, IR was significantly higher during the prenatal period than postpartum (P = 0.04). There was a significant positive correlation between prenatal psychological stress scores, HRV parameters (LFnu, LF/HF) and postnatal IR. Conclusion: Pregnancy is associated with higher psychological stress levels and IR than postpartum. Furthermore, the maternal cardiac autonomic marker could predict postnatal IR among healthy pregnant women.

Alterations in heart rate variability before and after percutaneous coronary intervention in patients with ischaemic heart disease

Objectives: Heart rate variability (HRV) is the beat-to-beat variation of heart rate and an important non-invasive tool to study the cardiac autonomic nervous system activity. Ischaemic heart disease (IHD) patients are often considered to have a state of sympathetic predominance. Elimination of myocardial ischaemia with percutaneous coronary intervention (PCI) could restore autonomic balance. Hence, this study aimed to evaluate HRV measures, after successful revascularisation among IHD patients. Materials and Methods: A total of 145 male IHD patients planned for coronary angiography were recruited. Fifteen minutes of electrocardiogram recording was done. Short-term HRV analyses of all the patients were acquired and time-domain indices (standard deviation of normal-to-normal intervals [SDNN], root-meansquared differences of successive R-R intervals [rMSSD]) and frequency-domain indices (low-frequency [LF] power, high-frequency [HF] power and total power [TP]) were analysed. Before and after PCI, all measurements were made. Results: This study included 145 male IHD patients with the mean age of 54.57 ± 10.81 years. There was a significant decrease in SDNN, rMSSD, LF, HF and TP whereas increase in LF/HF ratio following revascularisation. These changes in measures of neurocardiac regulation correlated with risk factors and medication on regression analysis. Conclusion: Increase in LF/HF ratio with the decrease in SDNN, rMSSD, LF, HF and TP in patients with IHD who underwent coronary intervention infers changed cardiac autonomic balance with this surgical procedure. These measures could be potentially used as prognostic measures in the future studies.

Cardiac autonomic function in Chagas disease: a narrative review / Função autonômica cardíaca na doença de Chagas: uma revisão narrativa / Función autonómica cardíaca en la enfermedad de Chagas: una revisión narrativa

Chagas disease (CD) is a severe health problem in countries of Latin America, including Brazil, and is characterised as an acute and chronic infection. CD can affect several organs and cellular tissues, in particular the heart, which can lead to sudden death. This work aimed to review the literature regarding cardiac autonomic function assessed by Heart Rate Variability (HRV) in CD in adult individuals. The search was carried out using the electronic databases PubMed, SciELO, and Web of Science between January 2013 and October 2020. A total of 19 articles were found, of which 14 were included in this review. HRV was demonstrated at baseline conditions, physical exercise, and cardiac rehabilitation. Quantifying CD progression assessed by HRV is an effective method to detect changes in the cardiac autonomic nervous system, even in asymptomatic individuals. Physical exercise can improve autonomic function in CD. Further clinical studies are needed to assess the anatomical-functional, metabolic, and immunological parameters associated with CD evaluated by HRV.

A doença de Chagas (DC) é um grave problema de saúde em países da América Latina, incluindo o Brasil, sendo caracterizada como infecção aguda e crônica. A DC pode afetar vários órgãos e tecidos celulares, em particular o coração, podendo levar à morte súbita. O objetivo deste trabalho foi revisar a literatura relacionada à função autonômica cardíaca avaliada pela Variabilidade da Frequência Cardíaca (VFC) na DC em indivíduos adultos. A busca foi realizada nas bases de dados eletrônicas PubMed, SciELO e Web of Science entre o período de janeiro de 2013 a outubro de 2020. Foram encontrados 19 artigos, dos quais 14 foram incluídos nesta revisão. A VFC foi demonstrada em condições basais, exercícios físicos e reabilitação cardíaca. Quantificar a progressão da DC avaliada pela VFC é um método eficaz para detectar alterações no sistema nervoso autônomo cardíaco, mesmo em indivíduos assintomáticos. O exercício físico pode melhorar a função autonômica na DC. Mais estudos clínicos são necessários para avaliar os parâmetros anátomo-funcionais, metabólicos e imunológicos associados à DC e avaliados pela VFC.

La enfermedad de Chagas (EC) es un grave problema de salud que enfrenta los países de América Latina y se caracteriza por ser una infección aguda y crónica. La EC puede afectar varios órganos y tejidos celulares, en particular el corazón, y puede provocar la muerte súbita. El objetivo de este estudio fue revisar la literatura que relaciona la función autónoma cardíaca evaluada por la Variabilidad de la Frecuencia Cardíaca (VFC) en la EC en individuos adultos. La búsqueda se realizó en las bases de datos electrónicas PubMed, SciELO y Web of Science desde enero de 2013 hasta octubre de 2020. Se encontraron 19 artículos, de los cuales 14 fueron incluidos en esta revisión. La VFC se ha demostrado en condiciones basales, ejercicio físico y rehabilitación cardíaca. La cuantificación de la progresión de la EC evaluada por la VFC es un método eficaz para detectar cambios en el sistema nervioso autónomo cardíaco, incluso en individuos asintomáticos. El ejercicio físico puede mejorar la función autónoma en la EC. Se necesitan más estudios clínicos para evaluar los parámetros anatómico-funcionales, metabólicos e inmunológicos asociados con la EC y evaluados por la VFC.

Is a short-stage protocol during an incremental exercise test reliable for heart rate variability threshold analysis?

Aim: Heart rate variability threshold (HRVT) is a valid method to determine parasympathetic depression during an incremental exercise test (IET). However, HRVT is usually assessed using the last 60s of each 180s stage of an IET, resulting in longer and demotivating tests. This study aimed to evaluate the agreement of HRVT analysis adopting the first and second minute of R-R interval (iRR) segment comparatively to a standard third-minute segment obtained at each 3-min stage on IET. Methods: Seventeen young male subjects (22.2 ± 3.1 years; 23.4 ± 2.3 kg/m2) underwent IET on a cycle ergometer. HRVT was considered the load corresponding to the point of stabilization of the SD1 index (HRVTV), or the first load with SD1 value < 3ms (HRVT<3), both assessed by the 1st (HRVT1V, HRVT1<3), 2nd (HRVT2V, HRVT2<3) and standard 3rd (HRVT3V, HRVT3<3) 60s iRR segment analyzed at each stage of IET. Agreement and reliability were assessed by the Bland-Altman analysis and the intraclass correlation coefficient (ICC), respectively. Results: High reliability and non-significant bias were observed considering HRVT1V vs HRVT3V (ICC = 0.92; p = 0.18) or HRVT2V vs HRVT3V (ICC = 0.94; p = 0.99). However, lower reliability was observed for HRVT1<3 vs HRVT3<3 (ICC = 0.79; p = 0.75) and for HRVT2<3 vs HRVT3<3 (ICC = 0.91; p = 0.33). Conclusion: HRVT can be similarly assessed by the 1st, 2nd or 3rd 60 seconds iRR segment, mainly when assessed by a visual method.(AU)

Epicardial Fat Thickness is Correlated with Vagal Hyperactivity in Patients with Neurally-Mediated Syncope

BACKGROUND: Epicardial fat tissue has unique endocrine and paracrine functions that affect the cardiac autonomic system. The head-up tilt test (HUTT) is a simple non-invasive measurement that assesses autonomic nervous system dysfunction. We investigated the association between epicardial fat thickness (EFT) and autonomic neural tone, such as vagal tone. METHODS: A total of 797 consecutive patients (mean age 46.5 years, male: 45.7%) who underwent HUTT and echocardiography between March 2006 and June 2015 were enrolled. EFT was measured during the diastolic phase of the parasternal long axis view. We excluded patients with prior percutaneous coronary intervention, old age (* 70 years old), valvular heart disease, symptomatic arrhythmias and diabetes. We divided patients into two groups based on the HUTT (positive vs. negative). RESULTS: There were 329 patients (41.3%) with a negative HUTT result and 468 patients (58.7%) with a positive result. The HUTT-positive patients showed a significantly lower waist circumference, body mass index and systolic and diastolic blood pressure, although a significantly higher EFT as compared to the HUTT-negative patients (HUTT-positive, 5.69 ± 1.76 mm vs. HUTT-negative, 5.24 ± 1.60 mm; p 5.4 mm was associated with a positive HUTT result with 51.7% sensitivity and 63.8% specificity (p < 0.001) on receiving operator characteristic analysis. Multivariate Cox regression analysis revealed that EFT (hazard ratio: 1.02, 95% confidence interval: 1.01–1.30, p = 0.004) was an independent predictor of HUTT-positivity. CONCLSION: EFT was significantly correlated with positive HUTT, which suggests an association between EFT and autonomic dysregulation.

Acute effects of different inspiratory resistive loading on heart rate variability in healthy elderly patients

BACKGROUND: The cardiovascular system is noticeably affected by respiration. However, whether different inspiratory resistive loading intensities can influence autonomic heart rate (HR) modulation remains unclear. OBJECTIVE: The objective was to investigate HR modulation at three different inspiratory resistive loading intensities in healthy elderly men. METHOD: This was a prospective, randomized, double-blind study that evaluated 25 healthy elderly men. Cardiac autonomic modulation was assessed using heart rate variability (HRV) indices. All of the volunteers underwent maximal inspiratory pressure (MIP) measurements according to standardized pulmonary function measurements. Three randomly-applied inspiratory resistive loading (30, 60 and 80% of MIP) intensities were then applied using an inspiratory resistance device (POWERbreathe, Southam, UK), during which the volunteers were asked to inhale for 2 seconds and exhale for 3 seconds and complete 12 breaths per minute. Each effort level was performed for 4 minutes, and HR and the distance between 2 subsequent R waves of electrocardiogram (R-R intervals) were collected at rest and at each intensity for further HRV analysis. RESULTS : The parasympathetic HRV (rMSSD, SD1 and HF) indices demonstrated lower values at 80% (rMSSD: 19±2 ms, SD1: 13±2 ms and HF: 228±61 ms2) than at 30% MIP (rMSSD: 25±3 ms, SD1: 18±2 ms and HF: 447±95 ms2; p<0.05). CONCLUSIONS: Lower inspiratory resistive loading intensities promoted a marked and positive improvement of parasympathetic sinus node modulation. .

Differential Association of Adiposity Measures with Heart Rate Variability Measures in Koreans

PURPOSE: Although obesity has been associated with imbalances in cardiac autonomic nervous system, it is unclear whether there are differential relationships between adiposity measures and heart rate variability (HRV) measures. We aimed to examine differences in the relationship between adiposity measures and HRV indices in a healthy Korean population. MATERIALS AND METHODS: In all, 1409 non-smokers (811 males, 598 females) without known histories of cardiovascular (CV), endocrine, or neurological diseases underwent adiposity measurements [(body mass index (BMI), percentage of body fat mass (PBF), and waist-to-hip ratio (WHR)], the HRV assessment (SDNN, RMSSD, LF, HF, LF/HF, and pNN50), and examination for CV risk factors (fasting glucose, LDL-cholesterol, HDL-cholesterol, triglycerides, hs-CRP, and blood pressure). RESULTS: Compared with BMI and PBF, WHR was more strongly correlated with each HRV index and more likely to predict decreased HRV ( or =15 percentile of each HRV index) in ROC curves analysis. In linear regression analysis, all adiposity measures were inversely associated with each HRV measure before adjusting for age, gender, and CV risk factors (p or =25 kg/m2, but not for those with BMI <25 kg/m2. CONCLUSION: WHR and PBF appear to be better indicators for low HRV than BMI, and the association between abdominal adiposity and HRV may be stronger in overweight subjects.

Decreased Cardiac Vagal Control in Drug-Naive Patients with Posttraumatic Stress Disorder

OBJECTIVE: Decreased cardiac vagal control (CVC) has been proposed in posttraumatic stress disorder (PTSD), but the results are mixed. Analyses with larger sample sizes and better methodology are needed. METHODS: Thirty-two drug-naive survivors with current PTSD, 32 survivors without PTSD and 192 matched controls were recruited for a case-control analysis. We used the PTSD checklist-civilian version (PCL-C) to assess posttraumatic symptoms severity. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV) parameters. Frequency-domain indices of HRV were obtained. The obtained results were evaluated in association with personality traits assessed by the Tridimensional Personality Questionnaire (TPQ). RESULTS: PTSD patients exhibited decreased LF-HRV and HF-HRV as compared to survivors without PTSD and to matched controls. The PTSD symptoms severity was associated with reduced mean RR intervals, Var-HRV, LF-HRV and HF-HRV. The harm avoidance score (which has been suggested to be associated with serotonergic activity) was negatively correlated with Var-HRV, LF-HRV and HF-HRV. CONCLUSION: These data suggest that PTSD is accompanied by decreased CVC, highlighting the importance of assessing HRV in PTSD patients. In view of the increased risk for cardiovascular diseases in these vulnerable individuals, one might consider the treatment to restore their autonomic function while reducing PTSD symptoms.

Generalized Anxiety Disorder, Comorbid Major Depression and Heart Rate Variability: A Case-Control Study in Taiwan

OBJECTIVE: Decreased heart rate variability (HRV) has been reported in generalized anxiety disorder (GAD), but the results are mixed. Little is known about the impact of comorbid major depression (MD) on HRV in GAD patients. Both issues necessitate further investigation. METHODS: Twenty unmedicated, physically healthy GAD patients, 20 GAD patients with a secondary diagnosis of MD, 40 MD patients and 60 matched controls were recruited. We used the Hamilton Anxiety Rating Scale and the Hamilton Depression Rating Scale to assess anxiety and depression severity, respectively. Cardiac autonomic function was evaluated by measuring HRV parameters. Frequency-domain indices of HRV were obtained. RESULTS: Three patient groups had more anxiety and depression symptoms than control subjects, but heart rates (HRs) were significantly elevated only in GAD patients with comorbid depression. Relative to controls, GAD patients had reduced HRV while GAD patients with comorbid depression displayed the greatest reductions in HRV among three patients groups. Correlation analyses revealed anxiety/depression severity significantly associated with HRs, variance, LF-HRV and HF-HRV. However, separately analyzing among individual groups and adjusting for HRV-associated covariables rendered the correlations non-significant. CONCLUSION: Our results suggest that reduction in HRV is a psychophysiological marker of GAD and individuals with comorbid GAD and MD may be distinguished based on psychophysiological correlates (for example, HF-HRV) from non-comorbid GAD patients. Taken into account that comorbid depression may confer increased risks for cardiovascular events in GAD patients, this subgroup of GAD patients may benefit better from cardiovascular risk reduction strategies.

EFFECTS OF EXERCISE INTERVENTION ON BLOOD LIPID LEVELS, GLYCOMETABOLISM, ADIPOCYTOKINE LEVELS, AND CARDIAC AUTONOMIC FUNCTION IN YOUNG FEMALES WITH HIDDEN OBESITY / 体力科学

We performed exercise intervention for 12 weeks in young females (22.3±2.5 yrs ; mean±SD) with a %fat value of 30% or more (dual energy X-ray absorptiometry : DXA) despite a body mass index (BMI) of less than 25 kg/m², which indicates hidden obesity, and the following results were obtained.The intensity of exercise was established as the double product break point calculated from heart rate and systolic blood pressure, and the subjects were instructed to exercise for 30 minutes or more for 3 or more times a week. Six weeks after exercise intervention, the BMI, body fat level, and plasma glucose level were lower than those before exercise intervention, and the %fat value was lower 12 weeks after intervention. Furthermore, cardiac autonomic function (CAF) was negatively correlated with changes in Total power and changes in fat (kg), suggesting that exercise-related improvement in CAF is involved in a decrease in %fat.

Correlation between Cardiac Autonomic Function Test and Subclinical Neuropathy in Type 1 Diabetic Children / 대한소아내분비학회지

PURPOSE:Autonomic neuropathy in adult diabetics is known to be common and poor in prognosis. Cardiac autonomic neuropathy increases sudden cardiac death and is present before apparant cardiac symptoms. Subclinical diabetic peripheral neuropathy is common with type 1 diabetes. In children, few studies for subclinical peripheral neuropathy and cardiac autonomic neuropathy were reported but the results were inconsistent. The authors investigated subclinical cardiac and peripheral neuropaties and evaluated correlation between nerve conduction velocity(NCV) and cardiac autonomic function(CAF) test in type 1 diabetic children and adolescents METHODS:Over 5 years from 1997 to 2002, 27 IDDM without clinical neuropathy were registered. Total 57 CAF and NCV were tested every 2 or 3 years. Duration of diabetes, average HbA1c during 1 year prior to the test, and urinary microalbumin excretion for 24 hours were assessed. Diabetic autonomic nervous function was evaluated by cardiovascular reflex test:falling systolic blood pressure in response to standing, heart rate changes in response to standing, beat-to-beat rate variation during deep breathing, RR interval change during and after Valsalva maneuver. Subclinical peripheral neuropathy was evaluated by NCV in both upper and lower extremities. Correlation of parameters according to NCV abnormality and microalbuminuria were analyzed. RESULTS:The age, duration of diabetes and microalbuminuria were not statistically different between children with normal and abnormal NCV. The level of HbA1c was associated with NCV abnormality. In a multivariate logistic model for NCV abnormality, level of HbA1c showed statistical significance after controlling the effects of age, duration of diabetes, and urinary microalbumin level, and the odd ratio was 1.532. The degree of CAF abnormality was marginally significant in the logistic model. Children with microalbuminuria showed older age and longer duration of diabetes than those without microalbuminuria. However, mean HbA1c level was not significantly different between the two groups. Degree of CAF abnormality was not significantly associated with microalbuminuria, either. In a general linear model including urinary albumin level as the dependent variable, none of independent variables was statistically significant. CONCLUSION: Therapy against neuropathy should be considered in patients with high HbA1c and abnormal CAF test even without clinically apparent neuropathy.

Assessment of Autonomic Nervous System with Analysis of Heart Rate Variability in Children with Spastic Cerebral Palsy

The purpose of this study was to investigate the function of the autonomic nervous system in children with spastic cerebral palsy (CP) through an analysis of heart rate variability (HRV) occurring with orthostatic stress. Twelve children with spastic CP and twelve normal children participated in this study. The echocardiogram (ECG) signals were recorded for 3 minutes in both the supine and 70 degrees C head-up tilt positions, and then the HRV signals underwent power spectrum analysis at each position. Two components were measured; a low- frequency (LF) component (0.05 - 0.15Hz) primarily reflecting sympathetic activity during orthostatic stress and a high-frequency (HF) component (0.15 - 0.4Hz) reflecting parasympathetic activity. In the supine position, there was no significant difference between any of the HRV components of the two groups. In the head-up tilt position, absolute and normalized LF were significantly increased and absolute HF was significantly decreased in the normal children (p < 0.05), but not in the children with spastic CP. The results of this study suggest that cardiac autonomic functions, such as vagal withdrawal and sympathetic activation which occur during head-up tilt position, are not sufficient to overcome the orthostatic stress arising in spastic CP children.