Cardiovascular Autonomic Function Tests Research Articles

Cardiovascular autonomic neuropathy and the risk of diabetic kidney disease.

Cardiovascular autonomic neuropathy (CAN) is known to affect patients with diabetes mellitus (DM) and cause adverse renal outcomes. We aimed to analyze the association between CAN and diabetic kidney disease (DKD). We enrolled 254 DM patients (mean age, 56.7 ± 15.2 years; male: female ratio, 1.17:1) with 19 (7.5%) type 1 DM patients and 235 (92.5%) type 2 DM patients. All patients had undergone cardiovascular autonomic function tests between January 2019 and December 2021 in a tertiary hospital in Korea. Cardiovascular autonomic neuropathy was categorized as normal, early, or definite after measuring three heart rate variability parameters. Diabetic kidney disease refers to a persistently elevated urinary albumin-creatinine ratio (uACR ≥30 mg/g) or reduced estimated glomerular filtration rate (eGFR <60 mL/min/1.73 m2). Logistic and Cox regression analyses were performed. Patients with elevated uACR (n=107) and reduced eGFR (n=32) had a higher rate of definite CAN. After adjusting for covariates, definite CAN was associated with elevated uACR (OR=2.4, 95% CI 1.07-5.36) but not with reduced eGFR (OR=3.43, 95% CI 0.62-18.90). A total of 94 patients repeated uACR measurements within 2 years (mean follow-up, 586.3 ± 116.8 days). Both definite and early CAN were independent risk factors for elevated uACR (HR=8.61 and 8.35, respectively; both p<0.05). In addition, high-density lipoprotein cholesterol, ACE inhibitors/angiotensin receptor blockers and glucagon-like peptide-1 receptor agonists were independent protective factors for elevated uACR (HR=0.96, 0.25, and 0.07, respectively; all p<0.05). Cardiovascular autonomic neuropathy is a potential indicator of DKD. Comprehensive management of DKD in the early stages of CAN may prevent microalbuminuria.

Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients.

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

Sudoscan as substitute for quantitative sudomotor axon reflex test in composite autonomic scoring scale and its correlation with composite autonomic symptom scale 31 in type 2 diabetes

ObjectiveThis study aims to evaluate the feasibility of substituting electrochemical skin conductance measurement using SUDOSCAN for sudomotor function testing in the Composite Autonomic Scoring Scale (CASS) and to correlate the results with the Composite Autonomic Symptom Scale 31 (COMPASS 31) among patients with type 2 diabetes mellitus (T2DM). MethodsFifty patients with T2DM underwent cardiovascular autonomic function testing and the SUDOSCAN test and completed the COMPASS 31 questionnaire. We developed a SUDOSCAN-based sudomotor subscore as a substitute for the original sudomotor subscore (based on the quantitative sudomotor axon reflex test [QSART]). The modified CASS score (SUDOSCAN-based sudomotor subscore combined with the adrenergic and cardiovagal subscores) and the original CASS score without suomotor assessment (sum of the adrenergic and cardiovagal subscores) were obtained according to the results of the cardiovascular autonomic function and SUDOSCAN tests. ResultsThe total COMPASS 31 score was significantly correlated with the modified CASS score (p = 0.019 and 0.037 for the raw and weighted scores, respectively) but not with the CASS score without sudomotor assessment. After adding the SUDOSCAN-based sudomotor subscore, the number of patients identified as having diabetic autonomic neuropathy (DAN) increased from 24 (48 %, based on the CASS score without sudomotor assessment) to 35 (70 %, based on the modified CASS score). The modified CASS score enhances the accuracy of assessing autonomic function and improves the diagnosis of diabetic autonomic neuropathy (DAN) among patients with T2DM. In medical settings where QSART is not accessible, SUDOSCAN testing offers a practical and efficient alternative.

Prevalence of cardiac autonomic neuropathy in patients with type 2 diabetes mellitus.

Cardiac autonomic neuropathy (CAN) is one of the microvascular complications of diabetes mellitus, which is due to the involvement of autonomic nerve fibers innervating the heart and blood vessels. CAN was found to have a greater degree of morbidity and mortality than their non-CAN counterparts as it is underdiagnosed. Hence, this study aims to determine the prevalence and severity of CAN in type 2 diabetics in the South Indian setting. Forty-two patients with type 2 diabetes mellitus were enrolled in the study. Patients underwent tests for CAN, with the severity of CAN estimated as a CAN score, which was the sum of the scores of the four cardiovascular autonomic function tests. Out of the 42 patients, a total of 36 patients (85.7%) were diagnosed with CAN. Among those with CAN, 24 patients had early CAN (57.1%), and 12 were diagnosed with definite CAN (28.6%). Patients with any form of CAN (early and definite CAN) had higher HbA1c and mean glucose values than those without CAN. CAN was also found to be more severe among older patients with diabetes. In the present study, we found that more than 50% of the study population had early CAN and around 28.6% patients had definite CAN indicating higher prevalence of CAN in our population. Also, there was a positive correlation between the severity of CAN and the age of the patients. This study highlights the importance of understanding the importance of screening the diabetic patients for CAN to prevent adverse cardiovascular events.

Autonomic Nerve Function Tests in Patients with Diabetes

The autonomic nervous system (ANS) regulates the internal functions of the body organs, such as heart rate, digestion, respiratory rate, pupil response, urination, and sexual arousal. The ANS is divided into two parts: the sympathetic and parasympathetic nervous systems. However, the ANS can be damaged or degenerated by metabolic problems including hyperglycemia, leading to diabetic autonomic neuropathy (DAN), which is a prevalent complication among diabetic patients. Cardiac autonomic neuropathy is an important form of DAN that results from an imbalance between the sympathetic and parasympathetic nerve responses. This imbalance can lead to symptoms such as resting tachycardia, postural hypotension, and orthostatic tachycardia along with other types of autonomic neuropathy. Special tests can be performed to evaluate and diagnose this condition, including cardiovascular autonomic function tests. The aim of this review is to discuss the various tests used to diagnose and monitor autonomic neuropathy in diabetic patients and how to use and interpret them effectively.

An insight into gender based variations of autonomic functions among young adults

Since this is a vital developmental phase, studying the health patterns of young adults, particularly cardiovascular health, is critical. Autonomic function testing (AFT) is a crucial non-invasive procedure for determining the state of one's cardiovascular system. There are only a few studies on autonomic responsiveness in young people. To study the autonomic responses to various cardiovascular autonomic function tests among young adult subjects and to look into the gender-based variations.Males made up 114 (50.67 percent) of the total 225 individuals, while females made up the rest. The study's target age group was 18-29 years old. The CANWIN analyser of genesis medical systems was used to investigate autonomic function tests such as resting heart rate, heart rate reaction to slow deep breathing (SDB), Valsalva Ratio (VR), 30:15 ratios response to standing, and blood pressure response to sustained handgrip. CANWIN is a state-of-the-art Cardiac Autonomic Neuropathy (CAN) Analysis System with interpretation for PC Windows*. The data was analysed statistically using STATA software (version 13.1).: Dysautonomia was seen in 150 of the 225 participants (66.66 percent). The number of dysautonomia participants was not statistically different between males and females (P value=0.15).: Anxiety, stress, a poor diet, and a disrupted sleep cycle could all contribute to the high number of dysautonomia patients. There have been a number of reports linking dysautonomia to nutritional deficits. To investigate the causative factors, more longitudinal studies including nutritional status assessments are needed.

Assessing the Feasibility of Using Electrochemical Skin Conductance as a Substitute for the Quantitative Sudomotor Axon Reflex Test in the Composite Autonomic Scoring Scale and Its Correlation with Composite Autonomic Symptom Scale 31 in Parkinson’s Disease

The Composite Autonomic Scoring Scale (CASS) is a quantitative scoring system that integrates the sudomotor, the cardiovagal, and the adrenergic subscores, and the Composite Autonomic Symptom Scale 31 (COMPASS 31) is based on a well-established comprehensive questionnaire designed to assess the autonomic symptoms across multiple domains. We tested the hypothesis that electrochemical skin conductance (Sudoscan) can be a substitute for the quantitative sudomotor axon reflex test (QSART) in the sudomotor domain and assessed its correlation with COMPASS 31 in patients with Parkinson's disease (PD). Fifty-five patients with PD underwent clinical assessment and cardiovascular autonomic function tests and completed the COMPASS 31 questionnaire. We compared the modified CASS (integrating the Sudoscan-based sudomotor, adrenergic, and cardiovagal subscores) and CASS subscores (the sum of the adrenergic and cardiovagal subscores). The total weighted score of COMPASS 31 was significantly correlated with both the modified CASS and the CASS subscore (p = 0.007 and p = 0.019). The correlation of the total weighted score of COMPASS 31 increased from 0.316 (CASS subscores) to 0.361 (modified CASS). When we added the Sudoscan-based sudomotor subscore, the case numbers for autonomic neuropathy (AN) increased from 22 (40%, CASS subscores) to 40 (72.7%, modified CASS). The modified CASS not only better reflects the exact autonomic function, but also improves the characterization and quantification of AN in patients with PD. In areas in which a QSART facility is not easily available, Sudoscan could be a time-saving substitution.

Heart rate-corrected QT interval prolongation is associated with decreased heart rate variability in patients with type 2 diabetes.

We investigated the association between the heart rate-corrected QT interval (QTc interval) measured by standard electrocardiography and heart rate variability (HRV) in patients with type 2 diabetes mellitus (T2DM). From March 1, 2009, to December 12, 2009, 411 patients with T2DM who underwent resting 12-lead electrocardiography and cardiovascular autonomic function testing concurrently without the exclusion criteria were consecutively recruited in this cross-sectional study. Time- and frequency-domain HRV variables were assessed for 5 minutes by beat-to-beat HRV recording. The QT interval was corrected for the heart rate using Bazett's formula. QTc interval measurements of >440 ms were considered abnormally prolonged. The mean age and diabetes duration were 56.3 ± 10.6 years and 9.6 ± 7.3 years, respectively. A total of 90 patients had QTc interval prolongation (21.9%). The participants with a prolonged QTc interval were older (59.4 ± 10.1 years vs 55.5 ± 10.6 years, P = .002), were more likely to be a woman (72.2% vs 51.7%, P = .001), had a higher prevalence of hypertension (46.7% vs 33.4%, P = .022), had a higher hemoglobin A1c level (8.8% ± 2.2% vs 8.2% ± 1.8%, P = .045), and had decreased values for the variables measuring HRV, except for the low frequency (LF)/high frequency (HF) ratio (total power [TP], 147.7 [74.1-335.9] ms vs 328.7 [185.7-721.7] ms, P = .002). After adjusting for multiple confounders, QTc interval prolongation was associated with the lowest quartile of the HRV parameters of TP (odds ratio [OR] = 3.99; 95% confidence interval [CI]: 2.29-6.96), HF (OR = 3.20; 95% CI: 1.84-5.58), LF (OR = 3.68; 95% CI: 2.10-6.43), standard deviation of the normal-to-normal interval (OR = 3.31; 95% CI: 1.89-5.77), and root-mean-square of the successive differences (OR = 1.98; 95% CI: 1.13-3.47) in patients with T2DM. Decreased values for the variables measuring HRV, except for the LF/HF ratio, might be associated with QTc interval prolongation in patients with T2DM.

Clinical autonomic nervous system laboratories in Europe: A joint survey of the European Academy of Neurology and the European Federation of Autonomic Societies: A joint survey of the European Academy of Neurology and the European Federation of Autonomic Societies.

Disorders of the autonomic nervous system (ANS) are common conditions, but it is unclear whether access to ANS healthcare provision is homogeneous across European countries. The aim of this study was to identify neurology-driven or interdisciplinary clinical ANS laboratories in Europe, describe their characteristics and explore regional differences. We contacted the European national ANS and neurological societies, as well as members of our professional network, to identify clinical ANS laboratories in each country and invite them to answer a web-based survey. We identified 84 laboratories in 22 countries and 46 (55%) answered the survey. All laboratories perform cardiovascular autonomic function tests, and 83% also perform sweat tests. Testing for catecholamines and autoantibodies are performed in 63% and 56% of laboratories, and epidermal nerve fiber density analysis in 63%. Each laboratory is staffed by a median of two consultants, one resident, one technician and one nurse. The median (interquartile range [IQR]) number of head-up tilt tests/laboratory/year is 105 (49-251). Reflex syncope and neurogenic orthostatic hypotension are the most frequently diagnosed cardiovascular ANS disorders. Thirty-five centers (76%) have an ANS outpatient clinic, with a median (IQR) of 200 (100-360) outpatient visits/year; 42 centers (91%) also offer inpatient care (median 20 [IQR 4-110] inpatient stays/year). Forty-one laboratories (89%) are involved in research activities. We observed a significant difference in the geographical distribution of ANS services among European regions: 11 out of 12 countries from North/West Europe have at least one ANS laboratory versus 11 out of 21 from South/East/Greater Europe (p= 0.021). This survey highlights disparities in the availability of healthcare services for people with ANS disorders across European countries, stressing the need for improved access to specialized care in South, East and Greater Europe.

Analysis of sleep, daytime sleepiness, and autonomic function in multiple system atrophy and Parkinson disease: a prospective study.

Sleep disorders, daytime sleepiness, and autonomic dysfunction are commonly reported among patients with multiple system atrophy and Parkinson disease (PD). We aimed to assess sleep and autonomic function in these patients to evaluate the relationships between sleep disorders, excessive daytime sleepiness, and autonomic function. Twenty patients with multiple system atrophy (n = 7) and PD (n = 13) underwent clinical assessment including questionnaires for autonomic function and sleep. Cardiovascular autonomic function tests and 2-night video-polysomnography were followed by administration of the Multiple Sleep Latency Test. Rapid eye movement sleep without atonia was quantified in the chin, flexor digitorum superficialis, tibial anterior, and sternocleidomastoid muscles. Rapid eye movement sleep behavior disorder was associated with orthostatic hypotension (P = .017) and constipation (P = .019) in PD. Patients with orthostatic hypotension had higher rapid eye movement sleep without atonia indices than those without orthostatic hypotension (P < .001). The Sleep Innsbruck Barcelona rapid eye movement sleep without atonia index ("any" chin and/or flexor digitorum superficialis) correlated with systolic/diastolic blood pressure fall upon tilt-table examination in patients with multiple system atrophy (P < .05) and with gastrointestinal (P = .010), urinary (P = .022), and total Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction scores (P = .006) in all patients. Patients with a pathological deep breathing ratio showed higher Sleep Innsbruck Barcelona indices (P = .031). Objective daytime sleepiness was exclusively present in PD (P = .034) and correlated with levodopa-equivalent dosage (P = .031). The relationship of autonomic dysfunction with rapid eye movement sleep without atonia in PD and multiple system atrophy is accounted for by shared brainstem neuropathology and likely identifies patients in a more advanced stage of disease. Excessive daytime sleepiness is found exclusively in PD and may be secondary to levodopa treatment and not related to α-synuclein disease. Eckhardt C, Fanciulli A, Högl B, etal. Analysis of sleep, daytime sleepiness, and autonomic function and multiple system atrophy and Parkinson disease: a prospective study. J Clin Sleep Med. 2023;19(1):63-71.

Evaluation of cardiovascular autonomic function in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a type of inflammatory arthritis that affects people all over the world. RA is a chronic systemic inflammatory autoimmune disease. It primarily affects the joints and is frequently accompanied by extra-articular symptoms such as rheumatoid nodules, neuropathy, and normochromic normocytic anaemia. Objectives- The aim of this study was to evaluate cardiac autonomic function in patients with rheumatoid arthritis and compare with healthy individuals. An observational, cross-sectional study was done between 50 having RA &amp; 50 normal healthy subjects not on any medication, on both males &amp; females between the age group of 30-60 years. Evaluation of autonomic nervous system was done with the help of non-invasive tests. Parasympathetic system was assessed by heart rate response to standing &amp; heart rate response to lying down position. Sympathetic system was assessed by blood pressure response to standing, BP response to Valsalva Maneuverer &amp; BP response to sustained hand grip. In individuals with Rheumatoid Arthritis, the diastolic blood pressure in standing position was significantly lower(p&amp;#60;0.01) than control group. Other parameters showed non- significant changes in RA group compared to control group. Discussion- study confirmed autonomic dysfunction occurs in patient with rheumatoid arthritis. Therefore, autonomic function may be the part of routine clinical examination in RA to reduce the cardiovascular autonomic morbidity Cardiovascular autonomic function tests in daily clinical examination helpful in early detection of autonomic dysfunction in rheumatoid arthritis.

Spectrum of Cardiovascular Autonomic Dysfunction and 24-hour Blood Pressure Variability in Idiopathic Parkinson's Disease.

Uncertainty prevails regarding the patterns of autonomic dysfunction in patients with idiopathic Parkinson's disease (IPD). This study was undertaken with the aim of assessing the complete spectrum of cardiovascular autonomic function tests (CAFTs) and blood pressure variability patterns in IPD patients while comparing the same with age-matched controls. Patients with IPD presenting to the Christian Medical College and Hospital from December 2016 to November 2018 along with age-matched controls were prospectively evaluated using CAFTs. The IPD patients also underwent ambulatory blood pressure (BP) monitoring (ABPM), and the diurnal systolic BP differences were used to classify into dippers (10-20%), non-dippers (0-10%), reverse dippers (<0%), and extreme dippers (>20%). Autonomic dysfunction (AD) was prevalent in 41 (68.3%) IPD patients even in early disease (median (inter-quartile range) symptom duration 2 (1-4) years, mean Hoehn and Yahr (H&Y) stage 2 (1.5-2.8). Both sympathetic and parasympathetic parameters were impaired among IPD patients when compared to healthy controls. (E: I ratio 1.17 ± 0.12 vs 1.26 ± 0.14 (P < 0.001), Valsalva ratio (VR) 1.33 ± 0.27 vs 1.55 ± 0.25 (P < 0.001), PRT100 9.6 ± 8.0 vs 3.1 ± 1.8 (P < 0.001), tilt-up SBPAvg change 8.8 (4.2-13.8) vs 1.8 (-2.9-6.1) (P < 0.001), tilt-up HRAvg change 4.8 (2.2-8.2) vs 1.9 (-0.7-5.1) (P < 0.001). BP variability was demonstrated in 47 (79.7%) of IPD patients, with reverse dipping pattern in 28 (47.5%) seen more frequently in this cohort. Timely detection of AD may be helpful not only in recognizing IPD in its pre-motor stages but also in optimizing management for this population of patients. BP variability and abnormal dipping patterns on ABPM can be a potential marker of dysautonomia.

Cardiovascular Autonomic Function Tests in Patients of Obsessive-Compulsive Disorder: A Cross-Sectional Study.

Background:Patients with psychiatric disorders are at an increased risk of developing cardiovascular disease, reducing life expectancy. Autonomic dysfunction has been linked to this increased risk; many studies have found reductions in heart rate variability (HRV). Only a few studies have systematically explored the relationship between obsessive–compulsive disorder (OCD) and autonomic function, and they have found contradicting results. The present study is intended to explore comprehensive autonomic functions in OCD patients and compare them with healthy controls.Methods:A total of 18 OCD patients meeting Diagnostic and Statistical Manual of Mental Disorders - 5 (DSM-5) criteria were enrolled to undergo comprehensive autonomic function testing, and the results were compared with 25 age- and sex-matched healthy controls.Results:Time-domain parameters of HRV such as standard deviation of the RR intervals, coefficient of variance of RR intervals, standard deviation of differences between adjacent RR intervals, root square of the mean of the sum of the squares of differences between adjacent RR intervals, and percentage of number of RR interval differences ≥ 50 ms were significantly lower in OCD patients, indicating lesser parasympathetic tone. Frequency-domain parameters such as total power and very low frequency were significantly lower in OCD patients, indicating a significant decrease in autonomic tone. Nonlinear parameters such as dispersion of points perpendicular to the line of identity and dispersion of points along the line of identity were significantly lower in OCD patients, indicating altered vagal and sympathetic tone. In autonomic reactivity tests, the fall in systolic blood pressure during the lying to standing test and change in diastolic blood pressure during the cold pressor test were significantly altered in OCD patients, indicating abnormal sympathetic reactivity. There was no significant correlation between autonomic parameters and the severity of OCD.Conclusion:OCD is characterized by a decreased parasympathetic tone and abnormal sympathetic reactivity compared to normal controls.

The effect of smoking on the cardiovascular autonomic functions tests

Tobacco smoking is one of the major causes of preventable morbidity and mortality all over world. Smoking affects the cardiovascular system by several mechanisms. The present study was planned to study the effect of smoking on the cardiovascular autonomic functions among smokers.This study comprises 50 male subjects aged between 20 to 30 years, who included 25 smokers who formed cases and 25 non-smokers who formed the control groups were selected for this study. The design for this study is cross-sectional survey. The subjects were from patients who attended medicine OPD. Inclusion and exclusion criteria are followed in selecting participants. 1: Prior informed written consents were obtained from them after explaining to them, the procedure and the purpose of the study tests; 2. Ethical approval was taken from ethical committee of BMCH, Chitradurga.The cardiovascular autonomic function tests were assessed by using a CANWIN AUTONOMIC ANALYSER which was available in the department.In our study, it was observed that there was significant difference between the mean values of the para-sympathetic function tests among the smokers and the non-smokers (i.e. p&amp;#60;0.01) The Resting Heart Rate had significantly increased and the Expiration: Inspiration Ratio, the 30:15 Ratio (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non-smokers. In this study, it was observed that there was no significant difference between the mean values of the Postural hypotension test (i.e. p&amp;#62;0.05) and that there was a highly significant difference between the mean values of the Sustained handgrip test in the smokers and the non-smokers (i.e. p&amp;#60;0.01). The Resting Heart Rate had significantly increased in case of smokers as compared to non-smokers due to increased sympathetic activity due to release of catecholamines. The Expiration: Inspiration Ratio, 30:15 Ratio (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non-smokers due to derangement in parasympathetic activity.In sustained handgrip test, rise in blood pressure is decreased in smokers as compared to non-smokers due to reduced sympathetic activity.

Effect of smoking on cardiovascular autonomic functions

Introduction: Cigarette smoking is a prime risk factor for cardiovascular morbidity and mortality. Chronic smoking results in autonomic dysfunction leading to increased cardiovascular risk in smokers. The present study was planned to study the effect of smoking on the Cardiovascular Autonomic Functions among smokers. Materials and Methods: Fifty male subjects who were in the age group of 25 to 45 years. They were grouped into 25 smokers and 25 non-smokers. The participant subjects were selected among the staff members, residents and the patients from the routine OPD in SVIMS. Prior to study, they were informed about the procedure and the purpose of the study tests and written consents were obtained from them. The Cardiovascular Autonomic Function Tests were assessed by using a POLYGRAPH which was available in the department. Results and Conclusion: After applying the ‘t’-test for the difference between the two sample means, it was observed that there was a highly significant difference between the mean values of the BMI(i.e.p&lt;0.01) and the para-sympathetic function tests among the smokers and the non – smokers(i.e.p&lt;0.00). The Resting Heart Rate had significantly increased and the Deep breathing difference, the postural tachycardial index (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non – smokers. After applying the ‘t’-test for the difference between the two sample means, it was observed that there was no significant difference between the mean values of the Postural hypotension test (i.e. p&gt;0.05) and that there was a highly significant difference between the mean values of the Sustained handgrip test in the smokers and the non – smokers (i.e. p&lt;0.00). KEY WORDS: Cardiovascular autonomic function tests, Smoking, Resting heart rate.

The Association Between Continuous Glucose Monitoring-Derived Metrics and Cardiovascular Autonomic Neuropathy in Outpatients with Type 2 Diabetes.

Background: Continuous glucose monitoring (CGM)-derived metrics, including time in range (TIR), are attracting attention as new indicators, beyond hemoglobin A1c, of glycemic control and diabetes complications. This study investigated the associations between CGM-derived TIR, hyperglycemia, and hypoglycemia metrics and cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes. Methods: A total of 284 patients with type 2 diabetes who underwent CGM using GOLD™ (Medtronic MiniMed) for 3 days or iPro™2 (Medtronic MiniMed) for 6 days and autonomic function tests within 3 months based on outpatient data were recruited. The definition of CGM-derived metrics was subject to the most recent international consensus. CAN was defined as an abnormal result in two or more parasympathetic test, and the severity of CAN was estimated as the sum of the scores of the five cardiovascular autonomic function tests. Results: A total of 84 patients (29.6%) were diagnosed with CAN, and the mean TIR was 57.0% ± 7.0%. A multiple logistic regression analysis revealed that the odds ratio (OR) of presence of CAN was 0.876 [95% confidence interval (CI): 0.79-0.98] per 10% increase in the TIR 70-180 mg/dL, after adjusting for age, sex, diabetes duration, any medications, and glycemic variability. A 10% increase in the TIR was significantly inversely associated with the severity of CAN (OR: 0.89, 95% CI: 0.81-0.98). Among the metrics of hyperglycemia, each 10% increase in a time above range (TAR) >180 mg/dL was also independently correlated with the presence of CAN (OR: 1.141, 97.5% CI: 1.01-1.29) and the severity of CAN (OR: 1.13, 97.5% CI: 1.01-1.26). Conclusion: A TIR 70-180 mg/dL and a TAR >180 mg/dL were significantly associated with CAN in outpatients with type 2 diabetes.

Cardiovascular Autonomic Functions and Its Association with Oxidative Stress Marker in Heavy Smoking and Smokeless Tobacco Users of Low Socioeconomic Status

Background: Tobacco usage is a major preventable cause for cardiovascular morbidity and mortality.Tobacco is used in both smoking and smokeless forms. Alteration in cardiac autonomic function is amajor predisposing factor for cardiovascular risk. There are only limited studies available which assessedautonomic functional status in smokeless tobacco users. This study was aimed to assess and compare thecardiac autonomic activity and oxidative stress in smoking and smokeless tobacco users with controls.Methods: Sixty seven apparently healthy volunteers from the construction workers of low socioeconomicstatus were recruited. Those who are having habit of using tobacco in any form (n=42) were categorizedinto smoking tobacco group (n = 22) based on the smoking index and fagerstrom score for smokelesstobacco group (n = 20). Those who never used tobacco in any form were included as control group (n= 25).Cardiovascular autonomic function tests were performed and serum malondialdehyde was measured fromvenous blood sample.Conclusion: In this study we found that there is definite alteration in cardiac autonomic function which isin correlation with the level of oxidative stress in heavy tobacco users. This alteration is seen more in heavysmokeless tobacco users in compare with smoking tobacco users.

Elevated cerebral blood flow in patients with pure autonomic failure.

Pure autonomic failure (PAF) results from an impaired peripheral autonomic nervous system, and clinical symptoms present with orthostatic hypotension. While the impact on cardiovascular indices of orthostatic intolerance are well-characterized, more limited information is available regarding cerebral hemodynamic dysfunction in PAF. The objective of this study was to test the hypothesis that cerebral blood flow (CBF) is reduced in PAF, and to quantify the relationship between CBF and clinical indicators of disease severity, including peripheral supine arterial blood pressure. Participants with PAF (n = 17) and age- and sex-matched normotensive healthy controls (n = 17) were examined using established clinical rating scales, cardiovascular autonomic function tests, and 3T MRI measurements of CBF. CBF-weighted images were also used to determine the prevalence of venous hyperintensities from the major dural sinuses as evidence of abnormal capillary flow. Nonparametric tests and general linear models were used to evaluate differences and correlations between study variables. Gray matter CBF was higher in PAF (51.1 ± 13.4mL/100g/min) compared to controls (42.9 ± 6.5mL/100g/min, p = 0.007). Venous hyperintensities were more prevalent in PAF relative to controls, and the presence and degree of venous hyperintensities was associated with higher mean CBF (p = 0.027). In PAF participants, CBF and supine systolic blood pressure were inversely related (Spearman's rho = -0.545, p = 0.024). Findings suggest that PAF patients may exhibit elevated CBF and provide evidence that this condition exerts a hemodynamic impact in the central nervous system.

Impact of sleep disturbances and autonomic dysfunction on the quality of life of patients with fibromyalgia.

Fibromyalgia, a painful musculoskeletal disorder is associated with sleep disturbances as well as autonomic dysfunction. Pathophysiology of fibromyalgia is yet not clear and neuroanatomical proximity of sleep and autonomic centre prompts probable involvement of the two impacting the quality of life of fibromyalgia patients. Present study was done with the objective to explore the extent of sleep disturbances and/or autonomic dysfunction in fibromyalgia and asses their impact on quality of life of fibromyalgia patients. Thirty consecutive fibromyalgia patients (diagnosed by ACR 2010) from out-patient department and 30 age-gender matched controls were enrolled after the ethical clearance. All participants were evaluated for: (1) sleep using Pittsburgh sleep quality index and medical outcomes study sleep scale-12 Revised, (2) Quality of life by 36 item short-form health survey-36v2TM and revised fibromyalgia impact questionnaire (only patients). Autonomic functions of patients were evaluated by standard cardiovascular autonomic function tests by Ewing's battery and heart rate variability (5-min) measurement. Fibromyalgia patients had increased sleep disturbances compared to controls (39.46±11, 59.61±2.31; p=0.0001) and very poor sleep quality (13.63±4.15, 3.03±1.56; p=0.0001) as well as quality of life (p=0.0001) which further deteriorated with increasing severity of fibromyalgia. Twelve patients had autonomic dysfunction but it was neither associated with sleep disturbances nor with quality of life. Mild to moderate grade fibromyalgia patients have significant sleep disturbance, poor sleep quality which remarkably impacts their quality of life. Autonomic dysfunction is not an early feature of disease. The study suggests that full spectrum of sleep disturbances and sleep quality should be explored in fibromyalgia syndrome (FMS) patients.

The Effect of High Temperature on Cardiovascular Autonomic Function Tests in Steel Plant Furnace Worker

Background:The high temperature in the working environment could be one of the risk factors for cardiovascular diseases in steel plant workers. The excessive high temperature at the working place leads to altered autonomic activity and is related to more cardiovascular risk.Aims and Objectives:The effect of high temperature on cardiovascular autonomic function tests in steel plant furnace worker.Material and Method:This was a case-control study for which 50 steel plant furnace workers and 50 controls were selected. The cardiovascular sympathetic function status in worker and control were analyzed by three tests: (i) Blood pressure (BP) response to sustained isometric handgrip test, (ii) BP response to the cold pressor test, and (iii) BP response to standing from a supine position (orthostasis). Statistical analysis was done by using an independent t-test.Results:Diastolic BP (DBP) response to sustained isometric handgrip and systolic BP (SBP) and DBP response to the cold pressor test showed that the increase BP in workers were more than controls but the difference was not statistically significant (P > 0.05). SBP response to standing from the supine position showed statistically significant (P < 0.001) greater fall in steel plant workers.Conclusion:The sympathetic autonomic dysfunction was seen in steel furnace workers in response to environmental stressor–excessive heat.