Conventional Autonomic Function Tests Research Articles

Inter relationship of sympathetic reflex response and oxidative stress in polycystic ovary syndrome

Background: Polycystic ovary syndrome (PCOS) is a very common reproductive endocrine disorder. Altered cardiovascular autonomic modulation and oxidative stress may predispose PCOS patients to cardiac events in the long term. Objective: To assess the relationship between sympathetic autonomic reactivity and oxidative stress in patients with polycystic ovary syndrome. Methods: This cross-sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka from September 2018 to August 2019 on 35 newly diagnosed obese (BMI ≥25kg/m2) PCOS patients aged 20-35 years. Age and BMI matched 35 apparently healthy subjects were also enrolled. Two noninvasive conventional autonomic function tests, such as systolic blood pressure (SBP) fall during active standing and diastolic blood pressure (DBP) rise during sustained handgrip were conducted on all subjects for evaluation of sympathetic reactivity. For assessment of oxidative stress, plasma malondialdehyde level as oxidant and plasma catalase level as antioxidant were measured in all subjects by spectrophotometry. For statistical analysis Independent sample “t” test, Pearson’s correlation test and multiple regression analysis were done. Results: In this study PCOS patients had significantly higher resting heart rate, SBP and DBP than healthy control (p<0.01). Fall of SBP during standing was significantly lower (p<0.05) while rise of DBP during sustained handgrip was significantly higher (p<0.05) in PCOS compared to healthy control. Plasma catalase level was significantly lower (p<0.01) and plasma malondialdehyde level significantly higher (p<0.001) in PCOS in comparison to healthy control. On correlation analysis, rise of DBP showed significant negative correlation (p<0.05) with plasma catalase level in PCOS. On multiple regression analysis rise of DBP showed significant negative (p<0.01) association with plasma catalase and significant positive (p<0.01) association plasma malondialdehyde in PCOS. Conclusion: Based on these results it is concluded that measures of sympathetic reactivity were related to oxidative stress in PCOS. J Bngladesh Soc Physiol 2021;16(1): 61-69

A comparative study between preoperative and postoperative conventional autonomic functions in congenital craniovertebral junction anomalies.

BackgroundAutonomic nervous system (ANS) is invariably affected by craniovertebral junction (CVJ) anomalies. The usual presentation is sudden after trivial trauma. When symptomatic, most of this autonomic dysfunction is clearly elicited clinically with bedside tests. Nonetheless, ANS functionality in relatively less symptomatic or asymptomatic patients is not known as no studies exist.Methodology:We performed a longitudinal prospective study of 40 less symptomatic patients who underwent surgery with conventional autonomic function tests (AFT) in pre- and post-operative periods. Correlation of its association with such anomalies is studied.Results:All 40 had both pre- and post-operative clinical follow-up, pre-operative AFT, whereas only 22 patients had follow-up AFT. The mean age for the group was 32 years and male: female ratio was 2.3:1. Mean Nurick's grade was 1.8, whereas Barthel's index was 83.75%. Clinical improvement was seen in almost 98% at follow-up. Orthostatic test showed a significant association with Nurick's grade. Barthel's index was significantly associated with degree of compression. The mean follow-up was 17.4 months. Most conventional AFTs were significantly decreased in the preoperative period (P ≤ 0.01). Both parasympathetic and sympathetic tone improved on follow-up with better improvement later. Overall clinical involvement of ANS was seen in 22.5% whereas subclinical involvement in the form of AFT impairment was seen in 100%.Conclusion:There is a definite involvement of subclinical ANS in all patients of CVJ anomalies irrespective of their symptomatology. Knowing the extent of involvement in the preoperative period can help prognosticate, prioritize regarding surgery as well as correlate with the extent of improvement.

Assessment of autonomic dysfunction between type I and type II diabetes mellitus

Introduction: The diabetes is the most common disease in the present world and India is country with highest incidence of Diabetes Mellitus in the world. The autonomic nervous dysfunction due to diabetes is the common complication of the diabetes. In this study autonomic dysfunction in pateints with type I and type 2 DM and its correlation with the duration of diseases is studied. Materials and Methods: The study was conducted on 30 type I diabetic patients and 40 type II diabetic pateints. All the diabetic patients were questioned about the presence of symptoms reported to be related to autonomic neuropathy. The conventional autonomic function tests were performed on all the subjects inclusive of sympathetic and parasympathetic tests. The scoring of positive and negative for autonmomic dysfuntion was done. Results: The duration of disease in type 1 diabetes, was 6 to 15 years and in type 2 diabetes it was 8 to 18 years with mean duration of 8.5 and 14 years respectively. The mean HbA1C in type 1 DM was 6.21±2.09 and it was 7.50±2.45 in type 2 DM. Comparison of autonomic function tests in the form of heart rate and BP response in subjects with type 1 and type 2 showed that there no significant statistical difference between the groups. Conclusion: It can be concluded the presence of autonomic dysfunction in type 1 and type 2 diabetes mellitus might be due to nerve damage. The duration of diabetes is directly related to such autonomic dysfunction. Keywords: Diabetes Mellitus type 1, Diabetes Mellitus type 2, Autonomic Functions Tests.

Relationship between parasympathetic reactivity and oxidative stress in Polycystic ovary syndrome

Background: Polycystic ovary syndrome (PCOS) is a very common reproductive hormone disorder. Altered cardiovagal autonomic modulation and oxidative stress may predispose PCOS patients to increased cardiovascular morbidity.
 Objective: To assess the relationship between parasympathetic reactivity and oxidative stress in patients with PCOS.
 Methods: This crosssectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbagh, Dhaka from September 2018 to August 2019 on 35 newly diagnosed obese (BMI ≥25kg/m2) PCOS patients aged 20-35 years. Age and BMI matched 35 apparently healthy women were also enrolled as control. Three noninvasive conventional autonomic function tests, such as heart rate response to deep breathing, standing and the Valsalva maneuver, were used for evaluation of parasympathetic reactivity. For assessment of oxidative stress, plasma malondialdehyde level (oxidant) and plasma catalase level(antioxidant) were measured in all subjects by spectrophotometry. Data were expressed as mean± SD. For statistical analysis Independent sample “t” test, Pearson’s correlation test and multiple regression analysis were done as applicable.
 Results: In this study PCOS patients had significantly higher (p<0.01)resting heart rate, systolic and diastolic blood pressure than that of healthy control. But Expiration: Inspiration ratio, Expiration:Inspiration difference and 30:15 ratio during standing were significantly lower (p<0.001, p<0.01 and p<0.05 respectively) in PCOS compared to control. In addition, plasma catalase level was significantly lower (p<0.01)and plasma malondialdehyde level significantly higher (p<0.001) in PCOS in comparison to healthy control. Multiple regression analysis showed plasma catalase as a significant positive predictor (p<0.05) of the Valsalva ratio in PCOS. Also, Valsalva ratio showed significant negative association (p<0.05) with plasma malondialdehyde (p<0.01)in PCOS.
 Conclusion: Based on these results it is concluded that impaired parasympathetic reactivity showed inverse relationship with oxidative stress in PCOS.
 J Bangladesh Soc Physiol. 2019, December; 14(2): 48-55

Assessment of Conventional Autonomic Function Tests in Patients with Acute Intermittent Porphyria

Background and Aim: To assess the autonomic nerve functions in latent and manifest patients of acute intermittent porphyria. The aim of the present study was to study cardiovascular responses to autonomic nerve functions in patients of acute intermittent porphyria, we also tried to find out the relative sensitivity of the various tests employed to study cardiac dysautonomia in these cases. Methods: The study was carried out on thirty cases of acute intermittent porphyria to assess the cardiovascular reflexes. Twenty five healthy subjects closely matched for age and sex served as control. The cases were diagnosed by modified Watson Schwartz test, the cases of acute intermittent porphyria were divided into three groups. Results: The values of different autonomic nerve function tests were compared with control group and among the different groups of patients. The results were complied, compared and a conclusion was drawn. Immediate heart rate response to standing is more sensitive test than the Valsalva maneuver. Immediate heart rate response to standing is more sensitive and quite reliable which can easily be performed at bed side or even in outpatient departments, the test is simple and non–invasive. In our opinion, the test, beat to beat variation of heart rate to single deep breath is though easy to perform and more understandable, but lacks the sensitivity of other two tests. Conclusion: Significant cardiac dysautonomia is present in asymptomatic group, it is more marked in acute attack group. Immediate heart rate response to standing could be a more sensitive and reliable test in this dysfunction.

To study correlation of body fat and blood lipids with autonomic nervous system activity in postmenopausal Indian women

Background: Obesity, physical inactivity, and altered estrogen metabolism play integrated role contributing to the disease risk profiles of postmenopausal women (PMW). Aim: To study the correlation of body fat and blood lipids with autonomic nervous system activity in PM Indian women. Subjects and Methods: A total of 60 PM sedentary women without any gross systemic disease were selected as a control group and 23 PMW, who were regularly doing morning walk for 1-year was selected as a study group. Body mass index (BMI), waist/hip (W/H) ratio were recorded; lipid profile analyzed, and conventional autonomic function tests were carried. Results were analyzed using SPSS version 16. Results: There was a significant difference in BMI, W/H ratio, lipid profile, autonomic function tests between the two groups. Aging and menopausal duration (MD) were positively correlated with pulse rate, systolic blood pressure, total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, orthostatic tolerance test (OTT), and negatively correlated with Valsalva ratio (VR), deep breath test (DBT), 30:15 relative risk (RR) intervals ratio, isometric hand-grip test (HGT), cold pressor test (CPT). BMI and W/H ratio were positively correlated with TC, triglyceride, LDL cholesterol, OTT, and negatively correlated with isometric HGT, CPT. TC and LDL were negatively correlated with VR, deep breath difference test, 30:15 RR interval ratios, isometric HGT, CPT, and positively correlated with OTT. Multiple regression analysis revealed LDL cholesterol as the only significant independent explanatory variable of DBT. LDL cholesterol and age were the significant independent explanatory variables of 30:15 RR interval ratios, CPT. TC, LDL cholesterol, and age were the significant independent explanatory variables of isometric HGT. Conclusions: Aging, MD, BMI, and W/H ratio all contribute significantly to worsening of autonomic functions and lipid profile. Multiple regression analysis revealed LDL cholesterol as the most significant contributor of worsening of autonomic functions in PM females and regular exercise can improve these parameters significantly.

ASSESSMENT OF CARDIOVASCULAR AUTONOMIC REACTIVITY IN PATIENTS WITH POLYCYSTIC OVARY SYNDROME

Polycystic ovary syndrome (PCOS) in association with obesity poses a significant cardiovascular risk. Autonomic dysfunction is an early marker of cardiovascul ar risk. The conventional autonomic function tests (CAFT) are standard noninvasive methods of evaluating cardiovascular autonomic re activities. The study was conducted to assess the autonomic reactivity in patients with PCOS using CAFT. Forty newly diagno sed patients with PCOS and 36 age - matched controls were recruited. Body mass index (BMI), waist - hip ratio (WHR), cardiovascular parameters such as basal heart rate (BHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and rate - pressure product (RPP), were measured in them. CAFT assessed were HR and BP response to standing (30:15 ratio), deep breathing (E:I ratio) and isometric handgrip (ΔDBP ihg ). Association of CAFT reactivity parameters with RPP was assessed by Pearson correlation. Individual association of CAFT reactivity parameters to RPP was assessed by multiple regression analysis. The cases had significantly increased BMI, WHR, BHR, SBP, DBP, MAP and RPP. E:I ratio was decreased and 30:15 ratio and ΔDBP ihg w ere increased in cases. 30:15 ratio and ∆DBP ihg had a significant positive correlation with RPP and E:I ratio showed negative correlation. Multiple regression analysis demonstrated independent association of RPP with E:I ratio and ∆DBP ihg . We conclude tha t PCOS patients have altered autonomic modulation in the form of increased sympathetic and decreased parasympathetic reactivity. The autonomic dysregulation is linked to myocardial performance in PCOS, which could expose PCOS patients to cardiovascular mor bidities.

Effect of progressive muscle relaxation on the adverse cardiovascular profile in women with polycystic ovarian syndrome

Background: The altered stress reactivity in polycystic ovarian syndrome (PCOS) may constitute a link between depression, overweight, and cardiovascular risk factors. Aims: To study the effects of progressive muscle relaxation (PMR) on the stress levels of PCOS patients and their influence on the cardiovascular risk factors. Subjects and Methods: This prospective pilot project was conducted on 100 PCOS patients in a tertiary care hospital of West Bengal, after receiving approval from the Institutional Ethical Committee and informed consent of the subjects. The stress levels were assessed and conventional autonomic function tests and the lipid profi les were analyzed. The subjects were divided into two groups using an online randomizer. One group received medication, while the other group received medication and practiced progressive muscle relaxation (PMR) for three months. All parameters were re‑evaluated at the end of three months. Results: The perceived stress scale was significantly less in subjects practicing relaxation exercises, as compared to subjects only on medication. The waist/hip ratio, pulse rate, and systolic blood pressure were significantly lower, while there was no difference in the body mass index (BMI) and diastolic blood pressure. Results of the autonomic function tests showed a significant parasympathetic tilt in subjects practicing PMR. In patients with PCOS, who were on PMR, cholesterol, triglycerides, and low‑density cholesterol (LDL) were significantly lower and high‑density cholesterol HDL was significantly higher. Conclusions: PCOS patients are a high‑risk group for developing the metabolic syndrome and relaxation therapies may be recommended as an adjuvant therapy, to tilt the autonomic balance to parasympathetic dominance, to improve the cardiovascular profile. Keywords: Autonomic functions, cardiovascular system, polycystic ovarian syndrome, stress

Assessment of cardiovascular autonomic function in patients with polycystic ovary syndrome

The study was conducted to assess the sympathovagal balance in patients with polycystic ovary syndrome (PCOS) using short-term heart rate variability (HRV) analysis and conventional autonomic function tests (CAFT). Thirty-one newly diagnosed patients with PCOS and 30 age-matched controls were recruited. Body mass index (BMI), waist : hip ratio (WHR), cardiovascular parameters such as basal heart rate (BHR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and rate-pressure product (RPP), and fasting blood glucose (FBG) were measured in both groups. Cardiovascular autonomic functions assessed were spectral analysis of HRV, heart rate and blood pressure response to standing (30:15 ratio), deep breathing (E:I ratio) and isometric handgrip (ΔDBP(ihg)). The cases had significantly increased BMI, WHR, BHR, SBP, DBP and RPP. Ratio of low-frequency to high-frequency power of HRV (LF-HF ratio), the marker of sympathovagal balance was significantly increased in cases compared to controls. Time-domain indices of HRV and E:I ratio were decreased, and 30:15 ratio, ΔDBP(ihg) and FBG were increased in cases. Though there was a significant correlation of LF-HF ratio with BMI, WHR, BHR, RPP and FBG, only BHR and RPP had independent contribution to LF-HF ratio. We conclude that PCOS patients have altered autonomic modulation in the form of increased sympathetic and decreased parasympathetic reactivity and HRV. The sympathovagal imbalance exposes them to cardiovascular morbidities.

Heart rate and blood pressure variability in patients with myasthenia gravis

This cross-sectional case control study included subjects aged between 18 and 65 years with diagnosis of myasthenia gravis (MG) in Osserman's Stage I and Stage IIa and those in remission with positive and negative acetylcholine receptor antibody (AChRAb). They were evaluated for heart rate variability (HRV) and other conventional autonomic functions. Patients with co-morbidities that can affect autonomic nervous system were excluded. Repetitive nerve stimulation test (RNST), nerve conduction test, AChRAb assay, and computerized tomography (CT) of chest were done in all the patients. All patients of MG who fulfilled the inclusion criteria had a minimum drug-free period of 6 h which was followed by HRV and other conventional tests. Thirty subjects fulfilling study criteria and an equal number of age and gender-matched healthy subjects were enrolled as controls. Autonomic function tests revealed significant changes in HRV (both time and frequency domain) parameters suggestive of parasympathetic deficiency as well as shifting of sympathovagal balance towards raised sympathetic tone. With regards to conventional autonomic function tests, there was statistically significant decrease in values of heart rate-based tests as well as blood pressure-based test (isometric handgrip test) in study group compared with controls, again indicative of significant parasympathetic deficiency and minimal sympathetic deficiency. We conclude that in MG, cholinergic transmission is affected more diffusely than previously thought.

Differential actions of antidepressant treatments on cardiac autonomic alterations in depression: A prospective comparison

Background Patients with depression have higher rates of cardiac morbidity and mortality. Alterations of cardiac autonomic functions associated with depression may partly explain this. Prospective studies comparing the effects of antidepressants on these abnormalities are limited due to confounding factors and co-morbidities. Methods Cardiac autonomic functions were studied in antidepressant naïve patients with major depression (without co-morbid medical or psychiatric disorders) before and after treatment with repetitive transcranial magnetic stimulation (rTMS; n = 30), specific serotonin reuptake inhibitors (SSRIs; n = 32) and tricyclic antidepressants (TCAs; n = 32). Conventional autonomic function tests and time- and frequency-domain measures of heart rate variability (HRV) were measured using standard procedures. Changes in autonomic functions were compared across the three treatment groups using repeated measures analysis of variance (ANOVA) using sex and age as covariates. Results Depression improved by comparable extent across patients treated with the three treatments. Overall, there was no change in cardiac autonomic functions. However, significant group × occasion interactions were noted for HRV measures. Both time- and frequency-domain HRV measures showed increase with rTMS and decrease with TCAs; they remained virtually unchanged with SSRIs. Limitations One of the major limitations of our work being we could not randomize the treatment groups. Conclusions The effects of antidepressant treatments on cardiac autonomic function abnormalities found in depression vary with the mode of treatment used. Long-term clinical implications of these effects on cardiac health of patients with depression need further studies.

Subclinical Autonomic Nervous System Dysfunction in Compressive Cervical Myelopathy

Laboratory evaluation of autonomic nervous system (ANS) in patients with cervical compressive myelopathy (CCM). To study the autonomic functions and heart rate variability (HRV) in patients with CCM and compare the findings after surgery. ANS dysfunction is well known after traumatic spinal cord injury. There are very few studies of ANS dysfunction in noncompressive myelopathy and there are no studies on compressive myelopathies. After excluding patients on cervical traction or with medical comorbidities, 29 adult patients with CCM were evaluated. Conventional autonomic function tests and HRV were studied in these patients. The same tests were done on 29 age- and sex-matched healthy controls. Student t test was used to find the significance of study parameters on continuous scale. Chi-square/Fisher exact test was used to find the significance of study parameters on categorical scale between two groups. Significance was assessed at 5% level. Patients with CCM as compared with controls, showed significant difference in following parameters; deep breathing, Valsalva ratio, 30:15 (longest RR interval (duration between two consecutive R waves of ECG) around 30th second and the minimum RR interval around 15 seconds after standing up), and orthostatic fall of blood pressure. Except 30:15, there was no significant change of other autonomic function tests after surgery. Among the HRV parameters, there was a trend in increase in total power and decrease in root-mean-square differences of successive RR intervals; however, it did not reach statistical significance. Patients with CCM have definite ANS dysfunction as compared to healthy age- and sex-matched controls. There is significant improvement in 30:15 ratio after surgery. HRV indices are also impaired and there is a trend for change in total power and root-mean-square differences of successive RR intervals suggesting loss of HRV.

Painful Diabetic Neuropathy Is Associated With Greater Autonomic Dysfunction Than Painless Diabetic Neuropathy

OBJECTIVEAlthough a clear link between diabetic peripheral neuropathy (DPN) and autonomic neuropathy is recognized, the relationship of autonomic neuropathy with subtypes of DPN is less clear. This study aimed to investigate the relationship of autonomic neuropathy with painless and painful DPN.RESEARCH DESIGN AND METHODSEighty subjects (20 healthy volunteers, 20 with no DPN, 20 with painful DPN, 20 with painless DPN) underwent detailed neurophysiological investigations (including conventional autonomic function tests [AFTs]) and spectral analysis of short-term heart rate variability (HRV), which assesses sympathovagal modulation of the heart rate. Various frequency-domain (including low frequency [LF], high frequency [HF], and total power [TP]) and time-domain (standard deviation of all normal-to-normal R-R intervals [SDNN] and root mean square of successive differences [RMSSD]) parameters were assessed.RESULTSHRV analysis revealed significant differences across the groups in LF, HF, TP, SDNN, and RMSSD (ANOVA P < 0.001). Subgroup analysis showed that compared with painless DPN, painful DPN had significantly lower HF (3.59 ± 1.08 [means ± SD] vs. 2.67 ± 1.56), TP (5.73 ± 1.28 vs. 4.79 ± 1.51), and SDNN (2.91 ± 0.65 vs. 1.62 ± 3.5), P < 0.05. No significant differences were seen between painless DPN and painful DPN using an AFT.CONCLUSIONSThis study shows that painful DPN is associated with significantly greater autonomic dysfunction than painless DPN. These changes are only detected using spectral analysis of HRV (a simple test based on a 5-min electrocardiogram recording), suggesting that it is a more sensitive tool to detect autonomic dysfunction, which is still under-detected in people with diabetes. The greater autonomic dysfunction seen in painful DPN may reflect more predominant small fiber involvement and adds to the growing evidence of its role in the pathophysiology of painful DPN.

A non-invasive method for testing neural circulatory control in man.

Exaggerated cardiovascular responsiveness is common in young men and may cause non-specific symptoms and poor performance. Conventional autonomic function tests are not clinically useful. We have therefore designed a thermal entrainment method to evaluate sympathetic and parasympathetic cardiovascular function in subjects with dystonic symptoms and orthostatic intolerance. Oscillations of thermal gradient in the skin were produced by standardised periodic stimulation of the lower part of the arm with warm and cool water. Vasomotor activity of the skin induced oscillations of arterial blood pressure which were thought to be regulated by sympathetic and parasympathetic heart rate control and by oscillation of the sympathetically controlled peripheral vascular resistance. We tested the method in subjects with cardiovascular symptoms (n = 7) and controls (n = 7). At supine rest, the frequency response of the heart rate variability to the thermal stimulation at frequencies of 0.01, 0.02, 0.03 and 0.1 Hz was significantly different (p = 0.008) between symptomatic subjects and controls. The gain of the heart rate control was increased to 0.03 Hz [-1.3(SEM 0.5) dB v -3.8(0.8) dB, p = 0.068] and decreased at 0.1 Hz [-3.9(1.1) dB v -1.5(0.6) dB, p = 0.076] in the test group compared to the control group. At stimulus frequencies of less than 0.03 Hz the individual overall heart rate variability of the subjects with symptoms stayed below the mean control value, at 60(6) ms v 79(15) ms, p = 0.16. The cutaneous temperature oscillations at the site of stimulation, frequency response of the oscillations of the skin blood flow and respiration to the thermal stimulation, and mean heart rate were similar in the both groups. The results show that this thermal entrainment method quantifies the increased sympathetic and decreased parasympathetic cardiac control of subjects with dystonic symptoms.

Changes in the human light reflex as a measure of the anticholinergic effects of drugs. A comparison with other measures

Single oral doses of atropine, nortriptyline, procyclidine and lactose dummy were administered double-blind to eight healthy young subjects in a balanced, crossover study. Television pupillometry was used to measure the anticholinergic effects of these drugs on the pupil diameter in darkness and the reflex response to light flashes. The sensitivity of this method was compared with conventional autonomic function tests, viz. salivary secretion, radial pulse, forearm sweat gland activity and distance to visual near point. Visual analogue scales were used to obtain subjective measures of sedative drug effects. The expected inhibition of parasympathetic activity was found in most instances with two exceptions: firstly, that nortriptyline failed to affect the pupil despite causing a tachycardia and secondly, that procyclidine gave a bradycardia. The results are discussed with reference to the possible advantages of television pupillometry over conventional pupil measurement in the detection of anticholinergic drug effects.