Heart Rate Variability in Patients of Ankylosing Spondylitis: A Systematic Review and Meta-Analysis.

Patients with ankylosing spondylitis (AS) have a significantly higher risk of cardiovascular morbidities. The participation of the autonomic nervous system (ANS) in AS is still unknown and inconclusive. Heart rate variability (HRV) is defined as the variability of the time interval between two consecutive heartbeats. This meta-analysis aims to detect the association of HRV and its various parameters with AS patients by comparing them to healthy controls. Research literature was searched in PubMed, Embase, and Cochrane Library databases from inception to April 2022. The Review Manager 5 (RevMan) Version 5.4 software was used to analyze the data. In addition, the protocol of systematic review is registered in the PROSPERO database with ID CRD42022336484. This study includes a total of nine case-control studies with a total of 923 patients; 409 with AS and 514 healthy controls. The root mean square of successive differences between normal heartbeats (RMSSD) [standardized mean difference (SMD); -0.47, 95% CI: -0.69 to -0.25, p < 0.0001], proportion of NN50 (pNN50) (SMD; -0.89, 95% CI: -1.74 to -0.04, p = 0.04) and HRV (SMD; -1.11, 95% CI: -1.53 to 0.69, P < 0.00001) were significantly low in AS cases compared to healthy controls. The HRV value was also significantly low in patients with high Bath ankylosing spondylitis disease activity (BASDAI) index (SMD: -1.45, 95% CI: -2.45 to -0.36, p < 0.009). HRV (parasympathetic activity) was significantly lowered in AS patients compared to healthy controls.

Vasoconstriction during non-hypotensive hypovolemia is not associated with activation of baroreflex: A causality-based approach.

Non-hypotensive hypovolemia simulated with oscillatory lower body negative pressure in the range of -10 to -20 mmHg is associated with vasoconstriction {increase in total peripheral vascular resistance (TPVR)}. Due to the mechanical stiffening of vessels, there is a disjuncture of mechano-neural coupling at the level of arterial baroreceptors which has not been investigated. The study was designed to quantify both the cardiac and vascular arms of the baroreflex using an approach based on Wiener-Granger causality (WGC) - partial directed coherence (PDC). Thirty-three healthy human volunteers were recruited and continuous heart rate and blood pressure {systolic (SBP), diastolic (DBP), and mean (MBP)} were recorded. The measurements were taken in resting state, at -10 mmHg (level 1) and -15 mmHg (level 2). Spectral causality - PDC was estimated from the MVAR model in the low-frequency band using the GMAC MatLab toolbox. PDC from SBP and MBP to RR interval and TPVR was calculated. The PDC from MBP to RR interval showed no significant change at -10 mmHg and -15 mmHg. No significant change in PDC from MBP to TPVR at -10 mmHg and -15 mmHg was observed. Similar results were obtained for PDC estimation using SBP as input. However, a significant increase in TPVR from baseline at both levels of oscillatory LBNP (p-value <0.001). No statistically significant change in PDC from blood pressure to RR interval and blood pressure to TPVR implies that vasoconstriction is not associated with activation of the arterial baroreflex in ≤-15 mmHg LBNP. Thereby, indicating the role of cardiopulmonary reflexes during the low level of LBNP simulated non-hypotensive hypovolemia.

COVID-19-induced Stress in Health-care Workers: Effect of 8-week Common Yoga Protocol on Autonomic Function and Inflammatory and Oxidative Stress Markers.

Background: COVID-19 pandemic posed a huge stress on health-care givers affecting their physical and mental health. Wellness strategies like yoga can improve flexibility, resilience, and outlook. Aim: The present study explored the effect of 8-week standard common yoga protocol (CYP) intervention on autonomic functions, emotional stress, oxidative stress, and inflammation markers in the nurse group of health-care givers. Materials and Methods: It is a randomized controlled trial where 50 nurses underwent CYP and 50 participated as controls. Anthropometric parameters, cardiovascular parameters, autonomic function including time and frequency domain parameters, biochemical parameters, and psychological stress using the questionnaire were assessed before and after 8-week CYP. Results: Total 88 nurses completed the study with 42 and 46 participants, respectively, in the CYP and control groups. CYP intervention resulted in a significant reduction in cardiovascular parameters systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, and rate pressure product (P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P = 0.002, respectively), perceived stress score and Depression, Anxiety, and Stress Scale psychological variables of depression, anxiety, and stress, and serum lipid parameters compared to the control group. CYP significantly increased total power, low frequency, high frequency, root mean square of successive differences between adjacent NN intervals, change in successive normal sinus (NN) intervals exceeds 50 ms, and pNN50% (P < 0.001, P = 0.006, P = 0.006, P = 0.039, P < 0.001, and P = 0.013, respectively) suggesting improved resting autonomic modulation and parasympathodominance due to higher vagal efferent activity. There were significant reductions in serum cortisol, tumor necrosis factor-alpha, interleukin (IL)-1, and IL-6 in both the groups. Serum telomerase significantly reduced (P = 0.024) and total antioxidant capacity (P = 0.036) increased in the CYP group post intervention. Conclusion: CYP intervention was beneficial in improving psychophysiological, autonomic, and biochemical profile of the nurse group of health-care workers.

Electroencephalography-based cortical sources of working memory in the subjects with opioid addiction: A pilot study.

Background & objectives: Working memory impairments in the subjects of opioid addiction may stem from an aberrant cortical activity in the executive areas, and may help in early identification of individuals with addictive tendencies and may also be used as a neurofeedback mechanism in adjunct to the existing therapeutics. Methods: Electrical neuroimaging via 128-channel electroencephalography (EEG) recording was done in 15 male subjects with opioid addiction (29.45±5.6 yr) during the performance of Sternberg Working Memory Task. EEG data were acquired and analyzed for cortical sources during task as compared to resting (baseline) condition. Results: Working memory deficits were manifested as decrease in accuracy percentage in the subjects with opioid addiction, while no significant difference was seen in reaction time, on comparison with laboratory-acquired matched controls. Standardized low-resolution brain electromagnetic tomography (sLORETA)-based EEG source analysis revealed higher cortical activity in the anterior cingulate cortex, inferior, middle and superior temporal gyri, inferior frontal gyrus, superior parietal lobule, inferior parietal lobule and precuneus, whereas significant lower activity was seen in superior and middle frontal gyri, parietal lobule, cingulate cortex and pre- and postcentral gyri when the task was compared to baseline in the subjects with opioid addiction. Further, a negative correlation was seen between the accuracy of task performance and activation ratio for the significant gyri in the subjects with opioid addiction. Interpretation & conclusions: EEG cortical sources revealed the failure of deactivation of default-mode network (DMN) during the task amongst the subjects with opioid addiction. In addition, there was a decrease in the executive function areas in the subjects with opioid addiction. This lack of sufficiently active executive network and persistence of DMN during the task (as compared to baseline) may potentially form the basis of functional impairments in the subjects with opioid addiction.