Cardiovascular Autonomic Deficits in Different Types of Achalasia.

Background and objective Achalasia cardia is a primary esophageal motility disorder, and the etiopathology of this disease's progression is not known. Moreover, autonomic dysfunction has not been studied in different types of achalasia. In light of this, we aimed to address this lack of data in this study. Methods The diagnosis of achalasia was done using high-resolution esophageal manometry (HRM)-based Chicago classification v4.0. Autonomic function tests (AFT) such as the head-up tilt test, deep breathing test (DBT), Valsalva maneuver (VM), handgrip test (HGT), and cold pressor test (CPT), as well as the heart rate variability (HRV) test, were performed among the cohort and the results were compared with those of 39 age- and sex-matched healthy controls. Results AFT and HRV tests were done on 62 patients (30 achalasia type I, 28 type II, and 4 type III) and compared with 39 age- and sex-matched healthy controls. The mean duration of symptoms, high Eckardt score, and dysphagia were most common in type I achalasia, followed by type II and III. The results of AFT showed a generalized loss of parasympathetic and baroreflex-independent sympathetic reactivity in all types of achalasia. However, baroreflex-dependent cardiovascular adrenergic reactivity was normal. Regarding cardiac autonomic tone, there was a loss of parasympathetic and sympathetic influence, but sympathovagal balance was maintained. The severity of the loss of autonomic functions was higher in type I, followed by type II. Conclusions In all types of achalasia, parasympathetic reactivity, baroreflex-independent sympathetic reactivity, and cardiac autonomic tone were lower compared to healthy controls, and the severity of dysfunction increased during the progression of the disease from type II to type I.

Effect of Yoga-Based Cardiac Rehabilitation Program on Endothelial Function, Oxidative Stress, and Inflammatory Markers in Acute Myocardial Infarction: A Randomized Controlled Trial.

Aims: The aim of this study was to evaluate the effects of yoga-based cardiac rehabilitation (Yoga-CaRe) on the endothelial system, oxidative stress, and inflammatory markers in patients with acute myocardial infarction (MI). Methods: A sub-study was conducted in two clinical sites of the Yoga-CaRe trial (a multicenter randomized controlled trial). Participants with acute MI were randomized and allocated to either the Yoga-CaRe program (13 sessions with encouragement to home practice) or enhanced standard care (three educational sessions). Endothelial function, oxidative stress, and inflammatory biomarkers were assessed using biomarkers such as asymmetric dimethylarginine (ADMA), endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), E-selectin, P-selectin, vascular cell adhesion molecule (VCAM), intercellular cell-adhesion molecule-1, total nitric oxide concentration (NOx), oxidized low-density lipoprotein (Oxd-LDL), superoxide dismutase, total antioxidant capacity (TAOC), tumor necrosis factor-alpha (TNFα), and C-reactive protein (CRP) at baseline and 12 weeks. Laboratory and statistical analysis were done by staff blinded to group allocation. Results: Eighty-two patients (of the 110 patients recruited) completed the study. The mean age was 53.1 ± 10.6 and 51.9 ± 10.7 years in enhanced standard care and Yoga-CaRe group, respectively. At 12 weeks, Yoga-CaRe significantly reduced ADMA, ET-1, and ICMA-1 than the enhanced standard care group. Although E-selectin and VCAM at 12 weeks were reduced in both groups, enhanced standard care had a significantly higher reduction than the Yoga-CaRe group. Among markers of oxidative stress, TAOC increased in the Yoga-CaRe group. We found no difference in eNOS, NOx, P-selectin, TNFα, CRP, and Oxd-LDL between the two groups. Conclusion: Yoga-CaRe improved the endothelial function (through a reduction in ET-1 and modulating adhesion molecules) and enhanced antioxidant capacity.

Effect of "365 Breathing Technique" on Intraocular Pressure and Autonomic Functions in Patients With Glaucoma: A Randomized Controlled Trial.

PRCIS: Patients with primary open angle glaucoma were advised to follow the "365 breathing technique" for 6 weeks in addition to their pharmacological glaucoma treatment. It helped to reduce intraocular pressure (IOP), stress biomarker-cortisol, and improve autonomic dysfunction. OBJECTIVE: To study the effect of the "365 breathing technique" on IOP, autonomic functions, and stress biomarkers in patients with primary open angle glaucoma. METHODS: In this randomized, controlled, interventional trial, after randomization, 40 patients in the intervention group followed "365 breathing" (three times a day, breathing rate: 6 cycles/min for 5 min) in addition to their pharmacological glaucoma treatment and 40 patients in the control group continued only with their pharmacological glaucoma treatment. IOP, serum cortisol, heart rate variability (HRV), and heart rate response to deep breathing test (DBT) were recorded at preintervention and 6 weeks postintervention. RESULTS: The mean IOP, serum cortisol, parameters of the HRV test, and DBT were comparable between the two groups at baseline. At the 6-week follow-up, in the intervention group, mean IOP was significantly lower (16.09 ± 2.24 vs 18.38 ± 1.58 mm Hg, P = 0.03) and serum cortisol were significantly lower (13.20 ± 3.11 vs 14.95 ± 2.60 mcg/dL, P = 0.038) compared with the control group. In the HRV test, time domain analysis showed a significant difference in the root mean square of the successive difference between RR interval values between both groups at 6 weeks ( P = 0.015) pointing towards higher postintervention parasympathetic activation in the intervention group. In frequency domain analysis (HRV test), the ratio of the low-frequency component to the high-frequency component was significantly lower in the intervention group at 6 weeks (1.65 vs 1.79, P = 0.019) indicating a shift in sympathovagal balance towards greater vagal modulation.There was a significant increase in delta heart rate ( P = 0.019) and expiratory:inspiratory ratio ( P = 0.011) in the intervention group at 6 weeks when compared with baseline values, indicating improved parasympathetic reactivity to DBT. CONCLUSION: "365 breathing" technique can reduce IOP and serum cortisol, and improve autonomic dysfunction in patients with glaucoma.

Assessment of Endothelial Reactivity by Measurement of Vascular Material Response to Shear Stress: A Feasibility Study.

Flow-mediated dilation (FMD) evaluates the relative change in arterial diameter during hyperemia to assess the endothelial response due to a shear stimulus. However, conventional FMD measures diameter response alone and the alterations in the arterial wall's material properties during reactive hyperemia, which also influence dilation, go unaddressed. In this work, we examine the material response (MR) of the artery during reactive hyperemia using clinically relevant stiffness markers for the assessment of endothelial reactivity (ER). For this, we have developed an in-house brachial cuff control (BCC) system to continuously acquire brachial pressure which can be integrated with simultaneous measurement of brachial diameter and used to quantify the relative changes in wall property during hyperemia non-invasively. The assessment of endothelial reactivity using material response (ERAMR) was conducted on 20 healthy participants (12M/8F) and the results were compared with conventional FMD (FMD%). The mean pressure response gave an inverse trend to that of diameter response with varying magnitudes during reactive hyperemia (18.71% from baseline for diameter and 2.45% for pressure), there was a significant difference in the measurement of FMD and ERAMR (P < 0.05). The larger distribution of ERAMR compared to FMD% in box-plots further implies the inclusion of within-subject variations. Hence, ERAMR can be a potential estimate of ER, given the need for intensive validations in this line on larger cohorts.Clinical Relevance- This study demonstrates the independent role of arterial wall material properties to quantify endothelial reactivity in response to a shear stimulus.

Normalization of Flow-mediated Dilation to Brachial Artery Material Property: A Feasibility Study.

Endothelial reactivity (ER) is widely measured using flow-mediated dilation (FMD) of brachial artery. Conventional measurement of FMD is influenced by factors such as input shear stress, arterial transmural pressure, diameter and thereby arterial material properties (ε). Thus, for a reliable interpretation of FMD, it has to be normalized with respect to the above confounding factors. Normalization of FMD with shear stress at the time of measurement has been reported to reduce measurement variability. However, its widespread usage among the research community is limited. In this work, we examine the feasibility of normalizing the brachial FMD index (FMD%) to ε : extrema (εp), baseline (εb) and extrema change (∆ε) post-ischemia using its inter-day variability against FMD. In-vivo measurements were performed on 10 participants for 2 consecutive days and simultaneous pressure-diameter cycles were collected to estimate the material properties during reactive hyperemia (RH). The box-whisker plot reveals differences in the mean and deviation of FMD to FMD|εb. A significant value for repeatability (ICC ≥ 0.6) was obtained for normalized FMD (FMD|εb) for specific stiffness index (ß), pressure-strain elastic modulus (Ep), and local pulse wave velocity (PWV) as compared to FMD. Hence, normalization of FMD% to arterial ε can potentially improve the measurement reliability of ER assessment.Clinical Relevance- This pilot study demonstrates the feasibility of brachial artery stiffness assessment during FMD and its potential use for normalizing the standard FMD measurement.

Baroreflex sensitivity is impaired in survivors of mild COVID-19 at 3-6 months of clinical recovery; association with carotid artery stiffness.

The association between the stiffening of barosensitive regions of central arteries and the derangements in baroreflex functions remains unexplored in COVID-19 survivors. Fifty-seven survivors of mild COVID-19 (defined as presence of upper respiratory tract symptoms and/or fever without shortness of breath or hypoxia; SpO2 > 93%), with an age range of 22-66 years (27 females) participated at 3-6 months of recovering from the acute phase of RT-PCR positive COVID-19. Healthy volunteers whose baroreflex sensitivity (BRS) and arterial stiffness data were acquired prior to the onset of the pandemic constituted the control group. BRS was found to be significantly lower in the COVID survivor group for the systolic blood pressure-based sequences (BRSSBP ) [9.78 (7.16-17.74) ms/mmHg vs 16.5 (11.25-23.78) ms/mmHg; p = 0.0253]. The COVID survivor group showed significantly higher carotid ß stiffness index [7.16 (5.75-8.18) vs 5.64 (4.34-6.96); (p = 0.0004)], and pulse wave velocity ß (PWVß ) [5.67 (4.96-6.32) m/s vs 5.12 (4.37-5.41) m/s; p = 0.0002]. BRS quantified by both the sequence and spectral methods showed an inverse correlation with PWVß in the male survivors. Impairment of BRS in the male survivors of mild COVID-19 at 3-6 months of clinical recovery shows association with carotid artery stiffness.

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.

Randomized double-blind, placebo-controlled study of oral gabapentin for prevention of neuropathy in patients receiving paclitaxel.

BACKGROUND: Peripheral neuropathy is a common dose-limiting side effect of paclitaxel. To date, there is no effective strategy to prevent paclitaxel-induced peripheral neuropathy. A recent small phase II study demonstrated the potential role of oral gabapentin in this setting. This phase III study is aimed to assess the efficacy of oral gabapentin in preventing paclitaxel-induced neuropathy. OBJECTIVE: To compare the efficacy of oral gabapentin with placebo in preventing clinically significant peripheral neuropathy (NCI CTCAEv5.0 grade 2 or higher) in patients receiving paclitaxel. METHODS: This is a randomized, placebo-controlled, double-blind, parallel-group superiority trial. The primary outcome is the development of grade 2 or higher chemotherapy-induced peripheral neuropathy. Secondary outcomes include any grade neuropathy, the percentage change in sensory nerve conduction velocities in peripheral nerves, time to development of any grade neuropathy, paclitaxel dose reductions and delays due to peripheral neuropathy, patient-reported outcomes, adverse events, and adherence to oral therapy. A total of 136 patients receiving paclitaxel will be randomly allocated (stratified by weekly vs. non-weekly administration) to receive either oral gabapentin or placebo till three weeks after the last dose of chemotherapy or occurrence of the primary outcome. CONCLUSION: This study aims to find if oral gabapentin reduces the incidence of grade 2 or higher chemotherapy-induced peripheral neuropathy in patients receiving paclitaxel. TRIAL REGISTRATION: The trial is registered prospectively with the Clinical Trials Registry of India (CTRI/2022/02/040030) on April 4, 2022.

Coronary artery disease and its vascular associates in patients with chronic nonsurgical hypoparathyroidism.

OBJECTIVE: Patients with chronic hypoparathyroidism (cHypoPT) are prone to intracranial-calcification, cataract and nephrocalcinosis. In this study, we systematically investigated the possibility of increased coronary artery calcification (CAC) and coronary artery disease (CAD) in them. DESIGN: Cross-sectional. PATIENTS AND MEASUREMENTS: Ninety-four nonsurgical cHypoPT (M:F = 50:44; age = 45 ± 15 years) with 18.6 ± 9.3 years of illness were assessed. Those with dyspnoea, angina, syncope, abnormal electrocardiogram, echocardiography or significant CAC underwent coronary angiography or myocardial-perfusion-stress imaging. Their lipid parameters and high-sensitivity C-reactive protein (hsCRP) were compared with age-matched healthy controls (Group A, n = 101). The prevalence of CAC in cHypoPT was compared with that of subjects referred from cardiology-clinics (Group B, n = 148, age = 52 ± 11 years). RESULTS: One of 94 cHypoPT had known CAD. On screening, 17 cHypoPT required evaluation for CAD. Two of 17 had severe coronary stenosis, and 12 showed subclinical CAD. CAC and aortic-valve calcification occurred in 21.5% and 11.8%. Clinical and subclinical CAD, CAC and aortic-valve calcification in cHypoPT ≥50 years of age was 8.1%, 27.0%, 52.8% and 27.8%, respectively. Frequency of age-adjusted CAC was comparable between cHypoPT and control Group B (30.2% vs. 30.7%, p = .93). Elevated hsCRP was higher in cHypoPT than in controls A (52% vs. 32%, p < .01). Factors associated with CAD in cHypoPT were CAC and hypertension. However, CAD and CAC showed no association with long-term calcemic or phosphatemic control and intracranial-calcification in cHypoPT. CONCLUSIONS: Clinical and subclinical CAD was observed in 3.2% and 12.8% of cHypoPT patients. The increased prevalence of CAD, CAC and aortic-valve calcification in cHypoPT above 50 years of age suggested their careful cardiac evaluation during follow-up.

Differential role of central and peripheral arterial stiffness in determining brachial artery resting retrograde flow in patients with ischemic heart disease vs healthy subjects.

Retrograde flow in endothelial cell cultures has been shown to induce a pro-atherogenic phenotype. Despite its potential role as a pathophysiological link between cardiovascular risk factors and atherosclerotic disease, resting retrograde flows between patients with cardiovascular disease and healthy subjects have not been compared. Further, the vascular characteristics governing retrograde flow in human arteries have not been systematically investigated. Association of central and peripheral vascular characteristics with retrograde flow profile was investigated in 32 healthy subjects and 47 patients with ischemic heart disease. Endothelial dysfunction was assessed by brachial ultrasound-based calculation of flow-mediated dilation (FMD) and sub-clinical atherosclerosis was estimated from carotid-intima media thickness (CIMT). Retrograde blood flow velocity (RBFV) and shear rate were comparable between the two groups (RBFV 1.82(0.97-3.32) vs 1.78(1.24-2.65) cm/s p = 0.79). Augmentation index was a significant determinant of retrograde flow in both patients and healthy subjects. Carotid artery incremental elastic modulus was an independent determinant of retrograde flow patterns in healthy subjects while ejection fraction, cf/cr PWV ratio and forearm vascular conductance emerged as independent determinants in patients. Retrograde flow patterns were also associated with FMD (RBFV r = -0.43, p = 0.004) and CIMT (r = 0.30, p = 0.041) in patients. The results of the study suggest a difference in the determinants of retrograde flow in patients and healthy subjects, with central arterial stiffness being a major contributor in healthy subjects while interaction between central, peripheral, and cardio-arterial factors influence retrograde flow in patients with ischemic heart disease.

Effect of Yoga Based Cardiac Rehabilitation on Blood Pressure Variability and Baroreflex Sensitivity: RCT in Patients Post MI.

To assess the effects of 12 weeks Yoga based Cardiac Rehabilitation program on Blood Pressure Variability and Baroreflex Sensitivity in Eighty patients post myocardial infarction. Randomized controlled trial with two parallel groups. A tertiary care institution in India. The Yoga group received 13 hospital-based structured yoga sessions in adjunct to the standard care. Control Group participants received enhanced standard care involving three brief educational sessions on importance of diet and physical activity. Beat to beat arterial pressure variability and baroreflex sensitivity was determined non-invasively. Baseline measurement was done at 3 weeks post Myocardial Infarction. The measurements were repeated at 13th week and at 26th week post MI. There was no significant difference between the groups in time domain indices of SBP variability. At 26th week post MI, after normalization the Low Frequency power increased in the yoga group as compared to the decrease in the standard care group (p = 0.02). Though the High Frequency power increased in both the groups, the magnitude of increase was higher in the standard care group (p = 0.005). However, the total power increased significantly in yoga group with a concurrent decrease in standard care group (p = < 0.001). The SBP All BRS was significantly different between the groups with an increase in the yoga group and a decline in standard care group (p = 0.003) at 13th week. A short-term Yoga based cardiac rehabilitation has additive effects in improving baroreflex sensitivity and dampening blood pressure variability post myocardial infarction in patients under optimal medication.The main trial is registered in Clinical Trials Registry-India (CTRI) (Ref. No: CTRI/2012/02/002408). In addition, CTRI has also been registered for the sub-study. (Ref. No: CTRI/2017/09/009925).

Aerobic and anerobic contamination of mobile phones of health personnels with probable transfer of bacterial microbes to their hands at a tertiary care hospital of India.

Background and Aims: Mobile phone (MP) contamination of health personnels (HPs) in hospitals is a potential health hazard to the patients and the HP themselves. However, transfer of microbes from MPs of HP to their hands has not been demonstrated before, which would make potential threat into an actual peril. The primary objective was to determine aerobic and anerobic bacterial contamination of MP and hands of HP. The secondary objective was to determine probable transfer of bacterial microbes from MP to hands of tested HP. Material and Methods: Three swabs each were taken from 374 HP first from their MP, second from their dominant hand and third from their dominant hand after cleaning with disinfectant followed by a mock phone call of one minute (DHM). Aerobic and anerobic bacterial microbes were identified with standard methods. Results: Three hundred twenty-two HPs were recruited. Bacterial contamination was seen in 92% MP, 85% dominant hands, and 68% DHM of tested HP. Of these, contamination with potentially pathogenic bacterias (PPB) was 50% in MP, 25.6% in hands, and 31% in DHM. Anerobic contamination (1.6%) was present on MP but not in hands or DHM. In 54.7% HP, there was presence of similar bacterial microbes in MP and DHM of which 30% were PPB. When disinfectant was used in non-protocolized way in DHM, decrease in aerobic spore forming bacteria (ASB) was seen but not of gram-positive and gram-negative bacterial microbes. Conclusion: There is significant aerobic bacterial contamination, including PPB, seen in MP, hands, and DHM of HP in a tertiary care hospital of India; however, anerobic bacterias are found only in MP. Similar bacterial microbes in MP and DHM point to probable transfer of aerobic bacterias from MP to hands of HP which does not decrease when hand disinfectants are used in non-protocolized way, which is a point of concern.

Evaluation of Sympathetic and Parasympathetic Tone and Reactivity in Adolescents with Specific Learning Disorder (Dyslexia).

OBJECTIVES: To evaluate the autonomic function in specific learning disorder (SLD) and comorbid SLD attention-deficit hyperactivity disorder (SLD-ADHD). METHODS: A cross-sectional study was conducted in a tertiary care hospital with 20 adolescent subjects each of confirmed SLD, SLD-ADHD, and healthy control (mean age 15.32 y). Heart-rate variability and autonomic-function tests were carried out using standard protocols. RESULTS: Heart-rate variability parameters, viz., mean RR interval, number of RR intervals which differ by ≥ 50 ms (NN50), percentage NN50, standard deviation of differences between adjacent RR intervals, root square of mean of the sum of the squares of differences between adjacent RR intervals, coefficient of variance and absolute power of high-frequency band (HF) recorded apparently lower levels in SLD and SLD-ADHD as compared to healthy control indicating lower parasympathetic tone. Whereas, higher absolute power of low- frequency band (LF) in SLD and SLD-ADHD than healthy control indicated enhanced sympathetic activity. Higher LF/HF and lower SD1/SD2 ratios in SLD and SLD-ADHD than healthy control indicated higher sympathetic tone over parasympathetic tone. Values of autonomic-function tests such as E:I ratio, change in heart rate during deep-breathing test, 30:15 ratio, and Valsalva ratio showed a decrease in SLD and SLD-ADHD as compared to healthy control implying reduction in parasympathetic reactivity. Increased values for rise in diastolic blood pressure in the isometric handgrip test and cold pressor test recorded in SLD as compared to healthy control, revealed the increased sympathetic reactivity. CONCLUSION: Overall, results of heart-rate variability and autonomic-function tests imply dysregulation of sympathetic and parasympathetic activities with sympathetic dominance in SLD and SLD-ADHD.

The effect of Bacillus coagulans Unique IS-2 supplementation on plasma amino acid levels and muscle strength in resistance trained males consuming whey protein: a double-blind, placebo-controlled study.

PURPOSE: The aim of the present study was to assess the effect of Bacillus coagulans Unique IS-2 supplementation on absorption and utilization of protein in resistance-trained males. METHODS: In this double blind, placebo-control trial, resistance-trained males (21.08 ± 2.84 years) were randomized to consume, either 20 g of whey protein powder {80% whey protein concentrate (WPC80), amounting to 15.4 g protein} with 2 billion CFU Bacillus coagulans Unique IS-2 (supplemental group) or 20 g of whey protein powder and lactose instead of Bacillus coagulans (placebo group) once daily for 60 days with a controlled resistance exercise protocol. The whey protein concentrate (WPC-80) given to both groups had a lactose content of 6.8%. Plasma-free amino acids (PFAAs) were determined at baseline, at 30 and 60 days of supplementation. Muscle strength, hypertrophy, VO2 max, and body composition, and other biochemical parameters were assessed at baseline and end line. RESULTS: A positive effect of probiotic Bacillus coagulans Unique IS-2 supplementation was observed on protein absorption as evidenced by an increase in total PFAA by + 16.1% (p = 0.004). Branched chain amino acids (BCAA) comprising isoleucine (p = 0.016), leucine (p = 0.001), and valine (p = 0.002) were increased by + 33.1% in ITT analysis as compared to placebo after 60 days. At 30 days an increase in isoleucine by + 35% (p = 0.113), leucine by + 43% (p = 0.032), and valine by + 32% (p = 0.017) was observed in ITT analysis. Probiotic effect was shown on exercise performance as evidenced by an increase in one RM of leg press and vertical jump power by + 16.61% (p = 0.024) and + 7.86% (p = 0.007), respectively. CONCLUSION: Significantly increased absorption of BCAA with supplementation of B. coagulans Unique IS-2 along with whey protein and improvement in leg press and vertical jump power was noted indicating the positive effect of the probiotic on muscle power in the lower body. TRIAL REGISTRATION NUMBER: CTRI/2017/03/008117; Date:16.03.2017.

High-frame-rate A-mode ultrasound for calibration-free cuffless carotid pressure: feasibility study using lower body negative pressure intervention.

PURPOSE: Existing technologies to measure central blood pressure (CBP) intrinsically depend on peripheral pressure or calibration models derived from it. Pharmacological or physiological interventions yielding different central and peripheral responses compromise the accuracy of such methods. We present a high-frame-rate ultrasound technology for cuffless and calibration-free evaluation of BP from the carotid artery. The system uses a pair of single-element ultrasound transducers to capture the arterial diameter and local pulse wave velocity (PWV) for the evaluation of beat-by-beat BP employing a novel biomechanical model. MATERIALS AND METHODS: System's functionality assessment was conducted on eight male subjects (26 ± 4 years, normotensive and no history of cardiovascular risks) by perturbing pressure via short-term moderate lower body negative pressure (LBNP) intervention (-40 mmHg for 1 min). The ability of the system to capture dynamic responses of carotid pressure to LBNP was investigated and compared against the responses of peripheral pressure measured using a continuous BP monitor. RESULTS: While the carotid pressure manifested trends similar to finger measurements during LBNP, the system also captured the differential carotid-to-peripheral pressure response, which corroborates the literature. The carotid diastolic and mean pressures agreed with the finger pressures (limits-of-agreement within ±7 mmHg) and exhibited acceptable uncertainty (mean absolute errors were 2.4 ± 3.5 and 2.6 ± 4.0 mmHg, respectively). Concurrent to the literature, the carotid systolic and pulse pressures (PPs) were significantly lower than those of the finger pressures by 11.1 ± 9.4 and 11.3 ± 8.2 mmHg, respectively (p < .0001). CONCLUSIONS: The study demonstrated the method's potential for providing cuffless and calibration-free pressure measurements while reliably capturing the physiological aspects, such as PP amplification and dynamic pressure responses to intervention.

Student perceptions on synchronous virtual versus face-to-face teaching for leader-centered and participant-centered postgraduate activities during COVID-19.

Consequent to the unprecedented COVID-19 pandemic, pedagogic changes were introduced in postgraduate courses in Physiology, where face-to-face teaching was replaced with synchronous virtual mode for leader-centered (seminar, symposium) and participant-centered (journal club, group discussion) academic activities. We hypothesized that the effectiveness of virtual and face-to-face modes as perceived by postgraduate students in terms of facilitating their overall learning may differ across the spectrum of leader-centered and participant-centered activities. To assess the same, we designed and administered a comprehensive, structured, and validated feedback questionnaire. Postgraduate students (n = 29) rated virtual sessions significantly more convenient, but less attentive and comprehensible, and reported better audiovisual experience during face-to-face sessions. Students rated flexibility to attend, self-paced learning, ability to revise, lookup for information in real time, and accessibility to distant expertise as important features of virtual sessions and instant feedback, eye-to-eye contact, and ability to interact in the group for face-to-face sessions. Virtual and face-to-face sessions were perceived as equally effective in facilitating their overall learning for the conduct of leader-centered seminars and symposia. However, face-to-face sessions were considered more effective for the conduct of participant-centered group discussions and journal clubs. During the pandemic, students perceive the synchronous virtual mode as an equally effective alternative for the conduct of leader-centered academic activities, but face-to-face teaching is still preferred for the conduct of participant-centered academic activities.

Association of incremental pulse wave velocity with cardiometabolic risk factors.

We investigate the association of incremental pulse wave velocity (ΔC; the change in pulse wave velocity over a cardiac cycle) with cardiometabolic risk factors and report the first and (currently) the largest population-level data. In a cross-sectional study performed in a cohort of 1373 general population participants, ΔC was measured using clinically validated ARTSENS devices. There were 455 participants in the metabolic syndrome (MetS) group whose average ΔC was ~ 28.4% higher than that of the non-metabolic syndrome (Non-MetS) group. Females with MetS showed ~ 10.9% elevated average ΔC compared to males of the Non-MetS group. As the number of risk factors increased from 0 to 5, the average ΔC escalated by ~ 55% (1.50 ± 0.52 m/s to 2.33 ± 0.91 m/s). A gradual increase in average ΔC was observed across each decade from the younger (ΔC = 1.53 ± 0.54 m/s) to geriatric (ΔC = 2.34 ± 0.59 m/s) populations. There was also a significant difference in ΔC among the blood pressure categories. Most importantly, ΔC ≥ 1.81 m/s predicted a constellation of ≥ 3 risks with AUC = 0.615, OR = 2.309, and RR = 1.703. All statistical trends remained significant, even after adjusting for covariates. The study provides initial evidence for the potential use of ΔC as a tool for the early detection and screening of vascular dysfunction, which opens up avenues for active clinical and epidemiological studies. Further investigations are encouraged to confirm and establish the causative mechanism for the reported associations.

Adaptive strategies to conduct participant-centric structured virtual group discussions for postgraduate students in the wake of the COVID-19 pandemic.

In the wake of COVID-19, the postgraduate activities in physiology were shifted from live (face-to-face teaching) to virtual mode. This transition posed a challenge to postgraduate students and faculty moderators, especially for participant-centric group discussion, wherein face-to-face interaction contributes significantly to active learner engagement. To bridge the gap between live group discussion (GD) and virtual GD in the conventional format (VGD), we implemented an innovative yet feasible multistep approach of conducting structured virtual group discussion (sVGD). It involved priming of students during the preparatory phase and incorporation of the Tuckman model of group dynamics, which consists of sequential substages of forming, storming, norming, and performing into the virtual format. Unsupervised synchronous and asynchronous, as well as supervised synchronous interactions within and in between the minigroups in a structured way, led to active engagement of students with one another and the moderator, despite the constraints imposed by the virtual format. After establishing the feasibility of the approach during the first GD (sVGD-1), sVGD-2 was conducted, further refining the approach, and feedback was obtained from the postgraduate students. Pre-GD feedback revealed that the live session was preferred over virtual for the conduct of GD, whereas both live GD and sVGD were perceived to be more effective than VGD in the post-GD feedback. Such pedagogical innovations may also help to address the challenges posed in traditional teaching across the undergraduate and postgraduate courses in medical education and beyond during such unforeseeable circumstances.

Brachial Artery "Low-Flow Mediated Constriction" Is Associated with Myocardial Perfusion Defect Severity and Mediated by an Altered Flow Pattern during Occlusion.

INTRODUCTION: The relationship between low flow-mediated constriction (LFMC), a new proposed measure of endothelial function, with cardiovascular disease severity and its hypothesized stimulus, that is, low flow, has not been comprehensively evaluated. The study evaluated association between change in brachial artery diameter during constriction with severity of myocardial perfusion defect (PD) and alterations in different components of flow profile. METHODS: Brachial artery responses to occlusion were assessed in 91 patients and 30 healthy subjects. Change in anterograde and retrograde blood flow velocities (delta anterograde blood flow velocity and retrograde blood flow velocity), anterograde shear rate and retrograde shear rate (delta ASR and RSR, respectively), and oscillatory shear index (delta) during forearm occlusion at 50 mm Hg above systolic pressure, from baseline was calculated. Myocardial perfusion was evaluated in patients using exercise single positron emission computed tomography and % myocardial PD was calculated from summed stress score. RESULTS: LFMC emerged as independent predictor of defect severity after correcting for age and gender (p = 0.014). Sixty-seven patients (73.6%) and 15 healthy subjects (50%) showed constriction during occlusion. In stepwise backward regression analysis, RSR contributed 35.5% and ASR contributed 20.1% of the total 63.9% variability in artery diameter during occlusion. CONCLUSION: The results suggest that LFMC is independently associated with myocardial perfusion severity and is "mediated" by an altered flow profile during occlusion.