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.

Planning and implementation of participant-centric group activity on research methodology: perceptions of postgraduate medical students in physiology.

Knowledge about the key steps in "research methodology" is necessary for all postgraduate students who are enrolled in the medical profession. The objective of the present study was to plan, design, and implement a participant-centric postgraduate skill development activity to inculcate the key principles and components of research methodology. It included 3 goal-oriented component group exercises, namely, 1) framing a research question, 2) critiquing a research article, and 3) writing a research protocol. Out of 25 eligible postgraduate students of our department, 20 participated in all three component group exercises, and they were included in the study. Feedback was obtained from them on a five-point Likert scale after the group exercises. In addition, students were also asked to provide open-ended comments for further improvement of the session. Data from participants' feedback suggested that the majority of the participants expressed satisfaction regarding the plan, conduct, and learning experience of the postgraduate activity. Therefore, participant-centric group activity could be an innovative approach in postgraduate medical education to inculcate the basics of research methodology. It can provide additional emphasis on the components of self-directed learning through individual exercises and unsupervised group dynamics. Supervised group dynamics can inculcate skills in critical thinking, acceptance, communication skills, and teamwork.NEW & NOTEWORTHY Postgraduate medical education is underpinned by supervised and unsupervised learning processes. The current study incorporates an innovative approach to inculcate the basic skills of "research methodology" through three goal-oriented participant-centric group exercises, namely, 1) framing a research question, 2) critiquing a research article, and 3) writing a research protocol. The activities encompass components of self-directed learning through unsupervised group dynamics. They focus on critical thinking, acceptance, communication skills, and teamwork during supervised group dynamics.

Introducing virtual classrooms for undergraduate physiology teaching during the COVID-19 pandemic: acceptance by students and subjective impact on learning.

The COVID-19 pandemic and worldwide lockdowns brought major changes in education systems. There was a sudden obligatory shift toward utilization of digital resources for teaching and learning purposes. Medical education, specifically physiology teaching, comprises hands-on training in the laboratory. It is challenging to offer a course like physiology in a virtual format. The objective of this study was to assess the effectiveness and influence of virtual classroom technology on online physiology education in a sample size of 83 first-year MBBS undergraduates. A questionnaire comprising questions related to technology accessibility and utilization, comprehensibility and effectiveness of instructions, faculty proficiency, and learning outcomes was administered to the group. The responses were collected and analyzed. Validation through principal components and factor analysis showed that online teaching is not very effective and has a limited application in the physiology education of undergraduate MBBS students. Our study also revealed that virtual physiology teaching of undergraduate medical students during the COVID-19 pandemic had a moderate level of effectiveness.NEW & NOTEWORTHY In the present qualitative study, we have conducted and validated an online physiology teaching platform at a medical college to continue medical education during the peak times of the COVID-19 pandemic and prolonged lockdowns. Furthermore, we have evaluated the effectiveness of online physiology teaching through multidimensional feedback from undergraduate MBBS students. It is experimental evidence of inadequate sustainability, moderate efficacy, limited application, and poor first-hand experience gained by the students in virtual physiology teaching in a preclinical and clinical setting.

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).

Developing a "dry lab" activity using lower body negative pressure to teach physiology.

In this paper we assessed how lower body negative pressure (LBNP) can be used to teach students the physiological effects of central hypovolemia in the absence of the LBNP and/or a medical monitor using a "dry lab" activity using LBNP data that have been previously collected. This activity was performed using published LBNP papers, with which students could explore LBNP as an important tool to study physiological responses to central hypovolemia as well as consider issues in performing an LBNP experiment and interpreting experimental results. The activity was performed at the All India Institute of Medical Sciences, New Delhi, with 31 graduate students and 4 teachers of physiology. Both students and teachers were provided with a set of questionnaires that inquired about aspects related to the structure of the activity and how this activity integrated research and knowledge, as well as aspects related to motivation of the students and teachers to perform the activity. Our results from student and teacher surveys suggest that a "dry lab" activity using LBNP to teach physiology can be an important tool to expose students to the basics of systems physiology as well as to provide useful insights into how research is performed. Providing insight into research includes formulating a research question and then designing (including taking into account confounding variables), implementing, conducting, and interpreting research studies. Finally, developing such an activity using LBNP can also serve as a basis for developing research capacities and interests of students even early in their medical studies.

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.

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.

Sequential analysis of heart rate variability, blood pressure variability and baroreflex sensitivity in healthy pregnancy.

OBJECTIVE: The aim of this study was to demonstrate the temporal profile of changes in heart rate variability (HRV), blood pressure variability (BPV), and cardiac baroreflex sensitivity (BRS) during the course of a healthy pregnancy. MATERIALS AND METHODS: This was a longitudinal study during which autonomic variability parameters (HRV, BPV, BRS) were assessed in 66 pregnant women at 11-13, 20-22 and 30-32 weeks of gestation. A lead II electrocardiogram tracing and beat-to-beat blood pressure were recorded with the subject breathing spontaneously in the supine position. Changes in the parameters were analyzed using repeated measures analysis of variance. RESULTS: Overall HRV (SDNN; standard deviation of all NN intervals) was found to decrease significantly over the course of pregnancy (p < 0.05). Similarly, indices which represent the parasympathetic component of these variables (SDSD [standard deviation of differences between adjacent NN intervals]; pNN50 [NN50 count {number of pairs of adjacent NN intervals differing by more than 50 ms} divided by the total number of all NN intervals]; high-frequency [HF] power) were also found to decrease significantly from the first to third trimester of pregnancy (p < 0.05). Low-frequency (LF) power increased over the course of pregnancy (p < 0.05). The LF/HF ratio increased significantly from first to third trimester of pregnancy (median: 0.66 [first trimester] vs.1.02 [second] vs. 0.91 [third]; p < 0.05) Overall BPV increased during the course of pregnancy, with a significant rise in the HF component of BPV and a significant fall in the LF component of BPV with advancing gestation (p < 0.05). BRS decreased over the course of pregnancy (median: 16.31, interquartile range [IQR] 11.04-23.13 [first trimester] vs. 11.42, IQR 8.54-19.52 [second] vs. 8.84, IQR 7.15-12.45 [third] ms/mmHg; p < 0.05). CONCLUSION: Pregnancy is associated with decreased vagal and increased sympathetic modulation of cardiac autonomic tone with advancing gestation, together with increased BPV. The reduction in cardiac BRS may play a role in increasing BPV and decreasing HRV over the course of pregnancy.

Effect of slow breathing on autonomic tone & baroreflex sensitivity in yoga practitioners.

BACKGROUND & OBJECTIVES: Slow breathing increases parasympathetic activity and baroreflex sensitivity (BRS) in healthy individuals, also similarly observed in yoga practitioners. Pranayama which is an important component of yoga when practiced at a slow pace was at a respiratory frequency of around 0.1 Hz (6 breaths/min). Therefore, it was hypothesized that yoga practitioners might have adapted to slow breathing. This study was aimed to decipher the role of yoga on cardiovascular variability during slow breathing (0.1 Hz) in yoga practitioners. METHODS: A cross-sectional study was undertaken in naïve-to-yoga individuals (n=40) and yoga practitioners (n=40) with an average age of 31.08 ± 7.31 and 29.93 ± 7.57 yr, respectively. The analysis of heart rate variability, blood pressure variability (BPV) and BRS during spontaneous and slow breathing was compared between the two groups. RESULTS: During slow breathing, the heart rate (P<0.01) was lower, respiratory rate interval (P<0.05) and pNN50 per cent (P=0.01) were higher, mean systolic BP (SBP) (P<0.05) and SDSD (Standard deviation of successive beat to beat systolic blood pressure differences) (P<0.01) of SBP variability were lower with sequence BRS (P<0.001) and α low frequency (P<0.01) and α high frequency (P<0.001) of spectral BRS were higher in yoga practitioners. INTERPRETATION & CONCLUSIONS: The present study indicated higher parasympathetic activity and BRS with lower SBP variability at rest and during slow breathing in yoga practitioners compared to naive group. Findings indicate that the short-term practice of slow breathing complements the augmented parasympathetic activity and BRS in the yoga group.

Contribution of systemic vascular reactivity to variability in pulse volume amplitude response during reactive hyperemia.

PURPOSE: The aim of the present study was to investigate why the magnitude of reactive hyperemia (RH) observed by pulse volume amplitude (PVA) after arm occlusion differs greatly among study subjects. METHODS: Healthy subjects (n = 12) in the age range of 22-30 years participated in this study. Vascular reactivity was assessed by measuring the changes in finger PVA simultaneously in the test (occluded arm) and control arm (contralateral non-occluded arm) using two separate Photoplethysmographic sensors. Short-term HRV was computed from simultaneously acquired lead II ECG signal to monitor the changes in cardiac sympathetic nervous activity. RESULTS: The observed coefficient of variation for inter-subject variability in PVA response in test arm during second minute of RH was 115.3%. In the control arm, significantly reduced PVA was observed during the period of occlusion as well as RH. This observation was corroborated by simultaneously acquired short-term HRV which showed a significant rise in total power (p value < 0.005) and low-frequency (LF) power (p value < 0.05) during release of occlusion when compared to the baseline. A significant positive correlation (Spearman r = 0.33; p = 0.02) was observed between % change in PVA in the control arm and in the test arm for first 3 min of RH. CONCLUSIONS: Sympathetic activation possibly plays an important role in mediating the inter-subject variability of vascular responses during reactive hyperemia which warrants simultaneous recording of both the test and the control arm responses during RH to accurately assess endothelial function.

The temporal trend of vascular function in women with gestational diabetes.

The objective of the study was to assess the temporal changes in vascular function during pregnancy in healthy women and in those with gestational diabetes mellitus (GDM). Assessment of vascular function was done at three time points, 11-13+6 weeks+days, 20-22+6 weeks+days and 30-32+6 weeks+days, by flow-mediated dilatation (FMD), augmentation index (AIx) and carotid-radial pulse wave velocity (crPWV) in women ( n=100) with singleton pregnancies. Out of the 100 women, 20 developed GDM, who were compared with 20 healthy, age-matched pregnant women in a nested case-control design. Women with GDM had lower FMD% in the third compared to the first trimester (6.77 (4.36-9.96) vs 9.76 (6.66-16.61)%; p = 0.026); however, FMD% was similar on inter-group comparison between GDM and healthy pregnancies. AIx was significantly higher in GDM than healthy pregnancies at both first (15.35 ± 10.57 vs 6.45 ± 9.81%; p<0.05) and second trimesters (15.00 ± 8.44 vs 2.50 ± 9.01%; p<0.05). A higher AIx in early pregnancy differentiates women with GDM from those with healthy pregnancies.

Acute effects on cardiovascular oscillations during controlled slow yogic breathing.

BACKGROUND & OBJECTIVES: Breathing exercises are believed to modulate the cardiovascular oscillations in the body. To assess the validity of the assumption and understand the underlying mechanism, the key autonomic regulatory parameters such as heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were recorded during controlled slow yogic breathing. Alternate nostril breathing (ANB) was selected as the yogic manoeuvre. METHODS: Twelve healthy volunteers (age 30±3.8 yr) participated in the study. ANB was performed at a breathing frequency of 5 breaths per minute (bpm). In each participant, the electrocardiogram, respiratory movements, beat-to-beat BP and end-tidal carbon dioxide were recorded for five minutes each: before, during and after ANB. The records were analyzed for HRV, BPV and BRS. RESULTS: During ANB, HRV analysis showed significant increase in the standard deviation of all NN intervals, low-frequency (LF) component, LF/HF (low frequency/high frequency) ratio and significant decrease in the HF component. BPV analysis showed a significant increase in total power in systolic BPV (SBPV), diastolic BPV (DBPV) and mean BPV. BRS analysis showed a significant increase in the total number of sequences in SBPV and DBPV and significant augmentation of α-LF and reduction in α-HF. The power spectrum showed a dominant peak in HRV at 0.08 Hz (LF component) similar to the respiratory frequency. The acute short-term change in circulatory control system declined immediately after the cessation of slow yogic breathing (ANB) and remained elevated in post-ANB stage as compared to the pre-ANB. INTERPRETATION & CONCLUSIONS: Significant increase in cardiovascular oscillations and baroreflex recruitments during-ANB suggested a dynamic interaction between respiratory and cardiovascular system. Enhanced phasic relationship with some delay indicated the complexity of the system. It indicated that respiratory and cardiovascular oscillations were coupled through multiple regulatory mechanisms, such as mechanical coupling, baroreflex and central cardiovascular control.

Association of impaired baroreflex sensitivity and increased arterial stiffness in peritoneal dialysis patients.

BACKGROUND: Peritoneal dialysis patients have high cardiovascular morbidity and mortality. The underlying mechanism of cardiovascular dysfunction remains unclear. Large arterial stiffness in chronic kidney disease (CKD) patients leads to increase in pulse wave velocity (PWV) and decrease in baroreflex sensitivity (BRS). Impairment in baroreflex function could be attributed to the alteration in mechanical properties of large vessels due to arterial remodeling observed in these patients. The present study was designed to study the association of BRS and PWV in peritoneal dialysis (PD) patients. METHODS: 42 CKD patients (21--without dialysis and 21--on PD) and 25 healthy controls were recruited in this study. BRS was determined by spontaneous sequence method. Short-term heart rate variability (HRV) and blood pressure variability (BPV) were assessed using power spectrum analysis of RR intervals and systolic blood pressure by time domain and frequency domain analysis. Arterial stiffness indices were assessed by carotid-femoral PWV using Sphygmocor Vx device (AtCor Medical, Australia). RESULTS: CKD patients had significantly high PWV and low BRS as compared to healthy controls. PWV had a significant negative correlation with BRS in CKD patients (Spearman r = -0.7049, P < 0.0001; BRS-Systolic BP). On subgroup analysis, PWV was higher with lower BRS in CKD patients on peritoneal dialysis (CKD-PD) as compared to those not on dialysis (CKD-ND). Negative relationship between PWV and BRS was found in both the groups. In addition, BRS was found to have a positive correlation with HRV in CKD patients as well as both the subgroups. CONCLUSION: Reduction in BRS is strongly associated with increase in PWV in PD patients. Large arterial stiffness probably explains this simultaneous impairment in baroreflex functioning and increase in pulse wave velocity observed in these patients. CKD patients are characterized by poor hemodynamic profile (low BRS, high PWV, and low HRV), and peritoneal dialysis patients had further worsened profile as compared to non-dialysis group.

Waist Circumference Rather than Body Mass Index is Better Indicator of Insulin Resistance in Type 2 Diabetes Mellitus in North Indian Population.

Obesity and insulin resistance (IR) are associated with type 2 diabetes mellitus (DM). Obesity can be quantified by body mass index (BMI) and waist circumference (WC). Similarly, IR is commonly quantified by fasting-plasma-insulin (FPI) and Homeostatic model assessment (HOMA-IR). We aimed our study to find correlation between obesity-parameters and IR especially in the Indian population where despite lower BMI there is more prevalence of type 2 DM. In 34 uncomplicated patients of type 2 DM weight and WC were measured and BMI was calculated. HOMA-IR and FPI level were estimated to assess IR. Significant correlation was found between HOMA-IR and WC (r = +0.368, P = 0.0324) but it was non-significant between HOMAIR and BMI. Correlations were also not significant between FPI and WC or BMI. In conclusion, HOMA-IR and WC are better measures of IR and obesity as compared to FPI and BMI, respectively in type 2 DM.

Cardiovascular responses during cold pressor test are different in Parkinson disease and multiple system atrophy with parkinsonism.

OBJECTIVE: Orthostatic hypotension (OH) is common in Parkinson disease (PD) and multiple system atrophy of parkinsonian type (MSA-P), but the pathophysiology of OH is different in the two. We hypothesised that the baroreflex-independent sympathetic reactivity may also be different in them. To evaluate this we assessed the sympathetic vascular reactivity and the heart rate response to the standard cold pressor test (CPT) in these patients. METHODS: The study was conducted in ten patients with PD with OH, 5 PD without OH, 13 MSA-P with OH, and 7 MSA-P without OH. Lead II ECG and finger PPG (photoplethysmography) were simultaneously acquired during a baseline period of 1 min followed by a 10 °C cold exposure (1 min) of the contralateral hand (CPT). The vascular response was then evaluated by computing the pulse transit time (PTT). RESULTS: The percentage decrease in PTT during the CPT was significantly higher in patients with PD as compared to MSA-P, irrespective of the presence or absence of OH (-2.74 ± 0.96 vs -0.05 ± 0.75 %, p = 0.03; PD vs MSA-P with OH and -3.04 ± 0.85 vs 0.48 ± 1.13 %, p = 0.04; PD vs MSA-P without OH). The rise in heart rate during CPT was similar in patients with PD and MSA-P with or without OH (4.95 ± 1.6 vs 5.99 ± 1.04, p = 0.28; PD vs MSA-P with OH and 5.62 ± 1.31 vs 13.15 ± 2.89, p = 0.06; PD vs MSA-P without OH). INTERPRETATION: Vasoconstrictor response to CPT is compromised in MSA-P as compared to PD, but the baroreflex-independent heart rate response is similar in the two.

Cardiopulmonary exercise performance after total cavopulmonary connection with or without prior superior cavopulmonary connection.

OBJECTIVE: To compare cardiopulmonary exercise capacity of patients undergoing primary total cavopulmonary connection (TCPC) with those undergoing TCPC after a prior bidirectional Glenn (BDG). METHODS: Out of 42 patients in this study, 24 had undergone primary TCPC while 18 had undergone staged TCPC. The peak oxygen consumption (O(2) peak), O(2) pulse, chronotropic index, and other exercise parameters were studied. RESULTS: There were no significant differences in O(2) peak (940 ± 538 vs. 1010 ± 417 mL/min, p=0.42) and O(2) pulse (5.76 ± 3.52 vs. 6.85 ± 2.95) of patients undergoing staged TCPC versus primary TCPC, respectively; however, chronotropic index (0.43 ± 0.23 vs. 0.30 ± 017, p=0.047) was significantly different. Exercise tolerance was the same in fenestrated versus nonfenestrated TCPC groups and age at TCPC less than or more than 7 years. However, O(2) peak and O(2) pulse of patients with extracardiac TCPC was better than patients with lateral tunnel TCPC (p values 0.05, 0.04 and respectively). Some parameters of exercise tolerance of patients with antegrade pulmonary blood flow (APBF) interrupted at the time of BDG were better than those with APBF open. CONCLUSION: There were no differences in the exercise parameters of patients undergoing a staged versus a primary TCPC, fenestrated versus nonfenestrated TCPC, and age at surgery less than or more than 7 years. Exercise parameters were better in the extracardiac conduit group versus lateral tunnel TCPC groups. Patients who had a TCPC after prior interruption of APBF had better exercise parameters.

Correction for blood pressure improves correlation between cerebrovascular reactivity assessed by breath holding and 6% CO(2) breathing.

BACKGROUND: Changes in cerebral blood flow velocity to hypercapnia are associated with changes in systemic blood pressure (BP). These confounding BP-dependent changes in cerebral blood flow velocity cause misinterpretation of cerebrovascular reactivity (CVR) results. The objective of the study was to determine the relationship between CVR assessed by breath holding and 6% CO2 breathing after correcting for BP-dependent changes in cerebral blood flow velocity. METHODS: In 33 patients of uncomplicated type 2 diabetes mellitus, CVR was assessed as percentage changes in cerebral blood flow velocity and cerebrovascular conductance index. RESULTS: Percentage change in cerebral blood flow velocity during breath holding was positively correlated with that of during 6% CO2 breathing (r = .35; P = .0448). CVR during breath holding and 6% CO2 breathing were better correlated when expressed as percentage changes in cerebrovascular conductance index (r = .49; P = .0040). Similarly, breath-holding test results expressed as percentage changes in cerebral blood flow velocity correctly identified only 37.5% of the poor reactors to 6% CO2 breathing. However, when the breath-holding test results were expressed as percentage changes in cerebrovascular conductance index, 62.5% of the poor reactors to 6% CO2 breathing were correctly identified indicating a better agreement between the test results obtained by the 2 methods. CONCLUSION: Cerebrovascular response to breath holding is better correlated with that of 6% CO2 breathing when changes in cerebral blood flow velocity were corrected for associated changes in BP.

Effect of controlled breathing exercises on the psychological status and the cardiac autonomic tone: Sudarshan Kriya and Prana-Yoga.

OBJECTIVE: The objective of the study was to observe the effect of controlled breathing exercises including Sudarshan Kriya (SK) and Prana-Yoga (PY) on the psycho-physiological status. METHODS: The study group included 60 healthy volunteers (M:30, F:30) in the age group of 18 to 30 years (21.3 ± 3.2 yrs), randomly divided in to three groups of 20 subjects each--(1) The SK group (2) the PY group and the (3) Control group. The psycho-physiological data was collected at the following four time interventions: Baseline, 6th, 60th and the 150th day. Psychological assessment was done using questionnaires and for the autonomic tone quantification Heart Rate Variability (HRV) analysis was done using the standard lead II electrocardiogram recordings. In a post-hoc analysis each group was further sub divided in to the following two patterns, based on the baseline values of normalized Low Frequency (LF) power (cutoff 64 ms2): (i) Pattern A-Subjects with low level LF power, and (ii) Pattern B- subjects with high level LF power. RESULTS: The stress management skills have shown significant increase in SK group but not in PY and Control group. Subjects of SK, PY, and control group showed significant increase in LF value and LF:HF ratio for pattern A and significant decrease for pattern B. Plotted LF value for pattern A & B in SK and PY practitioners showed convergence, coming to a mean value over the period of 150 days. The LF:HF ratio curve plotted over time for pattern A & B showed convergence in SK group only. No such convergence in LF value & LF/HF ratio for pattern A & B was seen in control group. CONCLUSION: In conclusion, Sudarshan Kriya positively modifies stress coping behavior and initiates appropriate balance in cardiac autonomic tone.

Effect of Yoga on Endothelial Function: A Systematic Review and Meta-Analysis.

Introduction: Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis; and it plays a central role in the development of cardiovascular diseases and many types of human diseases (diabetes, kidney failure, cancer, and viral infections). Strategies that are effective in protecting vascular endothelial function and retard or reversing endothelial dysfunction in the early stage appear to be potential in the prevention of vascular, cardiac, and many human diseases. Several studies have been carried out on the effects of yoga on endothelial function, but the results of these studies have not been synthesized. This study aimed at conducting a systematic review and meta-analysis to determine the effectiveness of yoga on endothelial function. Methods: A systematic review and meta-analysis of studies that assessed the effect of yoga practice on vascular endothelial function was done as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Scopus, Google Scholar, and Cochrane controlled register of trials (CENTRAL) were searched from inception to August 2022. The search strategy was constructed around yoga-based techniques and endothelial function. All the yoga-based interventional studies on endothelial function or dysfunction were included in this review. A narrative synthesis and descriptive analysis were done due to the diverse methodology of selected studies. We carried out a formal meta-analysis of controlled trials that assessed the effect of yoga on flow-mediated dilatation (FMD), a measure of endothelial function. Results: A total of 18 studies were included for review involving 1043 participants. Yoga training showed improved endothelial function in 12 studies, whereas 6 studies did not find any statistically robust effect. Meta-analysis (n = 395 participants, 6-studies, 7 comparisons) showed an increase in brachial FMD by yoga practice (mean difference = -1.23%; 95% confidence interval -2.23 to -0.23; p = 0.02). The heterogeneity between the studies was 43% (Tau2 = 0.70, χ2 = 10.49). The risk of bias was low to moderate in these studies. No adverse effects were reported. Conclusions: Yoga practice improved endothelial function. Yoga could be a safe and potential integrative medicine to improve endothelial function. However, as the statistical heterogeneity, that is, variation in the FMD among the studies was moderate, large clinical trials are necessary for its clinical recommendations.

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.