BACKGROUND:Inspiratory muscle training (IMT) is used in a broad range of populations to improve the strength and endurance of the respiratory muscles, to improve both athletic performance and clinical outcomes. However, the optimal approach to IMT remains uncertain, and IMT is frequently declined in the clinical setting. This study aimed to measure oxygen consumption (VO2) and perceived difficulty and unpleasantness during commonly cited IMT loads. METHODS:Thirty participants performed IMT at 4cmH2O and 30%, 50% and 80% of their maximal inspiratory strength (PImax). VO2 was measured using indirect calorimetry. After each load, a visual analogue scale was used to rate breathing difficulty (VAS-D) and unpleasantness (VAS-U) RESULTS: Median (IQR) VO2 was 4.42 (3.36-4.82) mL/min/kg at baseline, increasing to 4.90 (4.11-5.03) mL/min/kg, 4.38 (3.69-5.23) mL/min/kg, 4.64 (4.09-5.28) mL/min/kg and (4.82-6.51) mL/min/kg after IMT at 4cmH2O and 30, 50 and 80% PImax respectively (Friedman's ANOVA p < 0.001). VO2 increased by 0.013 mL/kg/min for every 1% of PImax increase in IMT load. Perceived difficulty and unpleasantness increased with IMT load. PImax significantly influenced the load-perception relationship: slope (95% CI) of load versus VAS-D in the combined model 0.37 (0.09-0.65)mm/%PImax, p = 0.01), additional influence of baseline PImax 0.003 (0.001-0.005) mm/%PImax/cmH2O, p = 0.009. CONCLUSIONS:IMT causes a load-dependent increase in VO2, with marked increases in breathing difficulty and unpleasantness at higher loads. The additional impact of the absolute magnitude of load provides insight into the perception of respiratory effort. These data help understand the factors that influence IMT prescription, in terms of exercise response and acceptability.
This study aimed to assess the association between brain glucose metabolism, measured using 2-deoxy-2-[18F]fluoro- d -glucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT), and heart rate variability (HRV). A total of 101 healthy men were included. Each participant underwent the following assessments: (1) brain 18 F-FDG PET, (2) anthropometric measurements, and (3) HRV test. PET scans were spatially normalised to MNI space using PET templates from SPM5 with pmod. An Automated Anatomical Labelling 2 atlas was used to define regions of interest (ROIs). For each ROI, the mean uptake was normalised to the individual's global cortical mean uptake, yielding a standardised uptake value ratio (SUVR). After logarithmic transformation of the regional SUVR, the effects of the root mean square of successive differences (RMSSD) on the regional SUVR were investigated using Bayesian hierarchical modelling. Our main finding was that RMSSD of 101 middle-aged males was positively associated with brain glucose metabolism in occipital lobe, parietal lobe, precuneus, and cuneus. A negative association was observed in the cerebellum, thalamus, and parahippocampus. These findings suggest that brain regions associated with psychiatric disorders and cognitive and affective functions are associated with parasympathetic activity, as measured by the RMSSD. This study provides new insights into the mechanisms regarding autonomic nervous system.
We quantified, using a new method, the contribution of heart rate (HR), stroke volume (SV) and total peripheral resistance (TPR) to the increase in mean arterial pressure (MAP), expressed as % of baseline during a 3-min static handgrip (HG) performed at 30% of maximum voluntary contraction by 11 subjects. Arterial pressure was measured noninvasively with Finapres Nova, SV with Doppler imaging. The increase in MAP was greater at the end of HG than at the end of the first minute of HG, the maximum individual increases in MAP ranged from 0% to 33%; the HR contribution was mostly positive, the SV contribution was mostly negative. The magnitude of the HR contribution was similar at the beginning and end of the HG both in subjects who experienced high and low MAP increases; a similar observation applies to the SV contribution. Only the TPR contribution was significantly correlated with the individual MAP increase. Assuming that the individual level of MAP is set during HG, the contribution of TPR by taking positive or negative values plays a main role as an adjustment factor that brings MAP to set level; compensating for insufficient or excessive contributions from HR and SV. Our results question the use of changes in MAP or TPR as an indicator of sympathetic reactivity; the increase in MAP is determined by the individual change in set level induced by HG, whereas the magnitude of the change in sympathetic activity is such as needed to achieve the desired increase in MAP.
PURPOSE:This study aimed to evaluate both inter- and intra-observer reliability of ultrasound-based muscle thickness measurements in able-bodied (AB) individuals, as well as intra-observer reliability in individuals with spinal cord injury (SCI). METHODS:Ultrasound measurements of the gluteus maximus, medius, minimus and biceps femoris long head were performed on 31 AB participants and 30 participants with SCI. Each AB participant was scanned on two occasions by three observers, with three repetitions per muscle per occasion. The muscle thickness in participants with SCI was measured using three repetitions during a single test occasion, conducted by one observer. A generalizability (G) study was conducted to assess the reliability of the measurements. RESULTS:In AB participants, intra-observer reliability for gluteal muscles ranged from G-coefficient: 0.57 to 0.89, and for biceps femoris long head from G-coefficient: 0.60 to 0.76. Inter-observer reliability in AB participants was G-coefficient:0.48-0.72 for the gluteal muscles and G-coefficient: 0.52 for the biceps femoris. In contrast, intra-observer reliability in participants with SCI was excellent across all muscles (G-coefficient: 0.95-0.99). CONCLUSION:Ultrasound can assess muscle thickness with moderate to good intra-observer reliability in AB participants, but with only poor to moderate inter-observer reliability. In contrast, intra-observer reliability was excellent in participants with SCI. Reliability depends on observer experience and varies across muscles and populations.
INTRODUCTION:Skeletal muscle is a critical organ influencing prognosis and overall health; however, the direct measurements of muscle mass are not easily attainable. This study aimed to estimate whole-body skeletal muscle volume (WBM) using pectoralis muscle area (PMA) derived from a single chest-CT slice and basic anthropometric data in a Korean population. METHODS:We analyzed PET-CT data from 201 adults (101 women, 100 men). WBM was segmented using deep learning-based software. The PMA was delineated and was divided into pectoralis major and minor. Sex-specific LASSO regression models were developed: Model 1 included total PMA, Model 2A pectoralis major, Model 2B pectoralis minor, and Model 2C both muscles as separate predictors while Model 3 was based on L3 muscle area for comparison. All models additionally included age, height, weight, and waist circumference. RESULTS:In females and in males, R² values were 0.76 and 0.75 (Model 1), 0.77 and 0.76 (Model 2C), and 0.84 and 0.81 (Model 3), respectively. Bland-Altman bias were 0.5% (95% CI: -13.6%, 14.7%), 1.1% (95% CI: -20.4%, 22.6%) (Model 1), 0.5% (95% CI: -13.7%, 14.7%) 1.0% (95% CI: -20.1%, 22.2%) (Model 2C), 0.4% (95% CI: -12.2%, 13.0%) and 1.0% (95% CI: -18.2, 20.3) (Model 3), respectively. CONCLUSION:WBM can be reliably estimated using PMA measured in a single chest-CT slice and basic body measurements (age, height, weight, and waist circumference). This method offers a practical and efficient surrogate for muscle assessment based on routinely acquired chest CT images.
INTRODUCTION:Tachycardia has previously been reported as a possible sign of neurovascular entrapment during upper-limb abduction and assumed to result from compression of the adrenergic nerve. However, this increase in heart rate could also be caused by a vascular factor, such as venous entrapment. The aim of this study was to determine whether heart rate increases specifically in the case of venous entrapment during upper-limb dynamic mobilization tasks. METHODS:One hundred and sixteen patients were asked to perform a provocative manoeuvre consisting of consecutive upper limb mobilizations by raising their arms to the "surrender" position (Su, 90° abduction) and then keeping their arms raised in front of the body ("prayer" position, Pra) prior to returning to the initial position ("End"). During this manoeuvre, simultaneous venous (V-PPG) and arterial (A-PPG) photoplethysmography (PPG) recordings were obtained. Participants were categorized by PPG recording analysis as having bilateral venous compression only (V-group) or having no vascular compression (C-group). All other responses (n = 75) were excluded. Heart rate responses in V-group and C-group were compared across arm positions using a linear mixed model. RESULTS:V-group (n = 17) showed a significantly higher heart rate during the 'Su' phase compared to the 'Rest' phase (+6.9 bpm, p < 0.001) and compared to the 24 patients of the C-group (+4.9 bpm, p = 0.02). CONCLUSION:This study suggests that the cardiovascular response to dynamic provocative manoeuvres is found specifically in the presence of positional venous upper-limb entrapment and likely results from decreased cardiac pre-charge rather than from adrenergic nerve excitation.
AIM:To investigate left atrial (LA) function assessed by peak atrial longitudinal strain (PALS) in an elderly population with silent paroxysmal atrial fibrillation (PAF) compared to age-matched control group. METHODS:From the STROKESTOP2-study, patients with newly diagnosed silent PAF were enrolled together in a randomly selected age-matched control group. All patients had NT-proBNP levels between 125 and 900 ng/L. Echocardiographic examinations were performed and analyzed offline using dedicated software. In addition to conventional echocardiographic variables, PALS was measured using a two-dimensional speckle tracking (2D-ST) biplane. RESULTS:The study population (mean age 76 ± 0.3) demonstrated significantly reduced PALS in patients with PAF (N = 69) compared to controls (N = 94) (23.9% ± 6.5% vs 30.7% ± 7.6%, p < 0.001). In the PAF group, 29 (42%) patients had normal LA volume index (LAVI) defined as ≤ $\le $ 34 mL/m2. When subgroups with normal LAVI were compared, PALS was reduced in PAF compared to controls (25.1 ± 8.0 vs 31.1 ± 7.8, p = 0.001). NT-proBNP levels did not differ between the PAF group (median 228 ng/L) and the control group (median: 217 ng/L) (p = 0.16). In multiple linear regression analysis, left ventricular global longitudinal strain, stroke volume index and LAVI were independent predictors of PALS. Receiver operating characteristic curve identified PALS threshold <22% for predicting risk of silent PAF. CONCLUSION:PALS was significantly reduced in PAF patients even in the absence of significant LA remodeling. PALS <22% predicts risk for silent PAF in general elderly population. In high-risk patients PALS could be used for AF screening enrichment.
PURPOSE:Cardiovascular diseases, primarily driven by atherosclerosis, remain the leading cause of death worldwide. Key risk factors include diabetes, hyperlipidemia, hypertension, smoking, genetic predispositions and notably, obesity-related visceral adipose tissue (VAT). Like VAT, epicardial adipose tissue (EAT) influences heart function by releasing inflammatory cytokines. This study evaluated the relationship between EAT thickness and coronary artery disease severity, its interaction with risk factors, and its prognostic value for major cardiac and cerebrovascular events in ST-segment elevation myocardial infarction (STEMI) patients after percutaneous intervention (PCI). METHODS:We analyzed 138 STEMI patients (124 males and 14 females) treated with primary PCI at our centre, documenting medical and demographic data, cardiovascular history, risk factors, time metrics, physical and clinical examinations, EAT thickness, and biochemical parameters. Follow-ups at 1 and 6 months post-discharge tracked major cardiovascular events. RESULTS:The average age of the patients was 55.14 ± 12.83 years, predominantly male (89.9%), with varying prevalences of diabetes (22.5%), hypertension (38.4%), hyperlipidemia (37%), metabolic syndrome (32.6%), and family history of cardiovascular disease (47.1%). EAT thickness ranged from 1.5 to 11 mm, averaging 3.91 ± 1.42. Patients were divided into tertiles by EAT thickness, showing significant differences in age, weight, body mass index (BMI), thrombolysis in myocardial infarction (TIMI) scores, and number of affected vessels but not in mortality (7.2%), Major adverse cardiac and cerebrovascular events (MACCE) (13.8%), or combined endpoint outcomes across tertiles. CONCLUSION:No correlation was found between EAT thickness and mortality or MACCE in STEMI patients, highlighting the need for validation in long-term studies.
The investigation and therapeutic trials of hematological and hemato-oncological diseases using nuclear medicine methods dates back to the 1930s. At that time, 32P was used as the isotope for various experimental procedures. Over the years, a wide variety of isotopes and techniques have been developed, some of which have established themselves as the gold standard in certain clinical indications, such as in the management of patients with lymphoma. Other nuclear medicine procedures are used as complementary techniques in more specific clinical scenarios. In recent years, the concept of theranostics has gained popularity in nuclear medicine. Radioendotherapies have been developed and some of them have already been FDA approved. Their promising results could potentially have a major impact on the treatment of patients with hemato-oncologic diseases. In this article we review some of the contemporary techniques used in nuclear medicine and recent developments of clinical indications in the field of hematology and oncology.
BACKGROUND:Upper airway stenosis may remain undiagnosed for extended periods. Ultrasound allows for the evaluation of the impact of respiratory diseases on diaphragmatic function. METHODS:Three patients presenting with symptoms suggestive of upper airway obstruction were assessed using diaphragmatic ultrasound. Simultaneously, inspired volumes were measured on a breath-by-breath basis. Inspiratory flow was calculated during both quiet and deep breathing by dividing inspired volume by excursion duration. RESULTS:Diaphragmatic function, studied by the measurement of excursion and thickening fraction, was preserved in all cases. However, the temporal profile of diaphragmatic excursion differed from that observed in healthy individuals. A reduction in inspiratory flow was observed and appeared to be related to the severity of obstruction, as determined by clinical presentation and flow-volume loop analysis. CONCLUSION:Based on these preliminary findings, the combination of diaphragmatic ultrasound and inspired volume measurement should be able to provide valuable information in the assessment of upper airway stenosis. Further prospective studies are warranted to confirm its clinical utility.
PURPOSE:To develop and evaluate a three-dimensional convolutional neural network for automated classification of PET/MRI images in head and neck cancer (HNC) patients, assessing its performance against radiologist interpretation and its potential as a diagnostic aid. METHODS:Data from 202 patients with HNC who underwent 18F-FDG PET/MRI were used to train and validate PET-, MRI-, and PET/MRI-based models. Of these data, 101 patients were labelled as positive in terms of having HNC, and 101 patients as negative. An additional test set of 20 patients was also evaluated, where 10 patients were labelled as positive and 10 as negative. The model performance was assessed using sensitivity, specificity, accuracy, and AUC. Grad-CAM was utilised to improve interpretability and classification results on the test set were compared with a radiologist. RESULTS:The PET-based model achieved an AUC of 0.92 on the test set, with an accuracy of 90%, a sensitivity of 100% and a specificity of 80%. PET/MRI and MRI-based models underperformed relative to the PET-based model. The radiologist achieved perfect classification accuracy. Analysis of Grad-CAM showed that the model classifications are based on real areas of interest. In addition, it gave valuable insight into using similar systems in identifying false positive findings. CONCLUSION:The PET-based model demonstrated high sensitivity, indicating its potential as a pre-screening tool for HNC. However, specificity requires improvement to reduce false-positive rates. Enhanced datasets and refinement of model architecture will be crucial before clinical adoption. Grad-CAM provides valuable insights into model decisions, aiding clinical integration.
OBJECTIVE:To study the reproducibility of diastolic function parameters from myocardial perfusion imaging (MPI) using ECG-gated single photon emission computed tomography (SPECT), and echocardiography in repeated imaging. METHODS:We studied the reproducibility of MPI diastolic function parameters peak-filling rate (PFR) and time to peak filling (TTPF) as well as echocardiographic parameters E/A, E/e', and E-wave deceleration time (DT). The study population consisted of 21 patients who underwent routine MPI with repeated rest acquisition and echocardiography. In a test-retest setting, appropriate diastolic measures were successfully obtained using SPECT in 20 patients, with E/A measured in 18, E/e' in 17, and DT in 16 patients. RESULTS:We found that PFR was well reproducible with the intraclass correlation coefficient (ICC) 0.887, and coefficient of variation (CV%) 10.5. However, TTPF was poorly reproducible (ICC 0.012, and CV% 17.5). E/A was highly reproducible (ICC 0.963, and CV% 12.5). Decent reproducibility was observed for E/e' (ICC 0.809, and CV% 18.6) and DT (ICC 0.833, and CV% 12.0). We further studied the correlation between these parameters. PFR (EDV/s) had negative correlation with DT (r = -0.538, p = 0.039) and E/A had positive with E/é (r = 0.689, p = 0.002). No other significant correlations were observed (p > 0.05 for all). We also examined how parameters classified patients as normal or abnormal regarding the diastolic function. E/A and E/e´, as well as E/A and PFR showed similar classifications in 88% of cases, with a Kappa value of 0.433, p = 0.074 for both. CONCLUSIONS:PFR obtained from repeated SPECT studies, along with the E/A ratio, is highly reproducible.
BACKGROUND:Hemodynamic failure in patients with steno-occlusive arterial disease is a major risk factor for stroke. Previous studies have identified impaired autonomic function in patients with carotid artery stenosis. Our study explores autonomic dysfunction and altered cerebrovascular hemodynamics in patients with stenosis and suspected hemodynamic failure. METHODS:To assess autonomic nervous system dysfunction, patients underwent heart rate variability (HRV) testing, an active stand test, and the Valsalva maneuver with simultaneous monitoring of heart rate, blood pressure, and cardiac output. Transcranial Doppler was used to measure relative changes in cerebral blood flow during Valsalva. RESULTS:Analysis of 13 patients and 19 controls revealed a significantly greater decrease in cerebral blood flow in the patient group during Valsalva, as evidenced by mean relative changes in time-averaged peak velocities ±SE of 0.80 ± 0.04 in patients compared to 0.96 ± 0.05 in controls (p < 0.05). There were no significant differences in mean arterial blood pressure or heart rate during the Valsalva maneuver. HRV analysis and the active stand test did not reveal autonomic dysfunction or orthostatic intolerance. CONCLUSION:Patients with steno-occlusive carotid artery disease exhibit impaired intracranial flow during Valsalva-induced blood pressure reduction. However, our results do not support the presence of significant autonomic dysfunction in patients with symptomatic large-vessel cerebrovascular disease as measured by HRV and blood pressure reduction during active stand.
The present study investigates the relationship between obesity and metabolic, hormonal, and clinical indicators in adolescent girls. A total of 75 girls aged 15-19 years (mean age: 17.53 ± 1.29 years) were enrolled, including 58 with excess weight or obesity and 17 with normal weight. Anthropometric parameters related to obesity, various clinical scores, fasting glucose, fasting insulin, insulin resistance indices, lipid profile, blood pressure, and thyroid-stimulating hormone (TSH) were assessed. Mann-Whitney U test compared differences between the groups, while Spearman's rho correlation analysed the associations among adiposity, metabolic, and clinical parameters. Simple linear regression predicted insulin resistance indices using BMI, WHR, and WHtR. Receiver operating characteristic (ROC) analysis evaluated the predictive ability of BMI, WHR, and WHtR for insulin resistance. Girls with obesity exhibited significantly higher weight, BMI, WC, WHR, and WHtR (p < 0.05). Acanthosis scores and insulin resistance indices strongly correlated with BMI, WHR, and WHtR, while lipid profile parameters showed no significant association with adiposity. Regression analysis identified BMI and WHtR as strong predictors of HOMA-IR, while WHR and WHtR inversely correlated with QUICKI and GIR. The McAuley Index moderately correlated with BMI and WHtR. ROC analysis confirmed BMI (AUC = 0.779, p = 0.000) and WHtR (AUC = 0.776, p = 0.000) as strong predictors of insulin resistance. Concluding that, obesity in adolescent girls is strongly linked to insulin resistance but not lipid profile parameters. BMI and WHtR emerge as reliable predictors, with acanthosis as a potential clinical marker.
Breath-hold ECG-gated cardiovascular magnetic resonance (CMR) imaging is challenging during exercise due to motion, ECG-problems, and lengthy scans. To facilitate time-resolved volumetric measures from exercise-CMR, we aimed to develop a method for constructing time-resolved ventricular cines from real-time free-breathing exercise-CMR. Time-resolved ventricular cines were semi-automatically constructed from real-time exercise-CMR by identifying end-expiratory timeframes, identifying one R-R interval within these timeframes, and synchronizing R-R intervals across slice positions. To investigate utility, ECG-gated rest CMR and real-time exercise-CMR images were collected from ten healthy volunteers and ten heart failure patients. The consistency of the left ventricular mass (LVM) was assessed between rest and exercise at end diastole (ED), mid systole (MS), end systole (ES), and early rapid filling (ERF). When comparing LVM between rest and exercise for healthy volunteers, bias ± SD was 1.5 ± 2.7 g at ED, 0.9 ± 3.3 g at MS, 1.3 ± 3.3 g at ES, and 1.2 ± 3.3 g at ERF. When comparing LVM between rest and exercise for heart failure patients, bias ± SD was 1.6 ± 2.8 g at ED, 1.0 ± 2.7 g at MS, 1.5 ± 2.6 g at ES, and 1.6 ± 2.5 g at ERF. The bias ± SD between ED and ES in standard rest images was 0.0 ± 0.7 g for healthy volunteers, and 0.0 ± 0.5 g for heart failure patients. The method for constructing time-resolved ventricular cines from real-time exercise-CMR demonstrated utility for time-resolved volumetric measurements in healthy volunteers and heart failure patients.
Although force transfer during elongation occurs longitudinally and transversely, the influence of transverse force transfer between the biceps femoris long head and short head remains unclear. This study aimed to investigate whether separating the intermuscular connections between the biceps femoris long head and short head alters tension in the biceps femoris long head. Eight human cadaver legs were used, and ultrasonic shear wave elastography measurements were performed under four conditions: (1) intact, (2) removal of all tissues from the skin to the deep fascia, (3) intermuscular dissection, and (4) biceps femoris short head detachment. Measurements were taken in four limb positions, defined by hip and knee joint angles, under each tissue condition. The shear modulus of the biceps femoris long head significantly increased by 62.2% after intermuscular dissection compared to fascia removal, and further increased by 174.7% after biceps femoris short head detachment. In contrast, the shear modulus of the biceps femoris short head significantly decreased by 36.0% following intermuscular dissection and by 75.1% after detachment. In conclusion, reducing biceps femoris short head tension while increasing biceps femoris long head tension may influence muscle stress distribution, particularly during movement.
OBJECTIVE:To compare measurements of skin perfusion pressure (SPP) and transcutaneous oxygen pressure (TcPO2) to predict postamputation wound healing according to amputation level. METHODS:This study was conducted as a prospective two-centre, head-to-head study. RESULTS:Fifty-two patients had SPP, TcPO2 measured (below and above the knee), and toe and ankle blood pressure measurements taken before major amputation. Paired measurements of SPP and TcPO2 were used to compare the methods. We found overall poor agreement between SPP and TcPO2 measurements, with crude agreement below the knee in 32 of 45 limbs (71%) and above the knee in 17 of 23 limbs (74%), with κ values of 0.32 and 0.13, respectively. Among the 29 patients whose SPP measurements below the knee indicated healing potential, seven were amputated above the knee. Blood pressure measurements above the cut-off values (30 mmHg for the toe and 80 mmHg for the ankle, above 40 mmHg SPP and TcPO2 values), were seen as an indicator of high healing potential. CONCLUSION:We found poor (71%-74%) crude agreement between SPP and TcPO2, concerning measurements above and below the knee, using the established diagnostic cut-offs for predicting a high probability of postamputation wound healing. We determined that SPP and TcPO2 evaluate different physiological properties of the microcirculation and cannot be interchanged. Additionally, we found that the actual amputation level is often chosen at another level than that suggested by SPP and TcPO2, indicating that the choice is based on a multitude of factors, including clinical, paraclinical and patient-related parameters.
BACKGROUND:This study aimed to examine the adherence to selected health-related fitness (HRF) tests in adults. In addition, we investigated how excluded participants or those who did not attend HRF tests differed in their background characteristics from those who attended. METHODS:Two population study samples comprising 3867 (1594 males) 20─69-year-old participants performing HRF tests, or 1249 (456 males) participants answering only the study questionnaire, were pooled for the analyses. The selected HRF tests were: one-leg stand, neck-shoulder mobility, jump-and-reach, modified push-ups, and 6-min walking test. The exclusion rate was analyzed separately for each test. RESULTS:In total, 14.9% of the participants were excluded from at least one test. Failure to meet the health criteria and unwillingness to perform the test were the most typical reasons for the exclusion. The exclusion rate was highest in the modified push-up test (13.2%), while in all other tests, the rate was less than 5%. Excluded participants were more likely (p < 0.001) older (46-69 years) (OR = 4.59), not meeting physical activity recommendations for endurance (OR = 2.28) and perceiving their health (OR = 3.69) and fitness (OR = 3.26) as poor. Similarly, participants who answered only the questionnaire were more likely (p < 0.01) to perceive their health (OR = 1.56) and fitness (OR = 1.41) as poor and not meeting physical activity recommendations for endurance (OR = 1.48). CONCLUSIONS:The assessed HRF tests were feasible in terms of low exclusion rates. Individuals that were excluded or not participating the tests differed in their background characteristics from those who attended highlighting the importance of feasible testing methods to achieve a representative population sample of participants.
Blood pressure (BP) management in acute ischaemic stroke presents uncertainties regarding whether systolic BP (sys), mean BP (mean), or diastolic BP (dia) should be used for therapeutic guidance. Repeated assessments of BP‐dependent cerebral autoregulation (CA) could help identify a suitable BP modality for this purpose. Forty‐nine patients (median age 75 [62–81] years; 13 women) with unilateral acute ischemic stroke (NIHSS 5 [1.75–15.0]), underwent stroke center care and dynamic cerebral autoregulation (dCA) assessments on days 1 to 3 after the stroke event. Using frequency‐dependent transfer function analysis between BP and cerebral blood flow velocity (CBFV), gain indicates the amplitude transmission, and phase shift represents the phase difference between the two. CA failure is typically indicated by a low or absent phase shift in the very low (0.02–0.07 Hz) or low frequencies (0.07–0.20 Hz) ranges, leading to a direct transmission of BP changes to CBFV changes. BP values were averaged, with their standard deviation indicating BP variability (BPV). Averaged sys, mean, or dia BP did not predict gain or phase, but BPV did. In the stroke‐affected hemisphere (AH), sys, mean and dia BPV on day 1 predicted low frequency gain on days 1 and 2 ( p < 0.02 ‐ p < 0.001). On day 2, dia more than mean BPV predicted linearly ( p < 0.001) very low frequency phase with small phase values associated with a low BPV and large phase values with high BPV values. In acute stroke, dia BPV predicts best phase shift, and could be a promising candidate for BP guidance.
INTRODUCTION:While both voluntary (VOL) and electrically stimulated (ES) contractions increase blood flow, ES induces greater oxidative stress, raising the risk of exercise induced muscle damage (EIMD), which can impair vascular function, and oxygen utilization. PURPOSE:We examined how ES and force-matched VOL contractions impact microvascular function and muscle oxidative capacity. METHOD:Utilizing a cross-over design, 16 healthy adults performed 40 isometric knee extensions (KE) via ES and VOL contractions. The following variables were assessed at baseline, 1 h, 24 h, and 48 h postexercise: knee extensor strength and soreness, microvascular function (hyperemic response to single passive leg movement (sPLM), and skeletal muscle oxidative capacity (SMOC) of the vastus lateralis. RESULT:Maximal voluntary contraction (MVC) was lower following ES than VOL at 24 h (324.7 ± 125.8 vs. 366.8 ± 125.6 N, p = 0.01) and 48 h (308.5 ± 124.7 vs. 379.0 ± 129.0 N, p = 0.001). Soreness (p ≤ 0.02) and muscle swelling (p ≤ 0.02) were greater after ES. Vascular function, quantified as the AUC for total hyperemic response following sPLM and measured by Doppler/ultrasound, was reduced following ES at 1 h (p = 0.01) and 24 h (p = 0.002). SMOC was more impaired after ES than VOL (p ≤ 0.03). There was a 31% decrease in oxygen recovery rate 1-h post-ES, with an additional 10% decline at 24-h and 48-h (p ≤ 0.03) compared to VOL. CONCLUSION:ES seemed to elicit EIMD, resulting in reduced MVC, impaired recovery, while affecting microvascular function and oxidative capacity.
