Browsing by Subject "Exercise Tolerance"

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    ItemOpen Access
    Commentary: The heart of the matter: Close clinical follow-up and exercise capacity in Fontan circulation.
    (The Journal of thoracic and cardiovascular surgery, 2021-08) Well, Andrew; Beckerman, Ziv
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    Congenital heart disease and pulmonary hypertension.
    (Heart Fail Clin, 2012-07) Gupta, Vedant; Tonelli, Adriano R; Krasuski, Richard A
    Many patients with congenital heart disease and systemic-to-pulmonary shunts develop pulmonary arterial hypertension (PAH), particularly if the cardiac defect is left unrepaired. A persistent increase in pulmonary blood flow may lead to obstructive arteriopathy and increased pulmonary vascular resistance, a condition that can lead to reversal of shunt and cyanosis (Eisenmenger syndrome). Cardiac catheterization is crucial to confirm diagnosis and facilitate treatment. Bosentan is the only medication to date to be compared with placebo in a randomized controlled trial specifically targeting congenital heart disease-associated PAH. Lung transplantation with repair of the cardiac defect or combined heart-lung transplantation is reserved for recalcitrant cases.
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    Disruption of STIM1-mediated Ca2+ sensing and energy metabolism in adult skeletal muscle compromises exercise tolerance, proteostasis, and lean mass.
    (Molecular metabolism, 2022-03) Wilson, Rebecca J; Lyons, Scott P; Koves, Timothy R; Bryson, Victoria G; Zhang, Hengtao; Li, TianYu; Crown, Scott B; Ding, Jin-Dong; Grimsrud, Paul A; Rosenberg, Paul B; Muoio, Deborah M

    Objective

    Stromal interaction molecule 1 (STIM1) is a single-pass transmembrane endoplasmic/sarcoplasmic reticulum (E/SR) protein recognized for its role in a store operated Ca2+ entry (SOCE), an ancient and ubiquitous signaling pathway. Whereas STIM1 is known to be indispensable during development, its biological and metabolic functions in mature muscles remain unclear.

    Methods

    Conditional and tamoxifen inducible muscle STIM1 knock-out mouse models were coupled with multi-omics tools and comprehensive physiology to understand the role of STIM1 in regulating SOCE, mitochondrial quality and bioenergetics, and whole-body energy homeostasis.

    Results

    This study shows that STIM1 is abundant in adult skeletal muscle, upregulated by exercise, and is present at SR-mitochondria interfaces. Inducible tissue-specific deletion of STIM1 (iSTIM1 KO) in adult muscle led to diminished lean mass, reduced exercise capacity, and perturbed fuel selection in the settings of energetic stress, without affecting whole-body glucose tolerance. Proteomics and phospho-proteomics analyses of iSTIM1 KO muscles revealed molecular signatures of low-grade E/SR stress and broad activation of processes and signaling networks involved in proteostasis.

    Conclusion

    These results show that STIM1 regulates cellular and mitochondrial Ca2+ dynamics, energy metabolism and proteostasis in adult skeletal muscles. Furthermore, these findings provide insight into the pathophysiology of muscle diseases linked to disturbances in STIM1-dependent Ca2+ handling.
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    Inspiratory Muscle Rehabilitation Training in Pediatrics: What Is the Evidence?
    (Canadian respiratory journal, 2022-01) Bhammar, Dharini M; Jones, Harrison N; Lang, Jason E
    Pulmonary rehabilitation is typically used for reducing respiratory symptoms and improving fitness and quality of life for patients with chronic lung disease. However, it is rarely prescribed and may be underused in pediatric conditions. Pulmonary rehabilitation can include inspiratory muscle training that improves the strength and endurance of the respiratory muscles. The purpose of this narrative review is to summarize the current literature related to inspiratory muscle rehabilitation training (IMRT) in healthy and diseased pediatric populations. This review highlights the different methods of IMRT and their effects on respiratory musculature in children. Available literature demonstrates that IMRT can improve respiratory muscle strength and endurance, perceived dyspnea and exertion, maximum voluntary ventilation, and exercise performance in the pediatric population. These mechanistic changes help explain improvements in symptomology and clinical outcomes with IMRT and highlight our evolving understanding of the role of IMRT in pediatric patients. There remains considerable heterogeneity in the literature related to the type of training utilized, training protocols, duration of the training, use of control versus placebo, and reported outcome measures. There is a need to test and refine different IMRT protocols, conduct larger randomized controlled trials, and include patient-centered clinical outcomes to help improve the evidence base and support the use of IMRT in patient care.
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    Magnitude of spinal muscle damage is not statistically associated with exercise-induced low back pain intensity.
    (Spine J, 2011-12) Bishop, Mark D; Horn, Maggie E; Lott, Donovan J; Arpan, Ishu; George, Steven Z
    BACKGROUND CONTEXT: Findings on imaging of noncontractile anatomic abnormalities and the intensity of low back pain have weak associations because of false-positive rates among asymptomatic individuals. This association might be stronger for contractile tissues. PURPOSE: The purpose of this study was to examine the relationship between location and reports of pain intensity in the low back and exercise-induced muscle damage to the lumbar paraspinal muscles. STUDY DESIGN: Nondiagnostic observational study in a laboratory setting. METHODS: Delayed onset muscle soreness was induced in the low back of healthy pain-free volunteers. Measures of pain intensity (100-mm visual analog scale [VAS]) and location (area on the pain diagram) were taken before and 48 hours after exercise. Muscle damage was quantified using mechanical pain thresholds, motor performance deficits, and transverse relaxation time (T2)-weighted magnetic resonance imaging (MRI). Changes pre- to postexercise in signal intensity on T2-weighted imaging within the erector spinae, pain intensity, pain area, mechanical pain threshold, and isometric torque were assessed using paired t tests. Bivariate correlations were conducted to assess associations among muscle damage, pain intensity, and pain drawing area. RESULTS: Twenty participants volunteered (11 women; average age, 22.3 years; average body mass index, 23.5) for study participation. Reports of pain intensity at 48 hours ranged from 0 to 59 mm on the VAS. Muscle damage was confirmed by reductions in mechanical threshold (p=.011) and motor performance (p<.001) and by changes in T2-weighted MRI (p=.007). This study was powered to find an association of at least r=0.5 to be statistically significant. Correlations of continuous variables revealed no significant correlations between pain intensity and measures of muscle damage (ranging between -0.075 and 0.151). There was a significant association between the remaining torque deficit at 48 hours and pain area. CONCLUSIONS: The results of this study indicate that there was no association between the magnitude of muscle damage in the lumbar erector spinae and reported pain intensity in the low back. In future studies, larger cohorts may report statistically significant associations, but our data suggest that there will be low magnitude potentially indicating limited clinical relevance.
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    Provoked exercise desaturation in patent foramen ovale and impact of percutaneous closure.
    (JACC Cardiovasc Interv, 2012-04) Devendra, Ganesh P; Rane, Ajinkya A; Krasuski, Richard A
    OBJECTIVES: This study was designed to assess the prevalence of provoked exercise desaturation (PED) in patients with patent foramen ovale (PFO) referred for cardiovascular evaluation and to evaluate the impact of PFO closure. BACKGROUND: Platypnea orthodeoxia syndrome is a rare, mechanistically obscure consequence of PFO that results in oxygen desaturation during postural changes. In our clinical experience, however, it is far less common than desaturation during exercise. METHODS: This was a single-center prospective study of 50 patients with newly diagnosed PFO. Each patient underwent standardized assessment for arterial oxygen saturation with pulse oximetry during postural changes and stair climbing exercise. Provoked exercise desaturation was defined as a desaturation of at least 8% from baseline to <90%. All patients who underwent closure were reevaluated 3 months after the procedure. Those with baseline PED were similarly reassessed for desaturation at follow-up. RESULTS: Mean age of the cohort was 46 ± 17 years, 74% were female, 30% had migraines, and 48% had experienced a cerebrovascular event. Seventeen patients (34%) demonstrated PED. Provoked exercise desaturation patients seemed demographically similar to non-PED patients. Ten PED patients underwent PFO closure (2 surgical, and 8 percutaneous). Drop in oxygen saturation was improved by an average of 10.1 ± 4.2% after closure (p < 0.001), and New York Heart Association functional class improved by a median of 1.5 classes (interquartile range: 0.75 to 2.00, p = 0.008). CONCLUSIONS: One-third of patients referred for assessment of PFO experience oxygen desaturation during stair exercise. Closure of PFO seems to ameliorate this phenomenon and improve functional status.