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Exercise physiology heart failure

Jeffrey L Ardell, John Andrew Armour
Cardiac control is mediated via a series of reflex control networks involving somata in the (i) intrinsic cardiac ganglia (heart), (ii) intrathoracic extracardiac ganglia (stellate, middle cervical), (iii) superior cervical ganglia, (iv) spinal cord, (v) brainstem, and (vi) higher centers. Each of these processing centers contains afferent, efferent, and local circuit neurons, which interact locally and in an interdependent fashion with the other levels to coordinate regional cardiac electrical and mechanical indices on a beat-to-beat basis...
September 15, 2016: Comprehensive Physiology
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Victor M Niemeijer, Ruud F Spee, Thijs Schoots, Pieter F F Wijn, Hareld M Kemps
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in chronic heart failure (CHF) patients is related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired CHF patients (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-minute exercise tests (bout 1 and 2) with measurements of pulmonary oxygen uptake kinetics, and SmO2 using near infrared (NIR) spatially resolved spectroscopy (SRS) at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Barry J Maron, Ethan J Rowin, Martin S Maron, Eugene Braunwald
Hypertrophic cardiomyopathy was first recognized as a disease of obstruction to left ventricular outflow, hence its early names and acronyms such as idiopathic hypertrophic subaortic obstruction. The nonobstructive subset of patients, incapable of developing mechanical impedance to left ventricular outflow at rest or with physiologic exercise, was initially recognized by the Braunwald group at the National Institutes of Health >50 years ago in the pre-imaging era and is now recognized as comprising about one-third of hypertrophic cardiomyopathy patients...
October 13, 2016: American Journal of Medicine
Alcides Rocha, Flavio F Arbex, Maria Clara N Alencar, Priscila A Sperandio, Daniel M Hirai, Danilo C Berton, Denis E O'Donnell, J Alberto Neder
BACKGROUND: Exercise oscillatory ventilation (EOV) is associated with poor ventilatory efficiency and higher operating lung volumes in heart failure. These abnormalities may be particularly deleterious to dyspnea and exercise tolerance in mechanically-limited patients, e.g. those with coexistent COPD. METHODS: Ventilatory, gas exchange and sensory responses to incremental exercise were contrasted in 68 heart failure-COPD patients (12 EOV+). EOV was established by standard criteria...
September 24, 2016: International Journal of Cardiology
Fausto Antonio Panizzolo, Andrew J Maiorana, Louise H Naylor, Lawrence G Dembo, David G Lloyd, Daniel J Green, Jonas Rubenson
BACKGROUND: Alterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants...
2016: PeerJ
Kristin Halvorsen Hortemo, Per Kristian Lunde, Jan Haug Anonsen, Heidi Kvaløy, Morten Munkvik, Tommy Aune Rehn, Ivar Sjaastad, Ida Gjervold Lunde, Jan Magnus Aronsen, Ole M Sejersted
Protein O-GlcNAcylation has emerged as an important intracellular signaling system with both physiological and pathophysiological functions, but the role of protein O-GlcNAcylation in skeletal muscle remains elusive. In this study, we tested the hypothesis that protein O-GlcNAcylation is a dynamic signaling system in skeletal muscle in exercise and disease. Immunoblotting showed different protein O-GlcNAcylation pattern in the prototypical slow twitch soleus muscle compared to fast twitch EDL from rats, with greater O-GlcNAcylation level in soleus associated with higher expression of the modulating enzymes O-GlcNAc transferase (OGT), O-GlcNAcase (OGA), and glutamine fructose-6-phosphate amidotransferase isoforms 1 and 2 (GFAT1, GFAT2)...
September 2016: Physiological Reports
Bruno-Pierre Dubé, Piergiuseppe Agostoni, Pierantonio Laveneziana
Exertional dyspnoea is among the dominant symptoms in patients with chronic heart failure and progresses relentlessly as the disease advances, leading to reduced ability to function and engage in activities of daily living. Effective management of this disabling symptom awaits a better understanding of its underlying physiology.Cardiovascular factors are believed to play a major role in dyspnoea in heart failure patients. However, despite pharmacological interventions, such as vasodilators or inotropes that improve central haemodynamics, patients with heart failure still complain of exertional dyspnoea...
September 2016: European Respiratory Review: An Official Journal of the European Respiratory Society
Benjamin P Woodall, Meryl C Woodall, Timothy S Luongo, Laurel A Grisanti, Douglas G Tilley, John W Elrod, Walter J Koch
GRK2, a G protein-coupled receptor kinase, plays a critical role in cardiac physiology. Adrenergic receptors are the primary target for GRK2 activity in the heart; phosphorylation by GRK2 leads to desensitization of these receptors. As such, levels of GRK2 activity in the heart directly correlate with cardiac contractile function. Furthermore, increased expression of GRK2 after cardiac insult exacerbates injury and speeds progression to heart failure. Despite the importance of this kinase in both the physiology and pathophysiology of the heart, relatively little is known about the role of GRK2 in skeletal muscle function and disease...
October 14, 2016: Journal of Biological Chemistry
Aghogho Odudu, Christopher W McIntyre
Cardiac dysfunction is a key factor in the high morbidity and mortality rates seen in hemodialysis (HD) patients. Much of the dysfunction is manifest as adverse changes in cardiac and vascular structure prior to commencing dialysis. This adverse vascular remodeling arises as a dysregulation between pro- and antiproliferative signaling pathways in response to hemodynamic and nonhemodynamic factors. The HD procedure itself further promotes cardiomyopathy by inducing hypotension and episodic regional cardiac ischemia that precedes global dysfunction, fibrosis, worsening symptoms, and increased mortality...
August 24, 2016: Seminars in Dialysis
Syed R Hussain, Andrea Macaluso, Stephen J Pearson
Moderate-intensity continuous training (MICT) has long been considered the most effective exercise treatment modality for the prevention and management of cardiovascular disease (CVD), but more recently high-intensity interval training (HIIT) has been viewed as a potential alternative to MICT in accruing such benefits. HIIT was initially found to induce significant improvements in numerous physiological and health-related indices, to a similar if not superior extent to MICT. Since then, many studies have attempted to explore the potential clinical utility of HIIT, relative to MICT, with respect to treating numerous cardiovascular conditions, such as coronary artery disease, heart failure, stroke, and hypertension...
November 2016: Cardiology in Review
Anoshia Raza, Kate Steinberg, Joseph Tartaglia, William H Frishman, Tanush Gupta
External Counterpulsation therapy was first developed over half a century ago as a resuscitative tool to support the failing heart and was based on hemodynamic principles of the intra-aortic balloon pump. Over the course of last few decades, it has evolved into the modern enhanced external counterpulsation (EECP) therapy, which has proven to be a safe, effective, and low-cost noninvasive treatment for patients with debilitating angina and chronic heart failure who are poor candidates for revascularization procedures and have sub-optimal results from other therapies...
August 19, 2016: Cardiology in Review
Nigel Harris, Deborah Dulson, Greig Logan, Isaac Warbrick, Fabrice Merien, David Lubans
The purpose of this study was to compare the acute physiological responses within and between resistance training (RT) and high intensity interval training (HIIT) matched for time and with comparable effort, in a school setting. Seventeen early adolescents (12.9 ± 0.3 y) performed both RT (2-5 repetitions perceived short of failure at the end of each set) and HIIT (90% of age predicted maximum heart rate), equated for total work set and recovery period durations comprising of 12 'sets' of 30 s work followed by 30 s recovery (total session time 12 min)...
August 16, 2016: Journal of Strength and Conditioning Research
Rui Liu, Justin W Kenney, Antigoni Manousopoulou, Harvey E Johnston, Makoto Kamei, Christopher H Woelk, Jianling Xie, Michael Schwarzer, Spiros D Garbis, Christopher G Proud
Cardiomyocytes undergo growth and remodeling in response to specific pathological or physiological conditions. In the former, myocardial growth is a risk factor for cardiac failure and faster protein synthesis is a major factor driving cardiomyocyte growth. Our goal was to quantify the rapid effects of different pro-hypertrophic stimuli on the synthesis of specific proteins in ARVC and to determine whether such effects are caused by alterations on mRNA abundance or the translation of specific mRNAs. Cardiomyocytes have very low rates of protein synthesis, posing a challenging problem in terms of studying changes in the synthesis of specific proteins, which also applies to other nondividing primary cells...
October 2016: Molecular & Cellular Proteomics: MCP
Paulino Alvarez, Bashar Hannawi, Ashrith Guha
Exercise limitation is the hallmark of heart failure, and an increasing degree of intolerance is associated with poor prognosis. Objective evaluation of functional class (e.g., cardiopulmonary exercise testing) is essential for adequate prognostication in patients with advanced heart failure and for implementing an appropriate exercise training program. A graded exercise program has been shown to be beneficial in patients with heart failure and has become an essential component of comprehensive cardiac rehabilitation in these patients...
April 2016: Methodist DeBakey Cardiovascular Journal
Libera Fresiello, Bart Meyns, Arianna Di Molfetta, Gianfranco Ferrari
The physiological response to physical exercise is now recognized as an important tool which can aid the diagnosis and treatment of cardiovascular diseases. This is due to the fact that several mechanisms are needed to accommodate a higher cardiac output and a higher oxygen delivery to tissues. The aim of the present work is to provide a fully closed loop cardiorespiratory simulator reproducing the main physiological mechanisms which arise during aerobic exercise. The simulator also provides a representation of the impairments of these mechanisms in heart failure condition and their effect on limiting exercise capacity...
2016: Frontiers in Physiology
Sergio Sanchez-Martinez, Nicolas Duchateau, Tamas Erdei, Alan G Fraser, Bart H Bijnens, Gemma Piella
We propose an independent objective method to characterize different patterns of functional responses to stress in the heart failure with preserved ejection fraction (HFPEF) syndrome by combining multiple temporally-aligned myocardial velocity traces at rest and during exercise, together with temporal information on the occurrence of cardiac events (valves openings/closures and atrial activation). The method builds upon multiple kernel learning, a machine learning technique that allows the combination of data of different nature and the reduction of their dimensionality towards a meaningful representation (output space)...
June 11, 2016: Medical Image Analysis
Adam R Wende, Martin E Young, John Chatham, Jianhua Zhang, Namakkal S Rajasekaran, Victor M Darley-Usmar
Understanding molecular mechanisms that underlie the recent emergence of metabolic diseases such as diabetes and heart failure has revealed the need for a multi-disciplinary research integrating the key metabolic pathways which change the susceptibility to environmental or pathologic stress. At the physiological level these include the circadian control of metabolism which aligns metabolism with temporal demand. The mitochondria play an important role in integrating the redox signals and metabolic flux in response to the changing activities associated with chronobiology, exercise and diet...
May 27, 2016: Free Radical Biology & Medicine
Tieh-Cheng Fu, Shu-Chun Huang, Chih-Chin Hsu, Chao-Hung Wang, Jong-Shyan Wang
UNLABELLED: Reduced exercise capacity negatively affects the ability of patients with heart failure (HF) to perform activities required for daily life, further decreasing their independence and quality of life (QoL). Cardiac rehabilitation (CR) can effectively improve aerobic fitness and overall health status in patients with HF. Low referral rate is an important limitation that may impede successful CR, whereas the automatic referral and liaison strategies performed by some healthcare providers manifestly increase the CR referral rate...
September 2014: Acta Cardiol Sin
Gordon R Reeves, Shuchita Gupta, Daniel E Forman
Symptom-limited (maximal) exercise testing before cardiac rehabilitation (CR) was once an unambiguous standard of care. In particular, it served as an important screen for residual ischemia and instability before initiating a progressive exercise training regimen. However, improved revascularization and therapy for coronary heart disease has led many clinicians to downplay this application of exercise testing, especially because such testing is also a potential encumbrance to CR enrollment (delaying ease and efficiency of enrollment after procedures and hospitalizations) and patient burden (eg, added costs, logistic hassle, and anxiety)...
September 2016: Journal of Cardiopulmonary Rehabilitation and Prevention
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