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cardiac output exercise

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https://www.readbyqxmd.com/read/28212401/preload-based-starling-like-control-of-rotary-blood-pumps-an-in-vitro-evaluation
#1
Mahdi Mansouri, Shaun D Gregory, Robert F Salamonsen, Nigel H Lovell, Michael C Stevens, Jo P Pauls, Rini Akmeliawati, Einly Lim
Due to a shortage of donor hearts, rotary left ventricular assist devices (LVADs) are used to provide mechanical circulatory support. To address the preload insensitivity of the constant speed controller (CSC) used in conventional LVADs, we developed a preload-based Starling-like controller (SLC). The SLC emulates the Starling law of the heart to maintain mean pump flow ([Formula: see text]) with respect to mean left ventricular end diastolic pressure (PLVEDm) as the feedback signal. The SLC and CSC were compared using a mock circulation loop to assess their capacity to increase cardiac output during mild exercise while avoiding ventricular suction (marked by a negative PLVEDm) and maintaining circulatory stability during blood loss and severe reductions in left ventricular contractility (LVC)...
2017: PloS One
https://www.readbyqxmd.com/read/28187374/the-strengths-and-weaknesses-of-non-invasive-parameters-obtained-by-echocardiography-and-cardiopulmonary-exercise-testing-in-comparison-with-the-hemodynamic-assessment-by-the-right-heart-catheterization-in-patients-with-pulmonary-hypertension
#2
Katarzyna Ptaszyńska-Kopczyńska, Anna Krentowska, Emilia Sawicka, Anna Skoneczny, Małgorzata Jasiewicz, Małgorzata Knapp, Włodzimierz J Musiał, Bożena Sobkowicz, Karol A Kamiński
PURPOSE: Pulmonary hypertension (PH) diagnosis requires invasive assessment by right heart catheterization (RHC), but screening and monitoring are performed using non-invasive methods: echocardiography and cardiopulmonary exercise testing (CPET). The aim of the study was to assess correlations between the parameters obtained in non-invasive testing and RHC in patients with PH of different etiologies. MATERIAL/METHODS: The study included 53 medical records of PH patients (32 women) aged 29-81 years...
June 14, 2016: Advances in Medical Sciences
https://www.readbyqxmd.com/read/28186430/cerebral-blood-flow-frontal-lobe-oxygenation-and-intra-arterial-blood-pressure-during-sprint-exercise-in-normoxia-and-severe-acute-hypoxia-in-humans
#3
David Curtelin, David Morales-Alamo, Rafael Torres-Peralta, Peter Rasmussen, Marcos Martin-Rincon, Mario Perez-Valera, Christoph Siebenmann, Ismael Pérez-Suárez, Evgenia Cherouveim, A William Sheel, Carsten Lundby, José Al Calbet
Cerebral blood flow (CBF) is regulated to secure brain O2 delivery while simultaneously avoiding hyperperfusion; however, both requisites may conflict during sprint exercise. To determine whether brain O2 delivery or CBF is prioritized, young men performed sprint exercise in normoxia and hypoxia (PIO2 = 73 mmHg). During the sprints, cardiac output increased to ∼22 L min(-1), mean arterial pressure to ∼131 mmHg and peak systolic blood pressure ranged between 200 and 304 mmHg. Middle-cerebral artery velocity (MCAv) increased to peak values (∼16%) after 7...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28183863/hemodynamic-responses-are-reduced-with-aerobic-compared-with-resistance-blood-flow-restriction-exercise
#4
Anthony K May, Christopher R Brandner, Stuart A Warmington
The hemodynamics of light-load exercise with an applied blood-flow restriction (BFR) have not been extensively compared between light-intensity, BFR, and high-intensity forms of both resistance and aerobic exercise in the same participant population. Therefore, the purpose of this study was to use a randomized crossover design to examine the hemodynamic responses to resistance and aerobic BFR exercise in comparison with a common high-intensity and light-intensity non-BFR exercise. On separate occasions participants completed a leg-press (resistance) or treadmill (aerobic) trial...
February 2017: Physiological Reports
https://www.readbyqxmd.com/read/28176968/decreased-left-ventricular-stroke-volume-is-associated-with-low-grade-exercise-tolerance-in-patients-with-chronic-obstructive-pulmonary-disease
#5
Sumito Inoue, Yoko Shibata, Hiroyuki Kishi, Joji Nitobe, Tadateru Iwayama, Yoshinori Yashiro, Takako Nemoto, Kento Sato, Masamichi Sato, Tomomi Kimura, Akira Igarashi, Yoshikane Tokairin, Isao Kubota
BACKGROUND: Low-grade exercise tolerance is associated with a poor prognosis in patients with chronic obstructive pulmonary disease (COPD). The 6 min walk test (6MWT) is commonly used to evaluate exercise tolerance in patients with COPD. However, little is known regarding the relationship between cardiac function and exercise tolerance in patients with COPD. The aim of this study was to identify predictive factors in cardiac function for low-grade exercise tolerance in patients with stable COPD...
2017: BMJ Open Respiratory Research
https://www.readbyqxmd.com/read/28168802/validation-of-impedance-cardiography-in-pulmonary-arterial-hypertension
#6
Marios Panagiotou, Ioannis Vogiatzis, Geeshath Jayasekera, Zafeiris Louvaris, Alison Mackenzie, Neil Mcglinchey, Julien S Baker, Alistair C Church, Andrew J Peacock, Martin K Johnson
BACKGROUND: Non-invasive methods of measuring cardiac output are highly desirable in pulmonary arterial hypertension (PAH). We therefore sought to validate impedance cardiography (ICG) against thermodilution (TD) and cardiac magnetic resonance (CMR) in the measurement of cardiac output in patients under investigation for PAH. METHODS: A prospective, cross-sectional study was performed to compare single-point measurements of cardiac output obtained by impedance cardiography (COICG ) technology (PhysioFlow(®) ) with (i) contemporaneous TD measurements (COTD ) at rest and steady-state exercise during right heart catheterization and (ii) CMR measurements (COCMR ) at rest obtained within 72 h...
February 6, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28166120/pulmonary-artery-wedge-pressure-relative-to-exercise-workrate-in-older-men-and-women
#7
Sam Esfandiari, Stephen P Wright, Jack M Goodman, Zion Sasson, Susanna Mak
PURPOSE: An augmented pulmonary artery wedge pressure (PAWP) response may explain exercise intolerance in some humans. However, routine use of exercise hemodynamic testing is limited by a lack of data from normal older men and women. Our objective was to evaluate the exercise PAWP response and the potential for sexual dimorphism in healthy, non-dyspneic older adults. METHODS: Thirty-six healthy volunteers [18 men (54±7 years)/18 women (58±6 years)] were studied at rest (Control) and during two stages of semi-upright cycle-ergometry, at heart rates of 100 bpm (Light Exercise) and 120 bpm (Moderate Exercise)...
February 4, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28153942/divergent-endothelial-function-but-similar-platelet-microvesicle-responses-following-eccentric-and-concentric-cycling-at-a-similar-aerobic-power-output
#8
Mark Rakobowchuk, Ophélie Ritter, Eurico Nestor Wilhelm, Laurie Isacco, Malika Bouhaddi, Bruno Degano, Nicolas Tordi, Laurent Mourot
Endothelial function and microvesicle concentration changes after acute bouts of continuous eccentric exercise have not been assessed previously nor compared to concentric exercise at similar aerobic power outputs. This method of training may be useful amongst some clinical populations, but acute responses are not well described. As such, twelve healthy males completed two experimental sessions of either 45 minutes of eccentric or concentric cycling at a matched aerobic power output below the ventilatory threshold...
February 2, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28150069/influence-of-gender-on-right-ventricle-adaptation-to-endurance-exercise-an-ultrasound-two-dimensional-speckle-tracking-stress-study
#9
Maria Sanz-de la Garza, Geneviève Giraldeau, Josefa Marin, Gonzalo Grazioli, Montserrat Esteve, Luigi Gabrielli, Carlos Brambila, Laura Sanchis, Bart Bijnens, Marta Sitges
BACKGROUND: Characteristic right ventricle (RV) remodelling is related to endurance exercise in male athletes (MAs), but data in female athletes (FAs) are scarce. Our aim was to evaluate sex-related influence on exercise-induced RV remodelling and on RV performance during exercise. METHODS: Forty endurance athletes (>10 training hours/week, 50% female) and 40 age-matched controls (<3 h moderate exercise/week, 50% female) were included. Echocardiography was performed at rest and at maximum cycle-ergometer effort...
February 1, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28140647/effects-of-maintaining-different-exercise-intensities-during-detraining-on-aerobic-capacity-in-thoroughbreds
#10
Kazutaka Mukai, Atsushi Hiraga, Toshiyuki Takahashi, Akira Matsui, Hajime Ohmura, Hiroko Aida, James H Jones
OBJECTIVE To determine whether racehorses undergoing regular exercise at 2 intensities or stall rest during a period of reduced training (detraining) would differentially maintain their cardiopulmonary and oxygen-transport capacities. ANIMALS 27 Thoroughbreds. PROCEDURES Horses trained on a treadmill for 18 weeks underwent a period of detraining for 12 weeks according to 1 of 3 protocols: cantering at 70% of maximal rate of oxygen consumption ([Formula: see text]o2max) for 3 min/d for 5 d/wk (canter group); walking for 1 h/d for 5 d/wk (walk group); or stall rest (stall group)...
February 2017: American Journal of Veterinary Research
https://www.readbyqxmd.com/read/28130844/effect-of-aging-on-hypoxic-exercise-cardiorespiratory-and-muscle-and-cerebral-oxygenation-responses-in-healthy-humans
#11
Lara Puthon, Pierre Bouzat, Paul Robach, Anne Favre-Juvin, Stéphane Doutreleau, Samuel Verges
This study assessed the effects of aging on cardiorespiratory and tissue oxygenation responses to hypoxia both at rest and during incremental maximal exercise. Sixteen young (20 - 30 years) and 15older (60 - 70 years) healthy subjects performed two maximal incremental cycling tests in normoxia and hypoxia (inspiratory oxygen fraction: 12%). Cardiorespiratory responses, prefrontal cortex and quadriceps tissue oxygenation (near infrared spectroscopy) were measured during exercise as well as during hypercapnia at rest...
January 28, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28108645/whole-body-hyperthermia-but-not-skin-hyperthermia-accelerates-brain-and-locomotor-limb-circulatory-strain-and-impairs-exercise-capacity-in-humans
#12
Steven J Trangmar, Scott T Chiesa, Kameljit K Kalsi, Niels H Secher, José González-Alonso
Cardiovascular strain and hyperthermia are thought to be important factors limiting exercise capacity in heat-stressed humans, however, the contribution of elevations in skin (Tsk) versus whole body temperatures on exercise capacity has not been characterized. To ascertain their relationships with exercise capacity, blood temperature (TB), oxygen uptake (V̇O2), brain perfusion (MCA Vmean), locomotor limb hemodynamics, and hematological parameters were assessed during incremental cycling exercise with elevated skin (mild hyperthermia; HYPmild), combined core and skin temperatures (moderate hyperthermia; HYPmod), and under control conditions...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28108178/reference-values-for-peak-exercise-cardiac-output-in-healthy-individuals
#13
Piergiuseppe Agostoni, Carlo Vignati, Piero Gentile, Costanza Boiti, Stefania Farina, Elisabetta Salvioni, Massimo Mapelli, Damiano Magrì, Stefania Paolillo, Nicoletta Corrieri, Gianfranco Sinagra, Gaia Cattadori
AIMS: Cardiac output (Q) is a key parameter in the assessment of cardiac function, its measurement being crucial for the diagnosis, treatment and prognostic evaluation of all heart diseases. Until recently, Q determination at peak exercise has been possible through invasive methods, so that normal values were obtained in studies based on small populations. METHODS AND RESULTS: Nowadays, peak Q can be measured noninvasively by means of inert gas rebreathing technique (IGR)...
January 17, 2017: Chest
https://www.readbyqxmd.com/read/28094132/cardiovascular-maladaptation-to-exercise-in-young-hypertensive-patients
#14
Maurizio Cusmà Piccione, Concetta Zito, Bijoy Khandheria, Antonio Madaffari, Alessandra Oteri, Gabriella Falanga, Domenica Donato, Myriam D'Angelo, Maria Ludovica Carerj, Gianluca Di Bella, Egidio Imbalzano, Pietro Pugliatti, Scipione Carerj
BACKGROUND: Impairment of the adaptive mechanisms that increase cardiac output during exercise can translate to a reduced functional capacity. We investigated cardiovascular adaptation to exertion in asymptomatic hypertensive patients, aiming to identify the early signs of cardiac and vascular dysfunction. METHODS AND RESULTS: We enrolled 54 subjects: 30 patients (45.1±11.9years, 19 males) and 24 age-matched healthy controls (44.4±9.6years, 14 males). Speckle-tracking echocardiography (STE) and echo-tracking were performed at rest and during exertion to assess myocardial deformation and arterial stiffness...
January 4, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28090146/rapid-weight-loss-in-the-context-of-ramadan-observance-recommendations-for-judokas
#15
REVIEW
A Aloui, H Chtourou, W Briki, M Tabben, A Chaouachi, N Souissi, R J Shephard, K Chamari
Judo is a weight-classified combat sport, and many athletes seek to compete at the lightest possible weight category to gain an advantage from competing against shorter/smaller, and supposedly weaker opponents. To achieve a desired weight, most judokas opt for rapid weight loss techniques. Short-duration maximal efforts are not greatly affected by "making weight", but prolonged and/or repeated exercise is significantly impaired. Negative effects on mood, ratings of perceived exertion, and cognitive function are also reported...
December 2016: Biology of Sport
https://www.readbyqxmd.com/read/28081223/high-intensity-jump-training-is-tolerated-during-60-days-of-bed-rest-and-is-very-effective-in-preserving-leg-power-and-lean-body-mass-an-overview-of-the-cologne-rsl-study
#16
Andreas Kramer, Jakob Kümmel, Edwin Mulder, Albert Gollhofer, Petra Frings-Meuthen, Markus Gruber
PURPOSE: Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance. METHODS: 23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase...
2017: PloS One
https://www.readbyqxmd.com/read/28081200/fitter-women-did-not-have-attenuated-hemodynamic-responses-to-psychological-stress-compared-with-age-matched-women-with-lower-levels-of-fitness
#17
Sisitha U Jayasinghe, Susan J Torres, Mais Hussein, Steve F Fraser, Gavin W Lambert, Anne I Turner
According to the 'cross stressor adaptation hypothesis', regular exercise acts as a buffer against the detrimental effects of stress. Nevertheless, evidence that higher levels of cardiorespiratory fitness moderate hemodynamic responses to acute psychological stress is inconclusive, especially in women. Women aged 30-50 years (in the mid-follicular phase of the menstrual cycle) with higher (n = 17) and lower (n = 17) levels of fitness were subjected to a Trier Social Stress Test (TSST). Continuous, non-invasive measurements were made of beat-to-beat, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), left ventricular ejection time (LVET), maximum slope, pulse interval (PI) and total peripheral resistance (TPR)...
2017: PloS One
https://www.readbyqxmd.com/read/28043677/pressure-volume-loop-derived-cardiac-indices-during-dobutamine-stress-a-step-towards-understanding-limitations-in-cardiac-output-in-children-with-hypoplastic-left-heart-syndrome
#18
James Wong, Kuberan Pushparajah, Adelaide de Vecchi, Bram Ruijsink, Gerald F Greil, Tarique Hussain, Reza Razavi
BACKGROUND: Children with a single systemic right ventricle, such as in hypoplastic left heart syndrome (HLHS), frequently experience reduced exercise capacity. Elucidating the causes could help with optimising treatment strategies. METHODS: Prospective data from 10 consecutive symptomatic patients with HLHS undergoing clinical cardiac magnetic resonance with catheterisation (XMR) were analysed. Mean age 8.6years (range 3.5-11.6years), mean time since Fontan completion 5...
March 1, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28043202/sex-specific-cardiopulmonary-exercise-testing-indices-related-to-hemodynamics-in-idiopathic-pulmonary-arterial-hypertension
#19
Ping Yuan, Tian-Xiang Chen, Bigyan Pudasaini, Jie Zhang, Jian Guo, Si-Jin Zhang, Lan Wang, Qin-Hua Zhao, Su-Gang Gong, Rong Jiang, Wen-Hui Wu, Jing He, Jin-Ming Liu, Qing-Hua Hu
BACKGROUND: Many studies have highlighted sex preponderance in idiopathic pulmonary arterial hypertension (IPAH). It is well established that there are differences in exercise capacities in the two sexes but how much of that difference reflects on disease severity or correlates to markers of severity in the two sexes is still not clear. Right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET) have been widely used for assessing functional capacity, prognosis and treatment response in IPAH...
January 1, 2017: Therapeutic Advances in Respiratory Disease
https://www.readbyqxmd.com/read/28038810/lvad-pump-speed-increase-is-associated-with-increased-peak-exercise-cardiac-output-and-vo2-postponed-anaerobic-threshold-and-improved-ventilatory-efficiency
#20
Carlo Vignati, Anna Apostolo, Gaia Cattadori, Stefania Farina, Alberico Del Torto, Silvia Scuri, Gino Gerosa, Tomaso Bottio, Vincenzo Tarzia, Jonida Bejko, Erminio Sisillo, Flavia Nicoli, Susanna Sciomer, Francesco Alamanni, Stefania Paolillo, Piergiuseppe Agostoni
BACKGROUNDS: Peak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca-Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO. We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. METHODS: Fifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation...
March 1, 2017: International Journal of Cardiology
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