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cardiac output exercise

Jonathan S Howard, Cherilyn N McLester, Thomas W Evans, John R McLester, Jimmy P Calloway
The PhysioFlow™ is a piece of equipment that uses bioimpedance cardiography to measure central hemodynamics. The purpose of this research was to explore the novel approach of monitoring central hemodynamics during free weight resistance exercise using bioimpedance cardiography throughout a 5 repetition maximum (5RM). Thirty participants ranging from beginner to advanced lifters (16 males and 14 females) completed a 5RM for back squat, seated push press, and bicep curl while connected to the PhysioFlow™ to assess the response of heart rate (HR), stroke volume (SV), cardiac output (Q), and ejection fraction (EF)...
2018: International Journal of Exercise Science
Marco Herbsleb, Andy Schumann, Berend Malchow, Christian Puta, P Christian Schulze, Holger W Gabriel, Karl-Jürgen Bär
The elevated cardiovascular risk of patients with schizophrenia contributes to a reduced life expectancy of 15-20years. This study investigated whether cardiac autonomic dysfunction (CADF) in schizophrenia is related to chronotropic incompetence, an established cardiovascular risk marker. We investigated thirty-two patients suffering from paranoid schizophrenia and thirty-two control subjects matched for age, sex, body mass index and fat free mass. A cardiopulmonary exercise test (CPET) was performed to study heart rate responses to exercise as well as submaximal (ventilatory threshold 1, VT1 ) and maximal endurance capacities (peak oxygen consumption, VO2peak ; peak power output, Ppeak )...
March 8, 2018: Schizophrenia Research
Cole S Bailey, Luke T Wooster, Mary Buswell, Sarvagna Patel, Paul P Pappagianopoulos, Kristian Bakken, Casey White, Melissa Tanguay, Jasmine B Blodgett, Aaron L Baggish, Rajeev Malhotra, Gregory D Lewis
OBJECTIVES: This study sought to characterize the functional and prognostic significance of oxygen uptake (VO2 ) kinetics following peak exercise in individuals with heart failure (HF). BACKGROUND: It is unknown to what extent patterns of VO2 recovery following exercise reflect circulatory response during exercise in HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). METHODS: We investigated patients (30 HFpEF, 20 HFrEF, and 22 control subjects) who underwent cardiopulmonary exercise testing with invasive hemodynamic monitoring and a second distinct HF cohort (n = 106) who underwent noninvasive cardiopulmonary exercise testing with assessment of long-term outcomes...
March 1, 2018: JACC. Heart Failure
Marcus Granegger, Martin Schweiger, Marianne Schmid Daners, Mirko Meboldt, Michael Hübler
PURPOSE: Rotary blood pumps are a promising treatment approach for patients with a total cavopulmonary connection and a failing cardiovascular system. The aim of this study was to investigate the hemodynamic effects of cavopulmonary support using a numerical model with closed-loop baroreflex and exercise mechanisms. METHODS: A numerical model of the univentricular cardiovascular system was developed, mimicking the hemodynamics during rest and exercise. Rotary blood pumps with different hydraulic pump characteristics (flat vs steep pressure-flow relationships) were investigated in the cavopulmonary position...
March 1, 2018: International Journal of Artificial Organs
Eoin Donnellan, Dermot Phelan
PURPOSE OF THE REVIEW: Markers of myocardial stress, including troponin, creatine kinase, and brain natriuretic peptide are frequently elevated after endurance athletic pursuits. Here, we summarize the current literature pertaining to the potential mechanism of cardiac enzyme release in athletes and seek to determine the clinical implications of these findings. RECENT FINDINGS: Recent studies have highlighted the potential adverse cardiac effects of long-term extreme endurance exercise...
March 8, 2018: Current Heart Failure Reports
Thomas Beltrame, Cleber Ferraresi, Nivaldo Antonio Parizotto, Vanderlei Salvador Bagnato, Richard L Hughson
Light-emitting diodes (LEDs) might have a beneficial impact on cytochrome-c oxidase enzyme activity. Thus, it was hypothesized that photobiomodulation by light-emitting diode therapy (LEDT) could influence aerobic metabolism dynamics. Possible LEDT-mediated aerobic improvements were investigated mainly by a precise characterization of the pulmonary O2 uptake dynamics during moderate exercise transitions. Eight healthy young adults were enrolled in this randomized, double-blind, placebo-controlled, crossover study...
March 7, 2018: Lasers in Medical Science
Stéphane Doutreleau, Irina Enache, Cristina Pistea, Bernard Geny, Anne Charloux
In this study, we hypothesized that adding CO2 to an inhaled hypoxic gas mixture will limit the rise of pulmonary artery pressure (PAP) induced by a moderate exercise. Eight 20-year-old males performed four constant-load exercise tests on cycle at 40% of maximal oxygen consumption in four conditions: ambient air, normobaric hypoxia (12.5% O2 ), inhaled CO2 (4.5% CO2 ), and combination of hypoxia and inhaled CO2 . Doppler echocardiography was used to measure systolic (s)PAP, cardiac output (CO). Total pulmonary resistance (TPR) was calculated...
March 3, 2018: Pflügers Archiv: European Journal of Physiology
Toru Kondo, Sumio Yamada, Chikako Asai, Takahiro Okumura, Daisuke Tanimura, Toyoaki Murohara
BACKGROUND: Skeletal muscle pump function may play a key role in maintaining cardiac output (CO), because of the lack of cardiac contractility reserve during incremental exercise in heart failure (HF) patients. We aimed to investigate the relationship between lower leg pump function and surrogate measures of CO during cardiopulmonary exercise testing (CPX) in HF patients.Methods and Results:Consecutive cardiac patients referred for CPX had their lower leg ejection fraction (LgEF) measured using strain gauge plethysmography as a marker of skeletal muscle pump function...
March 1, 2018: Circulation Journal: Official Journal of the Japanese Circulation Society
Daria Stypinski, Stephen A McQuarrie, Alexander J B McEwan, Leonard I Wiebe
The objective of this work is to evaluate the potential effect of cardiac stress exercise on the accumulation of [123 I]IAZA, a radiopharmaceutical used to image focal tissue hypoxia, in otherwise normal myocardium in healthy volunteers, and to determine the impact of exercise on [123 I]IAZA pharmacokinetics. The underlying goal is to establish a rational basis and a baseline for studies of focal myocardial hypoxia in cardiac patients using [123 I]IAZA. Three healthy male volunteers ran the 'Bruce' treadmill protocol, a clinically-accepted protocol designed to expose myocardial ischemia in patients...
February 22, 2018: Pharmaceutics
Stuart D Katz
Heart failure is a common form of heart disease associated with progressive exercise intolerance and high risk of adverse clinical outcome events. The pathophysiology of chronic systolic heart failure is fundamentally determined by the failure of the circulatory system to deliver oxygen sufficient for metabolic needs, and it is best explained by a complex interplay between intrinsic abnormalities of ventricular pump function and extracardiac factors that limit oxygen use in metabolically active tissues. This brief review highlights the role of extracardiac factors (peripheral factors) that may impact exercise capacity in patients with chronic systolic heart failure...
February 2018: Annals of the American Thoracic Society
Karl-Philipp Rommel, Maximilian von Roeder, Christian Oberueck, Konrad Latuscynski, Christian Besler, Stephan Blazek, Thomas Stiermaier, Karl Fengler, Volker Adams, Marcus Sandri, Axel Linke, Gerhard Schuler, Holger Thiele, Philipp Lurz
BACKGROUND: Although systolic right ventricular (RV) dysfunction has been shown to be a potent predictor for adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF), RV functional abnormalities in the course of the syndrome are not well characterized. We, therefore, sought to assess load-independent and load-dependent systolic and diastolic characteristics of RV function in stable outpatients with HFpEF. METHODS AND RESULTS: We invasively obtained RV and left ventricular pressure-volume loops in 24 HFpEF patients and 9 patients without heart failure symptoms with a conductance catheter during basal conditions and handgrip exercise...
February 2018: Circulation. Heart Failure
Joseph Hernandez, Steven G Chopski, Sam Lee, William B Moskowitz, Amy L Throckmorton
Background: Limited therapeutic options are available for Fontan patients with dysfunctional or failing single ventricle physiology. This study describes the evaluation of an alternative, non-invasive, at-home therapeutic compression treatment for Fontan patients. Our hypothesis is that routinely administered, externally applied compression treatments to the lower extremities will augment systemic venous return, improve ventricular preload, and thus enhance cardiac output in Fontan patients...
January 2018: Translational Pediatrics
Thomas Schmidt, Birna Bjarnason-Wehrens, Stephanie Mommertz, Meike Hannig, Sebastian Schulte-Eistrup, Detlev Willemsen, Nils Reiss
Following implantation of a left ventricular assist device (LVAD), acceptable functional performance is now being achieved; however, peak VO 2 and peak work load (watts) remain considerably limited. Maximum physical capacity is essentially dependent on generated cardiac output (CO) and arteriovenous oxygen difference (avDO 2 ). We investigated the changes in CO and avDO 2 during exercise in LVAD patients with an HVAD pump (HeartWare Inc., Framingham, MA, USA). Approximately 6 weeks after implantation, 20 patients (100% male, 60...
February 12, 2018: Artificial Organs
Veronica J Poitras, Robert W Hudson, Michael E Tschakovsky
Physical activity is critically important for type 2 diabetes management, yet adherence levels are poor. This might be partly due to disproportionate exercise intolerance. Submaximal exercise tolerance is highly sensitive to muscle oxygenation; impairments in exercising muscle oxygen delivery may contribute to exercise intolerance in type 2 diabetes since there is considerable evidence for the existence of both cardiac and peripheral vascular dysfunction. While uncompromised cardiac output during submaximal exercise is consistently observed in type 2 diabetes, it remains to be determined whether an elevated cardiac sympathetic afferent reflex could sympathetically restrain exercising muscle blood flow...
February 8, 2018: Journal of Applied Physiology
Yi Tang, Lei Yao, Zhihong Liu, Wenlin Xie, Xiuping Ma, Qin Luo, Zhihui Zhao, Zhiwei Huang, Liu Gao, Qi Jin, Xue Yu, Changming Xiong, Xinhai Ni, Yinkun Yan, Wenwei Qi
BACKGROUND: Studies have shown that peak circulatory power (peak CircP; peak oxygen uptake × peak systolic blood pressure) is a variable predictor of prognosis in patients with left heart failure. It remains unknown whether peak CircP also predicts outcome in patients with idiopathic pulmonary arterial hypertension (IPAH). METHODS: Patients with newly diagnosed IPAH who underwent symptom-limited cardiopulmonary exercise testing (CPET) from 1 January 2011 to 1 January 2014 in Fuwai Hospital were prospectively enrolled and followed for up to 66 months for cardiac events (mortality and lung transplantation)...
February 2018: Respiratory Medicine
K Terziyski, A Draganova
Characterized by periodic crescendo-decrescendo pattern of breathing alternating with central apneas, Central sleep apnea (CSA) with Cheyne-Stokes Breathing represents a highly prevalent, yet underdiagnosed comorbidity in chronic heart failure (CHF). A diverse body of evidence demonstrates increased morbidity and mortality in the presence of CSB. CSB has been described in both CHF patients with preserved and reduced ejection fraction, regardless of drug treatment. Risk factors for CSB are older age, male gender, high BMI, atrial fibrillation and hypocapnia...
February 7, 2018: Advances in Experimental Medicine and Biology
David Montero, Candela Diaz-Cañestro
BACKGROUND: Severe exercise intolerance (EI), demonstrated by impaired peak oxygen consumption, intrinsically characterizes heart failure with preserved ejection fraction (HFpEF). Controversy exists on the determinants of EI in patients with HFpEF according to case-control studies. The purpose of this study is to systematically review and clarify the main (Fick) determinants of EI in HFpEF. METHODS: We conducted a systematic search of MEDLINE, Scopus and Web of Science since their inceptions until January 2017 for articles assessing peak cardiac output and/or arteriovenous oxygen difference (a-vO2diffpeak) with incremental exercise in patients diagnosed with HFpEF and age-matched control individuals...
March 1, 2018: International Journal of Cardiology
Dejana Popovic, Ross Arena, Marco Guazzi
BACKGROUND: In heart failure (HF), a flattening oxygen consumption (VO2 ) trajectory during cardiopulmonary exercise test (CPET) reflects an acutely compromised cardiac output. We hypothesized that a flattening VO2 trajectory is helpful in phenotyping disease severity and prognosis in HF with either reduced (HFrEF), mid-range (HFmrEF), or preserved (HFpEF) ejection fraction. METHODS AND RESULTS: Overall, 319 HF patients (198 HFrEF, 80 HFmrEF, and 41 HFpEF) underwent CPET...
February 6, 2018: European Journal of Heart Failure
Miriam Kuhn, Andreas Hornung, Heidi Ulmer, Christian Schlensak, Michael Hofbeck, Gesa Wiegand
There are many complex cardiac malformations that are characterized by a functionally univentricular physiology. Staged surgical repair according to the Fontan principle separates the systemic and pulmonary circulations by connecting the systemic venous return to the pulmonary arteries. However, long-term follow-up studies demonstrate a gradual deterioration of cardiac function, particularly from the second or third decade. Noninvasive evaluation of the cardiac function is, therefore, important in the follow-up of these patients...
February 3, 2018: Pediatric Cardiology
Robert D Meade, Craig G Crandall, Daniel Gagnon, Glen P Kenny
Following exercise, mean arterial pressure (MAP) is reduced ~5-10 mmHg from pre-exercise baseline. In non-endurance-trained males, post-exercise hypotension results from peripheral vasodilation not offset by increased cardiac output (CO). By contrast, post-exercise hypotension occurs through a reduction in CO from pre-exercise baseline in endurance-trained males. The reason(s) explaining these divergent responses remain unknown. Exercise at fixed percentage of peak oxygen consumption (VO2peak) is associated with a greater rate of metabolic heat production in trained individuals and therefore elevated sweat rates, both when compared to untrained individuals...
February 1, 2018: Journal of Applied Physiology
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