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Exercise and heart

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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/28212075/towards-photoplethysmography-based-estimation-of-instantaneous-heart-rate-during-physical-activity
#2
Delaram Jarchi, Alex Casson
OBJECTIVE: Recently numerous methods have been proposed for estimating average heart rate using photoplethysmography (PPG) during physical activity, overcoming the significant interference that motion causes in PPG traces. We propose a new algorithm framework for extracting instantaneous heart rate from wearable PPG and ECG signals to provide an estimate of heart rate variability during exercise. METHODS: For ECG signals we propose a new spectral masking approach which modifies a particle filter tracking algorithm, and for PPG signals constrains the instantaneous frequency obtained from the Hilbert transform to a region of interest around a candidate heart rate measure...
February 13, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28211952/long-term-experience-with-first-generation-implantable-neurostimulation-device-in-central-sleep-apnea-treatment
#3
Henrik Fox, Thomas Bitter, Dieter Horstkotte, Olaf Oldenburg, Klaus-Jürgen Gutleben
BACKGROUND: Sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) are associated with shorter survival in patients with heart failure (HF). A novel treatment method for this patient group is unilateral phrenic nerve stimulation by the remedē® system, a transvenously implantable neurostimulation device, which has recently been studied in a large randomized, controlled trial. Previous literature has shown efficacy and safety of the treatment with this first-generation device, but hardly any data is available on long-term clinical parameters, the remedē® device's battery lifetime, device exchangeability, lead position stability, surgical accessibility and manageability...
February 17, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28210939/deep-phenotyping-of-systemic-arterial-hemodynamics-in-hfpef-part-1-physiologic-and-technical-considerations
#4
REVIEW
Julio A Chirinos
A better understanding of the pathophysiology of heart failure with a preserved left ventricular ejection fraction (HFpEF) is important. Detailed phenotyping of pulsatile hemodynamics has provided important insights into the pathophysiology of left ventricular remodeling and fibrosis, diastolic dysfunction, microvascular disease, and impaired oxygen delivery to peripheral skeletal muscle, all of which contribute to exercise intolerance, the cardinal feature of HFpEF. Furthermore, arterial pulsatile hemodynamic mechanisms likely contribute to the frequent presence of comorbidities, such as renal failure and dementia, in this population...
February 16, 2017: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/28209739/myocardial-ischemic-tolerance-in-rats-subjected-to-endurance-exercise-training-during-adaptation-to-chronic-hypoxia
#5
Petra Alánová, Anna Chytilová, Jan Neckář, Jaroslav Hrdlička, Petra Míčová, Kristýna Holzerová, Markéta Hlaváčková, Kristýna Macháčková, František Papoušek, Jana Vašinová, Daniel Benák, Olga Nováková, František Kolář
Chronic hypoxia and exercise are natural stimuli that confer sustainable cardioprotection against ischemia/reperfusion (I/R) injury but it is unknown whether they can act in synergy to enhance ischemic resistance. Inflammatory response mediated by tumor necrosis factor-α (TNF-α) plays a role in the infarct size-limitation by continuous normobaric hypoxia (CNH) whereas exercise is associated with anti-inflammatory effects. This study was conducted to determine whether exercise training performed under conditions of CNH (12% O2) affects myocardial ischemic resistance with respect to inflammatory and redox status...
February 16, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28209387/associations-of-cardiovascular-and-all-cause-mortality-events-with-oxygen-uptake-at-ventilatory-threshold
#6
Setor K Kunutsor, Sudhir Kurl, Hassan Khan, Francesco Zaccardi, Jari A Laukkanen
BACKGROUND: Oxygen uptake (VO2) at ventilatory threshold (VT), is a cardiopulmonary exercise testing parameter which may be a proxy for peak VO2. We aimed to assess the associations of VO2 at VT with sudden cardiac death (SCD), fatal coronary heart disease (CHD) and cardiovascular disease (CVD), and all-cause mortality. METHODS AND RESULTS: VO2 at VT was assessed during a submaximal exercise test using respiratory gas analyzers in the Kuopio Ischemic Heart Disease cohort of 1639 middle-aged men...
February 10, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28209386/dietary-therapy-in-heart-failure-with-preserved-ejection-fraction-and-or-left-ventricular-diastolic-dysfunction-in-patients-with-metabolic-syndrome
#7
REVIEW
Helene von Bibra, Alexander Ströhle, Martin St John Sutton, Nicolai Worm
BACKGROUND: Heart failure is an ongoing epidemic of left ventricular (LV) dilatation and/or dysfunction due to the increasing prevalence of predisposing risk factors such as age, physical inactivity, (abdominal) obesity, and type-2-diabetes. Approximately half of these patients have diastolic heart failure (HFpEF). The prognosis of HFpEF is comparable to that of systolic heart failure, but without any known effective treatment. DIASTOLIC DYSFUNCTION: A biomathematically corrected diagnostic approach is presented that quantifies diastolic dysfunction via the predominant age dependency of LV diastolic function and unmasks (metabolic) risk factors, that are independent of age and, therefore, potential targets for therapy...
January 5, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28209292/cholesterol-screening-and-treatment-practices-and-preferences-a-survey-of-united-states-pediatricians
#8
Sarah D de Ferranti, Angie Mae Rodday, Susan K Parsons, William L Cull, Karen G O'Connor, Stephen R Daniels, Laurel K Leslie
OBJECTIVES: To determine pediatricians' practices, attitudes, and barriers regarding screening for and treatment of pediatric dyslipidemias in 9- to 11-year-olds and 17- to 21-year-olds. STUDY DESIGN: American Academy of Pediatrics (AAP) 2013-2014 Periodic Survey of a national, randomly selected sample of 1627 practicing AAP physicians. Pediatricians' responses were described and modeled. RESULTS: Of 614 (38%) respondents who met eligibility criteria, less than half (46%) were moderately/very knowledgeable about the 2008 AAP cholesterol statement; fewer were well-informed about 2011 National Heart, Lung, and Blood Institute Guidelines or 2007 US Preventive Service Task Force review (both 26%)...
February 13, 2017: Journal of Pediatrics
https://www.readbyqxmd.com/read/28208954/effect-of-surgical-curve-correction-on-exercise-tolerance-and-physical-capacities-in-patients-of-severe-spinal-deformity
#9
Prateek C Patil, Ashok K Rathod, Mandar Borde, Vishwajeet Singh, Hemant U Singh
INTRODUCTION: Traditionally, surgical intervention for patients with a spinal deformity has been considered for cosmetic benefits, but surgical intervention can alter the lung physiology or volumes and in turn leads to increase in physical capacity and exercise tolerance. Therefore, we conducted this to determine whether a surgical correction would restore the lung physiology, physical capacity and exercise tolerance in patients with kyphoscoliosis. AIM: To evaluate the usage of six-minute walk test scores and modified Borg scores as tools/measures for exercise tolerance in patients with spinal deformity and to study the effects of surgical correction of spinal deformity on exercise tolerance with above parameters as the measures...
December 2016: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/28206674/effects-of-spinal-cord-stimulation-on-cardiac-sympathetic-nerve-activity-in-patients-with-heart-failure
#10
Jan Naar, Deborah Jaye, Cecilia Linde, Petr Neužil, Petr Doškář, Filip Málek, Frieder Braunschweig, Lars H Lund, Lars Mortensen, Bengt Linderoth, Göran Lind, Dianna Bone, Arthur J Scholte, Fred Kueffer, Jodi Koehler, Kambiz Shahgaldi, Otto Lang, Marcus Ståhlberg
BACKGROUND: Spinal cord stimulation (SCS) reduces sympathetic activity in animal models of heart failure with reduced ejection fraction (HF) but limited data exist of SCS in patients with HF. The aim of the present study was to test the primary hypothesis that SCS reduces cardiac sympathetic nerve activity in HF patients. Secondary hypotheses were that SCS improves left ventricular function and dimension, exercise capacity and clinical variables relevant to HF. METHODS: HF patients with a SCS device previously participating in the DEFEAT-HF trial were included in this crossover study with 6-week intervention periods (SCS-ON and SCS-OFF)...
February 16, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28205417/muscle-activation-and-heart-rate-responses-to-a-side-step-interval-exercise
#11
Robert S Thiebaud, Takashi Abe, Jonathan C Bravo, Nicolas Giovannitti, Avery P Sullivan
BACKGROUND: The side-step test is commonly used to assess agility. Side-step interval exercise may also be a potential way to improve cardiorespiratory and muscular fitness. However, the acute heart rate and muscle activation response to this type of exercise is not well established. In addition, different tempos can influence these responses. The purpose of this study was to determine the acute heart rate and muscle activation responses of a side-step interval exercise to different exercise tempos...
February 16, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28201825/heart-rate-and-oxygen-uptake-kinetics-in-type-2-diabetes-patients-a-pilot-study-on-the-influence-of-cardiovascular-medication-on-regulatory-processes
#12
Jessica Koschate, Uwe Drescher, Klaus Baum, Christian Brinkmann, Thorsten Schiffer, Joachim Latsch, Klara Brixius, Uwe Hoffmann
The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes...
February 15, 2017: Experimental and Clinical Endocrinology & Diabetes
https://www.readbyqxmd.com/read/28198783/effect-of-moderate-versus-high-intensity-interval-exercise-training-on-heart-rate-variability-parameters-in-inactive-latin-american-adults-a-randomised-clinical-trial
#13
Robinson Ramírez-Vélez, Alejandra Tordecilla-Sanders, Luis Andrés Téllez-T, Diana Camelo-Prieto, Paula Andrea Hernández-Quiñonez, Jorge Enrique Correa-Bautista, Antonio Garcia-Hermoso, Rodrigo Ramírez-Campillo, Mikel Izquierdo
We investigated the effect of moderate versus high-intensity interval exercise training on the HRV indices in physically inactive adults. Twenty inactive adults were randomly allocated to receive either moderate intensity training (MCT group) or high-intensity interval training (HIT group). The MCT group performed aerobic training at an intensity of 55-75%, which consisted of walking on a treadmill at 60-80% of the maximum heart rate (HRmax) until the expenditure of 300 kcal. The HIT group ran on a treadmill for 4 minutes at 85-95% peak HRmax and had a recovery of 4 minutes at 65% peak HRmax until the expenditure of 300 kcal...
February 1, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28198688/cardiopulmonary-exercise-testing-a-contemporary-and-versatile-clinical-tool
#14
REVIEW
Kenneth Leclerc
Cardiopulmonary exercise testing (CPET) helps in detecting disorders of the cardiovascular, pulmonary, and skeletal muscle systems. It has a class I (indicated) recommendation from the American College of Cardiology and American Heart Association for evaluating exertional dyspnea of uncertain cause and for evaluating cardiac patients being considered for heart transplant. Advances in hardware and software and ease of use have brought its application into the clinical arena to the point that providers should become familiar with it and consider it earlier in the evaluation of their patients...
February 2017: Cleveland Clinic Journal of Medicine
https://www.readbyqxmd.com/read/28198604/energy-requirements-of-tyre-pulling
#15
Per M Fredriksen, Asgeir Mamen
BACKGROUND: We have investigated the effect using walking poles and pulling tyres at 4 and 6 km·h-1 (1.11 and 1.67 m·s-1) speeds on oxygen uptake (V̇ O2) and heart rate. METHODS: Twelve subjects, 6 males, with a mean (SD) age of 25.2(6.9) years participated in field tests involving walking without poles, walking with poles and tyre pulling with poles. RESULTS: Increasing the load caused the largest increases in energy demand, more than 4 MET...
February 14, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28198075/exercise-induced-b-lines-identify-worse-functional-and-prognostic-stage-in-heart-failure-patients-with-depressed-left-ventricular-ejection-fraction
#16
Maria Chiara Scali, Lauro Cortigiani, Anca Simionuc, Dario Gregori, Mario Marzilli, Eugenio Picano
AIMS: Exercise stress echocardiography (ESE) is recommended by the European Society of Cardiology guidelines for the evaluation of heart failure (HF) patients. Recently, lung ultrasound (LUS) has been proposed for the assessment of extravascular lung water through B-lines. The aim of this study was to assess B-lines during ESE in HF. METHODS AND RESULTS: Standard transthoracic and LUS evaluation was performed during semi-supine ESE in 103 NYHA class I-III HF patients (76 male; mean age 64 ± 12 years) with depressed LVEF (35 ± 8%)...
February 15, 2017: European Journal of Heart Failure
https://www.readbyqxmd.com/read/28197275/cardiac-resynchronization-therapy-leads-to-improvements-in-handgrip-strength
#17
David R Warriner, Patricia Lawford, Paul J Sheridan
BACKGROUND: A reduction in skeletal muscle performance measured by handgrip strength is common in heart failure. No trial has investigated the role of cardiac resynchronization therapy, which leads to improvements in cardiac performance, on the function of skeletal muscle in patients with heart failure. METHODS: Nineteen patients were recruited, 18 male, age 69 ± 8 years, New York Heart Association class II-IV, QRS duration 173 ± 21 ms and left ventricular ejection fraction 26±8%...
June 2016: Cardiology Research
https://www.readbyqxmd.com/read/28197270/interesting-correlation-between-the-circulating-pentraxin-3-and-cardiac-rehabilitation-program-outcomes-in-coronary-artery-bypass-grafting-patients
#18
Habib Haybar, Babak Payami, Isa Khaheshi, Yasaman Ghotbi, Seyed Mahmoud Latifi, Ahmadreza Assareh
BACKGROUND: Pentraxin 3 (PTX3) is an inflammatory mediator, reaches to the high levels after ischemic heart diseases (IHD) and could be a helpful tool to predict cardiac rehabilitation (CR) outcomes. The aim of this study was to investigate the possibility of the circulating levels of PTX3 in prediction of CR outcomes in patients with IHD who had undergone coronary artery bypass grafting (CABG). METHODS: One hundred patients who had undergone CABG were included in this study...
April 2016: Cardiology Research
https://www.readbyqxmd.com/read/28196853/impaired-cardiac-and-skeletal-muscle-bioenergetics-in-children-adolescents-and-young-adults-with-barth-syndrome
#19
Adil Bashir, Kathryn L Bohnert, Dominic N Reeds, Linda R Peterson, Adam J Bittel, Lisa de Las Fuentes, Christina A Pacak, Barry J Byrne, W Todd Cade
: Barth syndrome (BTHS) is an X-linked condition characterized by altered cardiolipin metabolism and cardioskeletal myopathy. We sought to compare cardiac and skeletal muscle bioenergetics in children, adolescents, and young adults with BTHS and unaffected controls and examine their relationships with cardiac function and exercise capacity. Children/adolescents and young adults with BTHS (n = 20) and children/adolescent and young adult control participants (n = 23, total n = 43) underwent (31)P magnetic resonance spectroscopy ((31)P-MRS) of the lower extremity (calf) and heart for estimation of skeletal muscle and cardiac bioenergetics...
February 2017: Physiological Reports
https://www.readbyqxmd.com/read/28196528/exploring-the-impact-of-financial-barriers-on-secondary-prevention-of-heart-disease
#20
Kirnvir K Dhaliwal, Kathryn King-Shier, Braden J Manns, Brenda R Hemmelgarn, James A Stone, David J T Campbell
BACKGROUND: Patients with coronary artery disease experience various barriers which impact their ability to optimally manage their condition. Financial barriers may result in cost related non-adherence to medical therapies and recommendations, impacting patient health outcomes. Patient experiences regarding financial barriers remain poorly understood. Therefore, we used qualitative methods to explore the experience of financial barriers to care among patients with heart disease. METHODS: We conducted a qualitative descriptive study of participants in Alberta, Canada with heart disease (n = 13) who perceived financial barriers to care...
February 14, 2017: BMC Cardiovascular Disorders
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