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Results 251 - 300 of 833
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Sundareswaran Kartik S - - 2008
Little is known about the impact of the total cavopulmonary connection (TCPC) on resting and exercise hemodynamics in a single ventricle (SV) circulation. The aim of this study was to elucidate this mechanism using a lumped parameter model of the SV circulation. Pulmonary vascular resistance (1.96+/-0.80 WU) and systemic vascular ...
Bertagnolli Mariane - - 2008
Spontaneously hypertensive rats (SHRs) show increased cardiac sympathetic activity, which could stimulate cardiomyocyte hypertrophy, cardiac damage, and apoptosis. Norepinephrine (NE)-induced cardiac oxidative stress seems to be involved in SHR cardiac hypertrophy development. Because exercise training (ET) decreases sympathetic activation and oxidative stress, it may alter cardiac hypertrophy in SHR. The ...
Dawson Ellen A - - 2008
Prolonged exercise has been shown to result in an acute depression in cardiac function. However, little is known about the effect of this type of exercise on vascular function. Therefore, the purpose of the present study was to investigate the impact of an acute bout of prolonged strenuous exercise on ...
Rowland Thomas - - 2008
"Classic" cardiovascular drift is characterized by findings of decreasing stroke volume and mean arterial pressure, rising heart rate, and stable cardiac output during sustained constant-load exercise. Recent studies in adults indicate that when dehydration is prevented by fluid intake, this pattern is altered, with no change in stroke volume and ...
Scharhag Jürgen - - 2008
At present, the risk of myocardial damage by endurance exercise is under debate because of reports on exercise-associated increases in cardiac biomarkers troponin and B-type natriuretic peptide (BNP); these markers are typically elevated in patients with acute myocardial infarction and chronic heart failure, respectively. Exercise-associated elevations of cardiac biomarkers can ...
Fries Michael - - 2008
OBJECTIVE: Treatment options to ameliorate brain damage following cardiopulmonary resuscitation from cardiac arrest are limited. DESIGN: In a porcine model, we evaluated the effects of xenon treatment on neuropathologic and functional outcomes after cardiopulmonary resuscitation. SETTING: Prospective, randomized laboratory animal study. SUBJECTS: Male pigs. INTERVENTIONS: Following successful resuscitation from 8 ...
Peyton Philip J - - 2008
OBJECTIVES: To re-evaluate the accuracy and precision of a non-invasive method for measurement of cardiac output based on the differential CO(2) Fick approach using an automated change in respiratory rate delivered by a ventilator under control by a prototype measurement system. METHODS: Twenty-four patients during coronary artery bypass surgery, pre- ...
Calbet José A L - - 2008
During exercise in humans, the alveolar-arterial O(2) tension difference ((A-a)DO(2)) increases with exercise intensity and is an important factor determining the absolute level of oxygen binding to hemoglobin and therefore the level of systemic oxygen transport. During exercise in hypoxia, the (A-a)DO(2) is accentuated. Using the multiple inert gas elimination ...
He Zihong - - 2008
The human gene for heme oxygenase-1 (HMOX-1) plays an important role in the regulation of cardiovascular function and its adaptive response to a variety of stressors. The purpose of this study was to examine the possible association between HMOX-1 genotypes (for -1135A/G, -413A/T, and rs5755720 polymorphisms) and cardiac structural and ...
Ellidokuz Ender - - 2008
Opioid receptors involved in regulating the motility of the gastrointestinal tract have been localized in both contractile and neuronal tissues. Trimebutine, a peripheral opioid receptor agonist, modulates gastrointestinal motor activity in both directions and also may act on cardiac tissue. This study investigated the effects of trimebutine in clinical doses ...
Noakes T D - - 2008
OBJECTIVES: A recent editorial in Medicine and Science in Sports and Exercise concludes that the study of Hawkins and colleagues confirms "beyond any doubt the proposition of Hill and Lupton". It is not clear which of Hill and Lupton's propositions have been proved "beyond any doubt". METHODS: A review of ...
Scott Jessica M - - 2008
We tested the hypothesis that following an acute bout of exercise cardiovascular and cerebrovascular responses to lower-body negative pressure (LBNP) would be altered due to post-exercise hypotension (PEH). Ten healthy, male, endurance-trained athletes (mean age +/- SD = 29.6 +/- 5) were assessed for cardiovascular and cerebrovascular responses to LBNP ...
Khan Nouman U - - 2008
INTRODUCTION: Haemodynamically significant ventricular tachyarrhythmias are a frequent complication in the immediate post-operative period after cardiac surgery. Successful cardioversion depends on delivery of sufficient current, which in turn is dependent on transthoracic impedance (TTI). However, it is uncertain if there is a change in TTI immediately following cardiac surgery using ...
Drezner Jonathan A - - 2008
BACKGROUND: Sudden cardiac arrest is the leading cause of death in young athletes. However, limited studies have examined survival rates after exercise-related sudden cardiac arrest in the youth. OBJECTIVE: The Purpose of this study was to monitor exercise-related sudden death in the United States and to assess survival trends following ...
Jehi Lara - - 2008
Patients with refractory epilepsy face an elevated risk of sudden death, with rates as high as 1% per year. This phenomenon, known as sudden unexpected death in epilepsy (SUDEP), is believed to be a seizure-related occurrence, but the exact underlying mechanisms are uncertain. Both pulmonary and cardiac pathophysiologies have been ...
Sharman James E JE Department of Medicine, University of Queensland, Brisbane, Australia. - - 2008
NO modulates resting blood pressure and wave reflection. The effect of NO on exercise central hemodynamics is unknown but has important implications relating to cardiovascular risk. The aim of this study was to determine the contribution of NO to pulse pressure (PP) amplification and wave reflection during exercise. Twelve healthy ...
Crisafulli Antonio - - 2008
Previous studies have shown that the muscle metaboreflex, along with its effect on peripheral vasculature, is capable of inducing substantial enhancement in cardiac performance, stroke volume and cardiac output. This study was designed to determine whether the metaboreflex recruited by means of postexercise muscle ischaemia (PEMI) after running at two ...
Bickel Amitai - - 2008
BACKGROUND: Induction of pneumoperitoneum (PP) may lead to adverse cardiac functions secondary to changes such as decreased venous return and hypercarbia. The assessment of cardiac electrical activity by signal averaging may reflect various hemodynamic derangements and serve as a prognostic marker for arrhythmias. The aim of the study is to ...
Jakovljevic Djordje G DG Research Centre for Society and Health, Buckinghamshire Chilterns University College, Chalfont Campus, Gorelands Lane, Chalfont St Giles, Buckinghamshire HP8 4AD, UK. - - 2008
Several rebreathing methods are available for cardiac output (Q (T)) measurement. The aims of this study were threefold: first, to compare values for resting Q (T) produced by the equilibrium-CO(2), exponential-CO(2) and inert gas-N(2)O rebreathing methods and, second, to evaluate the reproducibility of these three methods at rest. The third ...
Wonders Karen Y - - 2007
Exercise-induced cardiac dysfunction (EICD) has been observed immediately following exhaustive exercise in trained individuals, but limited and conflicting data are available regarding EICD in a previously untrained population days after an exhaustive exercise bout. The purpose of this study was to examine the effects of a single bout of acute ...
Nie J - - 2008
Cardiac troponin release is generally found in adult athletes after continuous-type endurance exercises or sport competitions. The purpose of this study was to investigate whether the physical stress experienced by adolescents while playing basketball, an intense, intermittent-type sport, could induce transient elevations of the serum cardiac troponin T (cTnT) and ...
Knobloch Karsten - - 2009
BACKGROUND: The relationship of non-invasive CW Doppler cardiac output (COUSCOM) and stroke volume (SVUSCOM) and calculated COSTRINGER and SVSTRINGER based on the Stringer calculations in healthy athletes is unknown. METHODS: 20 athletes (19.9+/-11 years) underwent a standardized stepwise treadmill test including breath-by-breath spirometry, and non-invasive SVUSCOM and COUSCOM. Stringer formula ...
Vianna Lauro C - - 2008
Post-exercise cardiac vagal reactivation is well-investigated; however, the effect of water intake during this period has not been well studied. Therefore, our aim was to assess the influence of water intake on the cardiac vagal reactivation after 30 min of a submaximal cycling exercise. Ten healthy subjects (eight men) aged ...
Fišer B - - 2007
Re-evaluation of all functions of baroreflex by means of a simple mathematical model of circulation was the aim of the present study. The following states are modelled: 1. Rest. 2. Immediately after baroreceptor denervation. 3. Several days after denervation. 4. Physical exercise before denervation. 5. Physical exercise several days after ...
Karadag Bilgehan - - 2007
We report post-exercise cardiac asystole after treadmill exercise test in three patients without structural heart disease. Post-exercise asystole in healthy individuals is a potentially life-threatening incident with a presumably underestimated prevalence. It may be responsible for some of the sudden deaths in young persons and athletes. Although the underlying mechanism ...
Janssen Paul M L - - 2007
An increase in heart rate is the primary mechanism that up-regulates cardiac output during conditions such as exercise and stress. When the heart rate increases, cardiac output increases due to (1) an increased number of beats per time period, and (2) the fact that myocardium generates a higher level of ...
Shmueli Karin - - 2007
Heart rate fluctuations occur in the low-frequency range (<0.1 Hz) probed in functional magnetic resonance imaging (fMRI) studies of resting-state functional connectivity and most fMRI block paradigms and may be related to low-frequency blood-oxygenation-level-dependent (BOLD) signal fluctuations. To investigate this hypothesis, temporal correlations between cardiac rate and resting-state fMRI signal ...
Osthaus Wilhelm Alexander - - 2007
BACKGROUND: Monitoring of cardiovascular function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output (CO) and oxygen delivery is expensive and sometimes associated with adverse events. Therefore, we investigated the accuracy of a new noninvasive CO monitoring device using electrical velocimetry (EV) in comparison with ...
Kasikcioglu Erdem - - 2008
Although the underlying mechanisms responsible for cardiac dysfunction after prolonged exercise remains to be elucidated, it has reported cardiac deterioration following exhaustive exercise in the absence of underlying cardiovascular diseases, which has been attributed to cardiac fatigue. The objective of this study was to evaluate cardiac functions, exercise capacity, and ...
Ogoh S - - 2007
AIMS: Cardiac failure and ischaemic heart disease patients receive standard of care cardiac beta(1)-adrenergic blockade medication. Such medication reduces cardiac output and cerebral blood flow. It is unknown whether the beta(1)-adrenergic blockade-induced reduction of cardiac output in the presence of an exercise-induced reduction in cardiac-arterial baroreflex gain affects cerebral blood ...
Rowland T - - 2007
Traditional findings of circulatory responses to a bout of static exercise include an abrupt rise in systolic and diastolic blood pressure, small increases in cardiac output with no rise in stroke volume, and unaltered systemic vascular resistance. These characteristics are not, however, consistent with current concepts of circulatory adjustments to ...
Shah Amy - - 2007
BACKGROUND: Cardiovascular and cerebrovascular disease is 2-3 times more common in bipolar patients than the general population. Asymptomatic bipolar patients have electrocardiogram abnormalities at high rates. The question of heart function in asymptomatic bipolar subjects arises. METHODS: This study examined the impact of exhaustive exercise on cardiac function in untrained ...
Keren Hanan - - 2007
Noninvasive cardiac output (CO) measurement can be useful in many clinical settings where invasive monitoring is not desired. Bioimpedance (intrabeat measurement of changes in transthoracic voltage amplitude in response to an injected high-frequency current) has been explored for this purpose but is limited in some clinical settings because of inherently ...
Scognamiglio R - - 2007
Sudden cardiac death (SCD) occurs in patients with Bartter/Gitelman syndromes. Hypokalemia and QTc prolongation are suggested mechanisms. SCD, however, has also been described at normal potassium concentration. This study reports the cases of one Bartter and one Gitelman patient, who experienced an aborted SCD, and evaluates the possible mechanisms of ...
Shepherd Albert P - - 2007
Measured oxygen consumption rates (VO2) are being used less frequently for direct Fick cardiac output determinations during cardiac catheterization because the instruments that measure VO2 are usually cumbersome, expensive and difficult to use. A small, inexpensive VO2 device recently became available. Therefore, the aims of this report are: (1) to ...
Riera Salvador Quintana - - 2007
OBJECTIVES: To analyse how rescuers tolerate the effort derived of giving uninterrupted chest compressions during 2min. MATERIALS AND METHODS: Twenty-three healthy volunteers, nurses and doctors of the Intensive Care Unit (ICU), members of the hospital cardiac arrest team, were enrolled in the study. Using a training manikin, participants were asked ...
McMullen Julie R - - 2007
Physical activity protects against cardiovascular disease, and physiological cardiac hypertrophy associated with regular exercise is usually beneficial, in marked contrast to pathological hypertrophy associated with disease. The p110alpha isoform of phosphoinositide 3-kinase (PI3K) plays a critical role in the induction of exercise-induced hypertrophy. Whether it or other genes activated in ...
Querido Jordan S - - 2007
Constant cerebral blood flow (CBF) is vital to human survival. Originally thought to receive steady blood flow, the brain has shown to experience increases in blood flow during exercise. Although increases have not consistently been documented, the overwhelming evidence supporting an increase may be a result of an increase in ...
Myers Jonathan - - 2007
The carbon dioxide (CO(2)) rebreathing method is a noninvasive technique to estimate cardiac output during exercise, but few data are available on the validity and reliability of this measure in individuals with spinal cord injury (SCI). Sixteen male subjects with SCI (mean age 45 +/- 9, seven paraplegic and nine ...
Lorsomradee Suraphong - - 2007
OBJECTIVE: The purpose of this study was to determine whether a relationship exists between the inferior vena cava diameter (IVCD) or the superior vena cava diameter (SVCD) measured at the point of entry into the right atrium using transesophageal echocardiography (TEE) and the central venous pressure (CVP) under different experimental ...
Sakamoto Masaya - - 2006
Exercise-induced cardiac hypertrophy has been reported to have better prognosis than pressure overload-induced cardiac hypertrophy. Cardiac hypertrophy induced by exercise was associated with less cardiac fibrosis and better systolic function, suggesting that the adaptive mechanisms may exist in exercise-induced hypertrophy. Here, we showed a critical role of heat shock transcription ...
Green Daniel J - - 2006
PURPOSE OF REVIEW: To briefly review some recent studies of cardiac and vascular adaptation to acute exercise and exercise training. RECENT FINDINGS: Recent studies have suggested that prolonged strenuous bouts of exercise may be associated with transient impairment in systolic and diastolic function, referred to as 'cardiac fatigue'. Furthermore, some ...
McGaw Iain J - - 2006
The osmoregulatory physiology of decapod crustaceans has received extensive attention. Within this field there is a growing body of literature on cardiovascular and respiratory responses to low salinity. Most species exhibit a tachycardia coupled with an increase in ventilation rate and oxygen uptake. However, these previous experiments were conducted on ...
Staib Jessica L - - 2007
The expression of myocardial heat shock protein 72 (HSP72) postexercise is initiated by the activation of heat shock transcription factor 1 (HSF1). However, it remains unknown which physiological stimuli govern myocardial HSF1 activation during exercise. These experiments tested the hypothesis that thermal stress and mechanical load, concomitant with simulated exercise, ...
Nassis George P - - 2006
PURPOSE OF REVIEW: To critically evaluate the most recent literature on the methods used to assess body composition, cardiovascular and metabolic function in children and adolescents. RECENT FINDINGS: Although regional body composition can be fairly accurately calculated by dual-energy X-ray absorptiometry, the accuracy of noninvasive estimations of visceral adipose tissue ...
Hanson Linda M - - 2006
As rainbow trout approach exhaustion during prolonged exercise, they maintain maximum cardiac output despite the fact their venous blood, which bathes the heart, becomes hypoxic, acidotic and hyperkalemic. Because these factors are individually recognized to have detrimental inotropic and chronotropic effects on cardiac performance, we hypothesized that adrenergic stimulation is ...
Scharhag Jürgen - - 2006
BACKGROUND: Cardiac troponins I and T and brain natriuretic peptide are the accepted standards to serologically identify myocardial necrosis and elevated wall stress. In addition, they allow risk stratification in cardiovascular patients. The clinical significance of increases in cardiac markers after strenuous endurance exercise in obviously healthy athletes is unclear. ...
Balouch Jamal - - 2007
The open circuit acetylene uptake method is a useful non-invasive means of measuring cardiac output. However, because of accumulation of inhaled acetylene in tissues, the cardiac output uptake is underestimated, if residual acetylene is not allowed to wash out completely in between measurements. We determined the effect of applying a ...
Hsueh Chia-Hsiang - - 2006
An 18-year-old woman presented with exercise induced sudden collapse. Series of cardiac work up revealed no structural cardiac abnormalities. Bidirectional ventricular tachycardia occurred during a treadmill exercise test. Under the impression of catecholaminergic polymorphic ventricular tachycardia, we screened the cardiac ryanodine receptor gene for mutation. We identified a novel heterozygous ...
Kasikcioglu Erdem - - 2006
BACKGROUND: Although the underlying mechanisms responsible for cardiac dysfunction after prolonged exercise remains to be elucidated, it has reported cardiac deterioration following exhaustive exercise in the absence of underlying cardiovascular diseases, which has been attributed to cardiac fatigue. The study was designed to investigate the effects of after fatiguing exercise ...
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