Search Results
Results 301 - 350 of 1296
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Himpe D G - - 2002
BACKGROUND AND OBJECTIVE: The effects of administering albumin 5%, hydroxyethylstarch 6% and succinylated gelatine 4% on oxygen transport and left ventricular function were prospectively investigated in different experimental conditions: baseline, fluid load, after 10 min of myocardial ischaemia and after reperfusion. METHODS: Twenty-seven rabbits received at random one of three ...
Kawaguchi Osamu - - 2002
BACKGROUND: This study investigates the possibility of reducing myocardial oxygen consumption by dynamic cardiomyoplasty in chronic heart failure. The sheep model used is relevant for cardiac assist using direct mechanical cardiac compression. METHODS: In 7 sheep, heart failure was induced by staged intracoronary microembolization followed by dynamic cardiomyoplasty. Six months ...
Bosenberg Craig - - 2002
The heart plays a pivotal role in determining the oxygen supply to the body. As a result of its high oxygen extraction ratio, the myocardium must function efficiently to supply itself with oxygen. In the context of the ICU, the efficient functioning of the myocardium is confounded by a number ...
Linke Axel - - 2002
We assessed whether pregnancy results in enhanced nitric oxide (NO)-mediated control of myocardial oxygen consumption. Rats were studied before (C), at 1 wk (1w) or 2 wk (2w) of pregnancy, and at 4 days after giving birth (-4d). Left ventricular endothelial NO synthase (eNOS) protein expression was determined by immunoblotting. ...
Des Tombe A L - - 2002
Oxygen supply and demand of individual cardiomyocytes during the development of myocardial hypertrophy is studied using calibrated histochemical methods. An oxygen diffusion model is used to calculate the critical extracellular oxygen tension (PO(2,crit)) required by cardiomyocytes to prevent hypoxia during hypertrophic growth, and determinants of PO(2,crit) are estimated using calibrated ...
Shiga Toshiya - - 2002
Transesophageal echocardiography (TEE) has not been used during airway manipulation to assess the occasional occurrence of hemodynamic instability that occurs especially in cardiac patients. We describe a new technique using an endoscopy mask to perform TEE monitoring during airway manipulation with a large concentration of supplemented oxygen.
D?vila-Rom?n V?ctor G - - 2002
OBJECTIVES: The purpose of this study was to determine whether patients with idiopathic dilated cardiomyopathy (IDCM) exhibit alterations in myocardial fatty acid and glucose metabolism. BACKGROUND: Alterations in myocardial metabolism have been implicated in the pathogenesis of heart failure (HF); however, studies of myocardial metabolic function in human HF have ...
Chen YingJie - - 2002
BACKGROUND: Endogenous nitric oxide (NO) has been reported to inhibit oxygen consumption in the normal heart, so that nonselective inhibition of NO synthase (NOS) caused an increase of myocardial oxygen consumption (MVO2). Although endothelial NOS responses are depressed in congestive heart failure (CHF), inducible NOS (iNOS) may be expressed in ...
Csont Tamás - - 2002
Clinical studies have suggested that long-term nitrate treatment does not improve and may even worsen cardiovascular mortality, and the possible role of nitrate tolerance has been suspected. Nitrate tolerance has been recently shown to increase vascular superoxide and peroxynitrite production leading to vascular dysfunction. Nevertheless, nitrates exert direct cardiac effects ...
Nordhaug D - - 2002
OBJECTIVE: We hypothesised that acute ischemic left ventricular failure is characterised by depressed systolic and diastolic function combined with inefficiency in oxygen to mechanical work energy transfer. METHODS: Eight anaesthetised pigs (32+/-3 kg) were employed in an in vivo open chest model. Intraventricular combined pressure and conductance catheters were used ...
Nagaya Noritoshi - - 2002
This study investigated the effects of adrenomedullin on left ventricular myocardial contraction and relaxation, coronary blood flow, and myocardial oxygen consumption in comparison with those of atrial natriuretic peptide (ANP). Fourteen patients who had had myocardial infarctions were randomly assigned to receive IV infusion of adrenomedullin (0.05 microg/kg/min) or ANP ...
Ziegler André - - 2002
Despite their prime role in maintaining contractile performance, myocardial substrate uptake, substrate preference and metabolism are difficult to assess non-invasively. The objective of the present work was to extend the scope of cardiac 13C nuclear magnetic resonance (NMR) spectroscopy to the in vivo situation ('closed-chest model') and to quantitatively appraise ...
Recchia Fabio A - - 2002
Solid experimental evidence indicates that nitric oxide (NO) inhibits oxygen utilization in vitro and in vivo. The role played by NO in cellular metabolism is likely extended to the control of substrate utilization. Studies performed in normal hearts show that NO inhibits glucose uptake and that a reduced synthesis of ...
Ingelmo P - - 2002
Increased metabolic requirements by surgical trauma is responsible of the changes in cardiac index and oxygen delivery (DO2), represent compensatory adaptation in circulatory functions stimulated by increased metabolic needs. The amount of this compensation varies with age, gender, severity of illness, operation type, associated medical conditions, shock duration, complications, organ ...
Berlin Gösta - - 2002
O(2) transport and O(2) diffusion interact in providing O(2) to tissue, but the extent to which diffusion may be critical in the heart is unclear. If O(2) diffusion limits mitochondrial oxygenation, a change in blood O(2) affinity at constant total O(2) transport should alter cardiac O(2) consumption (VO(2)) and function. ...
Barnes Edward - - 2002
OBJECTIVES: In patients with coronary artery disease (CAD), we sought to demonstrate normal myocardial blood flow (MBF) and myocardial oxygen consumption (MMRO(2)) to post-ischemic myocardium that exhibited reversible dysfunction and the relation between the severity of the dysfunction and the preceding ischemia. BACKGROUND: In animal models of stunning, MBF and ...
Salem Jennifer E - - 2002
A moderate reduction in coronary blood flow results in decreased myocardial oxygen consumption, accelerated glycolysis, decreased pyruvate oxidation, and lactate accumulation. To quantitatively understand cardiac metabolism during ischemia, we have developed a mechanistic, mathematical model based on biochemical mass balances and reaction kinetics in cardiac cells. By numerical solution of ...
Kal Jasper E - - 2002
The effect of calcium channel blockers may affect the feedback mechanism between myocardial metabolic activity and coronary blood flow. To test this hypothesis the effect of calcium channel blockade on metabolic coronary flow regulation was studied. In 10 patients with stable coronary artery disease, coronary sinus blood flow and myocardial ...
Setty Srinath - - 2002
This study was designed to test if nitric oxide (NO) contributes to norepinephrine-induced right coronary vasodilation and if NO blunts the norepinephrine-induced increase in myocardial oxygen consumption (MVO(2)) in the right ventricle. In five anesthetized, open-chest dogs, mean aortic pressure, heart rate, right ventricular rate of pressure development over time ...
Yo K Y - - 2002
BACKGROUND: Brief myocardial ischaemia has been demonstrated to result in mechanical and coronary endothelial dysfunction, in which calcium may play a role. We examined whether the mechanical and vascular responses to calcium are altered in postischaemic, reperfused myocardium. METHODS: Regional myocardial oxygen consumption (MVO2), mechanical function and coronary blood flow ...
Ernest D - - 2001
OBJECTIVE: To determine the relative distribution of fluid within the extracellular fluid volume (ECFV) and the effect on oxygen delivery after infusing either normal saline or 5% albumin in cardiac surgical patients. DESIGN: Prospective, randomized, unblinded, interventional study. SETTING: Cardiac surgical intensive care unit in a 450-bed teaching hospital. PATIENTS: ...
Korvald C - - 2001
Mechanoenergetic inefficiency in postischemic nonnecrotic myocardium may partly be explained by an increased fatty acid (FA) oxidation rate. In the present study, left ventricular (LV) postischemic energy transfer was characterized in 10 intact anesthetized pigs. The LV was stunned by 11 brief left main coronary artery occlusions/reperfusions (20-min accumulated ischemia). ...
Cappola T P - - 2001
BACKGROUND: Dilated cardiomyopathy is characterized by an imbalance between left ventricular performance and myocardial energy consumption. Experimental models suggest that oxidative stress resulting from increased xanthine oxidase (XO) activity contributes to this imbalance. Accordingly, we hypothesized that XO inhibition with intracoronary allopurinol improves left ventricular efficiency in patients with idiopathic ...
Spindler M - - 2001
This review describes the temporal changes of high-energy phosphate metabolites during the cardiac cycle. Under baseline condition, the extent of cyclical changes ("cycling") of ATP, phosphocreatine and inorganic phosphate varies between 10-15%. Such energy oscillations are not augmented under various forms of metabolic stress including 1) inotropic stimulation, 2) acute ...
Weaver L K - - 2001
We report three cases of pulmonary edema associated with hyperbaric oxygen therapy, including one fatality. All three patients had cardiac disease and reduced left ventricular (LV) ejection fractions (EFs). Two patients had diabetes, and one patient had severe aortic stenosis. Hyperbaric oxygen therapy may contribute to pulmonary edema by increasing ...
Seguin C - - 2001
BACKGROUND: Cardiac dysfunction after brain death has been documented, but its mechanisms remain unclear. Myocardial ischemia has been suggested as a possible cause. The aim of the present study was to investigate the existence of an imbalance between myocardial oxygen delivery and demand as a possible cause of myocardial dysfunction ...
Brodeur J C - - 2001
Rainbow trout (Oncorhynchus mykiss) were exposed for 24 h to concentrations representing 100, 50 and 25% of the 96 h-LC50 of pentachlorophenol (PCP) or tetrachloroguaiacol (TCG), and their oxygen consumption, cardiac output, heart rate and stroke volume were measured at regular intervals. Oxygen consumption either remained stable at basal levels ...
DeVoe D - - 2001
This study investigated the utility of the Tritrac-R3D accelerometer as a reliable and valid instrument in the quantification of physical activity while backpacking in the field and to evaluate heart-rate responses and oxygen consumption to assess the feasibility of using the Tritrac-R3D to estimate caloric expenditure. Two 7-day backpacking expeditions ...
Derdeyn C P - - 2001
PURPOSE: To investigate the relationship between the patterns of cerebral infarction that have been associated with hemodynamic impairment and the presence of severe chronic hemodynamic compromise (increased oxygen extraction fraction) in a large prospectively enrolled group of patients with carotid artery occlusion. MATERIALS AND METHODS: At enrollment in a prospective ...
Schipke J D - - 2001
This manuscript brings together three newer concepts: myocardial hibernation, heterogeneity in myocardial blood flow and oxidative metabolism, and effects of hibernating animal serum on non-hibernators. Myocardial hibernation is viewed as a protective mechanism that helps to maintain myocardial integrity and viability by down-regulating contractile function as an adaptation to reduced ...
Erb J M - - 2001
BACKGROUND: The echocardiographic contrast agent Optison may be useful in patients undergoing cardiac surgery. This study investigates its effects on hemodynamics, cardiac performance, and oxygenation in this group of patients. METHODS: Parameters of hemodynamic stability, cardiac performance, and oxygenation were measured in 57 patients by transesophageal echocardiography, electrocardiography, invasive arterial ...
Yoshitani K - - 2001
This study was conducted to investigate whether jugular bulb venous oxygen saturation (SjVO(2)) predicted cognitive decline after cardiac surgery with hypothermic cardiopulmonary bypass (CPB). We studied 35 patients undergoing cardiac surgery. After the induction of anesthesia, a 5.5F fiberoptic oximetry catheter was retrogradely inserted into the jugular bulb, and SjVO(2) ...
Wallhaus T R - - 2001
Use of beta-adrenoreceptor blockade in the treatment of heart failure has been associated with a reduction in myocardial oxygen consumption and an improvement in myocardial energy efficiency. One potential mechanism for this beneficial effect is a shift in myocardial substrate use from increased free fatty acid (FFA) oxidation to increased ...
Koerner M M - - 2001
Acute heart failure in adults is the unfolding of heart failure in minutes, hours or a few days. Low output heart failure describes a form of heart failure in which the heart pumps blood at a rate at rest or with exertion that is below the physiological range and the ...
Ali M S - - 2001
PURPOSE: Near infrared spectroscopy (NIRS) is a promising non-invasive method for continuous monitoring of cerebral oxygenation during cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to study the agreement between tissue oxygen index (TOI) measured by spatially resolved spectroscopy (NIRO-300) and jugular bulb oxygen saturation (SjO2) in patients ...
Klein L J - - 2001
Estimation of myocardial oxygen consumption (MVO2) and myocardial blood flow (MBF) is important for the understanding of various (patho)physiological mechanisms and diseases. Clearance rates of carbon-11 labelled acetate, determined with positron emission tomography, allow estimation of MVO2 on a segmental level and non-invasively. In addition, MBF can be determined from ...
Kaye D M - - 2001
The precise mechanism by which beta-adrenoceptor blockers exert their beneficial actions in patients with heart failure remains unclear. Several possibilities have been proposed, including heart rate reduction, beta2-adrenoceptor-mediated modulation of catecholamine release, antagonism of the receptor-mediated toxic actions of norepinephrine on the myocardium, and favorable effects on myocardial energetics. In ...
White J M - - 2001
Music interventions have been used in medicine and nursing throughout history. Music therapy is an easy-to-administer, relatively inexpensive, noninvasive intervention that has been used to reduce heart rate, blood pressure, myocardial oxygen consumption, gastrointestinal function, anxiety, and pain. A review of theoretic and empirical base for the use of music ...
Ukkonen H - - 2001
Carbon-11 acetate positron emission tomography (PET) has been widely used to assess regional oxidative metabolism of the heart. However, the accuracy of [11C]acetate PET in assessing oxidative metabolism in infarcted myocardium remains controversial. Thirteen patients with stable coronary artery disease and old myocardial infarction were studied. The 15O-based PET studies ...
Gygax E - - 2001
A 190-kg patient was referred because of an acute type B aortic dissection. Conservative management was initially performed but the 34-year-old patient was shown to have an increasing aortic diameter 2 months later and was scheduled for elective repair of the thoracoabdominal aorta. To anticipate potential difficulties with perfusion and ...
Zehr K J - - 2001
OBJECTIVE: In acute cardiac rejection, changes in myocardial oxygen consumption occur; non-invasive detection of these metabolic changes would have obvious clinical utility. In the classic cervical, heterotopic, canine, transplant model, the heart is non-working. It has a low myocardial oxygen consumption. Creation of a working model with normal myocardial oxygen ...
Lee M K - - 2000
BACKGROUND: The volatile anesthetics may reduce cardiac contractility by limiting both membrane Ca2+ entry and altering intracellular Ca2+ release. Additional pharmacological effects of calcium channel blockers could potentially enhance anesthetic-induced depression. The aim of this study was to compare the direct cardiac effects of enflurane and a new volatile anesthetic, ...
Loke K E - - 2000
We investigated the role of kinin and nitric oxide (NO) in the modulation of cardiac O(2)consumption in Syrian hamsters with overt heart failure (HF) and age-matched normal hamsters. Using echocardiography, the hamsters with heart failure had reduced ejection fraction [31(+/-8) v 76(+/-5)%] and LV dilation [4.9(+/-0. 2) v 5.7(+/-0.3) mm, ...
Ukkonen H - - 2000
AIMS: Levosimendan, a novel calcium-dependent calcium sensitizer of the myocardial contractile proteins, also enhances diastolic relaxation and induces peripheral vasodilation by opening potassium channels. To assess the combined energetical effects of levosimendan infusion in vivo, we performed positron emission tomography in patients with decompensated chronic heart failure. METHODS AND RESULTS: ...
Belardinelli R - - 2000
The therapeutic effect of anti-ischemic compounds is related to their ability to improve the oxygen supply-demand balance of the ischemic myocardium by increasing myocardial blood flow (calcium-antagonists), by reducing regional myocardial oxygen consumption (verapamil, betablockers) and increasing peripheral pooling of blood (nitrates, nifedipine). All these actions are also accompanied by ...
Schwanke U - - 2000
In mammalian hearts, local myocardial flow (LMF) varies between 20 and 200% of the mean. It is not clear whether oxidative metabolism has a similar degree of heterogeneity. Therefore, we investigated the relation between LMF and local oxidative metabolism in isolated rabbit hearts. Buffer oxygenation with (18)O(2) resulted in labeled ...
De Backer D - - 2000
Weaning from mechanical ventilation is usually associated with an increase in oxygen consumption (VO2), which may stress the cardiovascular system. We studied relative changes in the cardiac index and oxygen extraction ratio (EO2) during successful weaning in patients after cardiac surgery (n = 52), cardiac transplantation (n = 17), or ...
Cheong K F - - 2000
OBJECTIVE: To compare the hemodynamic effects of sevoflurane-fentanyl with etomidate-fentanyl during anesthetic induction in patients with coronary artery disease with good left ventricular function. DESIGN: A prospective randomized trial. SETTING: University hospital. PARTICIPANTS: Twenty patients scheduled for elective coronary artery bypass graft surgery. INTERVENTIONS: Patients were allocated randomly to receive ...
Sunderdiek U - - 2000
OBJECTIVE: In stunned myocardium oxygen consumption is relatively high compared with the reduced ventricular function. On the other hand, inotropic stimulation is frequently required to improve postischemic ventricular dysfunction. However, inotropic agents which act via intracellular increased calcium result in a higher oxygen demand. Therefore Ca(2+)-sensitization might be a favorable ...
Myrmel T - - 2000
This paper gives an overview of mainly new aspects of myocardial oxygen consumption. Experimental models have quantified energy consumption in mechanical work, excitation-contraction coupling and metabolic processes. However, there are still contradictory observations between hemodynamic, thermodynamic and subcellular models and further knowledge of subcellular energy consumption is anticipated. The energy ...
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