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Results 251 - 300 of 1296
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Zhang Jianyi - - 2005
NO and O(2) compete at cytochrome-c oxidase, thus potentially allowing NO to modulate mitochondrial respiration. We previously observed a decrease of myocardial phosphocreatine (PCr)/ATP during very high cardiac work states, corresponding to an increase in cytosolic free ADP. This study tested the hypothesis that NO inhibition of respiration contributes to ...
Kim M A - - 2004
SETTING: University-affiliated general hospital. OBJECTIVE: To evaluate the pump performance of right heart before and after exercise in post-tuberculosis emphysema. DESIGN: In patients with post-tuberculosis or primary emphysema (similar lung volumes), body plethysmography, arterial blood gas analysis and echocardiography were performed at rest and after exercise. Right heart pump performance ...
Molavi Behzad - - 2004
PURPOSE OF REVIEW: The adoption of immediate reperfusion strategies to treat acutely occluded coronary arteries and the emergence of high-resolution molecular biology techniques have drawn attention to oxidative stress and reactive oxygen species generation in the cardiovascular system. Recent evidence suggests that oxidative stress is a common denominator in many ...
Kemming G I - - 2004
BACKGROUND: Hemodilution reduces hematocrit (Hct) and blood oxygen content. Tissue oxygenation is mainly preserved by increased cardiac output. As myocardial O2-demands increase, coronary vasodilatation becomes necessary to increase myocardial blood flow. Myocardial ischemia occurs at a critical Hct-value (Hctcrit), with accompanying exhaustion of coronary reserve. Hyperoxic ventilation is known to ...
Eriksson Ove - - 2004
Levosimendan is a novel drug developed for treatment of decompensated heart failure. Levosimendan is a calcium sensitizer that increases contractile force of the myocardium by enhancing the sensitivity of myofilaments to calcium without increasing intracellular calcium concentration. The present study was carried out to investigate whether levosimendan induces any changes ...
Foo K - - 2004
AIMS: To compare major determinants of myocardial oxygen demand (heart rate, blood pressure and rate pressure product) in patients with and without diabetes admitted with acute coronary syndromes. METHODS: A cross-sectional study of the relation between diabetes and haemodynamic indices of myocardial oxygen demand in 2542 patients with acute coronary ...
Inglessis Ignacio - - 2004
OBJECTIVES: We sought to determine whether or not inhaled nitric oxide (NO) could improve hemodynamic function in patients with right ventricular myocardial infarction (RVMI) and cardiogenic shock (CS). BACKGROUND: Inhaled NO is a selective pulmonary vasodilator that can decrease right ventricular afterload. METHODS: Thirteen patients (7 males and 6 females, ...
Aghajani Ebrahim - - 2004
OBJECTIVE: Myocardial oxygen consumption (MVO2) in the septic myocardium is increased despite reduced left ventricular mechanical work. We investigated the mechanism behind this energetic inefficiency in the septic myocardium. METHODS: To clarify whether energy consumption in basal metabolism or excitation-contraction (EC) coupling is elevated in the septic myocardium, we separated ...
Zheng Jie - - 2004
PURPOSE: To explore the relationship of myocardial T(2) and oxygenation for the quantification of myocardial oxygen extraction fraction (OEF). MATERIALS AND METHODS: A proposed myocardial T(2)-OEF relationship was evaluated by computer simulation and in nine normal dogs in vivo. The relationship was based on a simplified two-compartment T(2) model. In ...
Ingwall Joanne S - - 2004
The requirement of chemical energy in the form of ATP to support systolic and diastolic work of the heart is absolute. Because of its central role in cardiac metabolism and performance, the subject of this review on energetics in the failing heart is ATP. We briefly review the basics of ...
Vlahović Alja - - 2004
BACKGROUND: It has been shown that transient increase in left ventricular stiffness, assessed by Doppler-derived early filling deceleration time, occurs during the first 24 to 48 hours after myocardial infarction but returns to normal within several days. It has been reported that hyperbaric oxygen treatment has a favorable effect on ...
Adler Alexandra - - 2004
We investigated the role of nitric oxide (NO) in the control of myocardial O(2) consumption in the hearts of female Xenopus frogs, which lack a coronary vascular endothelium and in which the endocardial endothelium is the only source of NO to regulate cardiac myocyte function. Hence, frogs are an ideal ...
Hou Mingxiao - - 2004
Circulating levels of the potent vasoconstrictor peptide endothelin-1 (ET-1) are increased in congestive heart failure (CHF). Coronary blood flow and myocardial oxygen consumption (MVO2) are decreased in some models of CHF. This study tested the hypothesis that ET-1 induced coronary vasoconstriction limits oxygen availability in the failing heart. The effects ...
Vasiliauskas Donatas - - 2004
STUDY OBJECTIVE: The aim of the study was to evaluate the impact of a long-term (6-month) correct breathing stereotype on minute ventilation, capillary blood gases and acid-base balance in post-myocardial infarction patients. METHODS: Fifty-five men (age 57.2 +/- 12.5) were examined 2 months later after myocardial infarction. Spirometry and assessment ...
Nikolaidis Lazaros A - - 2004
To investigate the metabolic cost of catecholamine use in heart failure, we administered intravenous dobutamine or norepinephrine to dogs with moderate and severe LV dysfunction until LV contractile function was restored to normal levels. Both drugs were associated with significant increases in myocardial O(2) consumption, increased coronary blood flow requirements ...
Hirata Kumiko - - 2004
Epidemiologic studies suggest that tea consumption decreases the risk for cardiovascular events. However, there has been no clinical report examining the effects of tea consumption on coronary circulation. The purpose of this study was to evaluate the effects of black tea on coronary flow velocity reserve (CFVR) using transthoracic Doppler ...
Mukamal Kenneth J - - 2004
BACKGROUND: Previous studies have generally suggested no effect of coffee consumption on the risk of acute myocardial infarction. The effect of coffee consumption on prognosis after acute myocardial infarction is uncertain. METHODS: In an inception cohort study, we observed 1935 patients who were hospitalized with a confirmed acute myocardial infarction ...
Kaye David M - - 2004
The aim of the present study was to investigate the effects of CPAP (continuous positive airway pressure) support on myocardial energetics in patients with CHF (congestive heart failure). CPAP has been shown to decrease left ventricular afterload and to produce favourable short- and long-term haemodynamic and neurohormonal benefits in CHF ...
Michiels Carine - - 2004
As the average age in many countries steadily rises, heart infarction, stroke, and cancer become the most common causes of death in the 21st century. The causes of these disorders are many and varied and include genetic predisposition and environmental influences, but they all share a common feature in that ...
Sandstedt Bengt - - 2004
OBJECTIVE: Ventricular fibrillation (VF) is life-threatening because of its haemodynamic and metabolic effects. The purpose was to examine if VF also has primary effects per se. We therefore investigated the early effects of VF on myocardial blood flow, metabolic characteristics and catecholamine concentrations in patients undergoing surgery for aortic stenosis. ...
Samuels Louis - - 2004
The traditional extracorporeal membrane oxygenation circuit uses a centrifugal pump. These pumps require close monitoring and are subject to complications. In addition, they do not take advantage of the potential benefits of pulsatile flow. These extracorporeal membrane oxygenation circuits use a single pump with an inline oxygenator. If cardiac failure ...
Misfeld Martin - - 2004
OBJECTIVE: In coronary artery bypass surgery various parameters have been used to monitor patients clinical status. Direct monitoring of myocardial oxygenation can be performed by measuring intramyocardial partial oxygen tension pressure (p ti O2). This study was performed to determine the perioperative time course of this parameter in correlation to ...
Gunkel Cornelia I - - 2004
A mature horse developed acute signs of bronchoconstriction causing hypoxemia and hypercapnia during anesthesia for computerized tomography of the maxillary sinus after i.v. administration of diatrizoate contrast medium. The horse was treated with aerosolized albuterol, atropine, and oxygen insufflation and recovered uneventfully despite severe hypoxemia and low hemoglobin saturation. The ...
Spahn Donat R - - 2004
Transfusion guidelines in patients with coexisting cardiac diseases are similar to the ones in patients without such comorbidity, in that allogeneic blood transfusions most often are indicated at hemoglobin levels of less than 6.0 g/dL and hardly ever at hemoglobin levels greater than 10 g/dL. In the hemoglobin range of ...
Gatsura S V - - 2004
The mechanism of antiischemic effect of low-energy laser radiation was studied in rats with experimental myocardial infarction taking into consideration the effect of laser on hemoglobin affinity for oxygen and intensity of lipid peroxidation. Low-energy laser irradiation for 15 min in vitro decreased the area of myocardial infarction, slightly reduced ...
Harper S L - - 2004
The cardiovascular system is the first system to become functional in a developing animal and must perform key physiological functions even as it develops and grows. The ontogeny of cardiac physiology was studied throughout embryonic and larval developmental stages in the red swamp crayfish Procambarus clarkii using videomicroscopic dimensional analysis. ...
Ilangovan Govindasamy - - 2004
Oxygen plays a critical role in the pathophysiology of myocardial injury during both ischemia and subsequent reperfusion (I/R). Thus, oxygen concentration is an important variable to measure during I/R. In the present work, electron paramagnetic resonance (EPR)-based oximetry was used to measure the oxygen concentration during a series of I/R ...
Monnet X - - 2004
Initially described more than 30 years ago, the Pulmonary Artery Catheter (PAC) technique was becoming more and more used in the following years. This hemodynamic monitoring device can be used according 2 different therapeutic attitudes. The first one strives to achieve supranormal hemodynamic values, particularly in terms of cardiac index ...
Lloyd Steven G - - 2004
Interventions that stimulate carbohydrate oxidation appear to be beneficial in the setting of myocardial ischemia or infarction. However, the mechanisms underlying this protective effect have not been defined, in part because of our limited understanding of substrate utilization under ischemic conditions. Therefore, we used (1)H and (13)C NMR spectroscopy to ...
Kurzelewski M - - 2004
Evidence indicates that nitric oxide (NO) suppresses myocardial oxygen consumption (MVO(2)) and regulates myocardial substrate oxidation, however data from in vivo and isolated heart preparations are conflicting. In addition, cardiac endothelin (ET-1) release has been shown to increase with inhibition of NO synthase (NOS), however the effects of ET-1 on ...
Ivnitski-Steele Irena D - - 2004
BACKGROUND: Previous research has demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces cardiomyocyte growth arrest, thinner ventricle walls, and reduced number and size of coronary arteries during chick embryogenesis. Coronary vascular development is believed to be mediated, in part, by myocardial oxygen gradients and a subsequent increase in hypoxia-inducible factor 1alpha (HIF-1alpha) and ...
Mital Seema - - 2004
BACKGROUND: Nitric oxide (NO) binds to mitochondrial cytochrome oxidase to decrease myocardial oxygen consumption (MVO(2)). This regulation is disrupted in heart failure (HF) due to reduced NO. The present objective was to evaluate NO-mediated regulation of mitochondrial respiration in the myocardium of patients with congenital heart disease (CHD) and cardiomyopathy ...
Frøbert Ole - - 2004
Low O2 tension dilates coronary arteries and high O2 tension is a coronary vasoconstrictor but reports on O2-dependent effects on ventricular performance diverge. Yet oxygen supplementation remains first line treatment in cardiovascular disease. We hypothesized that hypoxia improves and hyperoxia worsens myocardial performance. Seven male volunteers (mean age 38 +/- ...
Body Richard - - 2004
A short cut review was carried out to establish whether supplemental oxygen reduces mortality in patients with uncomplicated acute myocardial infarction. Altogether 290 papers were found using the reported search, of which one presented the best evidence to answer the clinical question. The author, date and country of publication, patient ...
DeWall Richard A - - 2003
Open heart surgery was not possible before the early 1950s. The development of controlled cross-circulation at the University of Minnesota in 1953 was a major contributing factor toward operating safely on the interior of the heart. Cross-circulation required connecting a donor's arterial and venous blood vessels to those of a ...
Tossios Paschalis - - 2003
OBJECTIVE: Reactive oxygen species have been shown to contribute to myocardial stress in patients undergoing cardiac surgery, as demonstrated by myocardial 8-iso-prostaglandin-F(2)alpha and nitrotyrosine formation. We hypothesized that the reactive oxygen species scavenger N-acetylcysteine attenuates reactive oxygen species-mediated myocardial stress in patients undergoing cardiac surgery. METHODS: Forty patients undergoing coronary ...
Kounis N G NG School of Health, Patras Highest Institute of Education and Technolgy, Patras, Greece. - - 2003
Cardiorespiratory complications may occur during gastrointestinal endoscopy, and elderly people seem to be more vulnerable to these complications during endoscopic procedures involving the manipulation of abdominal viscera. To determine the incidence of cardiac arrhythmias, changes in oxygen saturation, heart rate and blood pressure during endoscopic retrograde cholangiopancreatography (ERCP) via Holter ...
Schiffmann Holger - - 2003
Na+-channel modulators exert their positive inotropic action without affecting the adenylate-cyclase pathway by an increase in the open probability of the sarcolemmal Na+ channels. Although inotropic effects in neonatal hearts are less pronounced compared with adult hearts, the Na+-channel modulator BDF 9148 increases contractility and relaxation velocity in immature myocardium. ...
Gibbs Colin L - - 2003
1. The background to current ideas in cardiac energetics is outlined and, in the genomic era, the need is stressed for detailed knowledge of mouse heart mechanics and energetics. 2. The mouse heart is clearly different to the rat in terms of its excitation-contraction (EC) coupling and the common assumption ...
Kuniyoshi Yukio - - 2003
OBJECTIVE: To evaluate the effect of systemic temperature on myocardial protection during extracorporeal circulation, we quantitatively evaluated the relationship between myocardial oxygen consumption and rectal temperature. MATERIALS AND METHODS: Myocardial oxygen consumption during cardiac arrest was calculated via blood gas analysis of venous blood samples collected from the coronary sinus. ...
Gorman Des - - 2003
Carbon monoxide (CO) is a dangerous exogenous poison and an essential endogenous neurotransmitter. This gas when inhaled has an anaesthetic effect, which is poorly understood, but which may be fatal if compensatory mechanisms are exhausted, if cardiac oxygen (O(2)) needs exceed myocardial oxygenation and/or if apnoea or asphyxia onsets. Although ...
Vanhanen Ingemar - - 2003
OBJECTIVE: To study cardiac uptake and release of substrates and the influence of intravenous glutamate in patients operated for unstable angina requiring intravenous nitrates. DESIGN: Nineteen patients were randomized to blinded infusion of glutamate or saline. Arterial-coronary sinus differences of substrates were measured before cardiopulmonary bypass (CPB) and during early ...
Martin Claus - - 2003
Nitric oxide (NO) is involved in the control of myocardial metabolism. In normoperfused myocardium, NO synthase inhibition shifts myocardial metabolism from free fatty acid (FFA) toward carbohydrate utilization. Ischemic myocardium is characterized by a similar shift toward preferential carbohydrate utilization, although NO synthesis is increased. The importance of NO for ...
Carvajal Karla - - 2003
Myocardial function depends on adenosine triphosphate (ATP) supplied by oxidation of several substrates. In the adult heart, this energy is obtained primarily from fatty acid oxidation through oxidative phosphorylation. However, the energy source may change depending on several factors such as substrate availability, energy demands, oxygen supply, and metabolic condition ...
Peterson Linda R - - 2003
OBJECTIVES: Our aim was to determine the effect of beta-adrenergic blockade on the prognostic value of peak oxygen consumption testing in patients with heart failure. BACKGROUND: Peak oxygen consumption has been shown to be a useful prognostic tool in patients with heart failure. However, studies demonstrating the utility of peak ...
Rosenstrauch Doreen - - 2003
One possible way to expand the human heart donor pool is to include non-heart-beating human donors. To begin validating this approach, we developed an ex vivo cardiac perfusion circuit to support large mammalian hearts in Langendorff mode and beating-ejecting mode and to assess and improve their ischemic tolerance. In vivo ...
Thompson Loren P - - 2003
This review examines the effect of high altitude and/or chronic hypoxia on cardiac mechanisms that influence perfusion of the fetal heart (e.g., tissue metabolism, coronary vessel growth, and coronary blood flow and vessel responsiveness). In response to intrauterine hypoxia, the fetal heart may either reduce its energy demand or increase ...
Fredriksen Per Morten - - 2002
BACKGROUND: We investigated the aerobic capacity of 168 adult patients who had undergone successful surgical repair of retralogy of Fallot at the University of Toronto Congenital Cardiac Centre for Adults. METHODS: We compared values of peak uptake of oxygen, peak heart rate, forced vital capacity, and forced expiratory volume in ...
Coetzee Andre - - 2002
OBJECTIVE: To examine the effect of acebutolol, a beta-adrenergic-receptor blocker, on severe regional myocardial ischemia, specifically the effects on regional myocardial function and metabolism. DESIGN: Randomized study. SETTING: Animal laboratory of the Department of Anesthesiology and Critical Care, University of Stellenbosch Medical School. PARTICIPANTS: Anesthetized open-chest pig model (n = ...
Perko Mario J - - 2002
The aim of the study was to assess changes in myocardial oxygenation in patients with ischaemic heart disease during surgical revascularisation. In 20 patients, regional oxygen saturation, oxyhaemoglobin and total haemoglobin concentrations were examined by near-infrared spectroscopy in the myocardium and in a non-ischaemic skeletal muscle, which served as a ...
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