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Results 401 - 450 of 1296
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Todaka K - - 1998
BAY y 5959 is a dihydropyridine derivative with positive inotropic actions mediated by a direct increase in intracellular calcium. We characterized the direct myocardial actions of this new agent in hearts isolated from seven normal dogs and from five dogs with repeated coronary microembolization-induced heart failure. Inotropic actions of BAY ...
Lilleberg J - - 1998
AIMS: The aim of the study was to evaluate the effects on systemic and coronary haemodynamics and myocardial substrate utilization of a new calcium sensitizer, levosimendan, after coronary artery bypass grafting. METHODS AND RESULTS: Twenty-three low-risk patients were included in this randomized and double-blind study. They received placebo (n = ...
Parmley W W - - 1998
From a therapeutic point of view, angina pectoris is best thought of as an imbalance between oxygen supply and demand. Oxygen supply to the heart can be increased by improving endothelial function to increase vasodilation. Non-endothelial-mediated vasodilation will also help increase coronary flow. Coronary vasodilators, such as the calcium blockers ...
Chen L - - 1998
The effects of periodic obstructive apneas on systemic and myocardial hemodynamics were studied in nine preinstrumented sedated pigs under four conditions: breathing room air (RA), breathing 100% O2, breathing RA after critical coronary stenosis (CS) of the left anterior descending coronary artery, and breathing RA after autonomic blockade with hexamethonium ...
Schulz R - - 1998
BACKGROUND: Modeling of the time-[1-(11)C]acetate activity curve assumes a constant concentration of labeled tricarboxylic acid cycle intermediates and associated metabolites, such as glutamate and aspartate, which may, however, decrease in short-term hibernating myocardium. METHODS AND RESULTS: In 12 anesthetized pigs, [1-(11)C]acetate was injected as a bolus into the cannulated left ...
Crystal G J - - 1998
BACKGROUND: Calcium produces constriction in isolated coronary vessels and in the coronary circulation of isolated hearts, but the importance of this mechanism in vivo remains controversial. METHODS: The left anterior descending coronary arteries of 20 anesthetized dogs whose chests had been opened were perfused at 80 mmHg. Myocardial segmental shortening ...
Andreas S - - 1998
Patients with congestive heart failure and Cheyne-Stokes respiration have a low arterial oxygen saturation, especially during sleep, which can be increased by breathing oxygen. Chronic alterations in blood gases are known to modulate the hypercapnic ventilatory response (HCVR). We therefore evaluated whether the HCVR is influenced by nocturnal nasal oxygen ...
van der Velden J - - 1998
1. The composition of myosin heavy chains (MHCs) was investigated in young (1- to 8-week-old) and mature (9- to 26-week-old) guinea-pigs using two monoclonal antibodies directed specifically against alpha-MHC and beta-MHC. In addition, maximum force and the rate of ATP consumption during isometric contraction were measured in chemically skinned trabeculae ...
Steffensen J F - - 1998
We performed in vivo studies to examine the idea that cardiac work is impaired in rainbow trout (Oncorhynchus mykiss) below a certain venous PO2 threshold. We hypothesized that coronary-ligated fish, swimming continuously at a reasonably high water velocity (1.5 body lengths x s(-1)) and exposed to progressive hypoxia, would fatigue ...
Kugiyama K - - 1998
Pharmacologic stress tests are used to evaluate the significance of coronary arterial stenosis, and adenosine and dobutamine are often used for this purpose. The aim of this study was to examine coronary hemodynamics in 16 patients with stable exertional angina who had organic stenosis (> 90%) in the left anterior ...
Spahn D R - - 1998
Haemodynamic parameters and oxygen consumption were determined in 20 patients with mitral regurgitation before and after a 12 ml.kg-1 isovolaemic exchange of blood for 6% hydroxyethyl starch. During haemodilution, mean (SEM) haemoglobin concentration decreased from 13.0 (0.4) to 10.3 (0.4) g.dl-1 (p = 0.001). With cardiac filling pressures maintained at ...
Sadoff J D - - 1997
OBJECTIVES: We tested the hypothesis that a reduction in myocardial cyclic GMP would increase myocardial O2 consumption and that renal hypertension (One Kidney-One Clip, 1K1C)-induced cardiac hypertrophy would change this relationship. METHODS: Either vehicle or LY83583 (10(-3) M, a guanylate cyclase inhibitor) was topically applied to the left ventricular surface ...
Huang Y F - - 1997
The cardiovascular effects of slow (over two minutes) intravenous infusions of thiopentone 750 mg in conscious instrumented sheep breathing 100% oxygen were examined for 30 minutes following the start of the infusion. The maximum rate of rise of left ventricular pressure (an index of myocardial contractility) decreased significantly from 1 ...
Chagoya de Sánchez V - - 1997
Acute myocardial infarction is the second cause of mortality in most countries, therefore, it is important to know the evolution and sequence of the physiological and biochemical changes involved in this pathology. This study attempts to integrate these changes and to correlate them in a long-term model (96 h) of ...
Bersin R M - - 1997
This article critically reviews the pharmacologic effects of the investigational drug dichloroacetate (DCA), which activates the mitochondrial pyruvate dehydrogenase enzyme complex in cardiac tissue and thus preferentially facilitates aerobic oxidation of carbohydrate over fatty acids. The pharmacologic effects of DCA are compared with other interventions, such as glucose plus insulin, ...
Wilson A T - - 1997
OBJECTIVE: To assess the incidence and degree of hypoxaemia in patients with acute myocardial infarction and evaluate the nation-wide perception and usage of oxygen therapy. DESIGN: Postal survey of all coronary care units (CCU) in England of their use of prescribed oxygen and pulse oximetry. Prospective randomised study of 50 ...
Doppenberg E M - - 1997
Reduced brain tissue oxygenation is frequently seen in severe head injury and after subarachnoid hemorrhage, and this is considered a major cause of secondary ischemic brain injury. In fact, in a previous study, we found a tight correlation between low brain tissue oxygen tension and poor outcome. Therefore, we tested ...
Friedman B J - - 1997
The isolated heart, typically perfused with crystalloid media equilibrated with >/=95% O2 to ensure adequate myocardial oxygen tension, is commonly used to study cardiac function. When hemoglobin is available for oxygen transport, equilibration with 21% O2 is considered adequate to meet metabolic demands. This study presents the measurement of myocardial ...
Opasich C - - 1997
AIM: Metabolic exercise abnormalities have been reported in chronic heart failure patients. This study sought to evaluate whether these abnormalities affected daily activity. METHODS AND RESULTS: In 16 patients with moderate-to-severe chronic heart failure and in eight controls we measured femoral flow (thermodilution) and metabolism (glucose, lactate, free fatty acids, ...
Choudhary S K - - 1997
In a 4-year-old boy with tetralogy of Fallot, a right modified Blalock-Taussig anastomosis was created because of severe myocardial dysfunction and repeated hypercyanotic spells. Post-operatively, systemic oxygen saturation improved and also myocardial function. It is postulated that hypoxia was responsible for myocardial dysfunction previously, and its elimination has resulted in ...
Nakaigawa Y - - 1997
We have studied the effects of i.v. bolus doses of magnesium sulphate (MgSO4) 60, 90 and 120 mg kg-1 on haemodynamic state, the coronary circulation and myocardial metabolism in nine dogs anaesthetized with pentobarbitone and fentanyl. MgSO4 produced dose-dependent decreases in arterial pressure, heart rate, left ventricular dP/dtmax and left ...
Rowbotham D S - - 1997
N-acetylcysteine improves survival in established acute liver failure following paracetamol overdose by reducing the incidence of multiorgan failure. These benefits are thought to be related to decreased tissue hypoxia by the enhancement of both oxygen delivery and oxygen extraction. Similar findings have been recorded in critically ill patients from an ...
Vergroesen I - - 1997
OBJECTIVE: Introduction and measurement of human myocardial oxygen supply:demand ratio as a reference for quantification of coronary microvascular vasodilating drug effects in clinical studies. Myocardial oxygen consumption is the major determinant of coronary blood flow; therefore, the true vasodilating properties of coronary vasodilating drugs that may have an effect on ...
Di Salvo T G - - 1997
BACKGROUND: The purpose of this study was to identify predictors of survival in patients referred for heart transplantation evaluation who had a peak oxygen uptake of 10 to 14 ml/kg/min measured during initial cardiopulmonary exercise testing. METHODS: Seventy-two patients were identified retrospectively from a database of 304 patients who underwent ...
Okuyama T - - 1997
BACKGROUND: Stimulation of myocardial alpha 1-adrenoceptors has been shown to exert positive inotropic effects through a cyclic AMP-independent mechanism. The purpose of this study was to examine if alpha 1-adrenoceptor stimulation is able to attenuate myocardial depression produced by exposure to halothane, and to test if alpha 1-adrenoceptor stimulation alters ...
Chen W - - 1997
1H NMR spectroscopy was used to detect the proximal histidyl Ndelta proton signal of deoxymyoglobin from canine hearts in vivo during graded myocardial ischemia. The NMR signal intensity provided an indicator of intracellular oxygenation in myocardium. The relationship between the myocardial blood flow and the deoxymyoglobin concentration was successfully measured ...
Phillips R A - - 1997
This study was undertaken to determine if shivering after cardiac surgery threatens stability during early surgical recovery. Twenty-six subjects were monitored for 6 postoperative hours to identify effects of increasing shivering severity on cardiac effort and peripheral oxygenation. Analyses show that there is an increase in effort and a decrease ...
Hsi W L - - 1997
The purpose of this study was to examine whether submaximal oxygen pulse divided by body weight (O2 pulse/BW) during an incremental exercise test discriminated between trained and untrained men, correlated to left ventricular ejection fraction (LVEF) at rest in post-myocardial infarction patients, and was sensitive and specific in detecting ventricular ...
Bagger J P - - 1997
Cytoprotection or metabolic modulation is a new principle in the treatment of angina pectoris. The effect of ranolazine (a cytoprotective drug) on ischemic threshold, coronary sinus blood flow, and myocardial metabolism was evaluated by means of two pacing sequences in nine male patients with coronary artery disease (CAD) and in ...
Sherman A J - - 1997
OBJECTIVES: This study sought to determine whether modest short-term reductions in coronary flow can produce subsequent proportionate reductions in myocardial function and O2 consumption compatible with myocardial hibernation. BACKGROUND: Acute studies indicate that myocardial energy utilization can be downregulated during moderate flow reduction. Whether this apparently beneficial adjustment persists into ...
Buckman R F RF - - 1997
OBJECTIVE: To compare the coronary and cerebral perfusion achieved using a novel method of minimally-invasive, direct cardiac massage to that obtained using bimanual, open-chest cardiac massage. DESIGN: Prospective, controlled animal study with repeated measures. SETTING: University research laboratory. SUBJECTS: Large domestic swine. INTERVENTIONS: Aortic, coronary sinus, jugular venous and pulmonary ...
Möbert J - - 1997
Isoprostanes are a family of prostaglandin-related compounds formed from arachidonic acid in a cyclooxygenase-independent manner as products of free radical-initiated lipid peroxidation. To elucidate the biological activity of the F2-and E2-isoprostanes, 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) and 8-iso-prostaglandin E2 (8-iso-PGE2), we measured hemodynamic effects in isolated perfused guinea pig hearts after cumulative ...
Ghomeshi H R - - 1997
OBJECTIVE: Our objective was to test the effects of exogenous L-aspartate and L-glutamate on myocardial energy metabolism during ischemia-reperfusion. METHODS: Phosphorus 31-magnetic resonance spectroscopy was used to observe cellular energetics and intracellular pH in isolated pig hearts perfused with blood (group A, n = 8) or blood enriched with 13 ...
Mrozek R - - 1997
OBJECTIVE: The aim of the study was to assess gastric mucosal pH during certain parts of a major cardiac procedure (hypo- and normothermic), and then throughout the first postoperative day. METHODS: Gastric mucosal pH was measured using a tonometer, in 15 patients subjected to elective CABG procedures. The patients were ...
Michalewicz L - - 1997
The calcium antagonists are a class of heterogeneous drugs, with a wide spectrum of direct and indirect cardiac effects that vary a great deal from one drug to another and depend upon formulation and duration of action. Calcium antagonists act by decreasing total peripheral resistance to lower arterial pressure. As ...
Cohn P F - - 1997
Non-invasive treatment continues to be the mainstay of anti-ischaemic therapy. The imbalance between myocardial oxygen supply and demand provides the basis for myocardial ischaemia, which may present as symptomatic, asymptomatic or, in most cases, a mixture of the two. Both symptomatic and silent ischaemia are major prognostic indicators in patients ...
Berry J M - - 1997
Whole-body hyperthermia (WBH) is a well-described investigational adjunct to systemic chemotherapy for the treatment of advanced malignancies. The hemodynamic consequences of this physiologic state may include tachycardia, which can produce acute myocardial ischemia in patients with coronary artery disease. Ischemic heart disease is currently considered a contraindication to WBH. We ...
Layland M - - 1997
OBJECTIVE: To determine the relationship between gastrointestinal intramucosal pH and myocardial oxygenation during isovolemic hemodilution in dogs with critical coronary artery stenoses. DESIGN: Prospective sequential evaluation of ileal intramucosal pH and regional myocardial function of a critically perfused area of myocardial tissue in a canine model of normovolemic hemodilution. SETTING: ...
Sherman A J - - 1997
BACKGROUND: Although cardiac myocytes and coronary vascular endothelium are known to express a constitutive form of NO synthase, the in vivo effects of tonic endogenous production of NO on myocardial O2 consumption and contractile performance remain unclear. METHODS AND RESULTS: The effects of blockade of NO synthase were determined in ...
Cheong K F - - 1997
Oxygen consumption values calculated by Fick's principle (cVO2) were compared to simultaneously obtained values measured by indirect calorimetry (mVO2) in two groups of patients; post-coronary artery bypass graft (post-CABG) and septic shock. In both groups of patients, oxygen consumption values derived using indirect calorimetry were higher than that from Fick's ...
Takaoka H - - 1997
Although conventional inotropic agents such as catecholamines increase myocardial oxygen consumption, a newly developed inotropic agent, a Ca2+ sensitizer, may be able to increase cardiac output with less myocardial oxygen consumption. By using right-side heart catheterization, we assessed the ratio of the increase in myocardial oxygen consumption per unit increase ...
Rabindranauth P - - 1997
We tested the hypothesis that increasing myocardial cyclic GMP levels would reduce myocardial O2 consumption and that renal hypertension (One Kidney-One Clip, 1K1C)-induced cardiac hypertrophy would change this relationship. Four groups of anesthetized open-chest New Zealand white rabbits (N = 26) were utilized. Either vehicle or 3-morpholinosydnonimine (SIN-1) (10(-4) M, ...
Hammar N - - 1997
OBJECTIVES: Little is known about the possible influence of different kinds of alcohol drinking pattern on the risk of acute myocardial infarction. In this study the association between average daily alcohol consumption, as well as large intakes of alcohol on single occasions, and myocardial infarction incidence was investigated. DESIGN: A ...
Barzaghi N - - 1997
Cardiopulmonary failure occurred in a 62-year-old patient a few hours after emergency cardiac retransplantation. Venoarterial extracorporeal membrane oxygenation was required to support biventricular dysfunction; thereafter, inhaled nitric oxide was given for residual hypoxemia and pulmonary hypertension. We report survival after venoarterial extracorporeal membrane oxygenation and inhaled nitric oxide treatment for ...
Graf B M - - 1997
BACKGROUND: The local anesthetic bupivacaine is an equal mixture of two optically active isomers known to exert different cardiotoxic profiles in vivo. Enantiomer-specific forms of bupivacaine may have differential effects on cardiovascular function, specifically on cardiac electrophysiology. The authors' aim was to determine if there were any direct functional differences ...
Zhang X - - 1997
BACKGROUND: ACE inhibitors potentiate kinin-nitric oxide (NO)-dependent coronary vascular dilation, and NO can modulate myocardial oxygen consumption. Whether ACE inhibitors also affect myocardial O2 consumption has not been established. METHODS AND RESULTS: Production of nitrite, a metabolite of NO in aqueous solution, in coronary microvessels and O2 consumption in myocardium ...
Niki K - - 1997
We evaluated the effects of disopyramide in terms of the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy (HOCM). The myocardial oxygen supply was evaluated by measuring coronary flow velocity and the myocardial oxygen demand was assessed by the pressure-volume area (PVA). The time velocity ...
Matsubara T - - 1997
BACKGROUND: The effects of oxygen free radicals on coronary vasoreactivity remain unknown. OBJECTIVE: To examine whether oxygen free radicals increase coronary arterial tone and sensitivity to vasoconstrictor stimulation in closed-chest dogs. METHODS: Oxygen radicals were generated by the reaction of xanthine plus xanthine oxidase (XXO) and effects of these substances ...
Moser D K - - 1997
BACKGROUND: Advanced heart failure is characterized by activation of the sympathetic nervous system and intense vasoconstriction. Biofeedback-relaxation techniques have been used successfully to treat conditions with similar pathophysiological features. OBJECTIVES: The purpose of this study was to determine if conscious control of skin temperature via a biofeedback-relaxation technique could produce ...
Walley K R - - 1997
We tested the hypothesis that the onset of myocardial anaerobic metabolism is fundamentally different from the whole body and other organs, where the onset of anaerobic metabolism occurs at a critical oxygen extraction ratio--not at a critical venous PO2. We measured oxygen saturation and PO2 of arterial and coronary venous ...
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