Search Results
Results 451 - 500 of 1296
< 5 6 7 8 9 10 11 12 13 14 15 >
Grinberg O Y - - 1997
Oxygen is essential for normal cardiac function and plays an important role in cardiac regulation. Electron paramagnetic resonance (EPR) oximetry appears to have some significant advantages for measuring oxygen tension (pO2) in the beating heart. This study presents the serial measurement of myocardial pO2 by EPR oximetry in the isolated ...
Wu S J - - 1996
Myocardial stunning refers to reversible postischemic myocardial dysfunction persisting after reperfusion. We report a patient who presented with biventricular failure, but exhibited neither definite electrocardiographic change nor elevation of serum cardiac enzyme levels in the post-cardiotomy period. The presentation was indicative of myocardial stunning. The patient's hemodynamics could not be ...
Myles P S - - 1996
We studied the relationship between oxygen delivery (DO2) and consumption (VO2) in twenty patients undergoing cardiac surgery, in order to determine if VO2 was dependent on DO2 (pathological oxygen supply dependence). We measured VO2 from expired gas analysis (VO2G) and compared this to that calculated using the reverse Fick method ...
Tzivoni D - - 1996
Myocardial ischaemia in daily life varies according to a circadian rhythm and is induced by many factors, including both increased myocardial oxygen demand and changes in coronary tone. In most patients, ischaemia is induced by a combination of different contributing factors, although the relative contribution of each mechanism varies from ...
Chen J W - - 1996
To determine the possible mechanism of the ischemic-like electrocardiogram (ECG) during exercise in the presence of anginal chest pain and normal coronary angiograms, both a treadmill exercise test (TET) and coronary hemodynamic study were prospectively performed in 33 consecutive patients (18 females and 15 males, aged 48 +/- 10 years) ...
Licker M - - 1996
Twenty-three patients undergoing elective coronary artery bypass graft surgery with moderate hypothermic bypass, under opiate-benzodiazepine anaesthesia were investigated during the first 7 h following surgery. Patients with recent myocardial infarct (< 6 weeks), reduced left ventricular ejection fraction (< 40%) or requiring inotropic support were excluded. During the first 3 ...
Yu M - - 1996
A relationship between survival and high cardiac index and oxygen delivery (DO2) has been documented for patients of all ages. Debate continues whether achieving these parameters decreases mortality or whether these parameters merely reflect better physiologic reserve. Younger patients who spontaneously generate high DO2 have low mortality rates and do ...
Keeley E C - - 1996
PURPOSE: Nicotine replacement therapy has become a popular therapy for smokers attempting to stop smoking. Unfortunately, some subjects continue to smoke while receiving it. Since nicotine is believed to be the primary constituent of cigarette smoke responsible for its acute adverse effects on myocardial oxygen supply and demand, concomitant nicotine ...
Cavaliere F - - 1996
OBJECTIVE: To investigate the utility of the arterial-venous PCO2 gradient (P(a-v)CO2) as a marker of the increased risk of postoperative complications in the early postoperative hours following myocardial revascularization. EXPERIMENTAL DESIGN: Prospective study. SETTING: The Postoperative Intensive Care Unit (ICU) of a University Hospital. PATIENTS: Thirty patients (28 males and ...
Holm C - - 1996
A high proportion of the mortality and morbidity associated with endoscopic procedures may be of cardiopulmonary origin. For this reason, the appropriate degree of monitoring and prophylactic measures to be used in the sedated patient undergoing endoscopy has become a topic of discussion during recent years. The development of myocardial ...
DiPierro F V - - 1996
BACKGROUND: Triiodothyronine (T3) administration after cardiopulmonary bypass has been shown to significantly improve cardiac performance. The present study was undertaken to elucidate the effects of T3, when administered as an intravenous bolus, on both cardiac energetics and stroke work-oxygen utilization (EW/LVVO2) efficiency. METHODS: In both unstressed and stressed hearts, energetics ...
Habler O P - - 1996
The influence of severe acute normovolemic hemodilution (ANH) on myocardial contractility (MC) was investigated in 14 splenectomized, anesthetized dogs. MC was assessed by the maximum rate of left ventricular pressure increase (LVdp/dt(max)), end-systolic elastance (Ees), and preload recruitable stroke work (PRSW) (conductance catheter, left ventricular pressure-volume relationship). Measurements of myocardial ...
Xie Y W - - 1996
The mechanism responsible for the regulation of cardiac function by endogenous nitric oxide (NO) remains unclear. In this investigation, O2 consumption by freshly isolated myocardial muscle segments from the left ventricular free wall of canine hearts was quantified by a Clark-type O2 electrode at 37 degrees C. S-nitroso-N-acetylpenicillamine (SNAP, 9 ...
Gurevicius J - - 1996
This study evaluated changes in coronary blood flow (CBF), myocardial oxygen consumption (MVo2), and myocardial segmental shortening (SS) during intracoronary administrations of enflurane in in situ canine hearts. The left anterior descending coronary artery (LAD) of 11 anesthetized and mechanically ventilated dogs was perfused at constant perfusion pressure (80 mm ...
Leaf D A - - 1996
Environmental exposure to inhaled carbon monoxide (CO) increases coronary artery disease risk. Sudden cardiac death, a frequent manifestation of coronary artery disease, is usually a result of ventricular dysrhythmia. The effect of exposure to CO at sea level (CO/SL) and simulated high (2.1 km) altitudes (CO/HA) on the incidence of ...
Marques-Vidal P - - 1996
The effect of alcohol consumption was assessed in 561 men with myocardial infarction and 643 healthy controls recruited from France and Northern Ireland between 1988 and 1991 in the ECTIM Study (Enquête Cas-Témoins de I'Infarctus du Myocarde). In total, patients consumed less wine than did controls, while non-wine-derived alcohol consumption ...
Pedersen H K - - 1996
RATIONALE AND OBJECTIVES: We investigated the possible cardiac effects of oxygen addition to contrast media (CM) during coronary arteriography in dogs that did and did not have ischemic heart failure. METHODS: Acute ischemic heart failure was induced by injecting small plastic microspheres into the left coronary artery of 18 dogs. ...
Lee D - - 1996
Carbon monoxide intoxication usually disturbs the normal human biochemical respiratory chain cascade from which high affinity of carboxyhemoglobin to oxygen causes ischemic insult to the human tissues and cells. Ubiquitous injuries to human cells have already been well documented for a long period of time. Here we reported a 42-year-old ...
Roekaerts P M - - 1996
The central sympatholytic effect of alpha 2 agonists may be beneficial during myocardial ischemia, but could be opposed by their peripheral vasoconstrictive effect. We studied the effects of mivazerol during periods of moderate coronary artery stenosis in anesthetized dogs. Mivazerol decreased heart rate (from 125 +/- 6 to 106 +/- ...
Alexi-Meskishvili V - - 1996
A 7-day newborn girl with d-transposition of the great arteries (d-TGA) and complex coronary anatomy developed global myocardial dysfunction after arterial switch operation despite establishment of an effective coronary circulation. Extracorporeal membrane oxygenation was used for circulatory support for 163 h after the operation. On day 7 after surgery she ...
Sadoff J D - - 1996
Previous studies from our laboratory have shown that an extrinsic nitric oxide (NO) donor (i.e., nitroprusside) caused vasodilatation and negative inotropy by activating guanylate cyclase and increasing myocardial cyclic GMP. We tested the hypothesis that endogenous myocardial NO production would limit myocardial oxygen consumption and function in vivo. We used ...
Ward H B - - 1996
The effectiveness of cardiopulmonary support (CPS) as a rescue method following failed angioplasty is unknown. The proximal left anterior descending (LAD) was occluded for 20 min in 21 dogs. Group 1 animals (n=15) were given CPS and group 2 animals (n=6) served as controls. During coronary occlusion, animals receiving CPS ...
Conversano A - - 1996
With positron emission tomography, the resting flow abnormalities underlying reversible left ventricular dysfunction in 17 patients with chronic coronary artery disease were delineated. The level of flow in reversible dysfuncTional segments (i.e., those demonstrating improvement after revascularization) was markedly variable, ranging from 0.32 to 1.25 ml/gm/min. In 20 of these ...
Budinger G R - - 1996
Although systemic oxygen consumption (V O2) is independent of O2 delivery (Q O2) in normal subjects, studies have suggested that supply dependence of V O2 may occur in patients with chronic diseases associated with reduced Q O2. In this regard, we previously found that Q O2 and V O2 increased ...
Smith H L - - 1996
The aim of the study was to examine the effect of spontaneous nocturnal hypoxaemia on myocardial ischaemia in patients with severe coronary artery disease. This was a prospective study of continuously measured oxygen saturation and ECG overnight in patients prior to coronary artery bypass graft surgery. Fifteen patients with angiographically ...
Friedman B J - - 1996
The objective of this study was to determine the effects of repetitive ischemia on myocardial oxygen tension (pO2), consumption, and delivery in crystalloid normoperfused (perfusion pressure>70 mmHg) and hypoperfused (perfusion pressure approximately 50 mmHg) constant flow isolated rat hearts. EPR oximetry with lithium phthalocyanine was used to measure myocardial pO2. ...
Fujita Y - - 1996
BACKGROUND: Although previous studies have shown that bupivacaine produces a dose-dependent vasoconstriction, the possible effects of decreased coronary blood flow on myocardial dysfunction during bupivacaine-induced cardiotoxicity have not been investigated. METHODS: We carried out the present study using the in situ beating hearts of six beagles. An autoperfusion circuit was ...
Ihnken K - - 1996
OBJECTIVES: Cardiopulmonary bypass (CPB) is usually instituted in a hyperoxic fashion (oxygen tension (pO2) 300-500 mm Hg), which may expose cyanotic infants to potential reoxygenation damage. Oxygen free radicals play an important role in this injury. The rate of production of this highly reactive toxic oxygen species is dependent on ...
Thorelius J - - 1996
The present study tests the hypothesis that the changes in myocardial lactate metabolism in the early period of coronary surgery are caused by raised adrenergic activity, and that these are preventable by the addition of thoracolumbar epidural blockade to high dose fentanyl/midazolam anesthesia. Twenty-seven male beta 1-blocked patients undergoing coronary ...
Jessen M E - - 1996
BACKGROUND: Many investigators have examined oxygen consumption in adult heats under conditions that simulate those encountered during cardiac operations and those that approximate basal metabolism. Few studies, however, have addressed this issue in neonatal myocardium. METHODS: Hearts from 3- to 9-day-old piglets were studied in a blood-perfused isolated heart preparation ...
Gratama J W - - 1996
Isoproterenol, used in the management of infants with left-to-right shunts and circulatory congestion, increases myocardial work load and oxygen consumption. In addition, it may selectively enhance myocardial fatty acid utilization. The less efficient oxidation of FFA could induce an oxygen wasting effect and thus further increase myocardial oxygen consumption. The ...
Hiesmayr M - - 1995
OBJECTIVE: The purpose was to study whether the hemodynamic benefit of a catabolic catecholamine (dobutamine) induces a certain oxygen cost for the myocardial energy demand and whether this effect would be less pronounced if an anabolic intervention, such as the administration of insulin, was used. DESIGN: A prospective and randomized ...
Locker G J - - 1995
Myocardial ischemia is a rare but severe and possibly life threatening manifestation of hyperthyroidism, but does not usually result in persistent ischemia. We report on a 71-year-old woman who had undergone total thyroidectomy with subsequent irradiation because of follicular carcinoma 3 years ago. Since then, she had been maintained on ...
Nakaigawa Y - - 1995
We have studied the effects of a 30-min infusion of propofol 6, 9, 12, 15, 18 and 21 mg kg-1 h-1 on cardiovascular haemodynamics, coronary circulation and myocardial metabolism in 12 mongrel dogs. Mean plasma concentrations of propofol after infusion of 6 and 21 mg kg-1 h-1 increased from 2.9 ...
Waagstein L - - 1995
OBJECTIVE: To study the direct effects of hypertonic saline on the function of non-ischemic and ischemic myocardium by the use of an isolated working rat heart model. DESIGN: A prospective, randomized, controlled study. SETTING: Animal laboratory at a university medical center. SUBJECTS: Adult Wistar rats (n = 32) of both ...
Zhou Z - - 1995
Dobutamine and pyruvate are two inotropic agents with different mechanisms of action. Although both agents alter postischemic myocardial dysfunction, their potential metabolic effects in the setting of in vivo myocardial stunning have not been addressed. In this study, the effects of dobutamine and pyruvate on systolic wall thickening, myocardial phosphorylation ...
Hurley J - - 1995
Twenty-three low risk coronary artery bypass graft patients underwent a controlled study of the effects of prophylactic perioperative dopexamine hydrochloride on haemodynamic indices and peripheral perfusion. The infusion commenced following induction of anaesthesia and continued for 24 h postoperatively. The study demonstrated that dopexamine significantly increased cardiac index compared with ...
Kelly R F - - 1995
High oxygen concentrations reduced infarct size in prereperfusion era studies; however, with reperfusion therapy, high oxygen tension carries the theoretical risk of exacerbating reperfusion injury by increasing toxic oxygen-derived free radicals. In this study, two groups of dogs underwent 90 minutes of coronary occlusion and 72 hours of reperfusion. The ...
Jacobs A - - 1995
BACKGROUND AND PURPOSE: Multitracer positron emission tomography (PET) was used to investigate local amino acid accumulation in brain tissue surrounding focal ischemia. METHODS: PET using 15O-labeled oxygen and water for measuring cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF), C15O for determination of blood volume (CBV) and ...
Elsasser S - - 1995
OBJECTIVE: To clarify the influence of an elevated carboxyhemoglobin (COHb) blood level on the course of acute myocardial infarction and to evaluate the administration of supplemental oxygen on the COHb level and the incidence of complications. DESIGN: Prospective clinical study with randomized, unblinded intervention. SETTING: Coronary Care Unit of a ...
Hall J L - - 1995
OBJECTIVE: Dobutamine stimulates the beta-receptors in the heart and increases myocardial blood flow and oxygen consumption 2-3-fold, similar to effects seen with exercise. The purpose of this study was to assess temporal changes in myocardial interstitial purine metabolites, adenosine monophosphate (AMP) and lactate during and following 30 min of dobutamine ...
Liedtke A J - - 1995
OBJECTIVES: This study sought to evaluate the functional and metabolic consequences of imposing a chronic external coronary stenosis around the left anterior descending coronary artery for 4 days in an intact pig model. BACKGROUND: A clinical condition termed hibernating myocardium has been described wherein as a result of chronic sustained ...
Rumsey W L - - 1995
This investigation evaluates the efficacy of a 99mTc-labeled nitroimidazole (BMS-181321) in identifying oxygen-deprived tissue in two canine models of myocardial ischemia. METHODS: For both models (A and B), epicardial microvascular oxygen pressure (mPO2) was monitored by measuring the oxygen-dependent quenching of phosphorescence lifetime of Palladium mesotetra (4-carboxyphenyl) porphine. In Model ...
Elbeery J R - - 1995
A new practical descriptor of metabolic to mechanical myocardial energy transfer (MET), termed the virtual work model, was evaluated in 32 conscious dogs and in 8 isolated canine hearts. An index of total mechanical energy expenditure (TME) was calculated as the sum of external energy (stroke work) and an internal ...
Pisarenko O I - - 1995
The effects of aspartate (Asp) and 2-oxoglutarate (2-OG) on metabolism and function of isolated rat heart during hypoxia and reoxygenation were studied. Hearts were subjected to oxygenated perfusion with Krebs-Henseleit buffer supplied with 11 mM glucose (20 min) and anoxic perfusion with the buffer saturated with N2 (20 min), followed ...
Effat M A - - 1995
Ischemia refers to inadequate supply of oxygen and metabolic substrate to an organ. The term myocardial ischemia covers a heterogeneous group of clinical syndromes, globally called ischemic heart disease, which includes chronic stable angina at one end of the spectrum and acute myocardial infarction at the other end. Between these ...
Rump A F - - 1995
The cardiotoxic effects of catecholamines have been explained in part by the generation of oxygen free radicals and aminochromes. The role of aminochromes remains however controversial. It has previously been demonstrated that adrenochrome, an oxidation product of adrenaline, shows cardiotoxic properties only at very high concentrations, and it has been ...
Herbertson M J - - 1995
Why the myocardial oxygen extraction ratio (ERm) is decreased during septic shock in humans is unknown. Therefore, we calculated ERm in 15 anesthetized pigs by measuring arterial and coronary venous oxygen content. We measured myocardial lactate flux, myocardial contractility, and global myocardial blood flow and its distribution. After baseline measurements, ...
Burch M - - 1995
Unexpected arterial oxygen desaturation occurred immediately after cardiopulmonary bypass in two children. Epicardial echocardiography demonstrated unroofing of the coronary sinus after a Fontan procedure in the first child and rapidly excluded this abnormality in the second, who had undergone closure of a sinus venosus defect and in whom there was ...
Buffington C W - - 1995
Whether calcium chloride (CaCl2) should be used to reverse myocardial dysfunction during cardiac operations remains a controversial issue. Calcium chloride may reduce, rather than increase, myocardial contractility and may produce exaggerated vasoconstriction in postischemic vessels in which the endothelium has been damaged. These possibilities were investigated in an open-chest porcine ...
< 5 6 7 8 9 10 11 12 13 14 15 >