Search Results
Results 601 - 650 of 1119
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Lambert C R - - 1995
We have previously demonstrated the utility of time-series analysis applied to 72-hour ambulatory electrocardiographic data in patients with coronary artery disease. The present investigation applied time-series analysis to long-term (120-hour) ambulatory electrocardiographic data to determine the minimal period of monitoring needed (1) to detect periodicity of ischemia-related variables in ambulatory ...
Singh N - - 1995
A significant proportion of myocardial ischemia is 'silent' in nature. Furthermore, this asymptomatic ischemia portends an adverse prognosis for patients with known coronary artery disease. Silent myocardial ischemia can be objectively assessed and quantified by a number of noninvasive means; however, ambulatory electrocardiographic monitoring has emerged as a preferred method ...
Goldschmidt Marc - - 1995
Ranolazine is a new, orally active pharmacologic agent that experimentally has been shown to favorably affect myocardial metabolism during myocardial ischemia. It has no direct action on myocardial hemodynamics but appers to improve ventricular functioning by blocking uptake of free fatty acids by the heart while shifting metabolism to anaerobic ...
Freysz M - - 1995
Myocardial ischemia sensitizes the cardiotoxic effects of bupivacaine, especially the propensity to ventricular fibrillation. To investigate this sensitization and to elucidate its mechanism, the influence of bupivacaine alone, or associated with ischemia, was studied on electrical fibrillation threshold in anesthetized, open chest pigs. Determination of fibrillation threshold was performed with ...
Marin-Garcia J - - 1995
Effects of myocardial ischemia on mitochondrial enzymes and mitochondrial DNA (mtDNA) were examined using the model of Ameroid constriction of canine cardiac vessels. Endocardium supplied by constricted coronary arteries was found to have significantly lower citrate synthase and complex IV activities compared to values obtained from either epicardium supplied by ...
Bertolet B D - - 1995
Daily life cardiac ischaemia is defined as reversible myocardial cellular hypoxia that occurs during activities of daily living, without artificial provocation. Most of these daily life ischaemic episodes are not associated with symptoms. However, it is not practical to distinguish silent versus symptomatic daily life ischaemia as both are associated ...
Ahluwalia G - - 1995
Twenty male diabetic patients (age range, 40-60 years) with normal autonomic function were studied to determine the prevalence of silent myocardial ischemia on exercise as well as ambulatory electrocardiography. The presence and extent of silent myocardial ischemia was also correlated with the severity of atherosclerotic coronary artery disease as determined ...
Conti C R - - 1995
This pilot study demonstrated that (1) patients with CAD and asymptomatic cardiac ischemia can be randomized to medical or revascularization strategies using a complex and demanding protocol, (2) asymptomatic cardiac ischemia can be suppressed in 40-50% of patients with clinically advanced coronary disease with relatively low to moderate doses of ...
Mickley H - - 1995
Ambulatory ST-segment monitoring is a relatively new device in the evaluation of myocardial ischemia. The method is unique in allowing us to continuously examine the patient over an extended period of time in a changing environmental milieu. In survivors of acute myocardial infarction the prevalence of ambulatory or transient myocardial ...
Rabinowitz B - - 1995
We compared the effects of brief and prolonged myocardial ischemia on tissue prostaglandin synthesis. Regional ischemia was induced in dogs and maintained for 5 or 30 minutes. Isolated rat hearts were subjected to global ischemia in a working heart preparation for periods of 5 or 20 minutes. De novo synthesis ...
Ellis J E - - 1994
We studied 61 patients undergoing elective major non-cardiac surgery in a randomized, double-blind, placebo-control clinical trial to test the hypothesis that the addition of clonidine to a standardized general anesthetic could safely provide postoperative sympatholysis for patients with known or suspected coronary artery disease. Patients were allocated randomly to receive ...
Nitta Y - - 1994
Vulnerability of aged hearts to ischemia may be due to defects in protective mechanisms provided by heat shock proteins (HSPs). To determine whether there is a defect in the induction of HSPs by ischemia in old hearts, HSP72 and HSP73 (inducible and constitutive HSP70, respectively) mRNA induction was examined in ...
Allman K G - - 1994
We studied 325 patients undergoing elective noncardiac surgery who had preoperative ambulatory ECG monitoring performed for a duration of 5130 h (range 8-24 h; mean 15.8 h). Sixty-four subjects (20%) had one or more episodes of ST segment depression consistent with myocardial ischaemia. Of all preoperative cardiovascular variables measured, the ...
Aronowski J - - 1994
BACKGROUND AND PURPOSE: This study explored the correlation between duration of focal ischemia and infarct volume in spontaneously hypertensive rats as a measure of outcome after neuroprotective intervention. METHODS: We used 2,3,5-triphenyltetrazolium chloride staining to discriminate infarcted tissue and calculate infarct volume 24 hours after temporary tandem common carotid/middle cerebral ...
Hong S C - - 1994
Ischemia-induced elevation of intracellular calcium triggers a cascade of events which is considered to play a major role in neuronal death. One candidate to participate in this process is the calcium-sensitive protease, calpain. This protease is activated by calcium, and is capable of degrading critical cytoskeletal and regulatory proteins. In ...
Purcell H - - 1994
In recent years it has become clear that episodes of transient myocardial ischemia commonly occur in patients with coronary artery disease in the absence of chest pain or angina equivalent. These episodes of "silent myocardial ischemia" are particularly well documented during continuous ambulatory electrocardiographic monitoring in daily life. Evidence suggests ...
Thomson I R - - 1994
The principal importance of intraoperative ischemia is its consistent association with adverse outcome. In coronary artery surgery the finding of prebypass ischemia is an important predictor, and postbypass ischemia is a critical predictor of adverse outcome. One in three patients with postbypass ischemia will suffer an adverse outcome in CABG. ...
Zarich S - - 1994
OBJECTIVES: The aim of this study was to determine the prevalence and characteristics of ambulatory myocardial ischemia in patients with diabetes mellitus and to delineate the relation between the presence and severity of autonomic nervous system dysfunction and the incidence and time of onset of myocardial ischemia. BACKGROUND: Conflicting data ...
Ito B R - - 1994
Activation of the complement cascade is involved in the myocardial injury resulting from transient ischemia and reperfusion. We previously showed that the complement anaphylatoxin C5a causes myocardial ischemia in vivo, mediated in part via thromboxane (Tx) A2. In the present study, we assess the role of platelets in the C5a-induced ...
Rauch U - - 1994
Depending on its duration, temporary myocardial ischemia leads to a disturbance of myocardial function before irreversible cellular necrosis is developed. Mechanical, electrical, and metabolic disturbances were suggested to be possible mechanisms accounting for the altered mechanical performance in ischemic hearts. To further investigate the alteration of myocardial energy metabolism on ...
Pancholy S B - - 1994
This study examined the prognostic predictors in 521 patients with angiographic evidence of coronary artery disease (CAD). All patients underwent exercise single-photon emission computed tomographic thallium imaging. The patients were divided into those with symptomatic ischemia defined as reversible thallium defects, S-T segment depression (or both) and angina during exercise ...
Hasdai D - - 1994
Endothelin is a potent vasoconstrictor with a wide range of effects on the heart. Changes in myocardial and circulating levels of endothelin have been described in various experimental models of myocardial ischemia, and in humans with acute myocardial infarction and different forms of angina pectoris. The role played by endothelin ...
Scognamiglio R - - 1994
Myocardial dysfunction and silent myocardial ischemia have been identified as important prognostic factors following acute myocardial infarction, also in low risk patients. In postinfarction patients, impaired left ventricular function is the result of fixed scar and reversible contractile dysfunction of viable stunning or hibernating myocardium. Post-extrasystolic potentiation (PESP) during 2-dimensional ...
Okuda K - - 1994
Technetium-99m-pyrophosphate (PYP) is bound to calcium in necrotic myocardium and has been used clinically to evaluate myocardial infarction. Technetium-99m-PYP is also reported to accumulate in myocardium with unstable angina pectoris and it is speculated that severe ischemia with noninfarcted tissue may also increase uptake of 99mTc-PYP. In this paper, 99mTc-PYP ...
Herderscheê D - - 1994
The frequency of silent infarction is an important issue because it is a marker of vascular disease. We studied the occurrence of silent infarction in a sample of patients from the Dutch TIA trial, in which patients were randomized between 30 and 283 mg of aspirin. A total of 91 ...
Koyanagi S - - 1994
The objective of this study was to examine the prevalence and pathogenesis of silent myocardial ischemia during exercise following myocardial infarction. Exercise-induced myocardial ischemia was assessed by 201Tl-SPECT (single photon emission computed tomography) 4.5 weeks after acute myocardial infarction in 229 patients. Exercise-induced myocardial ischemia occurred in 109 patients (48%), ...
Knatterud G L - - 1994
OBJECTIVES: The Asymptomatic Cardiac Ischemia Pilot (ACIP) study was initiated to determine the feasibility of a large trial in evaluating the effects of treatment of ischemia on outcome (mortality and myocardial infarction). The study was designed to examine the effects of medical treatment to control angina compared with treatment strategies ...
Pepine C J - - 1994
OBJECTIVES: The primary objectives of the Asymptomatic Cardiac Ischemia Pilot were 1) to compare the 12-week efficacy of three treatment strategies to suppress cardiac ischemia, and 2) to assess the feasibility of a prognosis trial in patients with asymptomatic cardiac ischemia. BACKGROUND: Cardiac ischemia has been associated with increased morbidity ...
Cohn P F - - 1994
The risk of infarction and sudden death is considerable in patients with silent ischemia, whether it occurs alone or is interspersed with episodes of angina. The ischemic activity can be modified or even abolished, most effectively with beta-blocker and nitrate therapy. But it is not yet clear whether treatment improves ...
Neustein S M - - 1994
Forty patients scheduled to undergo elective myocardial revascularization were included in a randomized, double-blind, placebo-controlled study to evaluate any influence of esmolol on the incidence of myocardial ischemia. Calibrated recordings of ECG leads II and V5 were continuously monitored with the QMED Monitor One TC (Qmed Inc, Clark, NJ) from ...
Arstall M A - - 1994
To determine the potential utility of the detection of silent myocardial ischemia after acute myocardial infarction for clinical decision making, we investigated the hypothesis that the occurrence of silent myocardial ischemia on ambulatory electrocardiographic (EGG) monitoring after acute myocardial infarction is independently predictive of adverse outcome in patients in whom ...
Creel C A - - 1994
Silent myocardial ischemia is a common occurrence that affects millions of Americans with coronary artery disease. Although the cause of painless angina is unknown, the consequences are well documented and mimic that of patients who have symptoms. Patients with silent myocardial ischemia, as evidenced by painless ST segment changes on ...
Leone B J - - 1994
The hypothesis that mild decreases in myocardial function may occur with preservation of normal levels of intramyocardial ATP was tested. A model of single vessel coronary stenosis using eight mongrel dogs in an open chest preparation was used. Myocardial oxygen supply was altered by performing acute normovolemic hemodilution with a ...
Bellemin-Baurreau J - - 1994
The effects of glibenclamide and BRL-38227 were studied in isolated rabbit hearts subjected to ischemia and programmed electrical stimulation. Coronary artery occlusion over 24 min decreased the ventricular effective refractory period in the ischemic zone. BRL-38227 (0.1 microM) showed significant coronary vasodilator effects, but failed to modify the ventricular effective ...
Goodman S G - - 1994
The role of ambulatory myocardial ischemia detection, in addition to exercise testing and myocardial perfusion scintigraphy, in the prediction of the angiographic severity of coronary artery disease in patients with stable angina was examined. Ninety-seven patients underwent ambulatory electrocardiographic monitoring, exercise testing with scintigraphy, and coronary angiography. In addition to ...
Van Dyck M J - - 1994
The influence of preoperative autologous blood donation on myocardial ischemia and arrhythmias was evaluated in 24 patients scheduled for coronary artery bypass grafting (CABG). All had a Holter recorder placed 24 hours before predonation (day 1), the cassette was changed prior to donation, and the recording continued for 24 hours ...
Patel J - - 1994
Ventricular arrhythmia production in the ischemic heart is considered to be influenced by prior infarction. Although beta-adrenergic blockade is known to have beneficial effects during acute ischemia, its anti-arrhythmic efficacy during post-infarction ischemia is not known. To explore this question, we have used a model with a relatively high incidence ...
McCrea S - - 1994
Repetitive ischemia causes more severe damage than a single insult of comparable duration. Gerbils were followed for 1 month postrepetitive ischemia and 100% mortality was demonstrated in the unprotected ischemia group by 12 days postischemia. Significant protection against mortality due to repetitive ischemia was offered by both CGS-19755 and combination ...
Kato K - - 1994
This study was performed to clarify the relationship between degree plus duration of myocardial ischemia and tissue succinate or lactate contents, and to assess whether their accumulation might be a metabolic marker of ischemic myocardium. Regional myocardial blood flow (MBF) was measured using the hydrogen gas clearance method in anesthetized ...
Andres J - - 1994
We used the isolated working rabbit heart preparation as a model to study the relationship between postischemic myocardial dysfunction and the energetic state of the heart in terms of mitochondrial function and myocardial high energy phosphate (HEP) contents. Normothermic global myocardial ischemia (10, 20 and 30 min) was induced. Cardiac ...
Camici P G - - 1994
Many variables, including food ingestion, circulating hormone, and the cardiac work load, affect myocardial metabolism. Important changes in myocardial metabolism are associated with myocardial ischemia. The study of myocardial metabolism by means of different invasive and noninvasive techniques allows a better understanding of both cardiac physiology and pathophysiology in humans.
Leung J M - - 1994
Acadesine (5-amino-4-imidazole carboxamide riboside) is a purine nucleoside analog that has been shown in animals to reduce myocardial ischemic injury by selectively increasing the availability of adenosine in ischemic tissues. Because patients undergoing coronary artery bypass graft (CABG) surgery are especially vulnerable to developing myocardial ischemia, we investigated whether perioperative ...
Parker J D - - 1994
BACKGROUND: The morning increase in asymptomatic ambulatory ischemia may be due to heightened coronary tone, increased physical activity, or both. If ambulatory ischemia is primarily due to physical activity, then alterations in the schedule of physical activity should be reflected in a corresponding alteration in the occurrence of ischemia. This ...
Bak M I - - 1994
Capacity for ATP resynthesis during recovery from ischemia or hypoxia is limited to the size of the adenine nucleotide pool, which is determined in part by the activity of cytosolic 5'-nucleotidase (5'-NT): AMP-->adenosine plus inorganic phosphate (Pi). To define in vivo regulation of 5'-NT, we used the tools of 31P ...
Hedman A G - - 1994
Silent ischemia has been called the silent killer. Pain does not kill patients with coronary heart disease--ischemia does, whether it happens to be painful or silent. An increased awareness of this still puzzling phenomenon may be of great importance in the pre- and perioperative management of patients with coronary heart ...
Fazzini P F - - 1993
To evaluate the prevalence of type I silent myocardial ischemia and silent myocardial infarction, 4,842 men aged 40 to 59 years, identified in occupational samples in Florence and Rome, and free from major heart disease, severe illnesses and chest pain, underwent a 3-stage diagnostic procedure. The first stage included resting ...
Harper J R JR - - 1993
INTRODUCTION: The purpose of our study was to determine if the slowing of longitudinal intraventricular conduction in the in situ porcine heart during acute regional no-flow ischemia was rate dependent. Further, we investigated whether any rate dependence could be correlated to a rate-dependent component of the ischemia-induced rise in extracellular ...
Smolenski R T - - 1993
The influence of global ischemia on myocardial nucleotide catabolite production and contraction was studied in Langendorff-perfused rat hearts. Hearts in the "ischemic" group were subjected to a 25 minute period of global ischemia at 30 minutes from the start of perfusion, and to two 30 s periods of global ischemia ...
Pomidossi G - - 1993
OBJECTIVES: The aim of this study was to assess whether transient episodes of symptomatic or silent myocardial ischemia after baroreceptor modulation of heart rate. BACKGROUND: Animal and human studies have shown that myocardial infarction is accompanied by an impairment of the baroreceptor influences on the sinus node. However, whether this ...
Pfisterer M - - 1993
OBJECTIVES: The objective of this observational study was to assess the incidence and prognostic significance of silent ischemia after percutaneous transluminal coronary angioplasty. BACKGROUND: Apart from coronary angioplasty, prognosis of patients with silent ischemia is similar to that of patients with angina pectoris. However, similar data concerning silent ischemia associated ...
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