Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since the advent of ambulatory ST-segment monitoring, it has been established that silent ischemia is common in patients with various coronary artery disease syndromes, and such silent episodes represent up to 80% of all ischemic episodes. It appears to be associated with an adverse prognosis when compared with similarly characterized patients without silent ischemia during daily life. Silent ischemia does not, however, bother the patients, by virtue of the fact that it is silent, and therefore treatment of such ischemia must be justified by an improved outlook for the patient, rather than symptom relief. There is no direct evidence to date that silent ischemia is associated with acute myocardial infarction or sudden cardiac death in a cause-and-effect relationship, or that reduction or eradication of silent ischemia will lead to an improved prognosis for the patient; indeed, we have been unable to demonstrate any significant improvement in outlook when using the various antianginal/antiischemic agents at our disposal. Until we can demonstrate a benefit to the patient by detecting and treating silent ischemia, we should not waste large resources attempting to eradicate something whose significance we do not understand.
 ...
PMID:Can we really justify the treatment of silent ischemia in 1992? No! 139 Mar 22

Myocardial perfusion agents labeled with 99mTc offer improved physical imaging properties compared to 201TI. Teboroxime is a new 99mTc-labeled compound for myocardial perfusion imaging that shows a high myocardial extraction and rapid clearance. Sixty-seven patients underwent planar teboroxime imaging with a rapid acquisition protocol. Agreement of teboroxime and 201TI for the presence or absence of disease occurred in 56/65 patients (86%). There was agreement (normal or abnormal) between the two agents in 156/195 vessels (80%) and 457/585 segments (78%). When abnormal segments (ischemia or infarction) were compared, teboroxime showed significantly more ischemic segments (89/135, 66%) than did 201TI (73/135, 54%, p < 0.05). Teboroxime offers accuracy comparable to 201TI for the diagnosis of coronary artery disease and may improve the detection of ischemic or viable myocardium. In addition, its rapid myocardial clearance permits stress/rest imaging in 60-90 min.
 ...
PMID:Planar myocardial perfusion imaging with technetium-99m-teboroxime: comparison by vascular territory with thallium-201 and coronary angiography. 140 45

The results from recent studies suggest that the endogenous opioid beta-endorphin (beta-E) is related to pain modulation. Therefore, plasma beta-E levels were studied in 23 patients with essential hypertension (EH) and in 7 patients with coronary artery disease (CAD) during asymptomatic ischemic events and in 5 patients with CAD during symptomatic ischemic events. Blood samples for beta-E were taken at the moment of silent ST depression, pointed with alarm by the real time ECG monitor "Q Med Monitor" (USA). Control blood samples were taken under the same conditions without ischemic events. Control plasma beta-E levels were significantly higher (p less than 0.01) in patients with EH as compared to that in both groups of patients with CAD (22.9 +/- 4.0 vs 7.0 +/- 1.9 and 4.5 +/- 1.6 pmol/l). At the time of silent ischemia, beta-E showed a significant increase in patients with EH (+10.1 +/- 2.1 pmol/l, p less than 0.01) and in patients with CAD (+10.7 +/- 1.3 pmol/l, p less than 0.05) as compared to the control levels. However, plasma beta-E showed no increase (+1.0 +/- 0.6 pmol/l, p greater than 0.1) during symptomatic ischemia as compared to the control levels. Thus, differences in the circulating levels of beta-E may be associated with the presence or absence of pain during myocardial ischemia.
 ...
PMID:[Plasma beta-endorphin level in "silent" myocardial ischemia during Holter ECG monitoring]. 140 1

The aim of our study was to assess the diagnostic value of exercise echocardiography compared with exercise ECG and coronary arteriography. Exercise echocardiography was performed in 60 consecutive patients referred for coronary arteriography because of suspected coronary artery disease. Echocardiography was carried out in combination with bicycle exercise ECG and was performed 1) at rest before exercise with the patient supine, 2) at peak exercise on the bicycle and 3) immediately after exercise in supine position. Conventional standard views were recorded by means of an image computer. For the regional wall motion analysis, images were displayed simultaneously from the rest, peak and post exercise situations in a quadscreen format. Ischemia was diagnosed when wall motion deteriorated from rest to peak or post exercise in at least one out of a total of 16 left ventricular segments. Analysis was made without knowledge of patient data or results of exercise ECG or coronary arteriography. No patient was excluded because of reduced echocardiographic image quality during exercise or other technical reason. Coronary arteriography was performed in all patients and used as reference. The sensitivity of exercise echocardiography was 91% and the specificity 100%. The predictive value of a positive test was 100% and the predictive value of a negative test 78%. For exercise ECG the corresponding values were 58%, 100%, 100% and 39% respectively. We conclude that exercise echocardiography seems to be useful for the diagnosis and exclusion of ischemic heart disease. This and other studies indicate that the method is more sensitive than exercise ECG.
 ...
PMID:[Exercise echocardiography. A new valuable method for demonstration or exclusion of myocardial ischemia]. 141 11

Early relaxation is characterized by a segmental outward wall movement during isovolumic relaxation. There is still no general agreement as to its significance. Some Authors have considered the phenomenon to be a specific marker of isolated coronary narrowing, others have regarded it as a normal variation of left ventricular relaxation and still others concluded that it is a compensatory phenomenon to local ischemia in another region. We used a method of quantitative assessment of regional left ventricular function and a videodensitometric analysis of coronary stenosis. In our study we didn't observe an improved systolic function of the regions that presented early relaxation, but a slight non significant reduction. We did neither observe any correlation between early relaxation and ischemia provoked by stress test nor between early relaxation and coronary artery disease. The amplitude of early relaxation was not statistically different between patients with and without stenosis of left anterior descending artery. We conclude that early relaxation is a normal variation of left ventricular relaxation.
 ...
PMID:[Early isovolumetric relaxation: correlation with the densitometric analysis of coronary stenosis]. 142 67

This study examined the importance of viability as a clinical issue in 532 patients with angiographically proven CAD who underwent exercise SPECT thallium imaging. Conventional 4-hour delayed images were used to differentiate scar tissue from ischemia (20 segments per patient). There were 90 patients (17%) with normal images, 274 patients (52%) with reversible defects only, and 168 patients (31%) with scar tissue either with or without associated ischemia. The patients with scar tissue were subdivided according to the number of segments with fixed defects and the number of additional reversible defects. There were 114 patients with scar tissue alone or more scar tissue than ischemia. Contrast ventriculography in these 114 patients revealed normal wall motion or ejection fraction in 50 patients. On the basis of results of thallium imaging alone, the issue of viability was probably significant in 114 patients (21%); however, when the ventriculographic data were also included, the issue was significant in only 64 patients (12%) (p < 0.001). Thus myocardial viability is an important issue in 21% of patients with CAD when conventional thallium imaging is used, but this percentage decreases to 12% when wall motion and ejection fraction data are also included. These data may be important in considerations for the need of metabolic imaging and emerging scintigraphic techniques.
 ...
PMID:The clinical relevance of myocardial viability in patient management. 144 3

The role of myocardial oxygen demand in the pathogenesis of silent ambulatory myocardial ischemia was evaluated by reviewing and assessing the methods and results of recent studies. The performance of simultaneous ambulatory electrocardiographic and blood pressure monitoring in 25 men with proven coronary artery disease (CAD) revealed significant increases in heart rate and blood pressure (p < 0.001) preceding most silent ischemic events. By plotting the mean heart rate obtained at 5-minute intervals during the 30 minutes before an ischemic event, the ischemic heart rate was shown to be significantly higher (95 +/- 15 vs 74 +/- 11 beats per minute [bpm]; p < 0.01) than the nonischemic heart rate. The evaluation of heart rate changes during ambulatory ischemia (in patients with CAD and ischemia induced by an exercise test using gradual work load increments) showed a significant heart rate increase (> 10 bpm) at 1-5 minutes preceding the onset of ST-segment depression. Heart rate increases during exercise testing according to the gradual work load increments of the National Institutes of Health protocol were compared with the heart rate preceding ischemic events during daily life monitored by ambulatory electrocardiography and were found to be closely related. In contrast, heart rate increases that occurred during exercise testing using the standard Bruce protocol were higher and correlated less with those preceding ischemia in daily life. Heart rate and blood pressure increased significantly in most silent ischemic episodes, indicating that increased myocardial oxygen demand plays a significant role in the pathogenesis of myocardial ischemia during daily life.
 ...
PMID:Role of myocardial oxygen demand in the pathogenesis of silent ischemia during daily life. 144 97

Myocardial ischemia may decrease conduction velocity and produce QRS prolongation in the surface electrocardiogram. In cases with normal intraventricular conduction, areas of the myocardium contributing to the development of the S wave receive blood from all 3 major coronary arteries, whereas in left anterior hemiblock or right bundle branch block, most of the blood supply to the areas of the myocardium contributing to the development of the S wave is from the left anterior descending (LAD) coronary artery. To test the hypothesis that the S wave will be prolonged with exercise only in patients with LAD coronary artery stenosis and left anterior hemiblock or right bundle branch block, 88 patients with normal intraventricular conduction, 66 with left anterior hemiblock and 36 with right bundle branch block were studied. Sixty-four, 32 and 21 patients had LAD, right and left circumflex coronary artery stenoses, respectively. In patients with normal coronary arteries, S-wave duration decreased with exercise regardless of the status of ventricular conduction. In patients with coronary artery disease and normal intraventricular conduction, the S wave was prolonged slightly with exercise, but in those with left anterior hemiblock and right bundle branch block, it was prolonged significantly (12.5 +/- 6 and 10.4 ms, respectively) only in those with LAD, but not in those with circumflex or right coronary artery stenosis. S-wave prolongation in patients with LAD coronary artery stenosis and left anterior hemiblock or right bundle branch block most likely is related to exercise-induced ischemia in the areas of the myocardium contributing to the development of the S wave.
 ...
PMID:Exercise-induced S-wave prolongation in left anterior descending coronary artery stenosis. 144 9

The natural history of peripheral arterial occlusive disease is discussed. Severe limb-threatening ischemia is the most serious consequence of chronic arterial occlusive disease. Severe ischemia and amputation can be considered as an endpoint in peripheral vascular disease. Severe limb ischemia is relatively uncommon in isolated aortoiliac disease and this is more than twice in patients with either femoropopliteal or multisegmental disease. Subsequent studies have also demonstrated that both smoking and diabetes are associated with a substantial risk for sudden ischemia. A clear majority of about 50% deaths are caused by associated coronary artery disease, 15% to stroke and 10% to vascular disease in the abdomen. Ankle systolic blood pressure is one of the most significant factors in the progression of peripheral arterial occlusive disease and also for cardiovascular mortality. In the future, men need to know how therapies as exercise, during regimens would influence the most frequent complications besides severe limb ischemia, namely brain infarction and coronary artery disease.
 ...
PMID:Natural history and evolution of peripheral obstructive arterial disease. 146 Mar 49

Two hundred five men, 40 to 70 years of age, admitted to the coronary care unit with unstable coronary artery disease (unstable angina or non-Q wave myocardial infarction), were randomized to double-blind placebo-controlled treatment with an intravenous infusion of recombinant tissue-type plasminogen activator (rTPA), 1 mg/kg body weight (maximum 100 mg) during 4 hours, in addition to aspirin, heparin, and beta-blockade. No severe complications occurred. Myocardial ischemia, defined as myocardial infarction, incapacitating angina despite medication, or signs of ischemia at the exercise test, was reduced by treatment with rTPA compared with placebo both at discharge, 53% compared with 70% (p = 0.02), and at 1 month, 61% compared with 80% (p = 0.005). Signs of myocardial ischemia during the exercise test were reduced at discharge 51.0% compared with 68% (p = 0.03) and at 1 month 48% compared with 62% (p = 0.09). Coronary angiography after 1 month showed no difference in major coronary lesions between the groups, nor was there any reduction in the number of performed coronary revascularization procedures. In conclusion, treatment with rTPA in unstable coronary artery disease in men reduced myocardial ischemia but did not significantly reduce the need for revascularization in long-term follow-up.
 ...
PMID:Thrombolysis with recombinant human tissue-type plasminogen activator during instability in coronary artery disease: effect on myocardial ischemia and need for coronary revascularization. TRIC Study Group. 146 94


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>