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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Echocardiography has many attributes that are desirable for diagnostic and research studies in acute myocardial infarction patients. It does not alter the physiologic state being evaluated, is relatively inexpensive, and does not interfere with other hospital procedures. For these reasons, the test may be repeated frequently and used to monitor the changes after acute infarction. Useful information about left ventricular volume, diastolic pressure, and segmental wall motion may be obtained. Because echocarciographic estimates of stroke volume, ejection fraction, and velocity of circumferential fiber shortening are based on motion seen in only one "ice-pick" view of the heart, it is likely that they will be less reliable in patients with asynergy of contraction. Although a definite diagnosis of acute myocardial infarction cannot be made by echocardiography, abnormalities of wall motion may occur very early and support a clinical impression of infarction. An echocardiogram may also reveal changes suggesting ischemia or infarction (abnormal motion) in patients who have atypical chest pain and no other objective evidence of coronary artery disease.
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PMID:Applications of echocardiography in acute myocardial infarction. 110 66

The operating characteristics of thallium stress testing for detection of significant epicardial coronary artery disease (CAD) in hypertensive subjects with chest pain or electrocardiographic (ECG) ischemia have not been previously defined. This becomes important because of the high prevalence of both hypertensive heart disease and CAD. Ninety-two hypertensives with a history of typical or atypical chest pain or ECG myocardial ischemia underwent coronary arteriography, 2D-guided echocardiography, and thallium-201 stress testing, combined with intravenous dipyridamole if the rate-pressure product was less than 20,000. Patients with myocardial infarction, prior revascularization procedure, valvular heart disease, and chronic ethanol abuse were excluded. The mean age was 54.8 +/- 9.9 years with 55% blacks and 46% women. Eighteen patients (19.6%) had significant (greater than or equal to 50% luminal diameter narrowing) epicardial CAD at catheterization, of whom 17 had positive thallium scans. Overall, there were 17 true positives, 47 true negatives, 27 false positives, and one false negative resulting in 94.4 +/- 5.4% sensitivity (95% confidence limits [95% CL] 71 to 100%), 63.5 +/- 5.6% specificity (95% CL 51 to 74%), 38.6 +/- 7.3% positive predictive value (95% CL 25 to 54%), 97.9 +/- 2.1% negative predictive value (95% CL 88 to 100%), and 69.6 +/- 4.8% overall accuracy (95% CL 59 to 79%). For hypertensive patients with chest pain or ECG myocardial ischemia, the high sensitivity and negative predictive value and low false negative rate support the role of thallium stress testing +/- dipyridamole as an exclusion test for significant CAD.
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PMID:A negative thallium (+/- dipyridamole) stress test excludes significant obstructive epicardial coronary artery disease in hypertensive patients. 153 15

A 60-year-old man with atypical chest pain not submitted to adequate diagnostic procedures was treated on an empirical basis with nifedipine 20 mg b.i.d. The patient was referred to our institution where a first symptom-limited exercise stress-test during treatment was performed; neither S-T alterations nor clinical symptoms were induced at the maximal tolerated work load. Therefore we suggested a short period of hospital stay to repeat the stress-test after a progressive tapering off of the drug with the aim of obtaining a more definite diagnosis. However the patient refused and an at-home nifedipine withdrawal was planned. Some days later a second test showed marked S-T segment elevation in leads V4 to V6; concomitant high-grade ventricular arrhythmias and anginal pain occurred. Both the ECG alterations and the clinical symptom promptly regressed interrupting the test and administering sublingual isosorbide dinitrate. A coronary angiography performed few days later showed only a single and no significant stenosis of the left anterior descending artery (60%). The clinical and electrocardiographic pictures were therefore attributed to stress-induced vasospastic ischemia. A week later a third maximal stress-test during further treatment with nifedipine was totally negative. The pathophysiological mechanisms of rest and stress-induced vasospastic angina and the usefulness of Ca-blocking agents are discussed.
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PMID:[A clinical case: coronary vasospasm induced by exercise after stopping nifedipine therapy]. 163 Jun 75

Exercise stress testing is routinely used for the noninvasive assessment of coronary artery disease and is considered a safe procedure. However, the provocation of severe ischemia might potentially cause delayed recovery of myocardial function. To investigate the possibility that maximal exercise testing could induce prolonged impairment of left ventricular function, 15 patients with angiographically proved coronary disease and 9 age-matched control subjects with atypical chest pain and normal coronary arteries were studied. Radionuclide ventriculography was performed at rest, at peak exercise, during recovery and 2 and 7 days after exercise. Ejection fraction, peak filling and peak emptying rates and left ventricular wall motion were analyzed. All control subjects had a normal exercise test at maximal work loads and improved left ventricular function on exercise. Patients developed 1 mm ST depression at 217 +/- 161 s at a work load of 70 +/- 30 W and a rate-pressure product of 18,530 +/- 4,465 mm Hg x beats/min. Although exercise was discontinued when angina or equivalent symptoms occurred, in all patients diagnostic ST depression (greater than or equal to 1 mm) developed much earlier than symptoms. Predictably, at peak exercise patients showed a decrease in ejection fraction and peak emptying and filling rates. Ejection fraction and peak emptying rate normalized within the recovery period, whereas peak filling rate remained depressed throughout recovery (p less than 0.002) and was still reduced 2 days after exercise (p less than 0.02). In conclusion, in patients with severe impairement of coronary flow reserve, maximal exercise may cause sustained impairement of diastolic function.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Symptom-limited exercise testing causes sustained diastolic dysfunction in patients with coronary disease and low effort tolerance. 201 41

To diagnose myocardial ischemia and differentiate the chest pain syndrome in 20 females with coronary heart disease and effort angina pectoris, exercise test and ECG monitoring were performed. Their results were then compared. The informative value of 24-hour ECG monitoring was higher than that of bicycle ergometry in detecting the objective signs of ischemia in patients with effort angina. The indisputable advantage of long-term ECG recording is that one can identify silent ischemia in females with routine physical activity in the outpatient settings. The method of 24-hour ECG monitoring cannot be considered to be sufficiently effective in the differential diagnosis of the atypical chest pain syndrome.
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PMID:[Comparison of exercise test and ECG monitoring results in women with ischemic heart disease]. 204 Dec 82

In patients with coronary artery disease, electrocardiographic signs of left atrial enlargement (LAE-negative P wave deflection greater than or equal to 1 mm2 in lead V1) are associated with increased left ventricular end diastolic pressure (LVEDP). We investigated the possibility that transient LAE could represent an additional criterion for diagnosing myocardial ischemia during exercise testing (EST). We studied 48 consecutive patients with chronic stable angina, positive EST and 201 Tl scintigraphy, and angiographically proven CAD; 200 other consecutive patients with atypical chest pain and normal stress/rest 201 Tl scintigraphy served as controls. During EST, transient LAE developed in 34/48 patients with CAD but in only 1/200 controls (p less than 0.001). When present, LAE preceded ST changes (6.1 +/- 1 min vs 8.2 +/- 2 min) and recovered earlier (4.7 +/- 4 min vs 5.8 +/- 3 min). The prevalence of 2-3 vessel CAD was significantly higher in patients with EST-induced LAE (54% vs 34%, p less than 0.05). In conclusion, transient ECG signs of LAE during EST represent a highly specific sign of reversible ischemia and are frequently associated with multivessel CAD. Although less sensitive than classical ST criteria, this sign may prove useful in patients exhibiting equivocal ST changes and in the presence of ventricular conduction disturbances.
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PMID:[Left atrial enlargement during the exercise test: a new electrocardiographic sign of transitory ischemia]. 215 Mar 44

In recent years, radionuclide studies have gained an important place in the evaluation of ischemic heart disease, be it as diagnostic procedures, as predictors of prognosis or for evaluation of therapy. For diagnostic purposes, myocardial perfusion studies using thallium-201 or newer technetium-99m bound perfusion agents have been used as well as radionuclide angiocardiography both at rest and during exercise/stress. Used in a Bayesian approach, these methods yield the highest diagnostic accuracy in patients with a 30% to 70% pre-test likelihood of disease, i.e. in the clinically difficult patients with atypical chest pain and/or non-specific ECG changes. In addition, scintigraphic studies have proved valuable in the setting of silent ischemia and acute myocardial infarction. These methods provide not only a yes/no answer to our diagnostic questions but allow one to assess severity, extent and localization of coronary artery disease. Portable devices are now being constructed which allow continuous ambulatory monitoring of left ventricular function by scintigraphic techniques.
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PMID:Radionuclide studies in the evaluation of ischemic heart disease. 218 64

Of 1,181 consecutive patients who underwent successful percutaneous transluminal coronary angioplasty (PTCA) as an initial revascularization procedure and who had at least 1 year of asymptomatic follow-up, 66 (6%) underwent repeat angiography because of recurrent symptoms or evidence of exercise-induced ischemia. Patients who had revascularization procedures within 1 year of PTCA were not included in the analysis. Mean time to recurrent ischemia was 30.8 +/- 17.4 months (range 12-89 months). At follow-up, 47 patients had angina, 13 had atypical chest pain, two had acute myocardial infarction, and four had positive exercise tests without symptoms. No patient showed spontaneous regression in the extent of coronary artery disease (CAD). As compared with the extent of CAD immediately after PTCA, the extent of CAD at follow-up did not change in 26 patients (39%); it increased by one vessel in 30 (45%), by two vessels in seven (11%), and by three vessels in three (5%). The pattern of CAD seen at follow-up compared with that seen after PTCA was as follows: 18 patients (27%), no change; seven (11%), restenosis only; 30 (45%), progression of CAD at other sites only; and 11 (17%), a combination of restenosis and progression of CAD at other sites. The time to recurrence of ischemia was significantly different between those with restenosis only versus those with progression only (20.1 +/- 9.2 vs. 38.3 +/- 18.5 months) (p less than 0.009). Progression of CAD was equally distributed between dilated and nondilated vessels; however, when progression occurred in the PTCA vessel, it was significantly more likely to be distal to the PTCA site (p less than 0.008).
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PMID:Recurrent ischemia more than 1 year after successful percutaneous transluminal coronary angioplasty. An analysis of the extent and anatomic pattern of coronary disease. 259 21

A 55-year-old man, previously treated for primary hypothyroidism, was admitted for evaluation of atypical chest pain. On physical examination, the pulse rate was 60 and blood pressure was 132/84 mmHg. Heart sounds were normal and no murmur was heard. Abdominal palpation showed no abnormal finding, and bruit was not heard. The electrocardiogram was normal and stress-induced ischemia was not found. The chest X-ray showed no sign of pulmonary hyperaemia or mass lesion, and central shadow was normal (CTR = 44%). During right heart catheterization, the pressures were normal in the cardiac chambers, pulmonary artery, and wedge position. A significant increase in oxygen saturation was disclosed at pulmonary artery level (10%) and the upper site of the inferior vena cava (22%). Coronary arteriography found coronary artery fistulas from the left main trunk, the left anterior descending artery, the left circumflex, and the right coronary artery to the pulmonary trunk. The left and right ventriculograms were normal. The digital subtraction angiography of celiac artery showed hepatic arteriovenous fistula. Ultrasonography and computed tomography found no mass lesion of the liver. Since combination of the bilateral coronary artery with pulmonary artery fistula, and hepatic arteriovenous fistula is very rare, the present case is worth noting for the investigation of the pathogenesis of congenital arteriovenous fistulas.
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PMID:[A case of bilateral coronary artery to pulmonary artery fistulas associated with hepatic arteriovenous fistula]. 261 12

In 17 anginal patients with critical narrowing of the left anterior descending artery, we studied the effects of acute ischemia, either induced by atrial pacing or by ergonovine, on transmyocardial platelet behavior. Six other patients with atypical chest pain and normal coronary arteries served as controls. Simultaneous arterial and great cardiac vein samples were drawn during control and ischemia to measure the levels of platelet factor four (PF4) and beta-thromboglobulin (BTG). During pacing-induced ischemia the great cardiac vein-arterial differences of PF4 and BTG decreased significantly, indicating a reduced platelet aggregability; no significant changes were observed in the control patients. By contrast, when ischemia resulted from ergonovine-induced spasm of the left anterior descending artery (five patients), the great cardiac vein-arterial differences increased, indicating enhanced platelet aggregability. Again no differences were observed in the patients with a negative ergonovine test. The results of our study suggest that the transcardiac platelet behavior may vary during different ischemic conditions. When ischemia is due to increased myocardial demands and flow is normal or increased, myocardial metabolites released from the ischemic area may oppose platelet aggregation. By contrast, spasm and the stagnant flow resulting from it may enhance platelet aggregation.
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PMID:Differential transmyocardial platelet behavior in response to pacing and ergonovine-induced myocardial ischemia. 294 47


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