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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixty patients of CAD were studied with 24 and 48 hours ambulatory electrocardiogram monitoring. The day-to-day natural variances of transient myocardial ischemia in this group were analysed. The ranges of variation of myocardial ischemia based on a 95% confidence interval were confirmed. The results showed that the day-to-day variances of ischemia between the different days were: (1) 43% in number of ischemia episodes, (2) 76% in duration, (3) 53% in integration, and (4) 48% in maximal degree of ST depression.
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PMID:[The natural variance of transient myocardial ischemia in coronary artery patients]. 209 53

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

Two-dimensional and Doppler echocardiographic studies and a hemodynamic investigation were performed during dipyridamole testing in 42 subjects (13 control subjects and 29 patients with coronary artery disease [CAD]), to evaluate the ability of dipyridamole Doppler echocardiography in identifying patients with ischemic left ventricular dysfunction. In the control group, after dipyridamole infusion, Doppler-derived parameters increased significantly from baseline (p less than 0.001). In patients with CAD, peak flow velocity, flow velocity integral and stroke volume failed to increase after dipyridamole infusion (0.89 +/- 0.21 to 0.85 +/- 0.18 m/s, difference not significant; 14 +/- 3 to 12 +/- 4 cm, difference not significant, and 56 +/- 13 to 50 +/- 14 ml/beat, p less than 0.05, respectively). Heart rate, rate pressure product, systemic vascular resistance and mean right atrial pressure had similar variations in the 2 groups. Changes in the 3 Doppler-derived parameters are closely related to the variations of peak positive dP/dt, stroke volume (thermodilution) and left ventricular end-diastolic pressure and are closely related to the coronary angiography jeopardy score and to the appearance of wall motion abnormalities. Thus, by combining Doppler and 2-dimensional echocardiography, dipyridamole-induced myocardial ischemia may be detected in a high percentage of CAD patients, providing a sensitive tool for identifying patients with high-risk coronary artery anatomy.
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PMID:Usefulness of the dipyridamole-Doppler test for diagnosis of coronary artery disease. 199 Aug 8

The aim of the study was to evaluate the value of analysis of left ventricular systolic intervals during Isuprel test in diagnosis of ischemic heart disease. 30 patients with ischemic heart disease without myocardial infarction in the past (group I) and after myocardial infarction (group II) as well as 15 healthy persons (group III) underwent the study. Electrocardiograms and polycardiograms were analyzed by means of Weissler's method. In patients with CAD during Isuprel test decrease of QS2I, LVETI, LVETI/S1S2 and increase of Q-1, ICT, PEPI, PEP/LVET were stated in comparison with healthy persons. Sensitivity of Isuprel test estimated by ST segment analysis was 80%, specificity 100%, predictive value for CAD confirmation 100% and for its exclusion 71.4%. Diagnostic value of Q-1, QS2I and LVETI intervals and PEP/LVET index did not statistically significantly differ from ST segment diagnostic value. Sensitivity of Isuprel test estimated by means of these intervals analysis was 63.3%, specificity 93.3-100%, predictive value for CAD confirmation 95-100%, and for its exclusion 56-57.7%. Analysis of left ventricular systolic intervals during Isuprel test is a valuable complement of an ECG examination.
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PMID:[Value of the analysis of left-ventricular systolic time intervals in the diagnosis of ischemic heart disease provoked by intravenous infusion of isoproterenol]. 262 7

The characteristics of ischemic episodes in exercise test and daily activities were observed in a silent myocardial ischemia (SMI) group and an anginal group (23 patients each). 15 patients in the SMI group were treated with nifedipine. In exercise test, the time of onset of ischemia was earlier and the ischemic threshold was lower in SMI group. During daily activities, the frequency of SMI was high. The heart rate just before onset of SMI was lower than the mean heart rate in 24-hour Holter monitoring. The highest frequency of SMI was found between 5 AM and 12 noon. Postinfarction patients had a higher frequency and a longer duration of SMI than noninfarction patients. The frequency and duration of SMI decreased in the 15 patients treated with nifedipine in SMI group. It is concluded that silent ischemic episodes were frequent and occurred easily. They might be associated with poor prognosis in CAD patients. Nifedipine was effective in reducing the frequency and duration of SMI in our patients.
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PMID:[Clinical characteristics of silent myocardial ischemia and the effect of nifedipine treatment]. 263 87

A considerable amount of data now exists that indicates that exercise ECG--due to its suboptimal sensitivity and specificity--has limited diagnostic and prognostic value in asymptomatic subjects, patients with chest pain of unclear etiology or those with chronic stable angina pectoris, and in patients recovering from acute myocardial infarction. Because of this and the well-recognized advantages of thallium-201 scintigraphy, there appears to be a strong rationale for recommending exercise perfusion imaging, rather than exercise ECG alone, as the preferred method for detecting CAD and staging its severity. This recommendation seems justified given the fact that (1) thallium-201 scintigraphy is far more sensitive and specific in detecting myocardial ischemia than exercise testing; (2) unlike stress ECG, thallium-201 scintigraphy can localize ischemia to a specific area of areas subtended by a specific coronary artery; and (3) thallium-201 scintigraphy has been shown to be more reliable to risk stratification of individual patients than exercise testing alone. The more optimal prognostic efficiency of thallium-201 scintigraphy is due, in part, to the fact that the error rate in falsely classifying patients as low-risk is substantially and significantly smaller with thallium-201 scintigraphy than with stress ECG.
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PMID:Comparative analysis of the diagnostic and prognostic value of exercise ECG and thallium-201 scintigraphic markers of myocardial ischemia in asymptomatic and symptomatic patients. 267 Feb 27

A positive exercise ECG with greater than or equal to 1.0 mm ischemic ST-segment depression, limited exercise duration, persistence of ischemic ST-segment depression past 8 minutes in the recovery period, and exertional hypotension is associated with increasing severity and extent of CAD. The sensitivity and specificity of the exercise ECG are not dependent on the prevalence of CAD in the population tested. The positive and negative predictive values of the exercise ECG are both dependent on the prevalence of CAD in the population tested. Exercise-induced ST-segment elevation greater than or equal to 1.0 mm is associated with severe myocardial ischemia, left ventricular aneurysm, left ventricular wall motion abnormalities, and coronary artery spasm in patients with variant angina. Ischemic ST-segment depression greater than or equal to 1.0 mm, exercise duration, maximal exercise heart rate, and blood pressure response to exercise are correlated with new coronary events in patients with documented CAD. Low-level exercise tests within 3 weeks of uncomplicated MI can identify patients at high risk for new cardiac events. Early post-MI patients with exercise-induced ischemic ST-segment depression greater than or equal to 1.0 mm, exercise-induced angina, an inadequate blood pressure response to exercise, or limited exercise duration during a low-level exercise test should undergo coronary angiography and be considered for possible coronary artery surgery or angioplasty. Exercise testing will also help in the medical treatment of patients with exercise-induced angina or malignant ventricular arrhythmias. An exercise test performed 6 months after MI also provides prognostic information not available from clinical evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diagnostic and prognostic value of exercise electrocardiography for coronary artery disease. 268 80

New developments in radiopharmacology of 123I-labeled metabolic tracers and single-photon emission computerized tomography (SPECT) allow now-a-days the assessment of parameters of cardiac energy metabolism in well-defined areas of the heart muscle. This article will present a brief outline of the basic pathophysiological principles used in the application of 123I-labeled phenyl fatty acids for the evaluation of CAD. First clinical results suggest an important application of cardiac fatty acid metabolic imaging to the detection, localisation and conceivable quantitation of myocardial ischemia, myocardial infarction and assessment of tissue viability. In addition to the diagnostic applications in CAD, cardiac fatty acid metabolic imaging may provide new perspectives to pathophysiological investigations of the coupling of local flow and substrate utilisation in vivo and the effect of therapeutic interventions.
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PMID:[Results of fatty acid SPECT of the myocardium in coronary disease]. 348 23

Myocardial perfusion scintigraphy with 201-TL was performed in a group of subjects affected by exercise-induced, rate-dependent left bundle branch block (LBBB). The aim of the study was: to define the significance of the exercise-induced conduction abnormality: "primitive" or "ischemic". 14 patients, aging 28-58 years (x = 42), 8 with chest pain (4 typical angina, 4 atypical angina) and 6 without any symptoms were studied. None had history of prior myocardial infarction or clinical and echocardiographic signs of heart disease. LBBB appeared at a heart rate ranging from 70 to 160 beats/min. 6 patients showed repolarization abnormalities (ST changes, deep and negative T wave) suggestive for ischemia, during successive QRS normalization. 201-TL-uptake was normal in 5 subjects; in the remaining 9 ones reversible TL defects were demonstrated in the septum (6), in the septum and apex (2), in the septum and inferior-apical wall (1). No patients had irreversible impaired perfusion. All the patients had normal coronary angiography, with negative ergonovine test for coronary artery spasm. In conclusion, in the majority of our subjects (64%) with exercise-induced LBBB, a reversible TL-uptake defect, usually located in the septum without diagnostic value of obstructive CAD, has been observed. Further studies will establish if the TL-defect is only an "apparent phenomenon" due to contraction abnormality secondary to LBBB, or, on the contrary, an expression of myocardial ischemia with normal coronary vessels as a consequence of the LBBB.
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PMID:[Study of myocardial perfusion by means of scintigraphy with thallium-210 in left bundle branch block induced by exertion]. 366 78

Many recent studies provide evidence that increased platelet activation occurs in a significant number of patients with atherosclerotic coronary artery disease. The mechanisms responsible for this activation are unknown, although there have been studies suggesting a correlation with abnormal lipoproteinemia, acute myocardial infarction, unstable angina, and exercise-induced myocardial ischemia. We studied 84 patients undergoing standardized treadmill exercise using either a Bruce [N = 63] or symptom-limited Naughton protocol [N = 21]. In contrast to ten healthy volunteer subjects, the patient group demonstrated a significant increase in plasma concentrations of platelet factor 4 [PF4] between pre- and postexercise blood samples confirming earlier reports of exercise-induced platelet activation and secretion. As with previous studies, however, only a subset of patients demonstrated this response. When the entire group was analyzed for the presence or absence of electrocardiographic ischemic changes and the presence of documented versus suspected coronary artery occlusions, there were no differences noted between groups that explained the variable responses measured. However, there was a significant difference between patient groups when analyzed by whether or not they were being treated with beta-blocking agents. Patients who were being treated with propranolol or one of the longer-acting beta-blocking agents did not have a significant increase in plasma PF4 following exercise, in contrast to patients who were not beta-blocked. Plasma concentrations of epinephrine, norepinephrine, and lactic acid were measured in 49 patients and all normal subjects. There was no correlation between the changes in plasma PF4 concentrations and any of these three variables, suggesting that platelet activation was not occurring through direct platelet activation by circulating catecholamines. This study provides further evidence that there is a subset of CAD patients with platelet hyperactivity. This is the first time that beta-blockade has been demonstrated to modify this platelet response. The effectiveness of beta-blocking agents in CAD may be in part related to their antiplatelet effect.
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PMID:Platelet factor 4 release during exercise in patients with coronary artery disease. 614 87


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