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

A total of 53 patients with a provisional diagnosis of ischemic heart disease and without any clinical evidence of valvular, congenital, or primary muscle heart disease were studied by echocardiography and biplane left ventricular cineangiography. For angiographic ejection fraction analysis, a program developed in our department for use on an Apple Macintosh computer interfaced to a digitizing tablet was employed. Echocardiographic outlines of systolic and diastolic images were traced with a digitizing system on the screen and ejection fractions were calculated by a program incorporated in the echo machine. Good echo windows allowing ejection fraction calculations were present in 35 patients. There was a good correlation between angiographic and echocardiographic ejection fraction (r = 0.7, SEE = 0.09), and wall motion assessment revealed no significant discrepancies between the two image modalities. The remaining 18 patients had poor echo windows, preventing accurate echocardiographic determination of the ejection fraction. However, limited assessment of left ventricular size and wall motion was possible in all patients and allowed the identification of those who had impaired left ventricular function as judged by angiography (angiographic ejection fraction < 35%). We conclude that even in patients with poor echo windows echocardiographic assessment of left ventricular function provides clinical information similar to angiography which should not be considered mandatory for the investigation of ordinary ischemic patients.
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PMID:Is angiographic ventriculography necessary for the assessment of ischemic patients? 139 83

In order to evaluate the radioactive microsphere technique used in our laboratory for measuring regional myocardial blood flow (RMBF) in dogs with myocardial ischemia, simultaneous blood flow measurements with three different nuclide (141Ce, 51Cr or 113Sn)-labeled microspheres were performed after coronary artery occlusion. There were excellent correlations between all paired RMBF values in 80 samples. The linear regression lines were expressed as: 51Cr = 1.09x 141Ce-0.02 (r = 0.996, SEE = 0.06); 113Sn = 0.99x 141Ce + 0.01 (r = 0.997, SEE = 0.05); 113Sn = 0.90x 51Cr + 0.03 (r = 0.991, SEE = 0.08). The duplicate variability ranged from 5.5 +/- 0.7 to 9.9 +/- 1.1%. When RMBF was measured before and after intravenous administration of nipradilol (0.2 mg/kg), a new beta-blocker, in a dog with myocardial ischemia, RMBF fell in the normal zone (23.6 +/- 1.6%), and did not change in the severely ischemic zone. Thus, this study demonstrated that RMBF can be measured accurately and repeatedly with radioactive microspheres in dogs with regional myocardial ischemia.
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PMID:[Regional myocardial blood flow measurement with radioactive microspheres in dogs with myocardial ischemia]. 168 61

Ultrafast computed tomography has been reported to be an accurate method of measuring left ventricular mass in dogs. To assess the interstudy, intraobserver and interobserver variability of left ventricular myocardial mass measurements in humans, left ventricular myocardial volume was measured three times within 24 h in 16 patients with ischemic heart disease. The mean percent difference of the mean of the three studies performed was -0.01 +/- 1.4% (range -2.9% to 3.6%). The regression analysis for the intraobserver variability at baseline was: Y = -4.33 + 1.03X; r = 0.99, SEE = 3.5 ml. The mean percent difference of the mean of the two sets of measurements performed by two independent observers was 0.28 +/- 2.1% (range -4.35% to 4.35%). The interobserver variability excluding papillary muscles at baseline study was: Y = -4.34 + 1.06X; r = 0.99, SEE = 1.5 ml. The regression analysis with versus without papillary muscles showed: Y = -8.72 + 0.97X; r = 0.96, SEE = 2.6 ml. Regression analysis to assess the variability of 24-h studies at end-systole versus end-diastole revealed: Y = 3.07 + 0.94X; r = 0.97, SEE = 1.8 ml. In conclusion, ultrafast computed tomography is a minimally invasive technique, with very low interstudy, intraobserver and interobserver variability for left ventricular myocardial volume and mass determinations in serial studies.
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PMID:Reproducibility of left ventricular myocardial volume and mass measurements by ultrafast computed tomography. 183

To characterize the sequential changes of myocardial perfusion scintigraphy in patients with coronary artery disease (CAD) after complete revascularization, 43 patients underwent exercise thallium-201 (201Tl) myocardial perfusion scintigraphy before and at 9 +/- 5 days, 3.3 +/- 0.6, and 6.8 +/- 1.2 months after percutaneous transluminal coronary angioplasty (PTCA). Only patients with single-vessel CAD, without previous myocardial infarction, and without evidence of restenosis at 6 to 9 months after PTCA were included. Perfusion scans were analyzed blindly with the use of a new quantitative method to define regional myocardial perfusion in the topographic distribution of each coronary artery, which was shown to be reproducible (r = .94 or higher and SEE of 7% or less, between repeated measures by one and two operators). At 4 to 18 days after PTCA, the mean treadmill walking time increased by 123 +/- 42 sec, mean exercise-induced ST segment depression decreased by 0.6 +/- 0.3 mm, group maximal heart rate increased by 20 +/- 9 beats/min, and group systolic blood pressure at peak exercise increased by 24 +/- 10 mm Hg, compared with pre-PTCA values (p less than .001). However, no group differences were noted in these variables between the three post-PTCA stages. Myocardial perfusion in the distribution of the affected (dilated) coronary artery, on the other hand, improved progressively. In the 45 degree left anterior oblique view for instance, myocardial perfusion increased at 9 days after PTCA (from 68 +/- 24% before PTCA to 91 +/- 9%, p less than .001) and at 3.3 months after PTCA (101 +/- 8%, p less than .05 vs 9 days after PTCA), but no further significant changes were seen at 6.8 months after PTCA (102 +/- 8%). Similar changes were noted in the other two views. No relationship between minor complications during PTCA and delayed improvement on the 201Tl was observed. Myocardial ischemia was diagnosed in 12 of the 43 scans recorded a few days after PTCA, but in none recorded at later stages. We conclude that 201Tl scans after PTCA often show delayed improvement and therefore, an abnormal myocardial perfusion scan soon after PTCA does not necessarily reflect residual coronary stenosis or recurrence.
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PMID:Sequential thallium-201 myocardial perfusion studies after successful percutaneous transluminal coronary artery angioplasty: delayed resolution of exercise-induced scintigraphic abnormalities. 296 82

This study examined the relation between left ventricular (LV) function and the severity of acute myocardial ischemia in a conscious dog model. The LV ejection fraction (EF) was measured by multigated equilibrium radionuclide angiography, and regional myocardial blood flow was measured with radioactive microspheres before and 10 minutes after distal and then proximal occlusion of the left anterior descending (LAD, 13 dogs) or left circumflex (LC, 13 dogs) coronary artery. Two methods were used to evaluate the extent of ischemia. The first method determined the mass of myocardium that was ischemic based on different degrees of reduced blood flow. The second method estimated the severity of ischemia expressed as blood flow deficit resulting from each coronary occlusion. Global LV function was very sensitive to ischemia, and the relation between change in function and the degree of ischemia were described best by linear functions. The best linear correlation between mass of ischemic myocardium and percent reduction in EF resulted from the ischemic region defined as all tissue with 25% or greater reduction in blood flow, r = 0.84 for LAD (Y = 0.96X + 1.8) and r = 0.75 for LC (Y = 0.53X + 2.0) occlusions. Defining ischemic mass by more severe reduction in blood flow resulted in exclusion of ischemic myocardium that affected function. The myocardial blood flow deficit also correlated linearly with percent reduction in EF, r = 0.89 for LAD (Y = 1.31X + 2.7) and r = 0.81 for LC (Y = 0.83X - 0.1) occlusions. The slope of the regression lines using both analyses of ischemia were significantly greater (p less than 0.01) for LAD than LC occlusions, indicating that for comparable degrees of ischemia LAD as compared to LC occlusion decreased EF to a greater extent. Calculation of EF from attenuated corrected volumes resulted in small changes in LAD, but not LC, EF and did not account for the disproportionate effects of LAD and LC ischemia. In a separate group of studies (n = 18) EF measured by radionuclide angiography after LAD or LC occlusions correlated well with biplane contrast angiography r = 0.93, SEE 5.1. These data suggest that disproportionately greater effects of LAD compared to LC ischemia on global EF in the dog are due primarily to different pathophysiologic responses to ischemia.
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PMID:Relation between myocardial perfusion and left ventricular function following acute coronary occlusion: disproportionate effects of anterior vs. inferior ischemia. 356 88

To define the in vivo relation between abnormal wall motion and the area at risk for necrosis after acute coronary occlusion, 11 open chest dogs were studied. Five dogs underwent left anterior descending coronary artery occlusion and six underwent left circumflex artery occlusion. Area at risk was defined at five short-axis levels (mitral valve, chordal, high and low papillary muscle and apex) using myocardial contrast echocardiography. Wall motion was measured in the cycles preceding injection of contrast medium. Two observers used two different methods to measure wall motion. In method A, end-diastolic to end-systolic fractional radial change for each of 32 endocardial targets was determined. The extent of abnormal wall motion was then calculated using three definitions of wall motion abnormality: akinesia/dyskinesia, fractional inward endocardial excursion of less than 10%, and fractional inward endocardial excursion of less than 20%. In method B, the information from the entire systolic contraction sequence was analyzed and correlated with a normal contraction pattern. The best linear correlation between area at risk (AR) and abnormal wall motion (AWM) was achieved using method B and expressed by the following linear regression: AWM = 0.92 AR + 3.0 (r = 0.92, p less than 0.0001, SEE = 1.7%). Of the three definitions of abnormality used in method A, the best correlation was achieved between area at risk and less than 10% inward endocardial excursion and was expressed by the following polynomial regression: AWM = -0.01 AR2 + 1.5 AR -0.14 (r = 0.92, p less than 0.001, SEE = 1.7%). These data demonstrate that there is a definite relation between area at risk and abnormal wall motion but that this relation varies depending on the method used to analyze wall motion. However, wall motion during acute ischemia is also influenced by the loading conditions of the heart. Because these may vary in a manner that is independent of the ischemic process, measurement of both risk area and abnormal motion may provide a more comprehensive assessment of cardiac function in myocardial ischemia than is provided by the measurement of either alone.
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PMID:Contrast echocardiography in acute myocardial ischemia. III. An in vivo comparison of the extent of abnormal wall motion with the area at risk for necrosis. 394 58

A method is described for three dimensional reconstruction of the left ventricle which uses four anatomically defined apical views. It is shown that the algorithms developed for reconstruction and volume estimation provide accurate results when applied to planar views with accurately defined boundaries. The linear regression equation was y = -6.32 + 1.04x, with SEE = +/- 3.4 ml, r = 0.999. For both "in vitro" and "in vivo" studies this method is found to be better than various geometrical models used to estimate volumes from two dimensional tomographic or projection views. The linear regression equation of in vitro fluid volume on volume estimate is y = 8.44 + 0.68x, with SEE = +/- 4.9 ml, r = 0.988. For pooled end diastolic and end systolic volumes (EDV and ESV) determined by three dimensional reconstruction (3-DR) and angiography the linear regression equation is y = 54.50 + 0.50x, with SEE = +/- 33.5 ml, r = 0.670. For stroke volume (SV), the regression equation is y = 21.10 + 0.40x, with SEE = +/- 12.8 ml, r = 0.750, and for ejection fraction (EF) it is y = 1.10 + 0.70x, with SEE = +/- 7.8%, r = 0.840. In patients with ischemic heart disease, the method presented is shown to be better than existing methods of volume estimation. Three dimensional perspective images can be plotted in any orientation as a visual aid to the cardiologist. In vivo studies demonstrate the feasibility of 3-DR, from anatomically defined apical views, in the clinical setting.
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PMID:Three dimensional reconstruction of the left ventricle from four anatomically defined apical two-dimensional echocardiographic views. 633 37

Premedication of patients requiring cardiac surgery should provide adequate analgesia, sedation and anxiolysis for the stress and pain associated with preoperative preparation and placement of monitoring catheters. Ideally, these effects would be achieved without producing respiratory depression and hypoxia, which could be life-threatening to patients at risk for myocardial ischemia. Ketorolac, a nonsteroidal, antiinflammatory agent, has previously been shown to provide postoperative pain relief comparable to that provided by morphine, without respiratory depression. This study compared the incidence of arterial blood desaturation, respiratory depression, and patient comfort after preoperative medication with scopolamine and ketorolac versus scopolamine and morphine. Scopolamine and ketorolac premedication provided sedation and analgesia comparable to that provided by scopolamine and morphine, without significant respiratory depression. Since ketorolac has no central respiratory depressant effect, it may be a useful alternative to morphine for premedication in the cardiac surgical patient.
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PMID:Ketorolac as a premedicant for coronary artery bypass surgery patients with normal ventricles. 813 95

The slope of the left ventricular (LV) end-systolic pressure-volume relation (ESPVR) has been established as a valuable clinical method to assess LV contractile function independent of LV loading factors. The purpose of the present study was to evaluate whether the ESPVR could be reliably determined from auscultatory blood pressure (BP) measurements and from LV volume measurement by contrast ventriculography (CVG). Twenty-four patients with suspected or known ischemic heart disease were studied by cardiac catheterization with simultaneous, blinded, intravascular and auscultatory pressure measurements. LV volume was determined by CVG. The auscultatory mean arterial blood pressure (MAP) derived from: [formula: see text] was found to be a useful measure of the LV end-systolic pressure in this connection. The correlation between invasively measured LV end-systolic pressure (ESP) and MAP was highly significant (r = 0.82; SEE = 6.9 mmHg; p = 0.001). The correlation between invasively and semi-invasively measured ESPVR fell close to the line of identity (r = 0.99; SEE = 0.23 mmHg.mL-1; p < 0.001). The replacement of ESP by MAP induced only a minimal error in the assessment of the ESPVR. A complete noninvasive determination of the ESPVR and LV contractility therefore seems possible by using the MAP and by measuring the end-systolic volume by radionuclide ventriculography or by echocardiography.
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PMID:The left ventricular end-systolic pressure and pressure-volume index. Comparison between invasive and auscultatory arm pressure measurements. 828 73