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共查询到20条相似文献,搜索用时 31 毫秒
1.
R M Schneider K B Roberts K G Morris J A Stanfield F R Cobb 《The American journal of cardiology》1984,53(2):294-301
Multigated equilibrium radionuclide angiography was used to quantitate global and regional ejection fraction (EF) in 26 awake dogs 10 minutes after distal and then proximal occlusion of the left anterior descending (LAD) or left circumflex (LC) coronary artery. Changes in global and regional EF were correlated with simultaneous measurements of the extent of acute left ventricular (LV) ischemia measured by radioisotope-labeled microspheres. The extent of ischemia, defined as the percentage of LV mass with greater than 25% reduction in blood flow from normal regional flow, was linearly related to the percent change in global EF after LAD (r = 0.84) and LC (r = 0.77) occlusions. The extent of ischemia also correlated with regional EF (r = 0.47 to 0.88 for LAD and r = 0.41 to 0.69 for LC occlusions). In 24 of 25 LAD occlusions and in all 20 LC occlusions that produced a measurable ischemic zone, the maximal percent change in regional EF exceeded the percent change in global EF. Two LAD occlusions and 2 LC occlusions reduced regional EF but not global EF. Thus, global and regional EF decreased in direct proportion to the extent of acute myocardial ischemia; regional ischemia produced greater changes in regional than in global EF. 相似文献
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M B Higginbotham K G Morris D A Bramlet R E Coleman F R Cobb 《The American journal of cardiology》1983,52(7):782-788
The effects of oral prazosin (PZ), 15 to 20 mg/day, on symptoms, exercise performance and left ventricular (LV) function were assessed in a 6-month, double-blind, placebo-controlled study of patients in New York Heart Association functional class III. Ejection fraction (EF) was measured at rest and during upright bicycle exercise by equilibrium radionuclide angiography; end-diastolic volume, stroke volume and cardiac output were derived from corresponding count measurements. Although there was no statistically significant difference between clinical responses in the prazosin and placebo groups, qualitative differences suggested a clinical response to prazosin. Of the 9 patients who received PZ, 5 improved to functional class II and 2 became asymptomatic; the 2 nonresponders deteriorated to functional class IV when PZ was stopped. Four of 9 patients who received placebo improved to functional class II and 2 deteriorated to class IV. Exercise time tended to increase in the prazosin group (from 541 ± 204 to 630 ±100 seconds at 6 months) and decrease in the placebo group (from 539 ± 141 to 435 ±148 seconds at 6 months), but neither change was significant. Prazosin effected a sustained decrease in mean blood pressure of approximately 10 mm Hg at rest, and a quantitatively similar but insignificant decrease during exercise. Radionuclide EF increased and LV end-diastolic counts decreased significantly at rest and during exercise in the prazosin group, but not in the placebo group. Because changes in EF and end-diastolic counts were similar, stroke counts and count output were unchanged. Thus, long-term oral PZ therapy caused sustained changes in blood pressure and LV function in most patients in functional class III, but these changes were not uniformly translated into clinical improvement or increased exercise tolerance. Prazosin does not appear to increase cardiac output during exercise in patients with heart failure. 相似文献
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Alan Chu Robert H. Murdock Frederick R. Cobb 《The American journal of cardiology》1982,50(5):1141-1144
Myocardial localization of thallium-201 was compared with direct measurements of myocardial perfusion in normal, acutely ischemic, and recently infarcted myocardium. Studies were performed in 6 chronically instrumented dogs that were subjected to myocardial infarction by occlusion of the proximal left circumflex coronary artery. Four days after myocardial infarction, thallium-201 and 9 ± 1 μm niobium-95-labelled microspheres were injected simultaneously after acute left anterior descending coronary arterial occlusion; the animals were killed 5 minutes later and the entire left ventricle was sectioned into 1 to 2 g samples. Regression analyses between thallium-201 activity and regional myocardial blood flow using all myocardial samples demonstrated a very close linear relation in each dog; r values were 0.98 or greater, indicating that the initial localization of thallium-201 in acutely ischemic and recently infarcted myocardium as a function of regional blood flow was essentially identical. Consequently, in each dog the regional distribution of thallium-201 closely approximated myocardial perfusion over a wide range of blood flow and potentially different local metabolic conditions that may be encountered in the clinical use of the isotope. 相似文献
7.
Importance of complete revascularization in performance of the coronary bypass operation 总被引:3,自引:0,他引:3
E L Jones J M Craver R A Guyton D K Bone C R Hatcher N Riechwald 《The American journal of cardiology》1983,51(1):7-12
Cardiac Data Bank records of 1,238 patients with triple-vessel disease (greater than or equal to 50% diameter reduction) who had undergone coronary bypass surgery were reviewed and divided into 2 groups depending on whether complete (n = 773) or incomplete (n = 465) revascularization had been accomplished. Patients with complete revascularization had a higher incidence of a normal preoperative electrocardiogram than did patients with incomplete revascularization (23 versus 14%, respectively, p less than 0.0001). The ejection fraction for both completely and incompletely revascularized patients was good (m = 0.60 and 0.57, respectively). The mean number of grafts per patient for the 2 groups was 3.8 and 2.6 (p less than 0.0001). There was no significant difference between the 2 groups with regard to postoperative inotropic requirements (8 and 7%), ventricular arrhythmias (1.8 and less than 1%), necessity for intraaortic balloon pumping (1.6 and 1.5%, hospital mortality (1.2 and 2.8%), or myocardial infarction (4.3 and 4.8%). Survival at 5 years was significantly greater (p less than 0.001) in patients with complete (88.5%) than in those with incomplete revascularization (83.5%). Reemployment occurred more often in patients with complete (52%) than in those with incomplete revascularization (40%) (p less than 0.001), and more patients were free of angina after complete (70%) than after incomplete revascularization (58%) (p less than 0.0005). Long-term survival appeared to be mediated primarily through improved revascularization rather than through differences in left ventricular function. 相似文献
8.
Ricky M. Schneider John F. Seaworth Mary L. Dohrmann Robert M. Lester Harry R. Phillips Thomas M. Bashore John T. Baker 《The American journal of cardiology》1982,50(4):682-688
Eighty men (group A) with clinical coronary artery disease underwent coronary angiography regardless of symptoms and previous therapy because they had a positive treadmill exercise test in stage I or II of the Bruce protocol. Thirty-four other men (group B) who also had an early positive treadmill test underwent coronary angiography because they had disabling angina pectoris despite medical therapy. We found left main coronary artery stenosis of 50% or greater of the vessel diameter in 28% of group A and 35% of group B (p >0.3). In contrast, only 10% of 93 other catheterized patients who had treadmill tests that were not early positive had left main coronary disease (p < 0.001). Fifty-four patients from group A who did not have left main stenosis of 50% or greater were treated medically. In this subgroup, 85% had 2 or 3 major coronary vessels with 75% or greater stenosis. These patients had a 36 month survival rate of 89.2%.We conclude that an early positive treadmill test identifies patients who have an increased likelihood of having left main coronary stenosis, even if they are minimally symptomatic. To identify left main coronary stenosis, catheterization may be justified in patients whose angina pectoris has been mild or not intensively treated when they have an early positive treadmill response. After left main coronary stenosis has been excluded, these patients may be treated medically with a low mortality. 相似文献
9.
Mark T. Upton Sebastian T. Palmeri Robert H. Jones R.Edward Coleman Frederick R. Cobb 《American heart journal》1982,104(6):1232-1243
Left ventricular function was evaluated by first-pass radionuclide angiocardiography in 42 patients at 3 and 8 weeks following acute myocardial infarction. Left ventricular ejection fraction, diastolic volume, and wall motion were measured at rest and submaximal exercise at 3 weeks and at rest, submaximal and maximal exercise at 8 weeks. The mean ejection fraction, end-diastolic volume, and wall motion index did not change between 3 and 8 weeks in any group either at rest or during submaximal exercise. Ventricular function was decreased at rest in patients with previous and anterior myocardial infarction, but not in patients with inferior and subendocardial myocardial infarctions. During maximal exercise at 8 weeks, nine patients (21%) had ST segment depression, whereas 25 patients (60%) had a decrease in ejection fraction or a deterioration in wall motion. These abnormalities of ventricular function during exercise occurred equally among the infarct groups. Radionuclide angiography in patients with recent myocardial infarction demonstrated highly variable ventricular function at rest and/or during exercise in each infarct subgroup. 相似文献
10.
John R. Stratton James L. Ritchie Karl E. Hammermeister J.Ward Kennedy Glen W. Hamilton 《The American journal of cardiology》1981,48(3):565-572
Apparent filling defects compatible with left ventricular thrombus are occasionally noted in equilibrium radionuclide angiocardlograms. To define the usefulness of the radionuclide angiogram in detecting left ventricular thrombus, the anterior and left anterior oblique radionuclide angiograms of 39 patients with proved presence or absence of thrombus were blindly interpreted. The presence of thrombus was proved at autopsy in 5 patients, at cardiac operation in 2, or on indium-111 platelet imaging in 6; the absence of thrombus was proved at autopsy in 24 or at cardiac operation in 2. Overall, 13 radionuclide angiograms were interpreted as posltive (n = 10) or equivocally positive (n = 3) for thrombus, and 26 studies were judged negative. The sensitivity of a positive or equivocally positive radionuclide angiogram for detection of thrombus was 77 percent (10 of 13 patients), the specificity 88 percent (23 of 26 patients), the positive predictive value 77 percent, the negative predictlve value 88 percent. If the three equivocal studies are instead considered negative for thrombus, the sensitivity was 62 percent, the specificity 92 percent, the positive predictive value 80 percent and the negative predictive value 93 percent. All thrombi were visualized in the anterior view in an area of akinetic or dyskinetic wall motion. A small group of 13 patients (8 with thrombus, 5 without) underwent two dimenslonal echocardiography, which was 100 percent sensitive and specific. The finding of a discrete filling defect or squared or cutoff ventricular apex in an area of abnormal wall motion in the anterior view of the radionuclide angiogram should suggest the diagnosis of ventricular thrombus, which may be confirmed by other noninvasive studies. 相似文献
11.
Monty M. Bodenheimer Vidya S. Banka Colleen M. Fooshee George A. Hermann Richard H. Helfant 《The American journal of cardiology》1978,41(4):718-725
Because the right anterior oblique view is widely accepted as the best “single” projection for assessing wall motion, the utility of this view during first pass radionuclide angiography was studied in 44 patients who also underwent contrast ventriculography and coronary arteriography. Of the 44 patients, 8 had a normal heart and 14 had coronary artery disease with normal wall motion on contrast ventriculography. All also had normal contraction on radionuclide angiography. On contrast ventriculography, 22 patients had coronary artery disease and asynergy involving 34 left ventricular segments. Of 17 segments localized to the anterior and apical asynergic areas on contrast ventriculography, 16 were accurately localized with radionuclide angiography. Similarly, of 17 inferior asynergic areas, 13 were also shown to be inferior on radionuclide angiography. In addition, quantitative assessment of the severity of asynergy using the hemiaxis method demonstrated a good correlation between asynergic severity as defined with radionuclide angiography and contrast ventriculography. Of 11 anterior areas, 7 defined as hypokinetic with contrast ventriculography demonstrated chordal shortening of 20.1 ± 5.2 percent (mean ± standard error of the mean) (P < 0.005 compared with normal) on radionuclide angiography. Similarly, four akinetic or dyskinetic segments on contrast ventriculography demonstrated a greater reduction (4.0 ± 4.0 percent) in chordal shortening on radionuclide angiography (P < 0.05 compared with hypokinetic segments). Akinetic apical and inferior segments as defined with contrast ventriculography also showed a marked reduction in wall motion to 10.4 ± 7.3 percent and 7.5 ± 4.1 percent, respectively.After appropriate background subtraction, determination of ejection fraction using radionuclide angiography showed a correlation of 0.839 between the left anterior oblique and right anterior oblique projections independent of the sequence of injection. In addition, ejection fraction determined with radionuclide angiography in the left (r = 0.824) and right (r = 0.801) anterior oblique views correlated well with ejection fraction assessed from contrast ventriculography. Thus, first pass radionuclide angiography performed in the right anterior oblique view is a sensitive noninvasive means of assessing the location and severity of asynergy as well as global left ventricular performance in patients with coronary artery disease. 相似文献
12.
Stephen K. Rerych Peter M. Scholz David C. Sabiston Robert H. Jones 《The American journal of cardiology》1980,45(2):244-252
Radionuclide angiocardiography provides accurate hemodynamic information during maximal exercise in erect subjects. Cardiac function was studied with this noninvasive technique in 12 male and 6 female college athletes before (BT) and after (AT) 6 months of swimming training. Measurements at rest and during maximal exercise of heart rate, left ventricular ejection fraction, end-diastolic volume, cardiac output and total body blood volume were determined from first pass and equilibrium precordial counting techniques. The results were as follows:
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