[Left ventricular function at rest and during exercise: assessment of ejection fraction, ejection rate and filing rate with radionuclide ventriculography (author's transl)].
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Adult↗
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Assessment of cardiac and renal function in children immediately after open-heart surgery: the significance of a reduced radionuclide ejection fraction (postoperative ejection fraction).
Ventricular ejection fractions, calculated from radionuclide studies, and inulin clearance, were determined in 33 infants and children immediately after surgical repair of their congenital or rheumatic heart defects. Of these children, the seven whose surgery did not require a period of ischemic arrest served as controls. The immediate postoperative ejection fractions in the 26 children who did undergo a period of ischemic arrest were significantly less than their preoperative values (P less than or equal to 0.001), but this decline was not observed in the control group. Ejection fraction tended to be depressed, transiently, in children 3-5 h after open-heart surgery. Early postoperative ejection fraction was significantly related to aortic cross-clamp time even when controlling for preoperative ejection fraction (r = 0.74, n = 25, P less than or equal to 0.001). Some striking declines in ejection fraction were observed among children whose aortic cross-clamp time exceeded 42 min. The decline in ejection fraction was transient; late postoperative (greater than 1 week) ejection fraction was not significantly different from preoperative values. Though glomerular filtration rates (GFRs) were often above normal, they were significantly correlated with ejection fraction (r = 0.74, n = 19, P less than or equal to 0.01). The lower GFRs were associated with the lower early postoperative ejection fractions.
Adolescent↗
Are right and left ventricular ejection fractions equal? Ejection fractions in normal subjects and in patients with first acute myocardial infarction.
Right and left ventricular ejection fractions (RVEF and LVEF) were determined by radionuclide imaging in 37 normal subjects and 37 patients by means of (1) the traditional way of calculating ejection fraction from first-pass time-activity curves of each ventricle generated from a single fixed ventricular region of interest, (2) dual first-pass time-activity curves generated from the end-diastolic and end-systolic regions, respectively, and (3) the multigated equilibrium method, also applying separate regions in end-diastole and end-systole for each ventricle. Values for RVEF measured by method 2 were significantly higher than values obtained by methods 1 and 3. In normal subjects, the values for RVEF measured by method 2 were equal to the values for LVEF determined by either this method or the equilibrium technique. Methods 1 and 3 had a tendency for underestimation of RVEF, probably because of inclusion of right atrial activity into the right ventricular region of interest. Methods 2 and 3 were applied to measure RVEF and LVEF, respectively, in 153 patients in the second week after first acute myocardial infarction. Among these, 25% had normal ejection fractions, 47% had a decrease in only LVEF, 8% a decrease in only RVEF, and 20% a decrease in both RVEF and LVEF.
Acute Disease↗
Visual quantitative estimation: semiquantitative wall motion scoring and determination of ejection fraction.
Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two-dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid-ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder-cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG (r = 0.969), which was significantly greater than visual estimation (r = 0.896, P < 0.01). The limits of agreement for VQE (+12% to -7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to -11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF (r = 0.967, P < 0.001). We conclude that VQE provides highly correlated estimates of EF with RVG.
Echocardiography↗
Automatic ventricular edge detection for determination of left ventricular volumes, ejection fraction and regional ejection fractions from first pass radioisotope angiography.
An automated method for detection of left ventricular (LV) outline (including the aortic and mitral valve planes) was developed for measurements of end-diastolic volume (EDV), end-systolic volume (ESV), global ejection fraction (EF), and regional EFs from first pass radioisotope ventriculography. The procedure includes: (1) interpolative background subtraction, (2) construction of gradient images, (3) automatic detection of valve planes, and (4) automatic radial search of LV outlines. The correlation between contrast angiography and Tc-99m first pass study was r = 0.84 (SEE = 23.4) for EDV, r = 0.93 (SEE = 12.8) for ESV, r = 0.84 (SEE = 6.91) for EF (via counts) and r = 0.80 (SEE = 8.56) for EF (via area-length method). Tests of intra-observer, inter-observer and inter-study variability revealed low level of variability. The results showed the potential of the automation of data processing for first pass radioisotope ventriculography.
Cardiac Volume↗
Is there a referral bias against catheterization of patients with reduced left ventricular ejection fraction? Influence of ejection fraction and inducible ischemia on post-single-photon emission computed tomography management of patients without a history of coronary artery disease.
OBJECTIVES: The objective of this work was to define the relationship between left ventricular perfusion/ function measures and referral rates to catheterization and revascularization early after stress gated myocardial perfusion single-photon emission computed tomography (MPS). BACKGROUND: Although revascularization yields the greatest survival benefit in patients with low ejection fraction (EF) and extensive coronary artery disease, referral patterns to catheterization and revascularization after noninvasive testing are not well defined. METHODS: We identified 3,369 patients without previous myocardial infarction or revascularization who underwent exercise or adenosine stress MPS and who were followed-up (97% complete) for occurrence of early (<60 days) post-single-photon emission computed tomography (SPECT) revascularization. Multivariable logistic regression modeling was used to determine the association of various patient characteristics and test results with performance of catheterization and revascularization as separate end points. RESULTS: In the first 60 days after stress MPS, 445 catheterizations (13.2%) and 254 revascularizations (7.5%) occurred, including 140 coronary artery bypass graft surgeries (4.1%) and 114 percutaneous coronary interventions (3.4%). Both post-stress gated EF and percent of the myocardium ischemic by stress MPS were independent predictors of revascularization. Logistic regression revealed that the likelihood of catheterization increased with both increasing ischemia and decreasing EF (c-index = 0.94, chi-square = 590). Predicted referral rates to catheterization increased with decreasing EF except in patients with severe ischemia (>15% of myocardium), where rates decreased with decreasing EF. Similar modeling of revascularization (c-index = 0.94, chi-square = 329) revealed that the likelihood of revascularization increased with increasing ischemia but, in general, decreased with decreasing EF. CONCLUSIONS: Although post-SPECT referral to both catheterization and revascularization is driven by ischemia, EF has the opposite effect on these two outcomes. Further studies evaluating the appropriateness of these referral patterns are warranted.
Adenosine↗
Left ventricular ejection fraction change with exercise versus ejection fraction at rest in coronary artery disease: implications for using ejection fraction variations in making therapeutic decisions.
Previous studies have differed regarding the prognostic importance of the change (Delta) in left ventricular ejection fraction (LVEF) with exercise among patients with known or suspected coronary artery disease (CAD). Data suggest that these discrepancies may be owing to patient selection, including wide interstudy variations in the range of LVEFrest at study entry; however, the impact of LVEFrest on LVEF exercise response has not been adequately addressed. To test the hypothesis that magnitude and variability in DeltaLVEF are systematically related to LVEFrest, we analyzed data from 2655 patients who underwent rest/exercise radionuclide cineangiography for evaluation of clinically evident CAD, stratified into 5 successive LVEFrest subgroups: <30% (n = 205), 30%-44% (n = 563), 45%-59% (n = 1529), 60%-75% (n = 324), and >75% (n = 34). The standard deviation of DeltaLVEF among patients with LVEFrest <30% was found to be half that among patients in the higher LVEFrest subgroups (P < 0.00001, global). The average magnitude of the rise and fall in LVEF with exercise also varied markedly among LVEFrest subgroups (P < 0.0001, global), being smallest among patients with LVEFrest <30%. These findings may explain differences in predictive accuracy of DeltaLVEF noted among various study populations. Further study is needed to determine whether LVEFrest should be used in selecting exercise-based prognostic descriptors in individual patients.
Blood Pressure↗
Rate of change of left ventricular ejection fraction during exercise is superior to the peak ejection fraction for predicting functionally significant coronary artery disease.
OBJECTIVE: To detect and characterise rapid temporal changes in the left ventricular response to exercise in patients with ischaemic heart disease and to relate these changes to the functional severity of coronary artery disease. BACKGROUND: The gamma camera does not allow the detection of rapid changes in cardiac function during exercise radionuclide ventriculography, the monitoring of which may improve the assessment of patients with ischaemic heart disease. METHODS: A miniature nuclear probe (Cardioscint) was used to monitor continuously left ventricular function during exercise in 31 patients who had coronary angiography for suspected coronary artery disease. A coronary angiographic jeopardy score was calculated for each patient. RESULTS: The coronary jeopardy score ranged from 0 to 12 (median 4). Ejection fraction fell significantly during exercise from 46% to 34%. Patients were divided into two groups based on the response of their ejection fraction to exercise. In 14 patients (group I), the peak change in ejection fraction coincided with the end of exercise, whereas in the other 17 patients (group II) the peak change in ejection fraction occurred before the end of exercise, resulting in a brief plateau. The peak change in ejection fraction and the time to its occurrence were independent predictors of coronary jeopardy (r = -0.59, p < 0.001 for peak change and r = -0.69, p < 0.001 for time to that change). The rate of change in ejection fraction was the strongest predictor of coronary jeopardy (r = -0.81, p < 0.001). In group I the peak change in ejection fraction was a poor predictor severity of coronary disease (r = -0.28, NS), whereas the time to peak and the rate of change in ejection fraction were good predictors (r = -0.65 and r = -0.73, p < 0.01). In group II the peak, the time to the peak, and the rate of change in ejection fraction were good predictors of coronary jeopardy (r = -0.75, r = -0.61, and r = -0.83, p < 0.01). CONCLUSION: The rate of change of ejection fraction during exercise can be assessed by continuous monitoring of left ventricular function with the nuclear probe, and is the best predictor of functionally significant coronary artery disease.
Adult↗
Left ventricular ejection fraction and first third ejection fraction early after acute myocardial infarction: value for predicting mortality and morbidity.
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Adult↗
Inter-observer variation in estimates by nuclear angiography of left ventricular ejection fraction and ejection rate.
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Cardiac Output↗
Heart rate index: an indicator of left ventricular ejection fraction. Comparison of left ventricular ejection fraction and variables assessed by exercise test in patients studied early after acute myocardial infarction.
The present study compares the variables assessed by standard exercise test with the left ventricular ejection fraction (LVEF) measured by multigated radionuclide angiocardiography (MUGA) in 77 patients early after myocardial infarction. The exercise test and MUGA were performed within two weeks after the myocardial infarction. A significant correlation (Spearman's correlation coefficient rs, p less than 0.05) was found between LVEF at rest and the following variables assessed at exercise test: 1) the heart rate at rest, 2) rise in heart rate, 3) ratio between maximal heart rate and heart rate at rest, 4) rise in systolic blood pressure, 5) rate pressure product at rest, 6) rise in rate pressure product, 7) ratio (rHR) between maximal rate pressure product and rate pressure product at rest, 8) total exercise time. The heart rate was corrected for effects caused by age (heart index (HR%)) and a significant correlation was found between 1) the HR% at rest, 2) the rise in HR% and the LVEF. A simple method to identify patients with an abnormal LVEF is described.
Adult↗
Image enhancement of severely hypoperfused myocardia for computation of tomographic ejection fraction.
UNLABELLED: Ejection fractions computed from 99mTc-sestamibi myocardial perfusion gated tomograms have demonstrated a high degree of accuracy and reproducibility. Although automated algorithms appear to provide reasonable endocardial outlines for patients over a broad spectrum of cardiac diseases, in cases of severe hypoperfusion, it is necessary to manually adjust contrast and brightness to judge whether borders are correct or must be altered. METHODS: Midventricular horizontal and vertical long axis gated tomograms were generated for 116 studies chosen on the basis of extensive, severe myocardial perfusion defects. Automated software transformed cinematic tomograms into images demonstrating uniform appearance of the myocardium throughout the cardiac cycle. Transformed images were introduced to edge detection algorithms for subsequent calculation of ventricular volumes and ejection fractions. RESULTS: Linear regression analysis demonstrated excellent intraobserver reproducibility for ejection fractions (r = 0.95) and volumes (r = 0.98). There was also good agreement of ejection fractions (r = 0.86) and volumes (r = 0.94) with values derived from an expert's manual drawings. In a subgroup of 22 patients, automated ejection fractions from transformed images demonstrated better agreement with independent first-pass values (r = 0.90) than did manual measurements derived from original data (r = 0.85). CONCLUSION: Image enhancement algorithms succeeded in providing accurate, reproducible gated SPECT ejection fractions in the most difficult class of patients exhibiting severe hypoperfusion.
Aged↗
[Measurement of the right ventricular ejection fraction during the acute phase of myocardial infarction using 81m krypton infusion. Comparison with the left ejection fraction].
The right ventricular ejection fraction is rarely measured, as conventional diagnostic methods (radiology, echocardiography) are confronted with the problem of representing the right ventricle as a simple tridimensional geometrical model. This is not necessary with the radio-isotopic techniques. However, all those used for the measurement of right ventricular ejection fraction lead to important methodological problems. We have therefore developed a technique of measuring this parameter with an infusion of 81 m Kr. This radioactive gas is pure gamma-ray emitter with a 13 second period. Dissolved and infused intravenously, it is eliminated during the first passage through the lung. The continuous separation of the generator of 81 m Kr is performed with isotonic dextrose solution which is then infused for a period of 7 minutes. During this time, the activity detected by the scintillation camera inclined in the 30 degrees RAO projection is stored, together with the electrocardiogram in a computer. The precordial radioactivity of the retrocardiac lung tissue is subtracted after injection of 74 MBq of 99 mTc microspheres. A graph of right ventricular activity can then be reconstructed and the right ventricular ejection fraction calculated. The left ventricular ejection fraction is then measured with 99 mTc--labelled RBCs. This method allows the right ventricular ejection fraction to be measured in the RAO projection, the best incidence for the separation of the right atrial from the right ventricular activity without interference from left ventricular activity because of the pulmonary elimination of the Krypton radioactivity. The measurement performed on a large number of cardiac cycles allows a continuous study of the right ventricular ejection fraction. At the end of the infusion there is no circulating radioactivity so that the measurement can be repeated. This technique was used in 17 patients with acute myocardial infarction. In the 7 patients with anterior infarcts reduction of the left ventricular ejection fraction was the predominant finding (21,6 +/- 6,8%). The right ventricular ejection fraction was 34,2 +/- 6,4%. On the other hand, patients with a postero-inferior infarction had little change in left ventricular ejection fraction (59,2 +/- 12%) but those with right ventricular extension of their infarcts had very reduced right ventricular ejection fractions (less than 23%). The measurement of right ventricular ejection fraction with 81 m Kr is a reliable atraumatic method for diagnosing right ventricular infarction by the quantification of its functional impairment.
Adult↗
The cardio-renal-anemia syndrome in elderly subjects with heart failure and a normal ejection fraction: a comparison with heart failure and low ejection fraction.
The prevalence and severity of anemia and renal dysfunction in heart failure patients with a normal ejection fraction (HFNEF) is uncharacterized. Two hundred eighty-five consecutive patients admitted to a community hospital with heart failure were stratified by the presence or absence of anemia and a normal or reduced ejection fraction. Comparisons of clinical variables were performed. In this sample, 62% of subjects were anemic, with no difference between those with a normal and a reduced ejection fraction (63% vs. 61%). Anemic HFNEF subjects had a lower glomerular filtration rate (37 +/- 21 mL/min vs. 52 +/- 35 mL/min; p < 0.05) and more severe self-reported symptom scores than nonanemic HFNEF subjects. Multivariate analysis confirmed the association of renal dysfunction and anemia. The authors conclude that the degree and magnitude of anemia in elderly inpatients with heart failure does not differ by ejection fraction. Worse symptoms and more severe renal dysfunction were seen in HFNEF subjects with anemia than in HFNEF subjects without anemia.
Aged↗
Serial left ventricular ejection fraction in acute myocardial infarction by cross-sectional echocardiography: correlation of changing ejection fraction with clinical course.
Left ventricular volume and ejection fraction were measured in 22 survivors of acute myocardial infarction by means of two-dimensional echocardiography and using a Simpson's rule algorithm. Ten of the 22 patients experienced complications. For the group as a whole, there were no significant trends in left ventricular volume and ejection fraction between the first and third days and the third month after infarction. In the subgroups with uncomplicated and complicated infarction, there were trends towards increasing and decreasing ejection fractions, respectively, which failed to attain statistical significance, however. The difference in ejection fraction between both subgroups had become significant at 3 months; 55.2 +/- 11.1% in uncomplicated v. 41.3 +/- 6.9% in complicated cases (P less than 0.01). Individual changes in ejection fraction falling outside the limits of reproducibility of the method as assessed previously were observed between day 1 and day 3 in only 2 patients with uncomplicated and in 2 patients with complicated infarction. Between day 1 and 3 months such changes occurred in 8 patients with uncomplicated infarction (upward in 5 and downward in 3), and in 8 patients with complicated infarcts (upward in 3 and downward in 5). We conclude that changes in ejection fraction as measured by two-dimensional echocardiography tend to correlate with complications.
Aged↗
Comparison of single plane videodensitometry-based right ventricular ejection fraction in right and left anterior oblique views to biplane geometry-based right ventricular ejection fraction.
To evaluate the reliability of the videodensitometric assessment of right ventricular ejection fraction, 38 patients were studied during diagnostic cardiac catheterization. Digital subtraction images of the right ventricle were obtained in both the right anterior oblique and the left anterior oblique views, using direct intraventricular injection of dilute contrast medium. From the end-diastolic and end-systolic images obtained in each view, analysis of the relative brightness values generated a videodensitometry-based right ventricular ejection fraction for both the right and the left anterior oblique views. These values were compared with those generated by applying the geometry-based Simpson's rule to the orthogonal images. Right ventricular ejection fraction ranged from 22 to 88%. Videodensitometric ejection fraction in the right anterior oblique view correlated well with that in the left anterior oblique view (r = 0.88) and each correlated well with geometry-based ejection fraction (r = 0.91 and 0.82, respectively). In a subset of 18 patients without significant cardiac disease, mean videodensitometric right ventricular ejection fraction was 68% (versus 61% in the abnormal subset), and it correlated closely with left ventricular ejection fraction (r = 0.82). Videodensitometric analysis of digital subtraction images provides a reliable method for calculating right ventricular ejection fraction that is independent of geometry and reliably separates normal from abnormal values. Application of videodensitometric techniques should simplify analysis of the response of the right ventricle to different interventions in patients with cardiac disease.
Adult↗
Effect of end-diastolic volume on the canine left ventricular ejection fraction.
Left ventricular ejection fraction is commonly used in the clinical assessment of ventricular function. However, the effect of changes in end-diastolic volume on ejection fraction is controversial. The present study examines the effect of changes in end-diastolic volume on ejection fraction in 26 anesthetized dogs on right heart bypass with controlled hemodynamics. At the end of each experiment, pressure-volume relationships were obtained in the potassium arrested heart following suturing of the mitral valve leaflets and clamping of the aortic root. This technique allowed determination of the end-diastolic volume from the end-diastolic pressure. Ejection fraction is highly dependent on end-diastolic volume and end-diastolic pressure at lower levels of end-diastolic volume and end-diastolic pressure. Ejection fraction increased from 30 +/- 1% (SEM) to 64 +/- 2% (p less than 0.001) when end-diastolic pressure was increased from 4 +/- 0.5 to 11 +/- 0.5 cm H2O. The corresponding end-diastolic volumes were 22 +/- 0.5 and 38 +/- 1 ml, respectively (p less than 0.01). Ejection fraction only increased from 64 +/- 2% to 71 +/- 1% (p less than 0.01) when end-diastolic pressure was increased from 11 +/- 0.5 to 18 +/- 1 cm H2O. The corresponding end-diastolic volumes were 38 +/- 1 and 50 +/- 1 ml (p less than 0.01), respectively. This dependence of ejection fraction on preload is present over a wide range of levels of aortic pressure. Similar directional changes in ejection fraction with preload were present after an adequate autonomic blockade, in the presence of either increased or decreased inotropic state and in the presence of an open or closed pericardium. Thus, the present study demonstrates that ejection fraction can be substantially altered by acute changes in end-diastolic volume. This factor should be taken into account when using ejection fraction for the clinical assessment of ventricular function.
Animals↗
Regional myocardial wall thickening and global ejection fraction in patients with low angiographic left ventricular ejection fraction assessed by visual and quantitative resting ECG-gated 99mTc-tetrofosmin single-photon emission tomography and magnetic resonance imaging.
We investigated the use of visual and quantitative technetium 99m tetrofosmin ECG-gated single-photon emission tomography (SPET) for the assessment of regional myocardial wall thickening (WT) and left ventricular (LV) ejection fraction (EF) in comparison with gated magnetic resonance imaging (MRI) in patients with a low angiographic LVEF. Gated SPET using 99mTc-labelled flow tracers offers potential for simultaneous assessment of myocardial perfusion and LV function. Few data are available on the use of visual and quantitative gated SPET in patients with low LVEF. In this study 21 patients with low angiographic LVEF (mean 37%+/-5%) were studied. Resting gated 99mTc-tetrofosmin SPET and gated MRI were performed within 48 h. WT was assessed by visual interpretation (five point score) and quantitative analysis based on count increase. There was good agreement for EF measurements by MRI and gated SPET (mean EF: 33%+/-12% vs 35%+/-11%, r = 0.86, P<0.001). Areas under receiver operator characteristic curves (AUC) for differentiation between MRI WT score points ranged from 0.60 to 0.66 for visual SPET WT analysis, from 0.59 to 0.71 for delta count increase values and from 0.46 to 0.60 for % WT, indicating substantial overlap between WT categories. Absolute agreement for visual WT between MRI and gated SPET ranged from 25% to 57% (kappa 0.03-0.25) depending on tracer uptake, and was limited in areas with moderate to severe perfusion defects (kappa 0.03-0.13). It is concluded that gated SPET provided reliable estimates of regional WT and global function in patients with low angiographic LVEF.
Coronary Angiography↗