Left ventricular volume and ejection fraction determined by gated blood pool emission tomography.

Electrocardiogram gated single photon emission computed tomography of the intracardiac blood pools is a recent development that involves the acquisition of images in multiple projections after in vivo erythrocyte labelling with technetium-99m and reconstruction of these images into tomographic sections in any desired plane. The technique was used in 25 subjects to measure left ventricular volume, by summing the areas of the ventricle in each of the tomographic sections, and the results compared with those using a counts based (non-geometric) technique from planar radionuclide ventriculography. Endocardium was defined with the aid of a contour at 43% of maximum left ventricular counts, and this contour was validated for a left ventricular phantom. Correlation between tomographic and counts based left ventricular volume was close. Similarly, ejection fraction correlated well. The technique is therefore an accurate method for determining left ventricular volume and ejection fraction, avoiding the assumptions about shape made by other geometric methods.     

Right ventricular ejection fraction measurement: Contrast ventriculography versus gated blood pool and gated first-pass radionuclide methods

Radionuclide methods of measuring the right ventricular (RV) ejection fraction (EF) provide noninvaslve means of evaluating right-sided cardiac function at rest and exercise. This study compared 2 radionuclide methods with a cast-validated contrast anglographic method of RVEF analysis in 21 consecutive patients who underwent RV contrast ventriculography and gated equilibrium blood pool radionuclide ventriculography. Eleven subjects had gated first-pass radionuclide studies that were technically adequate for EF analysis. RVEF was calculated by different operators for the contrast and radionuclide methods. The close correlation of the contrast angiographic method with both equilibrium blood pool and first-pass radionuclide methods supports the use of the radionuclide techniques.     

Left ventricular volume and ejection fraction determined by gated blood pool emission tomography

Electrocardiogram gated single photon emission computed tomography of the intracardiac blood pools is a recent development that involves the acquisition of images in multiple projections after in vivo erythrocyte labelling with technetium-99m and reconstruction of these images into tomographic sections in any desired plane. The technique was used in 25 subjects to measure left ventricular volume, by summing the areas of the ventricle in each of the tomographic sections, and the results compared with those using a counts based (non-geometric) technique from planar radionuclide ventriculography. Endocardium was defined with the aid of a contour at 43% of maximum left ventricular counts, and this contour was validated for a left ventricular phantom. Correlation between tomographic and counts based left ventricular volume was close. Similarly, ejection fraction correlated well. The technique is therefore an accurate method for determining left ventricular volume and ejection fraction, avoiding the assumptions about shape made by other geometric methods.     

Left ventricular ejection fraction. Physician estimates compared with gated blood pool scan measurements

Gated blood pool scanning (GBPS) is an expensive, frequently used test to assess the left ventricular ejection fraction (LVEF). To determine whether a simpler method of evaluating LVEFs was reliable, we compared the LVEFs derived by GBPS with those estimated in a cardiologist's examination in 125 hospitalized patients. Of the physician estimates, 56% were accurate to within 7.5%, while 17% were underestimates and 27% were overestimates. The variables that were most predictive of reduced LVEF included cardiomegaly and pulmonary venous congestion on chest roentgenogram and S3 gallop, hypotension, and sustained left ventricular apex beat on examination. Prior hypertension was correlated with an increased LVEF. Variables associated with physician error in estimating the LVEF included a history of hypertension, bronchodilator therapy, and right bundle-branch block seen on the electrocardiogram. These data suggest that although qualitatively accurate estimates of the LVEF can sometimes be made on the basis of clinical findings, GBPS should be performed when management decisions hinge on a precise knowledge of this value.     

Quantitative analysis of left ventricular ejection phase by means of left ventricular cineangiography

The left ventricular systolic ejection phase was cineangiographically analyzed in an attempt to evaluate left ventricular performance. Forty-eight patients were classified into five groups: (1) 9 controls; (2) 5 patients with PMD (congestive type) (COCM); (3) 9 patients with PMD hypertrophic type) (HCM), (4) 9 patients with ischemic heart disease (IHD); and (5) 16 patients with mitral stenosis (MS). The rate of volume change (deltaV/deltat) and the volume change as a percentage of stroke volume (deltaV/SV) in patients with COCM and IHD were lower in the early systole and higher in the mid-systole as compared with the control group. Normalized systolic ejection rate (NSER) and velocity of circumferential fiber shortening (Vcf) for the early and late systole were significantly lower in patients with COCM and IHD than in the control group. In two patients with IHD in whom normal indices of left ventricular performance and no asynergy were observed, NSER and Vcf were normal in the late systole but were significantly lower in the early systole. In all 48 patients, deltaV/deltat, deltaV/SV, NSER and Vcf were compared statistically with conventional ejection phase indices and isometric phase indices. delthV/SV for the midstystole showed a negative correlation with EF, MNSER and mVcf. NSER and Vcf for all three phases showed a good correlation with Vmax, max dp/dt and R-max dp/dt but a better correlation with EF, MNSER and mVcf. It was concluded that NSER and Vcf for the early systole were sensitive indices of left ventricular performance and may be utilized to detect subtle depression of left ventricular performance.     

Multiple gated cardiac blood pool imaging for left ventricular ejection fraction: Validation of the technique and assessment of variability

The intrinsic variability and accuracy of left ventricular ejection fraction determined by multiple gated cardiac blood pool imaging was evaluated in 83 patients. Ejection fraction by gated studies correlated well with data from first pass radionuclide angiocardiography (r = 0.94) and from contrast angiography (r = 0.84). Intra- and interobserver variabilities of absolute ejection fraction were minimal (mean ± standard deviation 1.4 ± 1.2 and 1.6 ± 1.5 percent, respectively) and were not different for normal (ejection fraction 55 percent or greater) and abnormal patients. Ejection fraction was determined twice in 70 patients: on the same day at intervals separated by 1 to 2 hours (41 patients) and on 2 different days (29 patients). Ejection fraction ranged from 18 to 91 percent and was normal in 37 patients. There was no difference in mean aerial variabilities of absolute ejection fraction for all repeat studies performed on the same and separate days (3.3 ± 3.1 versus 4.3 ± 3.1 percent (not significantly different). The mean variability of absolute ejection fraction for repeat studies in normal patients was significantly greater than in abnormal patients (5.4 ± 4.4 versus 2.1 ± 2.0 percent, P < 0.01). The incidence rate of absolute interstudy changes of 5 percent or more was significantly higher in normal than in abnormal patients (P < 0.01). This differential variability should be considered in interpreting sequential changes in left ventricular ejection fraction. To be attributed to nonrandom physiologic alterations, the absolute change in ejection fraction should be 10 percent or more in normal patients and 5 percent or more in abnormal patients.     

Lack of agreement between left ventricular volumes and ejection fraction determined by two-dimensional echocardiography and contrast cineangiography in postinfarction patients

OBJECTIVE: To assess the agreement between left ventricular (LV) volumes and ejection fraction (EF) determined by two-dimensional echocardiography (2-D echo) and by cineangiography in postinfarction patients. Design: LV end-diastolic and end-systolic volumes indexed (EDVI and ESVI) to body surface area as well as EF were determined by both methods in all patients. Setting: Multicenter trial conducted in five university hospitals. PATIENTS: 63 patients, 61 male, two female, mean age 55.5 +/- 10.4 years, suffering from a recent myocardial infarction. Eighty-one pairs of measurements were available. METHODS: The results of biplane 2-D echo measures, using apical four-chamber (4C) and two-chamber (2C) views were compared to those of a 30 degrees right anterior oblique cineangiography projection, using either the apical method of discs or the area-length 2-D echo method. Moreover, eyeball EF was estimated at 2-D echo and cineangiography, and was compared to the conventional methods. The agreement between results was assessed by the Bland and Altman method. RESULTS: The agreement between 2-D echo and cineangiography results was poor. Mean differences (MD) were -21.8 (EDVI, ml/m(2)), -9.5 (ESVI, ml/m(2)), and -0.9 (EF, %), respectively for 2-D echo method of discs versus cineangiography, and -23.2, -9.3, and -5.7 for area-length 2-D echo versus cineangiography. For EF (%), MD was -3.6 for eyeball cineangiography versus cineangiography, -1.3 for eyeball 2-D echo versus method of discs, and +0.30 for eyeball 2-D echo versus area-length 2-D echo, respectively. Two-dimensional echo is likely to underestimate LV volumes compared to cineangiography, especially for largest volumes. Even for EF, discrepancies are large, with a lack of agreement of 21%-25% between conventional methods, but agreement is better between eyeball EF and usual methods. CONCLUSIONS: Even with modern echocardiographic devices, agreement between 2-D echo and cineangiography-derived LV volumes and EF remains moderate, and both methods must not be considered interchangeable in clinical practice.     

Evaluation of the ejection fraction using 2 simplified echocardiographic methods in patients with ischemic heart disease and left ventricular asynergy

This study was undertaken to assess the reliability of two simplified echocardiographic methods (Method A and B) in evaluating ejection fraction (E.F.) in patients with left ventricular wall motion abnormalities (WMA). Method A was obtained with a microprocessor that allows the superimposition of a calibrated ellipse to left ventricular end-diastolic and end-systolic silhouettes; the shape of the ellipse was modified to obtain the best superimposition of the ellipse outline to the endocardium. E.F. was then obtained with the formula: VD-VS/VD where VD and VS were the ellipse volumes at end-diastole and end-systole. In method B E.F. was obtained averaging 3 regional E.F. obtained with a longitudinal axis and 3 different transverse diameters. In a group of 40 patients with WMA and excellent 2D echo images the correlation between echocardiographic and angiographic values was r = 0.76 for method A and r = 0.92 for method B. Method B was also tested in a group of 25 consecutive unselected patients with left ventricular WMA; in this group the correlation with angiographic values of E.F. was r = 0.84. In conclusion: in patients with WMA method B must be preferred because it is easier to perform and presents a better correlation with angiographic data than method A.     

Tomographic gated blood pool radionuclide ventriculography: analysis of wall motion and left ventricular volumes in patients with coronary artery disease

The use of planar radionuclide ventriculography to evaluate global and segmental ventricular function is limited by the superimposition of structures in some projections and the gross segmental resolution of the planar technique. Preliminary reports have suggested the feasibility of tomographic gated radionuclide ventriculography with rotating detector systems. This study tested the hypotheses that 1) tomographic radionuclide ventriculography detects segmental dysfunction at rest not identified with multiview planar studies and single plane contrast ventriculography, and 2) ventricular volumes and ejection fraction calculated from these studies provide data similar to those obtained with angiography and planar radionuclide ventriculography. Gated blood pool tomograms were acquired over 180 degrees at 15 frames per cardiac cycle during the initial 90% of the cardiac cycle. Compared with the multiview planar technique tomographic ventriculography showed an increased sensitivity for detecting left ventricular segments with significant coronary artery stenosis (97 versus 74%, p less than 0.025) without any loss in specificity. Compared with both planar radionuclide and contrast ventriculography, tomographic radionuclide ventriculography also detected more noninfarcted left ventricular segments supplied by stenosed coronary arteries (81 versus 39 and 32%, respectively, p less than 0.01). Tomographic radionuclide ventriculographic measurements of left ventricular volumes and ejection fraction showed close correlations with angiographic and planar radionuclide determinations. Gated blood pool tomography is a sensitive method for the evaluation of segmental wall motion and an accurate method for the measurement of global left ventricular volumes and ejection fraction.     

Reproducibility of the angiographic left ventricular ejection fraction in patients with coronary artery disease

Quantitative analysis of the single and repeated cine left ventriculogram was performed in 20 patients with coronary artery disease to determine both the intrinsic variance of individual beats separated by different time intervals and variance between analyses of different observers. In addition, ventriculograms obtained from left ventricular injections of contrast medium prior to coronary arteriography were compared to ventriculograms obtained from either left ventricular or pulmonary artery injections after arteriography. The time period between studies varied from 30 minutes to 90 minutes to four days. Analysis of the same ventriculogram by different observers resulted in an average difference in ejection fraction of 0.05 (pNS). The average difference in ejection fraction was 0.02 between two early beats of the same ventriculogram (pNS). The average difference between sequential ventriculograms was 0.07 (pNS), but individual variations greater than 0.10 were not uncommon, particularly between studies done before and after arteriography, or several days apart. Patients exhibiting wide variance in ejection fractions between two studies either had wide variance in other hemodynamic measurements or degree of asynergy, or both. This study provides a frame of reference for analysis of sequential ventriculograms in patients with coronary artery disease, especially in evaluating changes in the state of the disease or the effects of therapy. It is especially important that: (1) standard hemodynamic measurements be made before ventriculography, (2) the same radiographic techniques repeated whenever possible, and (3) the same person analyze the two ventriculograms.     

Comparison of estimates of left ventricular ejection fraction obtained from gated blood pool imaging,different software packages and cameras

Serial measurement of LVEF using gated blood pool (GBP) imaging is an established technique for monitoring LVEF in patients undergoing chemotherapy with cardiotoxic medication and in patients after heart transplants.11,2 The nuclear medicine department at Groote Schuur Hospital performs up to a thousand GBP studies annually. The majority of these studies are for patients receiving cardiotoxic chemotherapy and have a significant impact on patient management.In our hospital, the radiation oncologists consider not starting cardiotoxic chemotherapy if the LVEF is below 50% and terminating chemotherapy if there is a 10% decrease. In patients who have had heart transplants, the cardiologists start patients on glucocorticosteroids if a patient’s LVEF decreases by10%. It is therefore imperative that serial studies on an individual patient are comparable.Two software systems are used in our nuclear medicine department. The Siemens system (Siemens Medical Solutions, Chicago, USA) was introduced in February 2006 and the Hermes system (Hermes Medical Solutions, Stockholm Sweden) in September 2007. After the introduction of the Hermes system, we found large differences between the LVEFs calculated by the two systems. This was confirmed by a pilot study and is consistent with the literature that different software programs for processing equilibrium gated radionuclide studies cannot be used interchangeably.3-7The department also uses two different cameras, a General Electric (GE) Starcam 400 AC single-head and a Siemens Signature Series e.cam dual-head camera to acquire the raw data. These are then transferred to the Siemens and Hermes processing systems.This study was done to determine how the software packages used for processing GBP studies should be integrated into our department and if the use of different cameras for acquisition influences results. The study had two components. The first examined the values and reproducibility of estimates of LVEF from two software packages using data acquired on the GE gamma camera and processed independently by three operators. The second component examined the values and reproducibility of estimates of LVEF calculated with the same software packages using matched pairs of raw data acquired on both gamma cameras (GE and Siemens) processed by one operator.     

Effects of anger on left ventricular ejection fraction in coronary artery disease.

This study examined the comparative potency of several psychological stressors and exercise in eliciting myocardial ischemia as measured by left ventricular (LV) ejection fraction (EF) changes using radionuclide ventriculography. Twenty-seven subjects underwent both exercise (bicycle) and psychological stressors (mental arithmetic, recall of an incident that elicited anger, giving a short speech defending oneself against a charge of shoplifting) during which EF, blood pressure, heart rate and ST segment were measured. Eighteen subjects had 1-vessel coronary artery disease (CAD), defined by greater than 50% diameter stenosis in 1 artery as assessed by arteriography. Nine subjects served as healthy control subjects. Anger recall reduced EF more than exercise and the other psychological stressors (overall F [3.51] = 2.87, p = .05). Respective changes in EF for the CAD patients were -5% during anger recall, +2% during exercise, 0% during mental arithmetic and 0% during the speech stressor. More patients with CAD had significant reduction in EF (greater than or equal to 7%) during anger (7 of 18) than during exercise (4 of 18). The difference in EF change between patients with CAD and healthy control subjects was significant for both anger (t25 = 2.23, p = 0.04) and exercise (t25 = 2.63, p = 0.01) stressors. In this group of patients with CAD, anger appeared to be a particularly potent psychological stressor.     

Comparison of two different methods for the evaluation of left ventricular ejection fraction in patients with coronary artery disease

The evaluation of left ventricular ejection fraction (LVEF) may be troublesome in difficult clinical settings in patients with coronary artery disease (CAD). The aim of this study was to compare 2 simple geometrical and nongeometrical methods of LVEF evaluation that could overcome the typical technical limitations of ultrasound examination. The authors studied 26 patients with proven CAD (63+/-10 years) who underwent left ventricular (LV) catheterization and coronary angiography during the hospital stay. A complete 2D-Doppler echocardiography was performed and LVEF was evaluated with the formula by Wyatt (W-LVEF), which relates the left ventricle to a biplane ellipsoidal figure, and by the myocardial performance index (MPI) formula (MPI-LVEF), MPI being an index of systodiastolic function. Mean MPI-LVEF was 41+/-8% and was significantly lower with respect to contrast angiography (52+/-14%, p = 0.0003) and to W-LVEF (49+/-13%, p = 0.0009). There was no statistically significant correlation between MPI-LVEF and geometric (either angiographic or ultrasound) LVEF. Bland-Altman analysis showed lack of agreement between MPI-LVEF and any other method evaluated in the study. MPI-LVEF may not be reliable and accurate for the evaluation of systolic function in patients with CAD. Nonetheless, the evaluation of global LV function by means of MPI may represent a valuable and affordable alternative to expensive and time-consuming methods, especially in the presence of difficult technical settings.     

Predictors of right ventricular dysfunction in patients with coronary artery disease and reduced left ventricular ejection fraction

BACKGROUND: The frequency and determinants of right ventricular (RV) dysfunction in patients with coronary artery disease (CAD) and reduced left ventricular (LV) function have not been thoroughly investigated. METHODS: The study population consists of 80 consecutive patients, invasively evaluated at our centre. Entry criteria were: LV ejection fraction < 45%; angiographic evidence of obstructive CAD; disease history of more than 3 months' duration. Exclusion criteria were: recent myocardial infarction and unstable angina. All patients underwent cardiac catheterization with coronary, LV and RV angiography. RV dysfunction was defined as a RV ejection fraction < 35%, which corresponds to the mean-three standard deviations of controls. RESULTS: Sixty-five patients (81%) had multi-vessel disease and 57 (71%) had a previous myocardial infarction. Mean LV ejection fraction was 31 +/- 8%. Mean RV ejection fraction was 46 +/- 11%. Right ventricular dysfunction was present in 14 patients (18%). An occluded proximal right coronary artery was associated with significantly lower RV ejection fraction (38 +/- 12% versus 47 +/- 10%; P = 0.009) but not LV ejection fraction (30 +/- 8% versus 32 +/- 9%; P = 0.444). However, at multivariate analysis, only pulmonary hypertension was an independent significant predictor of RV dysfunction (P < 0.001; OR: 1.13; CI: 1.06 -1.22). CONCLUSION: Right ventricular dysfunction in patients with chronic ischaemic LV dysfunction is detected in less than 20% of cases. Proximal right coronary artery occlusion is associated with a reduced RV ejection fraction. However, the role of right coronary artery disease is overwhelmed by the haemodynamic burden of pulmonary hypertension, which represents the only independent predictor of RV dysfunction in our population.     

Tei指数评价左心室射血分数正常的尿毒症患者的左心室功能

目的利用Tei指数评价左心室射血分数（left ventricular ejection fraction, LVEF）正常的尿毒症患者的左心功能,以了解其临床应用价值。方法选取80例LVEF正常的尿毒症患者设为尿毒症组,50名健康人设为对照组,使用Vivid7pro对两组进行检测。检测左心房内径（LAD）、左心室舒张期末内径（LVDd）、左心室收缩期末末内径（LVDs）、室间隔（IVS）及左心室后壁厚度（LVPW）、LVEF、左心室短轴缩短率（LVFS）、二尖瓣血流频谱E峰及A峰、E／A比值、左心室等容收缩时间（ICT）及等容舒张时间（IRT）、主动脉射血时间（ET）,并计算左心室Tei指数。结果尿毒症组左心房内径、左心室舒张期末内径、左心室收缩期末内径、室间隔、左心室后壁厚度均较对照组增大,差异有统计学意义（P均〈O．01）。尿毒症组的二尖瓣血流频谱E峰及A峰较对照组明显增大（P均〈0．05）、左心室等容舒张时间比对照组延长（P〈0．01）、主动脉射血时间比对照组缩短（P〈0．01）、Tei指数比对照组明显延长（0．50±0．18眠0．33±0．12,P〈0．叭）,差异有统计学意义;尿毒症组E／A比值、左心室等容收缩时间、LVEF及左心室短轴缩短率与对照组比较,差异无统计学意义（P均〉0．05）。结论测量Tei指数能比单纯LVEF更好地评价尿毒症患者的左心功能,而且方便、快捷、有效。     

Comparative evaluation of thermodilution and gated blood pool method for determination of right ventricular ejection fraction at rest and during exercise

BACKGROUND: Since the development of a Swan-Ganz thermodilution ejection fraction catheter several studies have been published which compare this technique for obtaining right ventricular ejection fraction (RVEF(TD)) with alternative methods. However, the reliability of RVEF(TD) measurements under exercise conditions remains undetermined. Therefore, the aim of the present study was a comparative evaluation of RVEF(TD) with the established gated blood pool method (RVEF(GBP)) under exercise conditions. METHODS AND RESULTS: Twenty-two patients with different cardiac diseases underwent right heart catheterization, including RVEF(TD) and simultaneous RVEF(GBP) determination at rest and during supine bicycle exercise. Linear regression analysis showed a significant correlation between RVEF(TD) and RVEF(GBP) at rest (r = 0.73, p < or = 0.0005) and during exercise (r = 0.74, p < or = 0.0005). A Wilcoxon analysis showed a high probability of agreement of RVEF(TD) and RVEF(GBP) at rest and exercise (level of significance for error of the 0 hypothesis of 95.9/73.3%). CONCLUSION: The thermodilution ejection fraction catheter provides a useful device for reliable, repetitive and safe RVEF measurements, not only at rest but also under exercise conditions. This seems to be clinically important, because by it means RVEF, as a sensitive parameter of primary or secondary right ventricular dysfunction, can be determined in the course of standard right heart catheterization.