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Variable ejection fraction results were obtained with a cardiac phantom using different computer systems. The problems was traced to the phantom design. A modification produced more reliable results consistent with expected values.
The left ventricular ejection fraction was measured in 60 infants and children with congenital heart disease by both the equilibrium gated radionuclide technique and biplane left ventricular cineangiography. The median age of the patients studied was 2.25 years, and 17 were less than 1 year old. The correlation coefficient for the two sets of measurements was good and did not deteriorate in subgroups under 1 year old and with a large left to right shunt. In those infants with a right to left shunt the correlation was weak. Equilibrium gated radionuclide angiography is a valid and clinically valuable method of measuring left ventricular function in infants and children with congenital heart disease.
Left ventricular ejection fraction (LVEF) determined by first pass radionuclide (Nucl.) and biplane contrast angiocardiography (Angio.) was compared in 62 patients with suspected coronary artery disease under resting conditions and in 32/62 patients during bicycle ergometry at identical work load. At rest both methods correlated with r = 0.81 with similar heart rates in both determinations. The mean value of LVEF (Nucl.) was lower than the mean value of LVEF (Angio.), at 50 +/- 2 (SE) % and 58 +/- 2% respectively (p less than 0.001). During exercise a significant correlation between the two methods was again found (r = 0.76). This time no difference was detected between the mean values for LVEF (50 +/- 3% [Nucl.] vs 48 +/- 2% [Angio.], n.s.), which may be explained by the higher heart rates during the invasive study (123 +/- 5/min [Angio.] vs. 108 +/- 4/min [Nucl.], p less than 0.001), resulting in a higher degree of ischemia and hence a lower LVEF. The interobserver variability did not differ between the two methods.
To assess the reliability of right ventricular ejection fraction (RVEF) during exercise measured by thermodilution technique using a modified Swan-Gantz catheter with a fast-response thermister, we measured RVEF under several conditions in 19 patients with cardiac disease. Measurements were repeated 5 times in each condition, and average RVEF and coefficient of variation (CV) were evaluated. 1) Injectate volume did not affect RVEF and CV. 2) A reduction in RVEF occurred with the thermister moved from proximal portion to distal portion within the pulmonary artery. 3) There were no differences in measurements of RVEF and CV between those during spontaneous breathing and those during apnea. 4) Postural change from supine to sitting decreased RVEF (38 +/- 8 to 35 +/- 9%; p < 0.05) and increased CV (7 +/- 2 to 13 +/- 5%). 5) Exercise increased RVEF (35 +/- 9 to 37 +/- 10%; p < 0.05) but did not change CV (13 +/- 5 vs 13 +/- 5%) compared with rest in the sitting position. 6) Cardiac rhythm (sinus vs atrial fibrillation) did not affect CV. 7) Average value of RVEF and CV during exercise were not different among 3, 4, 5 times repeated measurements. We considered that thermodilution technique for RVEF was applicable to exercise test, and 3 measurements were enough to determine the average value of RVEF during exercise.
Two-dimensional echocardiographic data in orthogonal apical projections were used to calculate left ventricular ejection fraction and volumes in 18 patients, 10 of whom had asynergy. The left ventricular chamber was modeled as a stack of 20 elliptical discs in order to minimize errors associated with assumptions of regular geometry. Calculations were compared to data from biplane angiography and yielded correlation coefficients of 0.91 for ejection fraction and 0.90 for volumes. The technique significantly underestimated volumes; the average ventricular volume was 161 +/- 23 ml from cineangiography and 104 +/- 25 ml from echocardiography (p < 0.001). Since this technique utilizes the most readily obtained echocardiographic views and allows for variations in ventricular architecture, its potential utility in long-term, serial evaluation of cardiac function appears promising.
Two-dimensional echocardiography was used to determine the responses of left ventricular volumes, ejection fraction and segmental left ventricular motion to supine dynamic exercise in 22 professional athletes, comparing these responses with those in 22 age- and gender-matched healthy untrained individuals. End-systolic volume was significantly greater at rest and during exercise in the athletes (50 +/- 6 versus 29 +/- 4 ml and 40 +/- 5 versus 17 +/- 4 ml, respectively, p less than 0.001 for both). It decreased during exercise in all the untrained subjects, but did not change or increased in nine athletes (41%). End-diastolic volume was greater in the athletes at rest (143 +/- 12 versus 98 +/- 9 ml) and during exercise (157 +/- 14 versus 121 +/- 13 ml, p less than 0.01 for both). It increased in all the untrained subjects, but decreased or did not change in six athletes (27%). Ejection fraction was significantly lower in the athletes at rest and during exercise (65 +/- 4% versus 70 +/- 5% and 73 +/- 5% versus 86 +/- 5%, p less than 0.01 and 0.001, respectively); the values augmented normally in all the untrained subjects, but increased only by less than 5% units, did not change or decreased in nine athletes (41%). Eight athletes (36.5%) failed to demonstrate the expected symmetric hyperkinetic wall motion changes during exercise, which were seen in all the untrained subjects. No correlation was found between atypical responses to exercise and electrocardiographic patterns.(ABSTRACT TRUNCATED AT 250 WORDS)
UNLABELLED: The availability of gated SPECT has increased the interest in the determination of volume and ejection fraction of the left ventricle (LV) for clinical diagnosis. However, the same indices for the right ventricle (RV) have been neglected. The objective of this investigation was to use a mathematical model of the anatomical distribution of activity in gated blood-pool imaging to evaluate the accuracy of two ventricular volume and ejection fraction determination methods. In this investigation, measurements from the RV were emphasized. METHODS: The mathematical cardiac torso phantom, developed to study LV myocardium perfusion, was modified to simulate the radioactivity distribution of a 99mTc-gated blood-pool study. Twenty mathematical cardiac torso phantom models of the normal heart with different LV volumes (122.3 +/- 11.0 ml), RV volumes (174.6 +/- 22.3 ml) and stroke volumes (75.7 +/- 3.3 ml) were randomly generated to simulate variations among patients. An analytical three-dimensional projector with attenuation and system response was used to generate SPECT projection sets, after which noise was added. The projections were simulated for 128 equidistant views in a 360 degrees rotation mode. RESULTS: The radius of rotation was varied between 24 and 28 cm to mimic such variation in patient acquisitions. The 180 degrees and 360 degrees projection sets were reconstructed using the filtered backprojection reconstruction algorithm with Butter-worth filtering. Comparison was made with and without application of the iterative Chang attenuation correction algorithm. Volumes were calculated using a modified threshold and edge detection method (hybrid threshold), as well as a count-based method. A simple background correction procedure was used with both methods. CONCLUSION: Results indicate that cardiac functional parameters can be measured with reasonable accuracy using both methods. However, the count-based method had a larger bias than the hybrid threshold method when RV parameters were determined for 180 degrees reconstruction without attenuation correction. This bias improved after attenuation correction. The count-based method also tended to overestimate the end systolic volume slightly. An improved background correction could possibly alleviate this bias.
The inducibility of ventricular tachycardia by programmed stimulation was correlated with ventricular ectopic activity on ambulatory electrocardiogram, ejection fraction and clinical outcome in 36 patients after endocardial resection for medically refractory ventricular tachycardia. Ventricular tachycardia was noninducible postoperatively in 25 patients and was inducible in 11. After administration of antiarrhythmic drugs, ventricular tachycardia could no longer be induced in four patients and remained inducible in the other seven patients. All 36 patients had postoperative and 20 had preoperative ambulatory electrocardiograms obtained while they were not receiving drug therapy. Pre- and postoperative ambulatory electrocardiograms did not differ in mean hourly ventricular premature depolarization frequency, Lown arrhythmia grade or change in grade (pre- vs. postoperative). The majority of postoperative patients had repetitive forms of ventricular arrhythmia postoperatively and there was no difference between patients with inducible and noninducible ventricular tachycardia in regard to Holter monitoring characteristics. There was no significant difference in postoperative ejection fraction between patients with inducible and noninducible ventricular tachycardia postoperatively. Ventricular tachycardia has recurred in 2 of 29 patients who had no inducible tachycardia at the time of hospital discharge and were followed up for a mean of 1 year; it has recurred in one of seven patients in whom it was still inducible at the time of hospital discharge and who were followed up for a mean of 7 months.(ABSTRACT TRUNCATED AT 250 WORDS)
Hemodynamic changes were studied in 14 patients during pneumonectomy using a rapid computerized thermodilution catheter, which is capable of measuring right ventricular ejection fraction (RVEF). Measurements were also performed during perioperative period. Ten minutes after clamping pulmonary artery, RVEF, pulmonary artery resistance index (PVRI) and stroke volume index (SVI) showed an increased right ventricular afterload. The RVEF is a useful and fast responding monitor of right ventricular afterload. It has been suggested that the PVRI may be a reliable safety index to decide the indication of pneumonectomy. We conclude that the right ventricular ejection fraction measured by a rapid computerized thermodilution catheter, can be helpful in hemodynamic monitoring during perioperative period of pneumonectomy.
The relation between accuracy of 3-dimensional echocardiography (3DE) in determining left ventricular end-diastolic volume, end-systolic volume, and ejection fraction (compared with magnetic resonance imaging) and the number of component planes used for 3DE ventricular reconstruction was evaluated in 41 adult subjects with normal (n = 24) and abnormal (n = 17) left ventricles. Accuracy and confidence of 3DE gradually increased with use of additional component planes, so that > or = 10 planes from both parasternal and apical windows provided 3DE reconstructions that accurately predict magnetic resonance imaging-measured left ventricular volumes and ejection fraction with confidence.
The use of quantitative 99Tcm-EHIDA imaging with cholecystokinin and the measurement of gall bladder ejection fraction in a prospective study of 89 patients with right upper quadrant pain is described. Correlation with surgical and histological findings and clinical follow-up suggests that gall bladder ejection fraction < or = 35% is a reliable and accurate indicator of acalculous gall bladder disease.
Gated myocardial single-photon emission tomography (SPET) allows the evaluation of left ventricular ejection fraction (LVEF), but temporal undersampling may lead to systolic truncation and ejection fraction underestimation. The aim of this study was to evaluate the impact of temporal sampling on thallium gated SPET LVEF measurements. Fifty-five consecutive patients (46 men, mean age 62+/-12 years) with a history of myocardial infarction (anterior 31, inferior 24) were studied. All patients underwent equilibrium radionuclide angiography (ERNA) and gated SPET 4 h after a rest injection of 185 MBq (5 mCi) of thallium-201 using either 8-interval (group 1, n=25) or 16-interval gating (group 2, n=30). In group 2, gated SPET acquisitions were automatically resampled to an 8-interval data set. Projection data were reconstructed using filtered back-projection (Butterworth filter, order 5, cut-off 0.20). LVEF was then calculated using commercially available software (QGS). A higher correlation between gated SPET and ERNA was obtained with 16-interval gating (r=0.94) compared with the resampled data set (r=0.84) and 8-interval gating (r=0.71). Bland-Altman plots showed a dramatic improvement in the agreement between gated SPET and ERNA with 16-interval gating (mean difference: -0.10%+/-5%). Using multiple ANOVA, temporal sampling was the only parameter to influence the difference between the two methods. When using 8-interval gating, gated SPET LVEF was overestimated in women and underestimated in men (ERNA minus gated SPET = -4.0%+/-9.6% in women and 3.6%+/-7.6% in men, P=0.01). In conclusion, 16-interval thallium gated SPET offered the best correlation and agreement with ERNA, and should be preferred to 8-interval gated acquisition for LVEF measurement.
This study was designed to validate a modified computer program in evaluating the left ventricular ejection fraction (LVEF) by first pass radionuclide cardioangiography. This program was modified by us from the pulmonary background subtraction method postulated by Gal et al. Another three programs supplied by the computer company were included in the study to compare the accuracy among these program algorithms. From the results of 97 patients undergoing first pass and gated equilibrium cardiac blood pool studies, we found that the measured ejection fractions by these four programs were all correlated well with those by the equilibrium gated cardiac program (r = 0.81-0.86). The latter was already confirmed and verified in a previously published work using a Vanderbilt dynamic cardiac phantom. Except for the LVEF values obtained from our modified program, all values obtained from the other three programs were significantly lower than those obtained by the verified equilibrium program. However, the results obtained from our designed program correlated well with those obtained from the equilibrium method. Furthermore, none of the patient's raw data was rejected by this modified program.
The authors developed and tested a simplified technique for measuring the right ventricular ejection fraction (RVEF). Following in vivo 99mTc red cell labeling, equilibrium (ECG-gated) radionuclide angiocardiography was performed in the modified left-anterior-oblique projection using a 30 degree slant-hold collimator. A single region-of-interest was defined from the ejection fraction image, and background was corrected. In 11 normal patients, the mean RVEF was 0.59 +/- 0.08 (SD). In 20 patients with suspected disease, who had RVEF measured by both equilibrium and first-pass techniques, the correlation between the two methods was excellent (r = 0.95; RVEF [first-pass] = 0.74 RVEF [equilibrium] + 0.03; Sy,x = 0.05). Interobserver correlation was also excellent (r = 0.98; Sy,x = 0.03), as was the correlation between RVEFs measured at least 60 minutes apart (r = 0.98; Sy,x = 0.03). This method was more accurate than alternative techniques, using either a background region-of-interest adjacent to the right ventricle or a fixed right ventricular region-of-interest which included the infundibulum. This simplified technique provides a reproducible method for the sequential quantitative assessment of right ventricular performance.
BACKGROUND: Post-myocardial infarction global ejection fraction and infarct-related artery patency might be expected to be associated with health-related quality-of-life (HRQOL) outcomes, but this association has not been previously shown. The GUSTO-I Angiographic Study cohort 2-year follow-up afforded an examination of such potential relationships. METHODS AND RESULTS: A total of 1848 patients (87.7% response rate) who were enrolled in the GUSTO-I Angiographic Study were contacted for a telephone interview regarding their current HRQOL (physical function, psychological well-being, perceived health status, and social function) 2 years after MI. In multivariable models, left ventricular ejection fraction (EF) was significantly related to physical (P:=0.021) and social (P:=0.014) function, psychological well-being (P:=0.042), and perceived health status (P:=0.024). Infarct-related artery patency was not directly related to any HRQOL outcome. A decreasing EF was predictive of poorer outcomes in each HRQOL dimension. Men consistently had better outcomes in all HRQOL dimension with the exception of perceived health status. Increasing age was predictive of poorer outcomes in all dimensions of HRQOL except for psychological well-being where the inverse occurred; younger patients experienced greater depression, anxiety and worry than their older counterparts. The presence of comorbidities increased the likelihood of worse outcomes in all dimensions. CONCLUSIONS: This is the first study to demonstrate a significant relationship between EF and long-term HRQOL outcomes. This advantage in left ventricular function preservation should be added to the mortality advantage when considering the impact of treatment strategies for myocardial infarction.
UNLABELLED: The aim of the present study was to compare the short- arid long-term clinical results in CAD patients with an initial LV ejection fraction below 35% after coronary stenting and coronary artery bypass grafting (CABG). METHODS AND RESULTS: the study accrued 94 CAD patients with an initial LV ejection fraction below 35%. As dependent on the revascularization techniques performed, the patients were distributed into two groups. The first group comprised patients after intracoronary stenting. The second group included patients who had undergone CABG. Both groups were comparable in terms of the basic clinical criteria. The short-term clinical success of intervention in CS and CABG groups accounted for 97.6% and 97.7% respectively (p>0.05). The hospital lethality was significantly higher in the CABG group than in the CS group and was quoted as 13.7% versus 2.3% (p<0.05). No significant differences in the clinical status were recorded among patients with the clinical success. In the long-term period, the three-year survival in the CS and CABG groups accounted for 73.2% and 79.1% respectively (p>0.05). The incidence of unfavourable clinical events (UCE) in the CABG group was recorded significantly less frequently than in the CS group and constituted 21.9% versus 39% (p<0.05). Complete "freedom" from angina and UCE in the CABG group was recorded significantly more often among CABG group patients versus the CS group: 79.1% versus 60.9% respectively (p<0.05). CONCLUSION: As regards the immediate clinical efficacy both methods of revascularization are not statistically different. However, CABG is associated with a significantly higher hospital lethality. In turn, in the long-term period with the three-year survival in the study groups being statistically comparable), the incidence of UCE is recorded significantly most frequently in the CS group.
Left ventricular ejection fraction (LVEF) can be derived from gated single-photon emission tomographic (SPET) myocardial perfusion studies using either manual or edge detection techniques. In the presence of severe perfusion defects, however, difficulties may be encountered. In this article a method based on the assumption that the average position of the myocardial wall can be localized by means of statistical analysis of the distribution count density, and not on edge detection, is used to measure LVEF. SPET myocardial perfusion images, gated in eight time bins, were recorded in 50 patients 60 min after the injection of 925 MBq technetium-99m tetrofosmin. Masking of non-myocardial structures and thresholding resulted in images in which only myocardial walls had significant non-zero values. The distance of the wall relative to the centre of the cavity was calculated in the three-dimentional space as the first moment of the count rate distribution along radii originating in the centre of the cavity. LVEF was calculated using, for each time bin, the sum of the cube of all distances as an estimate of the cavity volume. The method required minimal operator interventions and was successful in all patients, including those with severe perfusion defects. Intraobserver and interobserver variability was excellent, with regression coefficients of 0.97 and standard deviations of 4.5% and 4.7%, respectively. For 30 patients, the measurements were validated against planar equilibrium radionuclide angiography (ERNA) that was obtained within an interval of 1 week. LVEF ranged from 12% to 88%. Agreement between the two methods was excellent (LVEFERNA=1.05+0.92 LVEFGSPET, r=0.93, P=0.023, SEE=7.06). The Bland-Altman analysis did not show any apparent trend in the differences between ERNA and gated SPET over a wide range of ejection fractions. The standard deviation of the differences was 3. 1%. In addition no relationship was found between the two methods and the severity of perfusion defects. In conclusion, accurate measurements of LVEF are obtained from gated SPET perfusion images using a method based on statistical analysis of the count rate density. This method did not deteriorate even in the presence of severe perfusion defects and could therefore be used in following patients after myocardial infarction.
Seventy-six patients were studied within one week of contrast ventriculography to assess the influence of differing background assignments on ejection fractions derived from gated equilibrium radionuclide anigograms. "Fixed" and "variable" left-ventricular regions on interest and five different backgrounds were used. Inter- and intra-observer variability were determined, and 15 patients underwent a second study 2 weeks later. Variable left-ventricular regions of interest produced higher ejection fractions than fixed ones. A computer-assigned background or a ring drawn manually around the left ventricle correlated best with contrast ventriculography, giving greater serial and inter- and intra-observer variability. Automated background assignments reduced variability and increased reproducibility, though not always associated with the best correlation with contrast ventriculography. Thus a variety of left-ventricular and background regions of interest gives excellent reproducibility and accuracy.