Comparison of radionuclide ventriculography and 2D echocardiography for the measurement of left ventricular ejection fraction following acute myocardial infarction

To compare the measurement of left ventricular ejection fractionobtained by two-dimensional echocardiography and by radionuclideventriculography in patients following acute myocardial infarction,49 consecutive patients with acute myocardial infarction underwentechocardiography and radionuclide ventriculography on the sameday, pre-discharge. Left ventricular ejection fraction was assessedby two blinded observers for each method and reproducibilitywas also assessed for each technique. The limits of agreementfor the differences in ejection fraction (%) between the twomethods was –11.4, 12.2; the mean difference 0.4 was notsignificantly different from zero. The limits of agreement forthe intra- and inter-observer differences in ejection fractionby radionuclide ventriculography were –9.4, 7.6 and –86,11.0, respectively; the mean differences –0.9 and 1.2were not significantly different from zero. The limits of agreementfor the intra- and inter-observer differences by echocardiographywere –5.8, 6.6 and –8.9, 9.5 respectively; the meandifferences 0.4 and 0.3 were not significantly different fromzero. Thus, two-dimensional echocardiography compares well withradionuclide ventriculography for the assessment of ejectionfraction without the disadvantage of radiation.     

The prevalence and prognosis of ventricular dyskinesis after myocardial infarction using radionuclide ventriculography

To assess the prevalence and prognosis of ventricular dyskinesis,radionuclide ventriculography was performed on 100 consecutivepatients just before discharge from hospital following theirfirst myocardial infarction; thereafter follow-up studies wereperformed after one and four months. Dyskinesis of the leftventricle was seen in 25 patients who had sustained transmuralinfarction which was anterior in 19 and inferolateral in six.Clinical examination poorly predicted dyskinesis; 20 patientsexhibited persisting ST segment elevation on the electrocardiogram,but only 10 had radiological cardiomegaly at the time of discharge.Mean left ventricular ejection fraction (LVEF) was significantlyreduced at discharge (0.23 ± 0.07, mean ± 1 S.D)and for the group failed to improve four months after infarction.However, 10 patients remained free from cardiac failure duringfollow-up and could be distinguished by otherwise good leftventricular regional wall movement.     

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.     

Range of normal values for left and right ventricular ejection fraction at rest and during exercise assessed by radionuclide angiocardiography

In order to reach a world-wide consensus on the normal rangeof left (LV) and right ventricular (RV) ejection fraction (EF)at rest and during exercise, pooled data of 1200 normal subjectsfrom 28 leading centres in the field of nuclear cardiology (68%of those contacted) was analysed. Weighted mean normal valuesfor LVEF at rest were 62.3±6.1% (1SD) with a lower limitof normal of 50% and for RVEF 52.3±6.2% (N=365) witha lower limit of normal of 40%. During exercise, LVEF increasedin 475 subjects by +8.0 EF% (range 3–15%), a normal increasebeing accepted to be 5% over a normal resting value for bothLVEF and RVEF. Subgroup analysis of results at rest revealedno significant differences regarding selection of normal subjects(based on normal catheterization findings vs. normal volunteerswith low probability of disease), age or sex. During exercise,however, significantly larger increases in LVEF measurementswere noted for men versus women (P<0.01), for normal volunteersversus subjects selected as ‘normals’ based on anormal coronary angiogram (P<0.001) and for younger versusolder subjects (P<0.001). Data on reproducibility and variabilityshowed that radionuclide angiocardiography can be consideredto be a reliable method today. No consensus was found for measurementsof regional LV function or wall motion mainly because of differencesin methodology used. These normal values may serve as generalguidelines for future applications of these techniques but factorswhich may influence the normal range as defined and discussedin this study should be recognized.     

Sensitivity and specificity of left ventricular ejection fraction by echocardiographic automated border detection: Comparison with radionuclide ventriculography

Background: Echocardiographic automated border detection (ABD) provides on-line, beat-to-beat estimation of left ventricular (LV) ejection fraction (EF). Sensitivity and specificity of using ABD-EF for diagnosing LV dysfunction in routine clinical situations have not been previously studied. Hypothesis: Analysis of ABD-EF data based on receiver operating characteristic (ROC) should provide useful information about sensitivity and specificity for clinical diagnosis of LV function based on ABD-EF. Methods: The study group included 50 consecutive patients with EF measured by both ABD and radionuclide ventriculography (RVG). ABD-EF was recorded for 25 consecutive heart beats in the apical four-chamber view. Data were analyzed statistically by linear regression, Bland-Altman plot, and ROC. In ROC analysis, abnormal LV function was defined RVG-EF ≤ 40%. Results: ABD and RVG showed a moderate correlation in the EF measurements: slope=0.93, intercept=17%, r=0.79 (n = 50). Interbeat variability in ABD was diminished by averaging consecutive beats; standard error of estimate (SEE) decreased from 15.6% without averaging to 12.5% with 25-beat averaging. Bland-Altman analysis indicated that ABD-EF compared unfavorably with RVG-EF, with limits of agreement from -11% to 39%. ABD-EF showed a systematic overestimation (p<0.005), which was compensated by increasing the threshold for abnormal ABD-EF to 56%. With the optimized threshold, ABD-EF provided 89% sensitivity and 89% specificity (85% overall diagnostic accuracy) for diagnosing abnormal LV function. Conclusion: This study explored the limitations of on-line echocardiographic measurement of EF in a clinical setting and provided useful data for assessing interbeat variability, sensitivity, and specificit.     

Determination of right ventricular ejection fraction by thermodilution catheter technique during exercise: a comparison with radionuclide ventriculography

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 (RVEFTD) with alternative methods. However, the reliability of RVEFTD measurements under exercise conditions remains undetermined. Therefore, the aim of the present study was to evaluate RVEFTD with the Gated Blood Pool method (RVEFGBP) under exercise conditions. Twenty patients with different cardiac diseases (coronary artery disease, valvular incompetence, cardiomyopathy) underwent right heart catheterization, including RVEFTD and simultaneous RVEFGBP determination at rest and during supine bicycle exercise. Cardiac index at rest-/exercise was 2.9 +/- 0.8/5.7 +/- 2.2 l/min/m2, mean pulmonary artery pressure was 15 +/- 5/25 +/- 8 mmHg, RVEFTD was 38 +/- 6/41 +/- 11% and RVEFRNV was 39 +/- 6/43 +/- 8%. Linear regression analysis showed a significant correlation between RVEFTD and RVEFGBP at rest (r = 0.72, p < or = 0.0005) and during exercise (r = 0.72, p < or = 0.0005). It is concluded that the Thermodilution Ejection Fraction Catheter is a useful device for reliable, repetitive and safe RVEF measurements, not only at rest but also under exercise conditions. This is clinically important, because RVEF, as a sensitive parameter of primary or secondary right ventricular dysfunction, can be determined in the course of standard right heart catheterization.     

Comparison of left ventricular ejection fraction by magnetic resonance imaging and radionuclide ventriculography in idiopathic dilated cardiomyopathy

To assess the validity of gated magnetic resonance imaging (MRI) in determining left ventricular (LV) ejection fraction (EF), MRI (Spin Echo, multislice-multiphase technique on the short-axis plane) was compared with equilibrium radionuclide ventriculography in 32 patients with idiopathic dilated cardiomyopathy. All patients underwent MRI and radionuclide ventriculography, performed consecutively on the same day (mean time interval between the 2 examinations: 40 minutes). Comparison with LVEF showed a high correlation (y = 0.79 X +3.51, r = 0.91; p less than 0.001). Mean difference between radionuclide ventriculography and MRI data was 1.7, with the 95% confidence interval 0.71 to 2.68: MRI slightly underestimated LVEF. MRI interobserver and intrapatient variability (assessed in 15 of 32 patients) showed a high correlation (r = 0.91, r = 0.98). In conclusion, data suggest that MRI, using the short-axis approach and the multislice-multiphase technique, is an accurate, noninvasive, highly reproducible method of evaluating LVEF in patients with idiopathic dilated cardiomyopathy.     

Site and type of acute myocardial infarct in relation to myocardial infarct size--dynamics of global ejection fraction in acute myocardial infarct

By the ejection fraction global (EFg) statements concerning the remaining function of the myocardium in acute myocardial infarction and thus individually concerning the prognosis (classification of risk groups) become possible. For the valuation of the dynamics of the EFg in a period up to 6 months after an acute myocardial infarction the EFg was multifariously controlled. Only patients with first myocardial infarction in localization on the anterior wall and Q-wave showed a significant dynamics of the EFg between the measurements acute and third week as well as acute and 6th month (absolutely 5.2%). --In re-infarction/Q-wave this could be confirmed also for the localization of the posterior wall in the period acute till third week. For the localization on anterior and posterior wall a dynamics of the EFg could also be calculated for the period acute and 6th month. Thereby the absolute increase of the EFg was between 4.0 and 4.6%. The dynamics of the EFg in the region of the anterior wall was 5.2% for the first infarction and only 4% for the reinfarction. Thus it is below the dynamics of the EFg in an effective thrombolytic therapy.     

Equilibrium radionuclide right ventriculography at rest and during exercise in patients with pulmonary hypertension

Using the method of equilibrium radionuclide ventriculography (RNV), the right ventricular ejection fraction (RVEF) at rest and at a standard workload of 250 kpm per min was determined in 25 control subjects and in 30 patients with pulmonary hypertension (8 patients with chronic obstructive bronchopulmonary disease, 12 with recurrent pulmonary embolism and 10 with pure mitral stenosis). In the same week as RNV, pulmonary artery pressure was registered in patients with pulmonary hypertension at rest and at standard workload. RVEF was significantly higher (45 +/- 5%) in normal subjects than in patients with pulmonary hypertension (33 +/- 5%) and during exercise increased, whereas in patients with pulmonary hypertension it did not markedly change or decreased. The RVEF correlated at rest (r = -0.6293, p less than 0.001) and during exercise (r = 0.6980, p less than 0.05) with the degree of pulmonary hypertension at rest and during exercise. The results show a good correlation between the RVEF and the degree of pulmonary hypertension in patients with pulmonary hypertension at rest and during exercise.     

Use of an exercise QRS score and radionuclide left ventricular ejection fraction in assessing prognosis after myocardial infarction

We have compared the prognostic value of a predischarge post-infarctionQRS score derived at rest and at submaximal exercise with ejectionfraction measured by gated radionuclide left ventriculographyin 65 patients. Seventeen patients died or had heart failure(group 1) and 48 were well or had angina (group 2) six monthsafter infarction. The mean QRS score derived from the restingelectrocardiogram for group I was significantly greater thanthat for group 2 (P<0.01) but the QRS scores at peak exercisedid not differ significantly between the two groups. The meanejection fraction for group 2 was significantly greater thanthat for group 1 (P< 0.001). Both the rest and peak exerciseQRS scores correlated weakly but significantly with ejectionfraction (P<0.001). The QRS score at rest had a greater sensitivityand specificity in predicting cardiac death and heart failurethan the QRS score at peak exercise. A sensitivity of 88% wasachieved with a resting ejection fraction less than 50% anda resting QRS score greater than 4. At these values the specificitieswere 58% and 63% respectively. Combining the blood pressureresponse to exercise with the QRS score and ejection fractionimproved the sensitivity of both with no loss of specificity. Therefore, the resting QRS score is comparable to eject ionfraction as a predictor of serious cardiac events after infarctionand the sensitivity of both may be improved by including anassessment of the blood pressure response to exercise. Becausea 12-lead electrocardiogram is cheap and widely available, thisQRS score may be used in risk stratification after infarction.     

Measurement of left ventricular ejection fraction in myocardial infarction by 2-dimensional echocardiography--comparison with radionuclide angiography

Left ventricular ejection fraction (LVEF) with 4 different algorithms (biplane and single-plane Simpson's rule and ellipsoid area-length method) was measured by 2-dimensional echocardiography (2 DE) in 42 patients with myocardial infarction (MI), and the results were compared with those with equilibrium radionuclide angiography (ERNA). The correlation coefficients were 0.98 for biplane Simpson's rule (apical 4 and 2 chamber view), 0.96 for biplane area-length method (apical 4 and 2 chamber view), 0.81 for single-plane Simpson's rule (apical 4 chamber view), and 0.77 for single-plane area-length method (apical 4 chamber view). The results indicated that biplane method is superior to single-plane method. Biplane area-length method is an alternative simple method for LVEF measurement in patients with MI.     

Course of the radionuclide left ventricular ejection fraction at rest and during exercise in surgically treated asymptomatic chronic aortic insufficiency

In order to preserve left ventricular (LV) function, aortic valve replacement may be contemplated in asymptomatic patients with aortic regurgitation when LV dilatation and dysfunction are not too advanced. Our study involved 10 asymptomatic patients with severe, isolated and pure aortic regurgitation. Before, and 6 months after the operation, the LV ejection fraction (LVEF) was measured at rest and during exercise on an ergometric bicycle by radionuclide angiography (multigated technique). Mean preoperative values were: age 52 +/- 14 years; cardiothoracic ratio 0.55 +/- 0.04; end-diastolic LV diameter 69 +/- 9 mm; end systolic LV diameter 47 +/- 7 mm; LV fibre shortening fraction 0.31 +/- 0.03; LVEF 0.55 +/- 0.10 at rest and 0.41 +/- 0.13 at exercise. After surgery, the cardiothoracic ratio value (0.51 +/- 0.03) and the LVEF value at rest (0.60 +/- 0.07) were not significantly different from the corresponding preoperative values, but the LVEF value during exercise was significantly increased (0.58 +/- 0.11, p less than 0.001). Among the 9 patients who before surgery showed a fall in LVEF at exercise, after surgery 5 had a rise (group B) and 4 had a fall (group A) in LVEF at exercise. Before surgery, group A patients had greater LV diameters than group B patients: end-diastolic diameter 76 +/- 6 mm vs 63 +/- 9 mm; end-systolic diameter 53 +/- 4 mm vs 43 +/- 7 mm (p = 0.07). These diameters were the only variables that predicted the postoperative changes in LVEF at exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Quantitation of right ventricular volumes and ejection fraction by three-dimensional echocardiography in patients: comparison with magnetic resonance imaging and radionuclide ventriculography

Three-dimensional echocardiography (3DE) provides volumetric measurements without geometric assumptions. Volume-rendered 3DE has been shown to be accurate for the measurement of right ventricular (RV) volumes in vitro and in animal studies; however, few data are available regarding its accuracy in patients. This study examined the accuracy of 3DE for quantitation of RV volumes and ejection fraction (EF) in patients, compared to magnetic resonance imaging (MRI) and radionuclide ventriculography (RNV). Twenty patients underwent MRI, gated equilibrium RNV, and 3DE using rotational acquisition from both the transesophageal and transthoracic approaches. RV volumes and EF were calculated from the 3DE data using multislice analysis (true Simpson's rule). RV volumes calculated by MRI (end-diastolic volume (EDV) 109.4 +/- 34.3 mls, end-systolic volume (ESV) 59.6 +/- 31.0 mls, and EF 47.7 +/- 17.1%) agreed closely with 3DE. For transesophageal echocardiography, EDV was 108.1 +/- 29.7 mls (r = 0.86, mean difference 1.3 +/- 17.8 mls); ESV was 62.5 +/- 23.8 mls (r = 0.85, mean difference 2.8 +/- 15.1 mls); and EF was 43.2 +/- 11.7% (r = 0.84, mean difference 4.5 +/- 9.7%). For transthoracic echocardiography, EDV was 107.7 +/- 27.5 mls (r = 0.85, mean difference 1.6 +/- 18.2 mls); ESV was 59.7 +/- 22.1 mls (r = 0.93, mean difference 3.2 +/- 19.6 mls); and EF was 45.2 +/- 11.5% (r = 0.86, mean difference 2.0 +/- 9.4%). There were close correlations, small mean differences and narrow limits of agreement between RNV-derived EF (43.4 +/- 12.1%) and both transesophageal (r = 0.95 mean difference 0.2 +/- 3.7%) and transthoracic 3DE (r = 0.95, mean difference 1.8 +/- 5.4%). Three-dimensional echocardiography is a promising new method of calculating RV volumes and EF, comparing well with MRI and RNV. The accuracy of transthoracic 3DE was comparable to that of the transesophageal approach. Three-dimensional echocardiography has the potential to be useful in the clinical assessment of RV disorders.     

Right ventricular ejection fraction in patients with acute anterior and inferior myocardial infarction assessed by radionuclide angiography

We measured right and left ventricular ejection fracttion (EF) from high frequency time-activity curves obtained during the initial passage of an intravenous bolus of 99mTc (Sn) pyrophosphate. In 22 normal controls right ventricular EF averaged 0.52 +/- 0.04 (SD). In 24 acute anterior or lateral infarction patients right ventricular EF was normal (0.56 +/- 0.10), while left ventricular EF was reduced (0.45 +/- 0.10, P less than 0.001 vs controls). In 19 acute inferior infarction patients left ventricular EF also was depressed (0.51 +/- 0.09, P less than 0.001 vs controls). Among 7 of 19 inferior infarction patients with right ventricular by scintigraphy, right ventricular EF was reduced (0.39 +/- 0.05; P less than 0.001 vs normals; P less than 0.01 vs inferior infarction patients without right ventricular involvement). In the latter group right ventricular EF averaged 0.51 +/- 0.10 (NS vs normals). We conclude 1) a single injection of 99mTc (Sn) pyrophosphate can identify right and left ventricular dysfunction and infarct location in acute myocardial infarction, 2) right ventricular EF is well-preserved except when inferior infarction involves the right ventricle.     

Prediction of mortality in hospital survivors of myocardial infarction. Comparison of predischarge exercise testing and radionuclide ventriculography at rest

The relative merits of resting ejection fraction measured by radionuclide angiography and predischarge exercise stress testing were compared for predicting prognosis in hospital survivors of myocardial infarction. Two hundred and fourteen survivors of myocardial infarction out of 338 consecutive patients with acute myocardial infarction were studied over a 14 month period. Hospital mortality was 13% (45 of 338) whereas 19 additional patients out of 214 died in the subsequent year (9%). High, intermediate, and low risk groups could be identified by left ventricular ejection fraction measurement. Mortality was 33% for nine patients with an ejection fraction less than 20%, 19% for 58 patients with an ejection fraction between 20% and 39%, and 3% for 147 patients with an ejection fraction greater than 40%. Mortality was high (23%) in 47 patients who were unable to perform the stress test because of heart failure (19) or other limitations (28). The patients could be stratified further into intermediate and low risk groups according to the increase in systolic blood pressure during exercise: six deaths occurred in 46 patients with a blood pressure increase of less than 30 mm Hg and two deaths occurred in 121 patients with an increase greater than or equal to 30 mm Hg. Maximum workload, angina, ST changes, and ventricular arrhythmias were less predictive than blood pressure changes. It is concluded that the prognostic value of radionuclide angiography at rest and of symptom limited exercise testing is similar. The latter investigation should be the method of choice since it provides more specific information for patient management.     

Prognostic value of predischarge radionuclide ventriculography at rest and exercise after acute myocardial infarction treated with thrombolytic therapy or primary coronary angioplasty

Background: Previous studies have demonstrated the prognostic value of radionuclide ventriculography at rest and exercise in patients post myocardial infarction (MI). The number of studies in patients treated with modern reperfusion techniques, including thrombolysis or primary angioplasty, however, is limited. Hypothesis: The aim of this study was to evaluate the prognostic significance of predischarge radionuclide ventriculography at rest and exercise in patients with acute MI treated with thrombolysis or primary angioplasty. Methods: A total of 272 consecutive patients with acute MI who were randomized to thrombolysis or primary coronary angioplasty underwent predischarge resting and exercise radionuclide ventriculography. Left ventricular ejection fraction at rest, decrease in ejection fraction during exercise >5 units below the resting value, angina pectoris, ST-segment depression, and exercise test ineligibility were related to subsequent cardiac events (cardiac death, nonfatal reinfarction) during follow-up. Results: During a mean follow-up of 30 ± 10 months, cardiac death occurred in 11 (4%) patients and nonfatal reinfarction in 14 (5%) patients. Resting left ventricular ejection fraction was the major risk factor for cardiac death. In patients with an ejection fraction <40%, cardiac death occurred in 16% compared with 2% in those with an ejection fraction ≥ 40% (p = 0.0004). In addition, cardiac death tended to be higher in patients ineligible than in those eligible for exercise testing (11 vs. 3%, p = 0.08). None of the other exercise variables (decrease in ejection fraction during exercise >5 units below the resting value, angina pectoris or ST-segment depression) were predictive for cardiac death. When all exercise test variables in each patient were combined and expressed as a risk score, a low risk (n = 185) and a higher risk (n = 87) group of patients could be identified, with cardiac death occurring in 1 and 10%, respectively. As the predictive accuracy of a negative test was high, radionuclide ventriculography was of particular value in identifying patients at low risk for cardiac death. Radionuclide ventriculography was not able to predict recurrent nonfatal MI. Conclusion: In patients with MI treated with thrombolysis or primary angioplasty, radionuclide ventriculography may be helpful in identifying patients at low risk for subsequent cardiac death. In this respect, left ventricular ejection fraction at rest was the major determinant. Variables reflecting residual myocardial ischemia were of limited prognostic value. Identification of a large number of patients at low risk allows selective use of medical resources during follow-up in this subgroup and has significant implications for the cost effectiveness of reperfusion therapies.