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PubMed1978

Assessment of cardiac performance with quantitative radionuclide angiocardiography: right ventricular ejection fraction with reference to findings in chronic obstructive pulmonary disease.

A reproducible noninvasive technique for measuring righ ventricular ejection fraction was developed using first pass quantitative radionuclide angiocardiography. Studies were obtained in the anterior position with a computerized multicrystal scintillation camera with high count rate capabilities. Right ventricular ejection fraction was calculated on a beat to beat basis from the high frequency components of the background-corrected right ventricular time-activity curve. In 50 normal adults, right ventricular ejection fraction averaged 55 percent (range of 45 to 65 percent). This radionuclide measure of right ventricular function was reproducible, with minimal inter- and intraobserver variability, and was sensitive to changes in inotropic state induced with isoproterenol. In 36 patients with chronic obstructive pulmonary disease, right ventricular ejection fraction ranged from 19 to 71 percent. All 10 patients with corpulmonale, as well as 9 additional patients, had an abnormal right ventricular ejection fraction. Arterial oxygen tension and forced expiratory volume were depressed significantly more in patients with abnormal right ventricular ejection fraction than in subjects with normal right ventricular function. There was no relation between abnormalities in right and left ventricular ejection fraction.

Adult↗
PubMed1994

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 fraction obtained by two-dimensional echocardiography and by radionuclide ventriculography in patients following acute myocardial infarction, 49 consecutive patients with acute myocardial infarction underwent echocardiography and radionuclide ventriculography on the same day, pre-discharge. Left ventricular ejection fraction was assessed by two blinded observers for each method and reproducibility was also assessed for each technique. The limits of agreement for the differences in ejection fraction (%) between the two methods was--11.4, 12.2; the mean difference 0.4 was not significantly different from zero. The limits of agreement for the intra- and inter-observer differences in ejection fraction by radionuclide ventriculography were--9.4, 7.6 and -8.6, 11.0, respectively; the mean differences--0.9 and 1.2 were not significantly different from zero. The limits of agreement for the intra- and inter-observer differences by echocardiography were--5.8, 6.6 and--8.9, 9.5 respectively; the mean differences 0.4 and 0.3 were not significantly different from zero. Thus, two-dimensional echocardiography compares well with radionuclide ventriculography for the assessment of ejection fraction without the disadvantage of radiation.

Adult↗
PubMed1980

Left ventricular ejection fraction changes during recovery from treadmill exercise: a preliminary report of a new method for detecting coronary artery disease.

To test the value of combining treadmill exercise with radionuclide angiography for detecting exercise-induced left ventricular dysfunction, ejection fractions were calculated at rest, peak supine bicycle exercise, and during three supine post-treadmill recovery periods (2-4 min, recovery 1;4-6 min, recovery 2;8-10 min, recovery 3) in ten coronary artery disease patients and eight normal subjects. Both the normal subjects and coronary artery disease patients had normal resting ejection fractions (greater than 0.50). In the normal subjects the mean ejection fraction increased significantly (p less than 0.005) from rest (0.61 +/- 0.03) to peak supine bicycle exercise (0.71 +/- 0.04), and the mean ejection fraction also remained significantly higher (p less than 0.005) at rest than during 10 min post-treadmill exercise. However, the coronary artery disease patients did not significantly change the mean ejection fractions from rest (0.59 +/- 0.06) to peak supine bicycle exercise (0.55 +/- 0.08), and the average ejection fraction during each one of the post-treadmill recovery periods was not significantly different from rest. At the third recovery period all the normals but no coronary artery disease patients had higher ejection fraction than the resting ejection fraction. We thus conclude that the magnitude of change in ejection fraction from rest to 8-10 min post-treadmill exercise in patients with normal resting ejection fraction may be helpful in identifying those with coronary disease.

Angiocardiography↗
PubMed1988

The reliability of measuring left ventricular ejection fraction by radionuclide cardiography: evaluation by the method of variance components.

A statistical model based on the method of variance components was applied to obtain confidence statements for single and repeat determinations of left ventricular ejection fraction by radionuclide techniques. With this approach variance caused by individual factors in the measurement procedure is estimated to allow calculation of confidence intervals based on single measurements and the detection limits for changes. Six study groups made up of a total of 143 subjects were examined by both multigated equilibrium and first pass imaging. Under favourable conditions (with an updated gamma camera and experienced observer) the 95% confidence interval with a single measurement of left ventricular ejection fraction by equilibrium imaging was +/- 3 ejection fraction units, compared with +/- 6 units with the first pass technique (one ejection fraction unit = 1/100 of the possible values from 0.00 to 1.00). The minimal significant changes (at the 5% level) in measured equilibrium left ventricular ejection fraction at intervals of 15 min, 3 days, 1, 3, and 4 weeks were +/- 4, +/- 4, +/- 5, +/- 5, and +/- 6 units, respectively. The corresponding minimal detectable changes in a subject's "true" left ventricular ejection fraction for the same intervals were +/- 7, +/- 7, +/- 10, +/- 10, and +/- 12 units respectively. With first pass imaging, only average values for the variation at repeat determination could be calculated. The minimal significant change in measured first pass left ventricular ejection fraction was +/- 7 units, and the minimal detectable change in "true" left ventricular ejection fraction was +/- 14 units. Measurements of left ventricular ejection fraction by equilibrium technique were generally more reproducible than first pass determinations because the variability caused by study acquisition, observer analysis, and residual errors was smaller. The method of variance components appears to be well suited to the evaluation of quantitative biological measurements in clinical use. The popularity of established procedures may obscure the lack of basic information about method evaluation.

Adult↗
PubMed1996

[Measurement of ejection fraction after acute myocardial infarction. A comparison of measurements by means of radionuclide technique one week and 8 weeks after the infarction].

Left ventricular ejection fraction was measured in 54 patients by means of radionuclide technique at one week after, and again at eight after acute myocardial infarction that had been treated with streptokinase. In 17 patients (31%) ejection fraction increased and in 15 patients (28%) it decreased > or = 5 ejection fraction units. In 22 patients (41%) ejection fraction remained unchanged. No obvious difference were found between the three groups as regards infarct localization, infarction size (enzyme activity), or level of first ejection fraction measurement. There was a statistically significant (p < 0.05) longer delay from start of chest pain until treatment was started among the patients with increased ejection fraction than among the patients with decreased ejection fraction.

Aged↗
PubMed1995

Do radionuclide and echocardiographic techniques give a universal cut off value for left ventricular ejection fraction that can be used to select patients for treatment with ACE inhibitors after myocardial infarction?

OBJECTIVE: To determine whether echocardiography and radionuclide angiography give comparable results when the left ventricular ejection fraction is measured early after myocardial infarction and thus whether, irrespective of the method used, a single value for the ejection fraction could be used as a guide for starting treatment with an angiotensin converting enzyme inhibitor. DESIGN: Prospective comparison of measurement of left ventricular ejection fraction by echocardiography and radionuclide angiography. SETTING: Coronary care units of two university teaching hospitals in Glasgow. PATIENTS: 99 patients studied within 36 hours of acute myocardial infarction. OUTCOME MEASURES: Left ventricular ejection fraction assessed by echocardiography and radionuclide angiography. RESULTS: 70 (77%) of the 99 patients had ejection fraction measured by both echocardiographic and radionuclide techniques, 30 in centre 1 and 40 in centre 2. In centre 1 the mean difference (SD) in ejection fraction (radionuclide angiography--echocardiography) was -8 (10%); 95% CI -12 to -4%. In centre 2 the mean difference was -14 (11%); 95% CI -17 to -11%. If patients had been treated with an ACE inhibitor on the basis of a radionuclide ejection fraction of < 40% then 93% in centre 1 (28 of 30) and 98% in centre 2 (39 of 40) would have been treated. This compares with 63% (19 of 30) and 50% (20 of 40), respectively if echocardiography had been used as a guide. CONCLUSION: Measurement of ejection fraction is highly dependent on the method used and it is therefore impossible to quote a universally applicable figure for left ventricular ejection fraction below which an ACE inhibitor should be used after myocardial infarction.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Magnetic resonance imaging of the heart for determination of ejection fraction.

In 28 patients with various cardiac diseases we compared ejection fractions obtained by magnetic resonance imaging in a single oblique slice with monoplane ventriculography in the right anterior oblique projection, the latter serving as the standard. Also, results were evaluated for clinical relevance and relation to image quality. The correlation between the two techniques was moderate (r = 0.65). According to our standardized limits for clinical relevance, insufficiently correlating ejection fractions were obtained in 14 patients. In 8 of these patients this was attributed to poor endocardial edge detection. Edge detection problems were more frequently encountered by imaging with echo-time 20 msec than with echo-time 32 msec. Other causes for mismatching of the obtained ejection fractions are discussed. It is concluded that determination of ejection fraction by single slice magnetic resonance imaging should not be used for clinical application. Improvement can be expected by using a contiguous slicing technique, a longer echo-time in the spin-echo pulse sequence, or in due course by application of newly developed fast-imaging pulse sequences.

Cardiomyopathy, Hypertrophic↗
PubMed1993

Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction.

OBJECTIVES: We tested the hypotheses that left ventricular chamber elastance would detect impaired contractile function in patients with long-term mitral regurgitation and a normal ejection fraction and that these patients would have unique temporal left ventricular size and ejection fraction responses to mitral valve surgery. BACKGROUND: Although it has been suggested that left ventricular contractile function may begin deteriorating in patients with long-term mitral regurgitation whereas ejection fraction remains normal, no data exist in humans. METHODS: We studied 11 control patients and 28 patients with long-term mitral regurgitation using micromanometer-measured pressures, biplane contrast cineventriculography and radionuclide angiography under control conditions and with alterations in load during right atrial pacing to calculate left ventricular chamber elastance and myocardial stiffness. RESULTS: The patients with mitral regurgitation were classified into subgroups: Group I, normal contractile function; Group II, impaired contractile function (reduced Emax) but normal ejection fraction, and Group III, impaired contractile function (reduced Emax) with reduced systolic myocardial stiffness. Twenty-two of the patients with mitral regurgitation underwent mitral valve surgery. In Group I, comparable decreases in left ventricular volume indexes (p < 0.01 and p = 0.05, respectively) were associated with no change in ejection fraction at 3 months and 1 year. In contrast, in Group II, reductions in volume indexes (p < 0.0001 and p < 0.001) were associated with a short-term decrease in ejection fraction (p < 0.001) that recovered at 1 year (p < 0.01 vs. short-term). Finally, in Group III, variable responses in volume indexes were associated with a consistent decrease in ejection fraction at 3 months and 1 year. CONCLUSIONS: An analysis of left ventricular chamber elastance provides data to support the concepts that 1) contractile function is impaired in some patients with long-term mitral regurgitation and a normal ejection fraction, 2) impaired contractile function may not be irreversible in all of these patients, and 3) an earlier consideration of mitral valve surgery may be warranted to preserve contractile function in these patients.

Adult↗
PubMed2006

Aortic valve replacement in true severe aortic stenosis with low gradient and low ejection fraction.

OBJECTIVE: The results of aortic valve replacement are uncertain among patients with severe aortic stenosis, reduced left ventricular ejection fraction, and low mean transvalvular gradient. The aim of the present study was to report on 27 patients who underwent surgery for aortic stenosis with left ventricular ejection fraction <or=30% and mean transvalvular gradient <30 mmHg. METHODS: The study was performed between January 2000 and December 2005. Twenty-seven patients with aortic stenosis with a calculated valve area <1.0 cm2, aortic mean transvalvular gradient <30 mmHg, and ejection fraction <or=30% were studied. Exclusion criteria were coronary artery disease, concomitant valvular operation, previous aortic valve replacement, or more than moderate aortic valve regurgitation. Preoperative clinical, echocardiography and dobutamine echocardiography, cardiac catheterization and coronary angiography, and operative data were recorded in all patients. Patients who were diagnosed with true aortic stenosis were divided into 2 groups according to left ventricular ejection fraction changes during dobutamine echocardiography, 16 with recruitable myocardium (group 1) versus 11 without (group 2). RESULTS: One patient from group 2 died. The functional capacities of all of the patients in group 1 significantly improved in the postoperative period (P = .001). All of the patients except for 1 in group 1 had improved left ventricular ejection fraction after the operation (P <.001). The comparison of the preoperative and postoperative functional status of these patients in group 2 was also statistically significant (P = .001). The 10 of the 11 patients in group 2 who were alive had left ventricular ejection fraction value changes that were not significant statistically (P = .096). The comparison of the improvement of functional capacities of the groups revealed a significant difference; that is, the improvement was higher in group 1 (P = .039). CONCLUSION: Left ventricular ejection fraction and functional capacity improved after aortic valve replacement in patients with left ventricular dysfunction, low mean transvalvular gradient, and aortic valve replacement in these patients has acceptable mortality rates with significantly improved functional status.

Aortic Valve Stenosis↗
PubMed1984

A comparison of cardiac biopsy grades and ejection fraction estimations in patients receiving Adriamycin.

One hundred fifty-eight patients receiving Adriamycin underwent 226 transjugular biopsy procedures. The specimens were evaluated by electron microscopy for evidence of drug-related cardiotoxicity. Ejection fraction determinations using echocardiographic or nuclear techniques at rest were available for 69% and 81% of the patients, respectively. Analysis of the data revealed a correlation between cumulative Adriamycin dose and biopsy grade (p less than 0.02). No similar relationship existed between cumulative Adriamycin dose and ejection fractions obtained at rest or between biopsy grades and ejection fractions. In patients who underwent serial endomyocardial biopsies and serial ejection fraction determinations, the correlation between changes in biopsy grade and ejection fraction was poor. A change in resting ejection fraction detected by either method did not reliably predict a change in biopsy grade. The poor correlation between ejection fractions and biopsy grades could be due in part to the sensitivity and specificity of the Adriamycin-related structural changes in contrast to the wider range of disease processes that can affect myocardial function, and to the fact that structural changes often precede the ejection fraction abnormalities. The greater sensitivity and specificity of the biopsy grade should prove useful in reducing the risks associated with evaluating new anthracyclines and potential myocardial protectors of Adriamycin toxicity.

Biopsy↗
PubMed1985

Prognostic significance of left ventricular ejection fraction after acute myocardial infarction. A bedside radionuclide study.

The prognostic significance of left ventricular ejection fraction measurements obtained at the bedside was assessed in 171 patients as soon as possible after acute myocardial infarction. Ejection fraction was measured with a radionuclide first pass portable probe method within a mean of 24 hours of the onset of major symptoms. The results were related prospectively to the subsequent incidence of ventricular fibrillation in hospital, and to hospital and postdischarge deaths in a mean follow up period of 15 (range 9-21) months. All eight episodes of primary ventricular fibrillation, all 12 deaths due to pump failure in hospital, and also 12 out of 13 postdischarge deaths occurred in that minority of 81 patients whose initial postinfarction left ventricular ejection fraction was less than 0.35. Multivariate correlation with clinical, enzymatic, and electrocardiographic indicators of myocardial infarction showed that the prognostic significance of these indicators could largely be explained by their association with low left ventricular ejection fractions. Left ventricular ejection fraction measured within the initial 24 hours after acute myocardial infarction predicts prognosis throughout the subsequent year.

Adult↗
PubMed1994

Improved densitometric measurement of left ventricular ejection fraction using dual-energy digital subtraction angiography.

The effects of misregistration artifacts and background corrections on the densitometric measurement of left ventricular ejection fraction (EF) from digital subtraction angiography (DSA) images were studied in 20 patients. Densitometric ejection fraction measurements were performed on both conventional time subtraction images and on dual-energy subtraction images. Dual-energy subtraction is not sensitive to the motion induced artifacts which often mar time subtraction images. While the time subtraction images had varying degrees of misregistration artifacts, none of the dual-energy studies contained significant misregistration artifacts. Densitometrically determined ejection fractions measured with and without correction for background signals were compared. Poor agreement between time subtraction ejection fractions determined with and without background correction (EFNO-BKG = 0.88 EFBKG - 6.0%, SEE = 8.1%, r = 0.83) demonstrated the sensitivity of time subtraction EFs to the performance of a background correction procedure. Conversely, densitometric measurement of ejection fraction using dual-energy subtraction was significantly less sensitive to the performance of a background correction (EFNO-BKG = 0.99 EFBKG - 5.3%, SEE = 4.3%, r = 0.96). Since background correction requires accurate definition of ventricular borders, but motion artifacts often preclude accurate border definition, it is concluded that dual-energy subtraction is a significantly more robust method for measuring left ventricular ejection fraction using densitometry. It is further concluded that identification of the systolic endocardial border is not required when performing densitometric EF measurements on dual-energy images. Drawing of the end-diastolic border alone is sufficient to produce an accurate ejection fraction measurement.

Adult↗
PubMed1985

Association between the exercise ejection fraction response and systolic wall stress in patients with chronic aortic insufficiency.

We studied the exercise ejection fraction response in 56 patients with chronic aortic insufficiency. All had left ventricular dilatation but preserved resting ejection fraction and minimal or no symptoms. The exercise ejection fraction increased by 0.05 units or greater in 18 (32%) patients (group I), remained within 0.05 units of the resting value in 18 (32%) patients (group II), and fell by 0.05 units or greater in 20 (36%) patients (group III). There were no significant differences among the groups in left ventricular end-diastolic dimension, end-systolic dimension, or fractional shortening by echocardiography or in resting left ventricular volumes and ejection fraction by radionuclide angiography. Left ventricular end-systolic wall stress was significantly higher in group III than in either group I or group II (89 +/- 20 vs 70 +/- 18 and 69 +/- 17 X 10(3) dyne/cm2; p less than .005). At peak exercise there were no differences among groups in systolic blood pressure. However, end-systolic volume increased from 65 +/- 28 to 77 +/- 36 ml/m2 in group III and fell from 50 +/- 21 to 28 +/- 18 ml/m2 in group I during exercise. Thus, at peak exercise end-systolic volume was nearly three times greater in group III than in group I. Although stress could not be determined directly during exercise, the directional changes in its determinants suggest that it also would have been higher in group III patients. A highly significant inverse correlation was present between the ejection fraction response and the change in end-systolic volume (r = -.87, p less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2005

Assessment of left ventricular ejection fraction by four different methods using 99mTc tetrofosmin gated SPECT in patients with small hearts: correlation with gated blood pool.

AIM: To compare the currently available gated SPECT software programs, quantitative gated SPECT (QGS), Emory Cardiac Toolbox (ECTb), Left Ventricular Global Thickening Fraction (LVGTF), and the recently developed Layer of Maximum Count (LMC) method with equilibrium Gated Blood Pool (GBP) scintigraphy in calculating the ejection fraction in patients with small hearts. METHODS: Twenty patients with small hearts (end diastolic volume <85 ml) were collected for the study. Gated myocardial perfusion SPECT and planar GBP were performed for all patients. The four methods QGS, ECTb, and LVGTF and LMC were used for volumes estimation and ejection fraction calculation. RESULTS: ANOVA analysis revealed significant differences among the methods in ejection fraction estimation (P<0.0001). The mean ejection fraction by GBP was significantly overestimated by QGS and ECTb and LVGTF (P<0.0001, P<0.0001 and P=0.006, respectively). The mean ejection fraction by GBP was not significantly different from that by the LMC method (P=0.213). Ejection fraction measurements by QGS and ECTb yielded moderate correlation with GBP values (r=0.588, P=0.006; and r=0.564, P=0.010, respectively). The ejection fraction by the LMC method was marginally correlated but LVGTF showed a non-significant correlation with GBP (r=0.438, P=0.053; and r=0.155, P=0.515, respectively). Agreement analysis for ejection fraction estimation by QGS and ECTb demonstrated a non-significant correlation between the difference and the mean. The LMC method showed a non-significant trend to decrease the difference with GBP as the mean increased. However, the LVGTF method significantly increased the difference as the mean increased. CONCLUSION: The currently available gated SPECT methods have moderate to poor correlations in addition to wide agreement limits with gated blood pool studies in patients with small hearts. Improvement of these methods to achieve better results in such patients is recommended. The newly developed LMC method yielded better results in the group with small hearts but with low interchangeability with GBP studies.

Female↗
PubMed1998

Estimation of Left Ventricular Ejection Fraction by Semiautomated Edge Detection.

Left ventricular (LV) volume and ejection fraction estimation from two-dimensional echocardiograms requires off-line analysis and time-consuming manual tracing. LV volumes may be estimated on-line with a semiautomated edge detection echocardiographic system [also known as acoustic quantification (AQ)], but there are few data that compare volumes obtained from the AQ method with volumes derived from off-line manual tracing of conventional two-dimensional echocardiograms. Echocardiograms were performed in 48 patients at two medical centers. LV volumes were measured from the apical view with the method of discs and area-length formulae and from the parasternal short-axis view with the modified ellipsoid model. Based on the criterion of >/=75% endocardial visualization, 25 (52%) of the short-axis views and 14 (29%) of the apical views were analyzed by a single investigator. End-diastolic and end-systolic LV volumes derived on line with the AQ system showed a very strong linear association with off-line, manually traced volumes (r = 0.96-0.99). Correlations for ejection fraction also were strong (r = 0.90-0.96). End-diastolic and end-systolic LV volumes, measured from the apical views, were underestimated by the AQ method. However, because the error was in the same direction, ejection fractions measured with the AQ system and by manual tracing of conventional echocardiograms were similar. Estimation of ejection fraction using a semiautomated edge detection echocardiographic system is a promising method for noninvasive evaluation of systolic function in carefully selected patients.

Journal Article↗
PubMed1986

Determination of left ventricular ejection fraction using ultrafast computed tomography.

We evaluated ultrafast CT as a method to measure left ventricular ejection fraction in 16 adults with congenital or acquired heart disease who underwent cardiac catheterization. CT scanning of the left ventricle was performed at 4 to 12 adjacent 1 cm levels (depending on heart size) at 50 msec/scan for one cardiac cycle, with the table positioned with an axial tilt of 10 to 20 degrees and a lateral slew of 5 to 10 degrees to best approximate the long axis of the left ventricle. Image enhancement was achieved by an injection of 25 ml of Renografin-76 via a peripheral vein, with scanning timed to coincide with maximal enhancement of the left ventricular cavity. Ejection fraction was computed by measuring the percent change in area of the left ventricle from diastole (largest area) to systole (smallest area) in a single slice at the mid-left ventricular level. Mean ejection fraction for the group was 58.1 +/- 15.1% (range 24% to 84%). The ejection fraction from left ventriculography, computed from biplane images using the Dodge (area-length) formula, was 59.6 +/- 12.3% (range 28% to 77%). There was an excellent correlation between left ventricular ejection fraction by CT and ventriculography (r = 0.91, y = 1.1x - 8.5, p less than 0.001). This study demonstrates that ultrafast CT can provide an accurate measure of left ventricular ejection fraction by simple methodology.

Adult↗
PubMed1979

Profiles of radionuclide left ventricular ejection fraction changes induced by supine bicycle exercise in normals and patients with coronary heart disease.

This paper presents the profiles of left ventricular ejection fraction (EF) during and following supine bicycle exercise in normal subjects and in patients with coronary heart disease, as well as the relationship of the described patterns to clinical parameters. Twenty normal men and 40 patients with coronary artery disease were studied using gated equilibrium radionuclide angiography (EQ-EF). In the normals, during exercise, EF increased by a mean of 25% of the resting value, with an increase of no less than 11%. The exercise-limiting symptom in patients with coronary artery disease was angina pectoris in 20 and fatique in the other 20 patients. In the angina patients, there was a mean decrease in EF of 20%, and in the other coronary artery disease patients ejection fraction change little. Only two patients with coronary artery disease increased from a normal resting value to peak exercise by more than 11%, and they had isolated right coronary lesions. An "overshoot" elevation of ejection fraction above resting levels was demonstrated following termination of exercise in most patients. The patients with a significant fall in exercise ejection fraction more frequently had abnormal exercise-induced ECG changes as well as abnormal left ventriculograms and more severe coronary artery disease at cardiac catheterization than the patients with little change in ejection fraction. We conclude that 1) normals could be separated from most patients with significant coronary artery disease in this study population; 2) ejection fraction must be measured at maximal exercise for it to have diagnostic value, since there could be normal rise before and after peak exercise and an abnormal response missed; and 3) the ejection fraction response to exercise reflects the severity of the underlying coronary artery disease. The described patterns of exercise-induced changes in left ventricular ejection fraction are important to consider when using this new technique to diagnose and evaluate patients with coronary artery disease.

Adult↗
PubMed1987

Effects of exercise tolerance, age, and gender on the specificity of radionuclide angiography: sequential ejection fraction analysis during multistage exercise.

We investigated the factors that determine the left ventricular ejection fraction response to exercise in 57 middle-aged, untrained patients with angiographically normal coronary arteries. The ejection fraction was measured by blood pool radionuclide angiography during each stage of exercise. Stepwise regression analysis was applied to 39 variables, and the resulting significant variables were then included in a logistic regression model to determine which of them would predict a normal ejection fraction response. By stepwise regression analysis, the best model (F = 5.6, p = 0.0004) was obtained by combining four variables: achieving 85% of maximal predicted heart rate, peak heart rate, number of exercise stages performed, and resting pulse pressure. Only the latter two variables were significant by logistic regression analysis. The specificity of greater than or equal to 5 ejection fraction unit increase at peak exercise was 42%, 75%, and 100% in patients who exercised one, two, or three stages, respectively. Furthermore, the increase in ejection fraction during each exercise stage was independent of age or gender. Thus the standard criteria of normality during exercise radionuclide angiography have high specificity only when applied to patients with good exercise performance, regardless of age or gender.

Adult↗