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Clinical utility of gated cardiac blood pool imaging in congestive left heart failure
Clinical Utility of Gated Cardiac Blood Pool Imaging in Congestive Left Heart Failure
ALLEN 6. NICHOLS, M.D.‘ KENNETH A. McKUSICK, H. WILLIAM STRAUSS,
M.D. M.D.
ROBERT E. DINSMORE, M.D. PETER C. BLOCK, M.D. GERALD M. POHOST, M.D. Boston, Massachusetts
From the Cardiac Unit and Nuclear Medicine Section, Massachusetts General Hospital, and the Department of Internal Medicine and Radiology, Harvard Medical School, Boston, Massachusetts. This study was supported in part by Grant HL17655 of the National Heart and Lung Institute, National Institutes of Health, Bethesda, Maryland. Requests for reprints should be addressed to Dr. Gerald M. Pohost, Cardiac Unit, Massachusetts General Hospital, Boston, Massachusetts 02114. Manuscript accepted May 16, 1976. Present address: Department of Medicine, College of Physicians and Surgeons, 630 West 168th Street, New York, New York 10032. l
Our experience with gated cardiac blood pool imaging in the evaluation of congestive left-sided heart failure was reviewed in 82 patients. Ventricular contraction patterns, right and left ventricular size, and regional wall motion were evaluated from technetium99m-albumin gated blood pool scans obtained in anterior and left anterior oblique projections. Patterns of ventricular function shown by scan were classified as follows: normal right and left ventricular size and contraction, normal left ventricular size wtth right ventricular enlargement, left ventricular volume overload, diffuse left ventricular hypokinesis, regional left ventricular asynergy, left ventricular aneurysm and hypertrophic cardiomyopathy. In 34 of 38 patients who underwent cardiac catheterization, the pattern of left ventricular dysfunction revealed by scan agreed with the findings on left ventriculography. Left ventricular end-diastolic diameters were significantly (p
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IMAGING IN CONGESTIVE LEFT HEART FAILURE-NICHOLS
SYSTOLE
ET AL.
DI ASTOLE
Figure 1. End-systolic and end-diastolic gated cardiac blood pool scans obtained in a normal subject in the anterior (ANT) and left anterior oblique (LAO) projections. Shown diagrammetrically are the cavities of the cardiac chambers in enddiastole. Ao = aorta, L V = left ventricle, PA = pulmonary artery, RA = right atrium, RV = right ventricle.
LAO
METHODS Patient Selection. Included in the study were all patients with congestive heart failure referred for gated cardiac blood pool imaging in the period from January 1975 to December 1976. A total of 55 men and 27 women ranging in age from 15 to 82 years (mean 55) were selected. All 82 patients had clinical signs and symptoms of leftsided heart failure as follows: dyspnea on exertion (96.4 per cent), orthopnea (68.3 per cent), paroxysmal nocturnal dyspnea (43.9 per cent), ventricular gallop sound (56.1 per cent), pulmonary rales (48.8 per cent) and abnormal apical impulse (62.2 per cent). In addition, the following signs of right-sided heart failure were present: jugular venous distension (41.5 per cent), peripheral edema (37.8 per cent) and hepatomegaly (28.1 per cent). The following abnormalities were present on chest films: cardiomegaly (9 1.6 per cent), interstitial edema (61.0 per cent), pulmonary vascular redistribution (58.5 per cent) and pleural effusion (35.4 per cent). Seventy-four of the patients (90.2 per cent) were receiving digitalis, and 65 (79.3 per cent) were also receiving diuretics. Coronary artery disease was the most common underlying cause of heart failure among the patients in this series, and all patients with heart failure resulting from coronary disease had had one or more myocardial infarctions. Technic for Gated Cardiac Blood Pool Imaging. After intravenous injection of 20 mCi of ggqc electrolytically-labeled human serum albumin, gated images were collected with an Anger scintillation camera,* equipped with a low energy all purpose parallel hole collimator. With the patient in the supine position, images were obtained in the anterior and left anterior oblique projections which best demonstrated the interventricular septum. Electrocardiographic gating was accom-
plished with a physiologic synchronizer.’ Images of endsystole and enddiastole were collected for 80 msec intervals during each cardiac cycle. The end-diastolic window was initiated by the R wave, and the end-systolic collection period was begun near the peak of the T wave, at an interval determined from the previous R-R interval. Each image contained 400,000 counts obtained over a 10 minute collection period. Images were collected in the core memory of a PDP-9f computer system in a 64 by 64 matrix and displayed on a 3 inch oscilloscopic screen interpolated to 128 by 128. lnterpretatlon of Gated Cardiac Scans. The studies were jointly interpreted by a cardiologist, cardiovascular radiologist and nuclear medicine specialist. All studies were read from the oscilloscope by alternate display of ehd-systolic and enddiastolic images to permit qualitative analysis of regional and global ventricular function. Maximal diameters of the right and left ventricular chambers of each scan were measured, and regional and global contraction of the left ventricle was scored qualitatively. Regional wall motion was assessed for three ventricular segments in the anterior projection (anterolateral, apical and inferior) and in three segments in the left anterior oblique projection (septal, posterior and inferoapical). Contraction of each segment was scored as normal, hypokinetic, akinetic or dyskinetic. In addition, each scan was classified into one of the following categories: normal left ventricle = normal size and contraction of all segments of the left ventricle; diffuse ventricular hypokinesis = concentric reduction in contraction of all six segments of the left ventricular wall in both projections, characteristic of primary myocardial disease [ 131; regional left ventricular asnyergy = localized, segmental hypokinesis, akinesis or dyskinesis of the left ventricular wall with regional inequalities of wall
Searle HP-Pho Gamma III Camera or Ohio Nuclear Series 100 Camera.
Brattle Instruments. t Digital Equipment Corp.
l
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GATED CARDIAC IMAGING IN CONGESTIVE LEFT HEART FAILURE--NICHOLS ET AL.
TABLE I --
__-
Patterns of Ventricular Dysfunction Congestive Heart Failure*
Gated Scan Findings Left ventricular volume overload Biventricular dilitation with diffuse hypokinesis Regional left ventricular asynergy Left ventricular aneurysm Right ventricular enlargement with normal sized left ventricle Normal right and left ventricular size and contraction
Observed on Gated Cardiac Blood Pool Scans in Patients with
- ._- __.__.__C!@&!.Cl Coronary ValvularHeartDisease -.No.
Artery Disease
AS
15
AR
MS
3
18
2
1
24
19
1
9 7
9
2
5
MR
._ ~__-._______ Congestive Hypertensive Cardiomyopathy
IO
Heart Disease 2
15 1
1
5
1
2
1
2
1
NOTE: AS = aortic stenosis; AR = aortic regurgitation; MS = mitral stenosis: MR = qitral regurgitation. Also included were single cases of hypertrophic cardiomyopathy, atrial myxoma and pericardial effusion detected by gated cardiac scan l
motion, i.e., the type of abnormality associated with coronary artery disease [ 51; left ventricular aneurysm = a large discrete bulge present in both end-systole and enddiastole and characterized by akinesis or dyskinesis [lo]; left ventricular volume overload= enlargement of the left ventricular cavity in enddiastole with a normal ejection fraction; hypertrophic cardiomyopathy = systolic obliteration of the left ventricular cavity with thickening and/or flattening of the interventricular septum [ 121; and pericardial effusion = the presence of a zone of diminished activity surrounding the heart and separating it from hepatic and pulmonary blood pool activity
1141. For quantitation of ventricular dimensions, the maximal transverse diameters of the right and left ventricular blood pools were measured in enddiastole from scans obtained
in the left anterior oblique projection. The margins of the collimator were used as a reference for magnification for correction of measured ventricular diameters. Normal valves for ventricular diameters measured by gated blood pool imaging were determined in a group of 10 subjects without congestive heart failure (Figure 1). Clinical Correlatlons. The medical history, physical signs and chest roentgenographic findings for each patient were reviewed retrospectively. Patterns of ventricular dysfunction assessed from gated cardiac images were correlated with the clinical etiology of heart failure. For the 36 patients who underwent cardiac catheterization, the pattern of left ventricular contraction observed on gated cardiac scan was compared with the pattern of left ventricular contraction observed by left ventriculography.
SYSTOLE
Figure 2. &ted scans of a patient with class IV heart failure following extensive anterior and inferior wall myocardial infarctions. The right and left ventricles and right atrium are enlarged. The anterolateral. inferior and basilar segments of the left ventricle are hypokinetic, consistent with multiple infarctions.
DIASTOLE
LAO
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GATED CARDIAC IMAGING IN CONGESTIVE LEFT HEART FAILURE-NICHOLS
ET AL
_ __-.----
-_~
SYSTOLE
RIASTOLE
ANT
LAO
i
RESULTS Summarized Classification of Gated Scan Findings. in Table I are the patterns of ventricular size and contraction correlated with the clinical diagnoses for the 82 patients. Twenty-four scans displayed regional left ventricular asynergy involving one or more ventricular segments (Figure 2) without evidence of aneurysm formation. Thirty-eight ventricular segments were described as hypokinetic, 18 were akinetic and 11 dyskinetic. Nineteen of these patients had histories of previous myocardial infarction, two had aortic valve disease, two had hypertensive heart disease, and one had idiopathic cardiomyopathy.
SYSTOLE
Figure 3. Large ventricular aneurysm involving the anterior and apical segments of the left ventricle in a 49 year old man. In this patient congestive heart failure had developed after an extensive anterior wall myocardial infarction two months eartier.
Nine scans revealed discrete dyskinetic or akinetic bulges in both end-systole and enddiastole consistent with ventricular aneurysm (Figure 3). All of these patients had previously had myocardial infarctions. Of the six of these patients who underwent catheterization, five were shown to have left ventricular aneurysms. One was shown by left ventriculography to have a large akinetic, nonaneurysmal segment of myocardium. Scans of 18 patients displayed biventricular enlargement with diffuse ventricular hypokinesis (Figure 4). Fifteen of these patients had congestive cardiomyopathy, two had previously had multiple myocardial infarctions, and one had severe aortic stenosis with terminal heart failure. Fifteen of the scans disclosed enlarged left ventric-
DIASTOLE
LAO Figure 4. Idiopathic congestive cardiomyopathy in a 50 year old man. Gated cardiac blood pool scans show marked biventricular dilatation and diffuse ventricular hypokinesis.
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IMAGING IN CONGESTIVE LEFT HEART FAILURE--NICHOLS
SYSTOLE
ET AL
DIASTOLE
A/VT
Figure 5. Gateedscans of a 49 year old woman with severe mitral regurgitation secondary to ruptured chordae tendinae. The left ventricle is enlarged in end-diasto/e and displays excellent contraction in end-systole. This pattern of ventricular contraction is consistent with ventricular volume overload and a large stroke volume.
LAO
ular cavities in enddiastole with normal ventricular contraction, consistent with increased stroke volume (Figure 5). Ten of these patients had moderate or severe mitral regurgitation and three had severe aortic regurgitation. Seven patients displayed right ventricular enlargement with normal left ventricular size and contraction (Figure 6). Five of these patients had mitral stenosis with pulmonary hypertension, one had mixed mitral valve disease, and one had hypertensive heart disease. Five patients were reported to have normal right and At left ventricular size and contraction (Figure-l).
catheterization two of these patients had moderate aortic stenosis, two had moderate mitral stenosis, and one had mild mitral regurgitation. Two patients in this series who presented with symptoms suggesting left heart failure proved to have large pericardial effusions identified by gated scan. Finally, one patient was found by scan to have a large left atrial myxoma causing left and right heart failure, and another was found to have hypertrophic cardiomyopathy associated with left heart failure. Determination of Ventricular Size. Maximal diameters of the right and left ventricular cavities measured from
SYSTOLE
DIASTOLE
ANT
LAO F/gure 6. Right ventricular enlargement in a 52 year oki man with moderate mitral stenosis and mild mitral regurgitation.
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GATED CARDIAC
TABLE II
IMAGING IN CONGESTIVE
LEFT HEART FAILURE-NICHOLS
ET AL
End-diastolic Ventricular Hemiaxial Diameters In Normal Subjects and in Patients with Congestive Heart
Failure Clinical Diagnosis Normal lschemic heart disease Congestive cardiomyopathy Left ventricular volume overload Left ventricular pressure overload Mitral stenosis
No.
Lefl Ventricular Diameter TKGiT~~fi~” f f f f
02. 0.2’ 0.5’ 0.3’
4.4 5.0 6.2 5.0
- 5.8 - a.9 - 10.3 - a.2
Right VentricularDiameter ~___.__ -.-_. Mean * SEM Range
IO 30 13 10
4.8 7.0 a.0 6.3
10
6.7 f 0.3”
5.5 - a.0
4.4 f 0.3’
3.2 - 6.5
5
4.6 f 0.3
4.0 - 5.1
5.2 f 0.3’
4.2 - 5.6
2.9 4.0 4.9 4.2
f f f f
0.1 0.27 0.2’ 0.2’
2.1 2.2 3.6 3.2
-
3.5 5.2 6.1 5.9
p < 0.001; 7 p < 0.02 by comparison with mean values for normal subjects l
end-diastolic blood pool images obtained in the 40 to 50 degree left anterior oblique projection are given in Table II. Mean values and ranges of ventricular diameters are shown for normal subjects and for groups of patients according to etiology of heart failure. The most extreme degrees of left ventricular dilatation were observed in patients with congestive cardiomyopathy. Patients with left ventricular failure associated with coronary artery disease and patients with left ventricular volume overload also had left ventricular diameters significantly above the normal range (p
curacy of gated cardiac imaging for determining the type of ventricular dysfunction present in patients with heart failure was obtained by correlating abnormalities detected by sated scan with cardiac catheterization findings in 36 patients. The pattern of left ventricular dysfunction shown by scan corresponded to the pattern demonstrated by left ventriculography in 34 of 36 (94 per cent) patients. Gated cardiac blood pool scan findings and left ventriculograms were equivalent for the following groups: left ventricular dilatation and diffuse hypokinesis (five patients with congestive cardiomyopathy); asymmetric ventricular asynergy (four patients with coronary artery disease); left ventricular
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aneurysm (four patients with previous myocardial infarction); normal left ventricular size with right ventricular dilatation (four patients with mitral stenosis): normal right and left ventricular size (two patients with aortic stenosis, and one patient with aortic regurgitation); and single cases of hypertrophic cardiomyopathy, pericardial effusion and diffuse ventricular hypokinesis secondary to severe aortic stenosis. The pattern of ventricular contraction displayed by gated scan failed to correspond to the pattern shown by left ventriculography in two patients. One was predicted to have apical and septal hypokinesis by scan but proved to have an apical aneurysm on left ventriculogram. The scan for the other patient was interpreted as showing normal wall motion, but ventriculography disclosed segmental hypokinesis. Indications For Gated Cardiac Blood Pool Scanning. Table Ill summarizes the clinical applications of gated cardiac imaging in the diagnostic evaluation and management of the 82 patients. The most common use of gated imaging was the detection of surgically resectable ventricular aneurysms among patients in whom heart failure developed after myocardial infarction. For this group of patients, gated imaging was frequently useful as a screening test to determine which patients should undergo angiographic study. Four patients were scheduled for catheterization because scans disclosed left ventricular aneurysms, and 10 patients were excluded from catheterization because gated scans showed diffuse hypokinesis without surgically resectable aneurysms. Three patients were shown by gated imaging to have ventricular aneurysms which were inoperable due to extensive ventricular dysfunction. In all these patients long-term anticoagulant therapy was begun. Gated imaging was useful as a noninvasive means of assessing ventricular function among patients with heart failure who were being evaluated for possible cardiac surgery. Eight patients were scheduled for
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GATED
CARDIAC
catheterization in part because gated scans disclosed left ventricular function adequate for operation with an acceptable risk. Conversely, 10 patients were excluded from catheterization because gated scans disclosed severely depressed left ventricular function precluding low risk operation. A total of 20 patients in this series were excluded from cardiac catheterization because of extensive left ventricular dysfunction revealed by gated imaging. Eighteen patients had been scheduled for cardiac catheterization before gated imaging was performed, and gated scan findings were not available to influence decisions regarding catheterization in these patients. An additional use of gated imaging was the determination of ventricular function among patients with severe chronic lung disease or marked obesity who complained of exertional dyspnea and fatigue. A further use of gated imaging was the evaluation of patients in whom heart failure developed after mitral valve replacement. In three patients sated imaging was useful for distinguishing the volume overload pattern of ventricular contraction due to surgically remediable paravalvular mitral regurgitation from inoperable, severe left ventricular dysfunction. Finally, the gated scan was used as a replacement for left ventricular angiography in seven patients undergoing catheterization in whom left ventricular cineangiography could not be performed for technical reasons. COMMENTS Gated radionuclide blood pool imaging permits noninvasive evaluation of ventricular size ‘and function in patients who present with congestive heart failure. In contrast to ventriculography performed during cardiac catheterization, gated cardiac imaging is performed without disturbing ventricular function or inducing arrhythmias. The contraction patterns of both ventricles are visualized simultaneously and can be repeatedly observed in multiple projections. As shown in this study, specific patterns of ventricular dysfunction are recognizable by gated cardiac scan among patients with congestive left heart failure. Recognition of these patterns facilitates decisions regarding the need for cardiac catheterization and the feasibility of surgical operation. The demonstration of severe dilatation and diffuse hypokinesis of the left ventricle among patients with idiopathic congestive cardiomyopathy or coronary artery disease with multiple myocardial infarctions is probably sufficient to obviate the need for cardiac catheterization, since cardiac surgery is unlikely to benefit these patients. In the present study, patients with idiopathic congestive cardiomyopathy were found to have the largest right and left ventricular dimensions, and the appearance of diffuse left ventricular hypokinesis was easily recognized.
IMAGING IN CONGESTIVE
TABLE Ill
LEFT
HEART
FAILURE---NICHOLS
Clinical Indications for Gated Cardiac Imaging Among 82 patients with Congestive Heart Failure _ indication
Detection
ET AL.
of ventricular
Determination
_
17
aneurysm
of left ventricular
11
function
9
Preoperative
evaluation
Assessment
of left ventricular
function
after myocardial infarction Determination of right ventricular
9 function
Replacement
for left ventriculography
Confirmation
of clinical diagnosis
6 7
of 9
cardiomyopathy Postoperative
No.
evaluation after mitral 3 2
valve replacement Detection
of pericardial
Detection
of hypertrophic
effusion
2
cardiomyopathy
1
Detection of atrial myxoma Clinical use of scan not given
7
In addition to obviating the need for cardiac catheterization, gated cardiac imaging was also useful for evaluating prognosis among these patients. Among patients with coronary artery disease, gated cardiac imaging was useful for determining the presence and extent of segmental contraction abnormalities, detecting ventricular aneurysms and identifying patients with extensive left ventricular dysfunction who were unlikely to benefit from operation. Gated imaging was particularly useful for the initial evaluation of patients with angina pectoris and heart failure resulting from prior myocardial infarction who were evaluated for coronary revascularization. Patients with heart failure due to ventricular aneurysms detected by gated cardiac imaging should be considered for cardiac catheterization and possible aneurysmectomy. Patients with ventricular aneurysms and severely depressed ventricular function shown by gated imaging should be considered for long-term anticoagulant therapy. Lastly, gated imaging can be used as a replacement for left ventriculography in patients with severe coronary disease and unstable angina who may tolerate contrast left ventriculography poorly. Among patients with valvular heart disease, gated cardiac blood pool imaging disclosed abnormalities of ventricular size, shape and function similar to those previously reported in angiographic studies [ 15-l 71. Left ventricular volume overload, such as that due to aortic or mitral regurgitation, causes an increase in left ventricular end-diastolic volume with a normal ejection fraction [ 18,191. Late in the course of the disease, volume overload may lead to further left ventricular dilatation and a reduced ejection fraction. This pattern can be recognized by serial gated studies, and detection of deterioration in the ejection fraction may be a useful noninvasive method for predicting when valve re-
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GATED CARDIAC IMAGING IN CONGESTIVE LEFT HEART FAILURE-NICHOLS
placement is indicated. Previous work in our laboratory suggests that end-diastolic volumes decrease in patients after valve replacement if the ejection fraction is normal or nearly normal preoperatively [ 201. Conversely, if the ejection fraction is substantially reduced (<40 per cent) preoperatively, little improvement in end-diastolic volume occurs postoperatively. Recent work by Borer et al. [21] suggests that gated cardiac imaging performed during exercise will detect more subtle abnormalities in ventricular function in patients with aortic regurgitation, since some patients with normal ejection fractions at rest will demonstrate a decrease in ejection fraction with exercise. An advantage of the gated scan over left ventricular angiography is that it permits simultaneous visualization of both right and left ventricles and provides a means for comparing their function. In the present series, right ventricular enlargement was most commonly associated with left ventricular failure. In addition to left ventricular dilatation, nearly all patients with congestive cardiomyopathy and many patients with coronary artery disease complicated by left heart failure had enlarged right ventricular cavities. In patients with congestive cardiomyopathy, right ventricular dilatation may in large part be related to heart muscle involvement [22]. However, in patients with anterior wall myocardial infarction, right ventricular dilatation is commonly related to left heart failure and less frequently to right ventricular infarction [ 231. Isolated right ventricular enlargement without associated left ventricular enlargement was commonly observed in patients with mitral stenosis. The gated blood pool scan demonstrated that these patients have normal or small left ventricular blood pools with left atrial enlargement and excluded left ventricular dysfunction as the cause of heart failure in these patients. Among patients with obesity, chronic obstructive pulmonary disease or other conditions obscuring physical signs of heart failure, gated cardiac imaging is useful for determining relative degrees of right and left heart involvement.
ET AL.
Some patients with valvular heart disease have symptoms which seem out of proportion to the extent of heart failure detectable by physical, roentgenographic or echocardiographic evaluation. Before proceeding to cardiac catheterization, gated cardiac blood pool imaging may be very helpful for determining whether ventricular dysfunction is a contributing cause of heart failure. If left ventricular ejection fraction and enddiastolic volume are normal, heart failure is unlikely to be the result of left ventricular dysfunction. Finally, patients with unusual and frequently unexpected causes of heart disease, such as pericardial effusion, left atrial myxoma, and hypertrophic cardiomyopathy, may have evidence suggesting the underlying diagnosis on the gated cardiac scan. In the present series, patterns of left ventricular function disclosed by gated imaging correlated highly with ventriculography. Two patients out of 36 who underwent left ventriculography nad wall motion abnormalities shown by ventriculography which were not detected by gated imaging. One patient had apical and septal hypokinesis on gated imaging but at ventriculography proved to have an apical aneurysm. Another patient with normal left ventricular function by gated imaging was shown to have segmental hypokinesis by ventriculography. Although gated imaging occasionally tended to underestimate the severity of regional ventricular dysfunction, severe abnormalities were always detected by gated imaging. In summary, gated cardiac imaging is broadly applicable to the evaluation and management of patients with congestive heart failure. It is clinically useful for: (1) evaluating left ventricular size and global function; (2) detecting regional left ventricular wall motion abnormalities; and (3) evaluating right ventricular size and function. It provides the clinician with information which facilitates decisions regarding the need for cardiac catheterization and assists in the prognostic evaluation of patients with congestive heart failure.
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2.
3.
4.
5.
792
Pi B, Strauss HW: Current concepts: evaluation of ventricular function by radioisotopes. N Engl J Med 296: 1097, 1977. Strauss HW, Zaret BL, Hurley PJ, et al.: A scintiphotographic method for measuring left ventricular ejection fraction in man without cardiac catheterization. Am J Cardio128: 575, 1971. Parker JA, Seeker-Walker R, Hill R, et al.: A new technique for the calculation of left ventricular ejection fraction. J Nucl Med 13: 649, 1972. Green MU, Brody WR, Douglas MA, et al.: Count rate measurement of left ventricular ejection fraction from gated scintigraphic images. J Nucl Med 17: 557, 1976. Zaret BL, Strauss HW,; Hurley PJ, et al.: A noninvasive scintiphotographic method for detecting regional ventricular
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7.
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dysfunction in man. N Engl J Med 284: 1165, 1971. Berman DS, Sale1 AF, DeNardo GL, et al.: Clinical assessment of left ventricular contraction patterns and ejection fraction by high resolution gated scintigraphy. J Nucl Med 16: 865, 1975. Strauss HW, Pitt B: Common procedures for the noninvasive determination of regional myocardial perfusion, evaluation of regional wall motion and detection of acute infarction. Am J Cardiol 38: 731, 1976. Rigo R, Strauss HW, Taylor DR, et al.: Left ventricular function in acute myocardial infarction evaluated by gated scintiphotography. Circulation 50: 678, 1974. Rigo P, Murray M, Taylor DR, et al.: Right ventricular dysfunction detected by gated scintiphotography in patients with acute inferior myocardial infarction. Circulation 52:
GATED CARDIAC
10.
11.
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16.
268, 1975. Rigo P, Murray M, Strauss HW, et al.: Scintiphotographic evaluation of patients with suspected left ventricular aneurysm. Circulation 50: 985, 1974. Pohost GM, Pastore JO, McKusick KA, et al.: Detection of left atrial myxoma by gated radionuclide cardiac imaging. Circulation 55: 88, 1977. Pohost GM, Vignola PA, McKusick KA. et al.: Hypertrophic cardiomyopathy: evaluation by gated cardiac blood pool scanning. Circulation 55: 92, 1977. Bulkley BH, Hutchins Gfvt, Bailey I, et al.: Thallium201 imaging and gated cardiac blood pool scans in patients with ischemit and idiopathic congestive cardiomyopathy: a clinical and pathologic study. Circulation 55: 753, 1977. Wagner HN Jr, MacAfee JG, Mozley JM: Diagnosis of pericardial effusion by radioisotope scanning. Arch Intern Med 108: 679, 1961. Dodge HT, Kennedy JW, Peterson JL: Quantitative angiographic methods in the evaluation of valvutar heart disease. Prog Cardiovasc Dis 16: 1, 1973. Kennedy JW, Yarnall SR. Murray JA. et al.: Quantitative angiocardiography. IV. Relationships of lefl atrial and ventricular pressure and volume in mitral valve disease. Circulation 41: 817, 1970.
IMAGING IN CONGESTIVE
17. 18.
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22. 23.
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ET AL.
Jones JW, et al.: Left ventricular volumes in valvular heart disease. Circulation 29: 887, 1964. Bolen JL, Alderman EL: Ventriculographic and hemodynamic features of mitral regurgitation of cardiomyopathic, rheumatic and nonrheumatic etiology. Am J Cardiol 39: 177, 1977. Kennedy JW, Dotes J, Steward DK: Left ventricular function before and following aortic valve replacement. Circulation 56: 944, 1977. Shea WH. Boucher CA, Curfman GD, et al.: Early reversibility of left ventricular dilatation following relief of chronic valvular regurgitation (abstract). Circulation 54 (Suppl II): 11-215, 1976. Borer JS, Bacharach SL, Green NIV. et al.: Exercise-induced lefl ventricular dysfunction in symptomatic and asymptomatic patients with severe aortic regurgitation assessed by radionuclide angiography (abstract). Am J Cardiol 39: 204. 1977. Hudson REB: Pathology of cardiomyopathy. Cardiovasc Clin 4: 4, 1972. Rigo P, Murray M. Taylor DR. et al.: Right ventricular dysfunction detected by gated scintiphotography in patients with acute inferior myocardial infarction. Circulation 52: 268, 1975.
The Amerlcan Journal of Medlclne
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ALLEN 6. NICHOLS, M.D.‘ KENNETH A. McKUSICK, H. WILLIAM STRAUSS,
M.D. M.D.
ROBERT E. DINSMORE, M.D. PETER C. BLOCK, M.D. GERALD M. POHOST, M.D. Boston, Massachusetts
From the Cardiac Unit and Nuclear Medicine Section, Massachusetts General Hospital, and the Department of Internal Medicine and Radiology, Harvard Medical School, Boston, Massachusetts. This study was supported in part by Grant HL17655 of the National Heart and Lung Institute, National Institutes of Health, Bethesda, Maryland. Requests for reprints should be addressed to Dr. Gerald M. Pohost, Cardiac Unit, Massachusetts General Hospital, Boston, Massachusetts 02114. Manuscript accepted May 16, 1976. Present address: Department of Medicine, College of Physicians and Surgeons, 630 West 168th Street, New York, New York 10032. l
Our experience with gated cardiac blood pool imaging in the evaluation of congestive left-sided heart failure was reviewed in 82 patients. Ventricular contraction patterns, right and left ventricular size, and regional wall motion were evaluated from technetium99m-albumin gated blood pool scans obtained in anterior and left anterior oblique projections. Patterns of ventricular function shown by scan were classified as follows: normal right and left ventricular size and contraction, normal left ventricular size wtth right ventricular enlargement, left ventricular volume overload, diffuse left ventricular hypokinesis, regional left ventricular asynergy, left ventricular aneurysm and hypertrophic cardiomyopathy. In 34 of 38 patients who underwent cardiac catheterization, the pattern of left ventricular dysfunction revealed by scan agreed with the findings on left ventriculography. Left ventricular end-diastolic diameters were significantly (p
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Volume 65
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GATED CARDIAC
IMAGING IN CONGESTIVE LEFT HEART FAILURE-NICHOLS
SYSTOLE
ET AL.
DI ASTOLE
Figure 1. End-systolic and end-diastolic gated cardiac blood pool scans obtained in a normal subject in the anterior (ANT) and left anterior oblique (LAO) projections. Shown diagrammetrically are the cavities of the cardiac chambers in enddiastole. Ao = aorta, L V = left ventricle, PA = pulmonary artery, RA = right atrium, RV = right ventricle.
LAO
METHODS Patient Selection. Included in the study were all patients with congestive heart failure referred for gated cardiac blood pool imaging in the period from January 1975 to December 1976. A total of 55 men and 27 women ranging in age from 15 to 82 years (mean 55) were selected. All 82 patients had clinical signs and symptoms of leftsided heart failure as follows: dyspnea on exertion (96.4 per cent), orthopnea (68.3 per cent), paroxysmal nocturnal dyspnea (43.9 per cent), ventricular gallop sound (56.1 per cent), pulmonary rales (48.8 per cent) and abnormal apical impulse (62.2 per cent). In addition, the following signs of right-sided heart failure were present: jugular venous distension (41.5 per cent), peripheral edema (37.8 per cent) and hepatomegaly (28.1 per cent). The following abnormalities were present on chest films: cardiomegaly (9 1.6 per cent), interstitial edema (61.0 per cent), pulmonary vascular redistribution (58.5 per cent) and pleural effusion (35.4 per cent). Seventy-four of the patients (90.2 per cent) were receiving digitalis, and 65 (79.3 per cent) were also receiving diuretics. Coronary artery disease was the most common underlying cause of heart failure among the patients in this series, and all patients with heart failure resulting from coronary disease had had one or more myocardial infarctions. Technic for Gated Cardiac Blood Pool Imaging. After intravenous injection of 20 mCi of ggqc electrolytically-labeled human serum albumin, gated images were collected with an Anger scintillation camera,* equipped with a low energy all purpose parallel hole collimator. With the patient in the supine position, images were obtained in the anterior and left anterior oblique projections which best demonstrated the interventricular septum. Electrocardiographic gating was accom-
plished with a physiologic synchronizer.’ Images of endsystole and enddiastole were collected for 80 msec intervals during each cardiac cycle. The end-diastolic window was initiated by the R wave, and the end-systolic collection period was begun near the peak of the T wave, at an interval determined from the previous R-R interval. Each image contained 400,000 counts obtained over a 10 minute collection period. Images were collected in the core memory of a PDP-9f computer system in a 64 by 64 matrix and displayed on a 3 inch oscilloscopic screen interpolated to 128 by 128. lnterpretatlon of Gated Cardiac Scans. The studies were jointly interpreted by a cardiologist, cardiovascular radiologist and nuclear medicine specialist. All studies were read from the oscilloscope by alternate display of ehd-systolic and enddiastolic images to permit qualitative analysis of regional and global ventricular function. Maximal diameters of the right and left ventricular chambers of each scan were measured, and regional and global contraction of the left ventricle was scored qualitatively. Regional wall motion was assessed for three ventricular segments in the anterior projection (anterolateral, apical and inferior) and in three segments in the left anterior oblique projection (septal, posterior and inferoapical). Contraction of each segment was scored as normal, hypokinetic, akinetic or dyskinetic. In addition, each scan was classified into one of the following categories: normal left ventricle = normal size and contraction of all segments of the left ventricle; diffuse ventricular hypokinesis = concentric reduction in contraction of all six segments of the left ventricular wall in both projections, characteristic of primary myocardial disease [ 131; regional left ventricular asnyergy = localized, segmental hypokinesis, akinesis or dyskinesis of the left ventricular wall with regional inequalities of wall
Searle HP-Pho Gamma III Camera or Ohio Nuclear Series 100 Camera.
Brattle Instruments. t Digital Equipment Corp.
l
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TABLE I --
__-
Patterns of Ventricular Dysfunction Congestive Heart Failure*
Gated Scan Findings Left ventricular volume overload Biventricular dilitation with diffuse hypokinesis Regional left ventricular asynergy Left ventricular aneurysm Right ventricular enlargement with normal sized left ventricle Normal right and left ventricular size and contraction
Observed on Gated Cardiac Blood Pool Scans in Patients with
- ._- __.__.__C!@&!.Cl Coronary ValvularHeartDisease -.No.
Artery Disease
AS
15
AR
MS
3
18
2
1
24
19
1
9 7
9
2
5
MR
._ ~__-._______ Congestive Hypertensive Cardiomyopathy
IO
Heart Disease 2
15 1
1
5
1
2
1
2
1
NOTE: AS = aortic stenosis; AR = aortic regurgitation; MS = mitral stenosis: MR = qitral regurgitation. Also included were single cases of hypertrophic cardiomyopathy, atrial myxoma and pericardial effusion detected by gated cardiac scan l
motion, i.e., the type of abnormality associated with coronary artery disease [ 51; left ventricular aneurysm = a large discrete bulge present in both end-systole and enddiastole and characterized by akinesis or dyskinesis [lo]; left ventricular volume overload= enlargement of the left ventricular cavity in enddiastole with a normal ejection fraction; hypertrophic cardiomyopathy = systolic obliteration of the left ventricular cavity with thickening and/or flattening of the interventricular septum [ 121; and pericardial effusion = the presence of a zone of diminished activity surrounding the heart and separating it from hepatic and pulmonary blood pool activity
1141. For quantitation of ventricular dimensions, the maximal transverse diameters of the right and left ventricular blood pools were measured in enddiastole from scans obtained
in the left anterior oblique projection. The margins of the collimator were used as a reference for magnification for correction of measured ventricular diameters. Normal valves for ventricular diameters measured by gated blood pool imaging were determined in a group of 10 subjects without congestive heart failure (Figure 1). Clinical Correlatlons. The medical history, physical signs and chest roentgenographic findings for each patient were reviewed retrospectively. Patterns of ventricular dysfunction assessed from gated cardiac images were correlated with the clinical etiology of heart failure. For the 36 patients who underwent cardiac catheterization, the pattern of left ventricular contraction observed on gated cardiac scan was compared with the pattern of left ventricular contraction observed by left ventriculography.
SYSTOLE
Figure 2. &ted scans of a patient with class IV heart failure following extensive anterior and inferior wall myocardial infarctions. The right and left ventricles and right atrium are enlarged. The anterolateral. inferior and basilar segments of the left ventricle are hypokinetic, consistent with multiple infarctions.
DIASTOLE
LAO
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GATED CARDIAC IMAGING IN CONGESTIVE LEFT HEART FAILURE-NICHOLS
ET AL
_ __-.----
-_~
SYSTOLE
RIASTOLE
ANT
LAO
i
RESULTS Summarized Classification of Gated Scan Findings. in Table I are the patterns of ventricular size and contraction correlated with the clinical diagnoses for the 82 patients. Twenty-four scans displayed regional left ventricular asynergy involving one or more ventricular segments (Figure 2) without evidence of aneurysm formation. Thirty-eight ventricular segments were described as hypokinetic, 18 were akinetic and 11 dyskinetic. Nineteen of these patients had histories of previous myocardial infarction, two had aortic valve disease, two had hypertensive heart disease, and one had idiopathic cardiomyopathy.
SYSTOLE
Figure 3. Large ventricular aneurysm involving the anterior and apical segments of the left ventricle in a 49 year old man. In this patient congestive heart failure had developed after an extensive anterior wall myocardial infarction two months eartier.
Nine scans revealed discrete dyskinetic or akinetic bulges in both end-systole and enddiastole consistent with ventricular aneurysm (Figure 3). All of these patients had previously had myocardial infarctions. Of the six of these patients who underwent catheterization, five were shown to have left ventricular aneurysms. One was shown by left ventriculography to have a large akinetic, nonaneurysmal segment of myocardium. Scans of 18 patients displayed biventricular enlargement with diffuse ventricular hypokinesis (Figure 4). Fifteen of these patients had congestive cardiomyopathy, two had previously had multiple myocardial infarctions, and one had severe aortic stenosis with terminal heart failure. Fifteen of the scans disclosed enlarged left ventric-
DIASTOLE
LAO Figure 4. Idiopathic congestive cardiomyopathy in a 50 year old man. Gated cardiac blood pool scans show marked biventricular dilatation and diffuse ventricular hypokinesis.
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IMAGING IN CONGESTIVE LEFT HEART FAILURE--NICHOLS
SYSTOLE
ET AL
DIASTOLE
A/VT
Figure 5. Gateedscans of a 49 year old woman with severe mitral regurgitation secondary to ruptured chordae tendinae. The left ventricle is enlarged in end-diasto/e and displays excellent contraction in end-systole. This pattern of ventricular contraction is consistent with ventricular volume overload and a large stroke volume.
LAO
ular cavities in enddiastole with normal ventricular contraction, consistent with increased stroke volume (Figure 5). Ten of these patients had moderate or severe mitral regurgitation and three had severe aortic regurgitation. Seven patients displayed right ventricular enlargement with normal left ventricular size and contraction (Figure 6). Five of these patients had mitral stenosis with pulmonary hypertension, one had mixed mitral valve disease, and one had hypertensive heart disease. Five patients were reported to have normal right and At left ventricular size and contraction (Figure-l).
catheterization two of these patients had moderate aortic stenosis, two had moderate mitral stenosis, and one had mild mitral regurgitation. Two patients in this series who presented with symptoms suggesting left heart failure proved to have large pericardial effusions identified by gated scan. Finally, one patient was found by scan to have a large left atrial myxoma causing left and right heart failure, and another was found to have hypertrophic cardiomyopathy associated with left heart failure. Determination of Ventricular Size. Maximal diameters of the right and left ventricular cavities measured from
SYSTOLE
DIASTOLE
ANT
LAO F/gure 6. Right ventricular enlargement in a 52 year oki man with moderate mitral stenosis and mild mitral regurgitation.
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TABLE II
IMAGING IN CONGESTIVE
LEFT HEART FAILURE-NICHOLS
ET AL
End-diastolic Ventricular Hemiaxial Diameters In Normal Subjects and in Patients with Congestive Heart
Failure Clinical Diagnosis Normal lschemic heart disease Congestive cardiomyopathy Left ventricular volume overload Left ventricular pressure overload Mitral stenosis
No.
Lefl Ventricular Diameter TKGiT~~fi~” f f f f
02. 0.2’ 0.5’ 0.3’
4.4 5.0 6.2 5.0
- 5.8 - a.9 - 10.3 - a.2
Right VentricularDiameter ~___.__ -.-_. Mean * SEM Range
IO 30 13 10
4.8 7.0 a.0 6.3
10
6.7 f 0.3”
5.5 - a.0
4.4 f 0.3’
3.2 - 6.5
5
4.6 f 0.3
4.0 - 5.1
5.2 f 0.3’
4.2 - 5.6
2.9 4.0 4.9 4.2
f f f f
0.1 0.27 0.2’ 0.2’
2.1 2.2 3.6 3.2
-
3.5 5.2 6.1 5.9
p < 0.001; 7 p < 0.02 by comparison with mean values for normal subjects l
end-diastolic blood pool images obtained in the 40 to 50 degree left anterior oblique projection are given in Table II. Mean values and ranges of ventricular diameters are shown for normal subjects and for groups of patients according to etiology of heart failure. The most extreme degrees of left ventricular dilatation were observed in patients with congestive cardiomyopathy. Patients with left ventricular failure associated with coronary artery disease and patients with left ventricular volume overload also had left ventricular diameters significantly above the normal range (p
curacy of gated cardiac imaging for determining the type of ventricular dysfunction present in patients with heart failure was obtained by correlating abnormalities detected by sated scan with cardiac catheterization findings in 36 patients. The pattern of left ventricular dysfunction shown by scan corresponded to the pattern demonstrated by left ventriculography in 34 of 36 (94 per cent) patients. Gated cardiac blood pool scan findings and left ventriculograms were equivalent for the following groups: left ventricular dilatation and diffuse hypokinesis (five patients with congestive cardiomyopathy); asymmetric ventricular asynergy (four patients with coronary artery disease); left ventricular
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aneurysm (four patients with previous myocardial infarction); normal left ventricular size with right ventricular dilatation (four patients with mitral stenosis): normal right and left ventricular size (two patients with aortic stenosis, and one patient with aortic regurgitation); and single cases of hypertrophic cardiomyopathy, pericardial effusion and diffuse ventricular hypokinesis secondary to severe aortic stenosis. The pattern of ventricular contraction displayed by gated scan failed to correspond to the pattern shown by left ventriculography in two patients. One was predicted to have apical and septal hypokinesis by scan but proved to have an apical aneurysm on left ventriculogram. The scan for the other patient was interpreted as showing normal wall motion, but ventriculography disclosed segmental hypokinesis. Indications For Gated Cardiac Blood Pool Scanning. Table Ill summarizes the clinical applications of gated cardiac imaging in the diagnostic evaluation and management of the 82 patients. The most common use of gated imaging was the detection of surgically resectable ventricular aneurysms among patients in whom heart failure developed after myocardial infarction. For this group of patients, gated imaging was frequently useful as a screening test to determine which patients should undergo angiographic study. Four patients were scheduled for catheterization because scans disclosed left ventricular aneurysms, and 10 patients were excluded from catheterization because gated scans showed diffuse hypokinesis without surgically resectable aneurysms. Three patients were shown by gated imaging to have ventricular aneurysms which were inoperable due to extensive ventricular dysfunction. In all these patients long-term anticoagulant therapy was begun. Gated imaging was useful as a noninvasive means of assessing ventricular function among patients with heart failure who were being evaluated for possible cardiac surgery. Eight patients were scheduled for
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CARDIAC
catheterization in part because gated scans disclosed left ventricular function adequate for operation with an acceptable risk. Conversely, 10 patients were excluded from catheterization because gated scans disclosed severely depressed left ventricular function precluding low risk operation. A total of 20 patients in this series were excluded from cardiac catheterization because of extensive left ventricular dysfunction revealed by gated imaging. Eighteen patients had been scheduled for cardiac catheterization before gated imaging was performed, and gated scan findings were not available to influence decisions regarding catheterization in these patients. An additional use of gated imaging was the determination of ventricular function among patients with severe chronic lung disease or marked obesity who complained of exertional dyspnea and fatigue. A further use of gated imaging was the evaluation of patients in whom heart failure developed after mitral valve replacement. In three patients sated imaging was useful for distinguishing the volume overload pattern of ventricular contraction due to surgically remediable paravalvular mitral regurgitation from inoperable, severe left ventricular dysfunction. Finally, the gated scan was used as a replacement for left ventricular angiography in seven patients undergoing catheterization in whom left ventricular cineangiography could not be performed for technical reasons. COMMENTS Gated radionuclide blood pool imaging permits noninvasive evaluation of ventricular size ‘and function in patients who present with congestive heart failure. In contrast to ventriculography performed during cardiac catheterization, gated cardiac imaging is performed without disturbing ventricular function or inducing arrhythmias. The contraction patterns of both ventricles are visualized simultaneously and can be repeatedly observed in multiple projections. As shown in this study, specific patterns of ventricular dysfunction are recognizable by gated cardiac scan among patients with congestive left heart failure. Recognition of these patterns facilitates decisions regarding the need for cardiac catheterization and the feasibility of surgical operation. The demonstration of severe dilatation and diffuse hypokinesis of the left ventricle among patients with idiopathic congestive cardiomyopathy or coronary artery disease with multiple myocardial infarctions is probably sufficient to obviate the need for cardiac catheterization, since cardiac surgery is unlikely to benefit these patients. In the present study, patients with idiopathic congestive cardiomyopathy were found to have the largest right and left ventricular dimensions, and the appearance of diffuse left ventricular hypokinesis was easily recognized.
IMAGING IN CONGESTIVE
TABLE Ill
LEFT
HEART
FAILURE---NICHOLS
Clinical Indications for Gated Cardiac Imaging Among 82 patients with Congestive Heart Failure _ indication
Detection
ET AL.
of ventricular
Determination
_
17
aneurysm
of left ventricular
11
function
9
Preoperative
evaluation
Assessment
of left ventricular
function
after myocardial infarction Determination of right ventricular
9 function
Replacement
for left ventriculography
Confirmation
of clinical diagnosis
6 7
of 9
cardiomyopathy Postoperative
No.
evaluation after mitral 3 2
valve replacement Detection
of pericardial
Detection
of hypertrophic
effusion
2
cardiomyopathy
1
Detection of atrial myxoma Clinical use of scan not given
7
In addition to obviating the need for cardiac catheterization, gated cardiac imaging was also useful for evaluating prognosis among these patients. Among patients with coronary artery disease, gated cardiac imaging was useful for determining the presence and extent of segmental contraction abnormalities, detecting ventricular aneurysms and identifying patients with extensive left ventricular dysfunction who were unlikely to benefit from operation. Gated imaging was particularly useful for the initial evaluation of patients with angina pectoris and heart failure resulting from prior myocardial infarction who were evaluated for coronary revascularization. Patients with heart failure due to ventricular aneurysms detected by gated cardiac imaging should be considered for cardiac catheterization and possible aneurysmectomy. Patients with ventricular aneurysms and severely depressed ventricular function shown by gated imaging should be considered for long-term anticoagulant therapy. Lastly, gated imaging can be used as a replacement for left ventriculography in patients with severe coronary disease and unstable angina who may tolerate contrast left ventriculography poorly. Among patients with valvular heart disease, gated cardiac blood pool imaging disclosed abnormalities of ventricular size, shape and function similar to those previously reported in angiographic studies [ 15-l 71. Left ventricular volume overload, such as that due to aortic or mitral regurgitation, causes an increase in left ventricular end-diastolic volume with a normal ejection fraction [ 18,191. Late in the course of the disease, volume overload may lead to further left ventricular dilatation and a reduced ejection fraction. This pattern can be recognized by serial gated studies, and detection of deterioration in the ejection fraction may be a useful noninvasive method for predicting when valve re-
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placement is indicated. Previous work in our laboratory suggests that end-diastolic volumes decrease in patients after valve replacement if the ejection fraction is normal or nearly normal preoperatively [ 201. Conversely, if the ejection fraction is substantially reduced (<40 per cent) preoperatively, little improvement in end-diastolic volume occurs postoperatively. Recent work by Borer et al. [21] suggests that gated cardiac imaging performed during exercise will detect more subtle abnormalities in ventricular function in patients with aortic regurgitation, since some patients with normal ejection fractions at rest will demonstrate a decrease in ejection fraction with exercise. An advantage of the gated scan over left ventricular angiography is that it permits simultaneous visualization of both right and left ventricles and provides a means for comparing their function. In the present series, right ventricular enlargement was most commonly associated with left ventricular failure. In addition to left ventricular dilatation, nearly all patients with congestive cardiomyopathy and many patients with coronary artery disease complicated by left heart failure had enlarged right ventricular cavities. In patients with congestive cardiomyopathy, right ventricular dilatation may in large part be related to heart muscle involvement [22]. However, in patients with anterior wall myocardial infarction, right ventricular dilatation is commonly related to left heart failure and less frequently to right ventricular infarction [ 231. Isolated right ventricular enlargement without associated left ventricular enlargement was commonly observed in patients with mitral stenosis. The gated blood pool scan demonstrated that these patients have normal or small left ventricular blood pools with left atrial enlargement and excluded left ventricular dysfunction as the cause of heart failure in these patients. Among patients with obesity, chronic obstructive pulmonary disease or other conditions obscuring physical signs of heart failure, gated cardiac imaging is useful for determining relative degrees of right and left heart involvement.
ET AL.
Some patients with valvular heart disease have symptoms which seem out of proportion to the extent of heart failure detectable by physical, roentgenographic or echocardiographic evaluation. Before proceeding to cardiac catheterization, gated cardiac blood pool imaging may be very helpful for determining whether ventricular dysfunction is a contributing cause of heart failure. If left ventricular ejection fraction and enddiastolic volume are normal, heart failure is unlikely to be the result of left ventricular dysfunction. Finally, patients with unusual and frequently unexpected causes of heart disease, such as pericardial effusion, left atrial myxoma, and hypertrophic cardiomyopathy, may have evidence suggesting the underlying diagnosis on the gated cardiac scan. In the present series, patterns of left ventricular function disclosed by gated imaging correlated highly with ventriculography. Two patients out of 36 who underwent left ventriculography nad wall motion abnormalities shown by ventriculography which were not detected by gated imaging. One patient had apical and septal hypokinesis on gated imaging but at ventriculography proved to have an apical aneurysm. Another patient with normal left ventricular function by gated imaging was shown to have segmental hypokinesis by ventriculography. Although gated imaging occasionally tended to underestimate the severity of regional ventricular dysfunction, severe abnormalities were always detected by gated imaging. In summary, gated cardiac imaging is broadly applicable to the evaluation and management of patients with congestive heart failure. It is clinically useful for: (1) evaluating left ventricular size and global function; (2) detecting regional left ventricular wall motion abnormalities; and (3) evaluating right ventricular size and function. It provides the clinician with information which facilitates decisions regarding the need for cardiac catheterization and assists in the prognostic evaluation of patients with congestive heart failure.
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2.
3.
4.
5.
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Pi B, Strauss HW: Current concepts: evaluation of ventricular function by radioisotopes. N Engl J Med 296: 1097, 1977. Strauss HW, Zaret BL, Hurley PJ, et al.: A scintiphotographic method for measuring left ventricular ejection fraction in man without cardiac catheterization. Am J Cardio128: 575, 1971. Parker JA, Seeker-Walker R, Hill R, et al.: A new technique for the calculation of left ventricular ejection fraction. J Nucl Med 13: 649, 1972. Green MU, Brody WR, Douglas MA, et al.: Count rate measurement of left ventricular ejection fraction from gated scintigraphic images. J Nucl Med 17: 557, 1976. Zaret BL, Strauss HW,; Hurley PJ, et al.: A noninvasive scintiphotographic method for detecting regional ventricular
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dysfunction in man. N Engl J Med 284: 1165, 1971. Berman DS, Sale1 AF, DeNardo GL, et al.: Clinical assessment of left ventricular contraction patterns and ejection fraction by high resolution gated scintigraphy. J Nucl Med 16: 865, 1975. Strauss HW, Pitt B: Common procedures for the noninvasive determination of regional myocardial perfusion, evaluation of regional wall motion and detection of acute infarction. Am J Cardiol 38: 731, 1976. Rigo R, Strauss HW, Taylor DR, et al.: Left ventricular function in acute myocardial infarction evaluated by gated scintiphotography. Circulation 50: 678, 1974. Rigo P, Murray M, Taylor DR, et al.: Right ventricular dysfunction detected by gated scintiphotography in patients with acute inferior myocardial infarction. Circulation 52:
GATED CARDIAC
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268, 1975. Rigo P, Murray M, Strauss HW, et al.: Scintiphotographic evaluation of patients with suspected left ventricular aneurysm. Circulation 50: 985, 1974. Pohost GM, Pastore JO, McKusick KA, et al.: Detection of left atrial myxoma by gated radionuclide cardiac imaging. Circulation 55: 88, 1977. Pohost GM, Vignola PA, McKusick KA. et al.: Hypertrophic cardiomyopathy: evaluation by gated cardiac blood pool scanning. Circulation 55: 92, 1977. Bulkley BH, Hutchins Gfvt, Bailey I, et al.: Thallium201 imaging and gated cardiac blood pool scans in patients with ischemit and idiopathic congestive cardiomyopathy: a clinical and pathologic study. Circulation 55: 753, 1977. Wagner HN Jr, MacAfee JG, Mozley JM: Diagnosis of pericardial effusion by radioisotope scanning. Arch Intern Med 108: 679, 1961. Dodge HT, Kennedy JW, Peterson JL: Quantitative angiographic methods in the evaluation of valvutar heart disease. Prog Cardiovasc Dis 16: 1, 1973. Kennedy JW, Yarnall SR. Murray JA. et al.: Quantitative angiocardiography. IV. Relationships of lefl atrial and ventricular pressure and volume in mitral valve disease. Circulation 41: 817, 1970.
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Jones JW, et al.: Left ventricular volumes in valvular heart disease. Circulation 29: 887, 1964. Bolen JL, Alderman EL: Ventriculographic and hemodynamic features of mitral regurgitation of cardiomyopathic, rheumatic and nonrheumatic etiology. Am J Cardiol 39: 177, 1977. Kennedy JW, Dotes J, Steward DK: Left ventricular function before and following aortic valve replacement. Circulation 56: 944, 1977. Shea WH. Boucher CA, Curfman GD, et al.: Early reversibility of left ventricular dilatation following relief of chronic valvular regurgitation (abstract). Circulation 54 (Suppl II): 11-215, 1976. Borer JS, Bacharach SL, Green NIV. et al.: Exercise-induced lefl ventricular dysfunction in symptomatic and asymptomatic patients with severe aortic regurgitation assessed by radionuclide angiography (abstract). Am J Cardiol 39: 204. 1977. Hudson REB: Pathology of cardiomyopathy. Cardiovasc Clin 4: 4, 1972. Rigo P, Murray M. Taylor DR. et al.: Right ventricular dysfunction detected by gated scintiphotography in patients with acute inferior myocardial infarction. Circulation 52: 268, 1975.
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