The value of echocardiographic regional wall motion abnormalities in detecting coronary artery disease in patients with or without a dilated left ventricle

To evaluate the usefulness of echocardiographic regional wall motion abnormalities (RWMA) in detecting coronary artery disease (CAD) in patients with left ventricular (LV) dysfunction and a normal-sized or dilated left ventricle, 103 patients were studied by two-dimensional echocardiography (2DE) and cardiac catheterization. In 60 patients (group I) who had LV dysfunction and a dilated left ventricle by echo (patients with dilated cardiomyopathy), RWMA were detected in 44 patients and 36 (86%) of them had significant CAD, usually two- or three-vessel obstruction; of the 16 patients with dilated cardiomyopathy (DCM) and diffuse LV hypokinesis, eight (50%) had evidence of CAD. Thus the presence of RWMA by 2DE had an 83% sensitivity, a 57% specificity, and a 77% predictive accuracy in detecting CAD in patients with DCM and thus in distinguishing ischemic from idiopathic DCM. In 43 patients with LV dysfunction but normal LV size (group II), the sensitivity, specificity, and predictive accuracy of RWMA in detecting significant CAD was 95%, loo%, and 95%, respectively. We conclude that the detection of RWMA by 2DE is highly suggestive of significant CAD in patients with LV dysfunction and normal-sized or dilated left ventricle; the finding, however, of diffuse LV hypokinesis does not exclude CAD in these patients, especially when the left ventricle is dilated. (AM HEART J 109:799, 1985.)

Roberto Medina, M.D., Ioannis P. Panidis, M.D., Joel Morganroth, M.D., Morris N. Kotler, M.D., and Gary S. Mink, M.D. PhiZadeZphia, Pa.

Differentiation of congestive or dilated cardiomyo- pathy (DCM) due to coronary artery disease (CAD) from idiopathic DCM may have important prognos- tic and therapeutic implications.‘~2 Various radionu- elide techniques and positron emission tomography have been utilized to distinguish these two forms of DCM.3-6 The detection of left ventricular (LV) regional wall motion abnormalities (RWMA) by echocardiography (echo) is often thought to be a reliable indicator of the presence of significant coronary artery obstruction and prior myocardial infarction.7-g This study was undertaken to compare the usefulness of two-dimensional echocardiograph- ic (2DE) RWMA in detecting significant CAD in patients with LV dysfunction and normal-sized or dilated left ventricle.

From Likoff Cardiovascular Institute, Hahnemann University School of Medicine.

Received for publication Aug. 14, 1984; revision received Oct. 12, 1984; accepted Nov. 20, 1984.

Reprint requests: Ioannis P. Panidis, M.D., Hahnemann University School of Medicine, Cardiac Ultrasound Laboratory, Broad and Vine Sts., Phila- delphia, PA 19102-1192.

METHODS

Study patients. Over a 3-year period, 103 patients (mean age 55 + 11 [range 19 to 831 years) comprising 85 men and 18 women were included in this study. Entry criteria included: (1) a technically satisfactory M-mode and 2DE study; (2) evidence of LV dysfunction (segmental or diffuse wall motion abnormalities) on echo; (3) left heart catheterization including coronary angiography per- formed within 6 months of the echo study; and (4) no evidence of discrete LV aneurysm, primary valvular heart disease, congenital heart disease, severe LV hypertrophy (defined as LV wall thickness of 2 13 mm) or car pulmo- nale.

Echocardiographic studies. M-mode and 2DE studies were performed utilizing a mechanical sector scanner (ATL Mark III) or a phased array system (Varian V-3000 and Diasonics V-3400) using a 2.25 MHz transducer. M-mode echocardiographic data were obtained in each case simultaneously from the 2DE study. The following echocardiographic data were obtained: (1) left ventricular end-diastolic dimension measured from the M-mode study at the level of chordae tendineae and at the onset of the QRS complex of a simultaneously recorded ECG according to the standards of the American Society of Echocardiographylo; (2) segmental or regional LV wall

799

800 Medina et al.

Group I

50 Dilated LV

1

(XMcm)

45 n

Group II

Normal Size LV (<5.6cm)

cl No CAD

RWMA OH RWMA OH

Fig. 1. Correlation between the type of wall motion abnormality (regional or diffuse) by 2DE and the presence of coronary artery disease (CAD) in patients with dilated or normal-sized left ventricle (L V). Abbreviations: DH = diffuse hypokinesis; R WMA = regional wall motion abnormality.

motion abnormalities defined as the presence of an area of the left ventricle appearing hypokinetic when in an adja- cent area ventricular wall motion was normal or when an area of LV myocardium appeared akinetic or dyskinetic when the rest of the left ventricle appeared diffusely hypokinetic.” All patients were studied in the left lateral decubitus position and parasternal long-axis, short-axis, and apical 2DE views were obtained. Images were dis- played at 30 frames/set and were recorded on a video recording system. Slow-motion and frame-by-frame anal- ysis were performed on each study patient.

Cardiac catheterization. Left heart catheterization was performed by the Judkins or the Sones technique. Left ventricular ejection fraction was obtained from a right anterior oblique view on a single-plane left ventriculogram by the area-length method.‘* The presence, severity, and location of coronary artery lesions were noted in each case. Significant CAD was defined as the presence of a L 70% obstructive lesion of the vessel diameter in one or more of the coronary arteries. For the purpose of this study, left main coronary artery was considered equivalent to signif- icant obstruction of the left anterior descending and circumflex arteries.

Data analysis. The echocardiographic and angiographic studies were qualitatively analyzed by two independent groups of investigators, neither having knowledge of the other’s conclusions until the time of data correlation. When differences existed between observers, a conclusion was reached by consensus. The sensitivity, specificity, and predictive accuracy of LV RWMA by 2DE in predicting the presence of significant CAD were defined as follows: sensitivity = (true positives [TP])/(true positives + false negatives [FN]); specificity = (true negatives [TN])/(true negatives + false positives [FP]); and predictive accura- cy = (TP + TN)/(TN + FN + TP + FP).

April, 1985

American Heart Journal

3VD

El 2 VD

cl 1 VD

All Patients RWMA DH

N = 46 N = 36 N=8

Fig. 2. Number of coronary arteries involved in patients with “ischemic” dilated cardiomyopathy (CCM) and regional wall motion abnormalities (R WMA) or diffuse hypokinesis (DH) of the left ventricle by 2DE. VD = ves- sel disease.

RESULTS

The mean interval between the 2DE study and cardiac catheterization was 2.2 (range 1 to 6) months. A RWMA was detected by 2DE in 83 of 103 (80% ) patients, while 20 (20% ) patients had diffuse LV hypokinesis. Of the 83 patients with RWMA on 2DE, 77 (83%) had evidence of significant CAD by cardiac catheterization, while 10 of the 20 (50% ) patients with no RWMA also had CAD. Thus the presence of RWMA by echo has an overall 89% sensitivity, 63% specificity, and 84% predictive accuracy in suggesting CAD in this study popula- tion.

Patients were then divided in two groups accord- ing to the presence or absence of LV dilatation (LV end-diastolic diameter 2 5.6 cm). Group I included 60 patients, mean age 55 +- 11 years, with a dilated left ventricle by M-mode. echo; 43 patients with a mean age of 54 f 11 years and a normal LV size comprised group II.

Group I. The 60 patients in this group had conges- tive or dilated cardiomyopathy, defined as the pres- ence of significant LV dysfunction and LV dilata- tion by echo. In 44 of the 60 (73 % ) patients, RWMA was detected by 2DE, whereas 16 (27%) patients had diffuse LV hypokinesis. Of the 44 patients with RWMA by 2DE, significant CAD (one or more vessel coronary obstruction) was found in 38 (86 % ) patients, while in six (14%) patients coronary arte- ries were normal (Fig. 1). The distribution of coro- nary artery involvement in these 38 patients is shown in Table I and Fig. 2; two- or three-vessel disease was present in 33 (87 % ) of these patients. Of the five patients with single-vessel disease, four had involvement of the left anterior descending artery.

Of the 16 patients with diffuse LV hypokinesis and no evidence of RWMA by echo, eight patients

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Table I. Distribution of coronary artery disease in the study patients

1 VD 2 VD 3 VD Total CAD No CAD Total

RWMA by echo Dilated LV Normal LV size Total RWMA

DH by echo Dilated LV Normal LV size Total

5 13 20 38 6 44 s 14 2.3 22 0 39 14 27 36 II 6 83

0 3 5 8 8 16 9 9 4 2 -2 4 0 3 I 10 10 20

Total ii 56 zi E i6 103

Abbreviations: LV = left ventricle; RWMA = regional wall motion abnormalities; DH = diffuse hypokinesis; CAD = coronary artery disease; 1 VD = single- vessel disease: 2 VD = double-vessel disease; 3 VD = triple-vessel disease.

(50% ) had evidence of CAD and all had two- or three-vessel coronary involvement. Thus the pres- ence of RWMA by 2DE has an 83% sensitivity, a 57% specificity, and a 77% predictive accuracy in predicting CAD in patients with dilated cardiomy- opathy.

Group II. Of the 43 patients with LV dysfunction but normal LV size by echo, 39 had RWMA and four had a diffuse hypokinetic pattern by 2DE. All 39 patients with RWMA had evidence of coronary disease by cardiac catheterization (Fig. 1). The distribution of coronary artery involvement in these patients is shown in Table I. Of the four patients with diffuse LV hypokinesis, two had evidence of CAD. Thus, the finding of RWMA by 2DE in patients with LV dysfunction but normal LV size has a sensitivity of 95%, a specificity of 100%) and a predictive accuracy of 95% in suggesting the pres- ence of CAD.

DISCUSSION

Clinical features of ischemic DCM. The term “ische- mic” cardiomyopathy was first introduced by Burch et alI3 to characterize the severe myocardial dys- function and congestive heart failure that may result from occlusive CAD. This term has been used subsequently to describe patients with multiple myocardial infarctions or extensive multiple vessel CAD and severe LV dysfunction.‘*-l6 These patients may or may not have had overt or occult myocardial infarction, angina pectoris, or congestive heart fail- ure.17 Some clinical features of ischemic DCM differ from those of idiopathic DCM. In the former group, chest pain and ECG Q waves are more common.‘* However, as many as 52 % of patients with idiopath- ic DCM report vague chest pain despite the presence of normal or even dilated coronary arteries.18

Prognosis is poor in patients with DCM, only 25 % to 40% of these patients are alive 5 years after catheterization.‘, l*, lg Death is sudden and unexpect-

ed in up to 45% of patients.‘,‘* Franciosa et al.’ reported that patients with ischemic cardiomyopa- thy treated medically have a worse prognosis than those with idiopathic DCM. Although coronary bypass grafting may be warranted in patients with severely disabling angina and mild congestive heart failure,‘* the effect of surgical treatment on the functional status and survival of patients with ische- mic cardiomyopathy is controversial23 2o An improved survival and quality of life in surgically treated patients, especially when LV ejection frac- tion is >15%, has been reported.20 Thus the differ- entiation of ischemic from idiopathic DCM may have important prognostic and therapeutic implica- tions.

Differentiation of ischemic from idiopathic DCM.

Thallium-201 myocardial perfusion imaging may be helpful in detecting the presence of CAD when complete and extensive (involvement of more than 40% of the outer LV perimeter) perfusion defects are seen.3r4 When partial defects are present in patients with chronic congestive heart failure, idio- pathic cardiomyopathy cannot be distinguished from CAD with any degree of certainty.* RWMA on radionuclide ventriculogram have been observed in patients with idiopathic DCM and normal coronary arteries.5

Echo differentiation of ischemic from idiopathic DCM.

The presence of a thin, hyperreflective and akinetic septum or LV posterior wall on M-mode echo along with dilatation of the left ventricle have been con- sidered as diagnostic features of ischemic cardiomy- opathy.21,22 The presence of RWMA of the left ventricle by 2DE has been suggested as a reliable indicator of the presence of CAD.7-g However, the usefulness of 2DE in differentiating idiopathic car- diomyopathy from cardiomyopathy due to CAD has not been fully evaluated. A recent study23 found that an increased density or fibrosis of the papillary muscles may be a sign of previous myocardial infarc-

802 Medina et al.

tion and ischemic cardiomyopathy. In our study population, the presence of RWMA by 2DE had a sensitivity of 83%) a specificity of 57%) and a predictive accuracy of 77% in identifying the pres- ence of CAD in patients with dilated cardiomyopa- thy. Evidence of severe segmental hypokinesis when the remainder of the left ventricle has a normal wall motion, and segmental akinesis or dyskinesis in the presence of diffuse LV hypokinesis are suggestive of an ischemic etiology. However, as in radionuclide ventriculographic studies,5 RWMA were not uncom- mon in patients with DCM and normal coronary arteries. This finding may be explained by focal myocardial necrosis or fibrosis in patients with congestive cardiomyopathy and normal coronary arteries or by underestimation of the severity of CAD by the coronary angiogram. However, in 50% of patients with diffuse wall motion abnormalities, evidence of CAD was found. The absence of segmen- tal wall motion abnormalities in these patients may be explained by the presence of either multiple locations of prior infarctions or extensive myocardi- al fibrosis, and it is usually observed in patients with more severe global hypokinesis. The vast majority of patients with ischemic DCM had extensive two- or three-vessel diseaseI (Fig. 2). In patients with one- vessel involvement, the left coronary descending artery was the one affected in 80% of the cases.

Limitations of the study. Since all patients in our study had undergone cardiac catheterization, selec- tion bias may be introduced. A large number of patients have been referred for chest pain, and in those patients CAD may have been more common. The assessment of wall motion abnormalities by 2DE was qualitative and subjective and may be affected by inter- or intraobserver variability. The finding of CAD in patients with DCM does not necessarily imply that CAD was the cause of conges- tive cardiomyopathy. A causal relationship between the two entities is not definitely established in our study. The cause of congestive cardiomyopathy in patients with normal coronary arteries is also not known in our study since no myocardial biopsy was performed, and it was assumed to be idiopathic.

Clinical implications. Differentiation of ischemic from idiopathic dilated cardiomyopathy may be important in the prognosis and management of such patients. The presence of RWMA assessed by 2DE was found in this study to be an excellent indicator of CAD in patients with LV dysfunction and a normal LV size, and a fairly good indicator of CAD in patients with LV dilation (dilated cardiomyopa- thy). However, when diffuse hypokinesis was observed by 2DE, 50% of the patients had evidence of CAD.

April, 1985

American Heart Journal

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Franciosa JA, Wilen M, Ziesche S, Cohn JN: Survival in men with severe chronic left ventricular failure due to either coronary heart disease or idiopathic dilated cardiomyopathy. Am ,J Cardiol 51:831, 1983. Yatteau RF, Peter RH, Behar VS, Bartel AC, Rosati RA, Kong Y: Ischemic cardiomyopathy: The myopathy of coro- nary artery disease. Natural history and results of medical versus surgical treatment. Am J Cardiol 34:520, 1974. Saltissi S, Hockings B, Croft DN, Webb-Peploe MM: Thalli- um-201 myocardial imaging in patients with dilated and ischemic cardiomyopathy. Br Heart J 46:290, 1981. Dunn RF. Uren RF. Sadick S. Bautovich G. McLauehlin A. Hiroe M, Kelly MS:‘Comparison of thallium-201 scanning in idiopathic dilated cardiomyopathy and severe coronary artery disease. Circulation 66:804, 1982. Greenbere J. Boucher CA. Okada RD. Murahv JH. Palacios 1. Pohost ~G”Mf Strauss W: Incidence of regional wall motion abnormalities in primary congestive cardiomyopathy (abstrl. J Am Co11 Cardiol 1:723, 1983. Eisenberg JD. Smith JL, Sobel BE, Geltman EM: Dilferenti- ation of ischemic from non-ischemic cardiomyopathy by positron emission tomography (PET) (abstr). Circulation 68:111-386, 1983. Kerber RE, Marcus ML, Ehrhardt J, Wilson R, Abboud FM: Correlation between echocardiographically demonstrated segmental dyskinesis and regional myocardial perfusion. Cir- culation 52:1097, 1975. Kisslo .JA, Robertson D, Gilbert BW, Von Ramm, 0, Behar VS: A comparison of real-time, two-dimensional echocardiog- raphy and cineangiography in detecting left ventricular asy- nergy. Circulation 55:134, 1977. Weiss ,JL, Bulkley BH, Hutchins GM, Mason SJ: Two- dimensional echocardiographic recognition of myocardial injury in man: Comparison with postmortem studies. Circula- tion 63:401, 1981. Sahn DJ, DeMaria A, Kisslo J, Weyman A: Recommenda- tions regarding quantitation in M-mode echocardiography: Results of a survey of echocardiographic measurements. Circulation 58:1072, 1978. Gibson RS, Bishop HL, Stamm RB, Crampton RS, Beller GA, Martin RP: Value of early two dimensional echocardiog- raphy in patients with acute myocardial infarction. Am J Cardiol 49:1110, 1982. Dodge HT. Hay RE, Sandler H: An angiocardiographic method for directly determining left ventricular stroke vol- ume in man. Circ Res 11:739, 1962. Burch GE, Giles TD, Colcolough HL: Ischemic cardiomyopa- thy. AM HEART .J 79:291, 1970. Johnson RA, Palacios I: Dilated cardiomyopathies of the adult. N Engl J Med 307:1051, 1982. Dash H, -Johnson RA, Dinsmore RE, Harthorne dW: Cardio- myopathic syndrome due to coronary artery disease. I. Rela- tion to angiographic extent of coronary disease and to remote myocardial infarction. Br Heart J 36:733. 1977. Raftery EB. Banks DC, Oram S: Occlusive disease of the coronary arteries presenting as primary congestive cardiomy- opathy. Lancet 2:1147, 1969. Shabetai R: Cardiomyopathy: How far have we come in 25 years, how far yet to go? J Am Co11 Cardiol 1:252, 1983. Massumi RA. Rios JC. Gooch AS. Nutter D. DeVita VT. Datlow DW: Primary myocardial ‘disease. Report of fifty cases and review of the subject. Circulation 31:41, 1965. Fuster V. Gersh BJ. Giuliani ER. Taiik AJ. Brandenburg RO. Frye RL: The natural history of ‘idiopathic dilated card&my: opathy. Am J Cardiol 47:525, 1981. Manley JC, King JF, Zeft HJ, Johnson WD: The “bad” left ventricle. Results of coronary surgery and effect on late survival. J Thorac Cardiovasc Surg 72:841, 1976. Corya BC. Feigenbaum H, Rasmussen S, Black MJ: Echocar- diographic features of congestive cardiomyopathy compared with normal subjects and patients with coronary artery disease. Circulation 49:1153, 1974.

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22. Abbasi AS, Chahine RA, MacAlpin N, Kattus AA: Ultra- Kotler MN, Panidis, I, Vassallo R: Differentiation of ischemic sound in the diagnosis of primary congestive cardiomyopa- from congestive cardiomyopathy: Two-dimensional echocar- thy. Chest 63:937, 1973. diographic analysis of papillary muscle morphology (abstr).

23. DePace NL, Ross J, Mintz GS, Nestico P, Morganroth J, Circulation 68:111-26, 1983.

Diagnostic precision of echocardiography in mitral valve prolapse

In order to determine the precision with which currently used echocardiographic criteria can be applied for the diagnosis of mitral valve prolapse, three independent observers (A, B, and C) blindly analyzed the separate M-mode and two-dimensional echocardiograms of 50 patients, 27 of whom had previously been identified clinically as having echocardiographic evidence of prolapse. Observer A’s intraobserver repeatability for M-mode echocardiography was Q2%, Observer B’s was 84%, and Observer C’s was 90%. For two-dimensional echocardiography, Observer A’s intraobserver repeatability was 98%, Observer B’s was 80%, and Observer C’s was 82%. We believe that the variability in intraobserver repeatability is related to the frequency with which individual observers diagnosed prolapse. The interobserver repeatability for M-mode echocardiography for Observer A versus B was 84%, for Observer A versus C it was 80%, and for Observer B versus C it was 66%. The interobserver repeatability for two-dimensional echocardiography for Observer A versus B was 54%, for Observer A versus C it was 70%, and for Observer B versus C it was 52%. There was no significant difference between the inter- and intraobserver variability of M-mode versus two-dimensional echocardiography. Review of cases in which readings were discrepant revealed that these cases usually had relatively mild changes. Clinicians should be aware of the inherent variability of echocardiographic interpretation when they make a diagnosis of mitral valve prolapse. (AM HEART J 109:803, 1985.)

L. Samuel Wann, M.D., Charles M. Gross, M.D., Richard J. Wakefield, M.D., and

John H. Kalbfleisch, Ph.D. Milwaukee and Wood, Wise.

Reid’ and Barlow et aL2 recognized the relationship between midsystolic clicks and mitral valve disease over 20 years ago. Left ventricular angiography was subsequently used to show billowing of the mitral valve into the left atrium and consequent mitral regurgitation,3 but it was the advent of echocardi- ography which led to widespread recognition of mitral valve prolapse as a common cardiovascular abnormality. Two-dimensional echocardiography has been purported to be the diagnostic “gold standard” for mitral valve prolapse.4

From the Cardiology Division, Medical College of Wisconsin; and the Research Service, Veterans Administration Medical Center.

Supported in part by grants from the National Institutes of Health, National Heart, Lung, and Blood Institute; from the Veterans Administra- tion; and by the American Heart Association, Wisconsin affiliate.

Received for publication July 16, 1984; revision received Oct. 11, 1984; accepted Nov. 20, 1984.

Reprint requests: L. Samuel Warm, M.D., Cardiology Division, Medical College of Wisconsin, 8700 W. Wisconsin Ave., Milwaukee, WI 53226.

Standard criteria for the M-mode echocardio- graphic recognition of mitral valve prolapse include late systolic5v6 or pansystolic7ts posterior bowing of the mitral leaflets. The usual criterion for the diag- nosis of mitral valve prolapse by two-dimensional echocardiography is extension of mitral leaflet tissue to the left atrial side of the plane of the mitral anulu~.~~~-~~ Although these criteria are widely used in clinical practice, the consistency with which they can be applied has not been rigorously tested. This study was therefore undertaken to examine the inter- and intraobserver variability in the echocar- diographic diagnosis of mitral valve prolapse.

METHODS

Echographic examination. The M-mode and two- dimensional echocardiographic recordings of 50 patients were reviewed. Echocardiograms were obtained with a commercially available phased-array sector scanner using a 2.25 MHz transducer (Irex Medical Systems, Ramsey, N.J.). Multiple views were obtained in every case, includ-