Dipyridamole thallium-201 scintigraphy for improved detection of left anterior descending coronary artery stenosis in patients with left bundle branch block

In patients with left bundle branch block (LBBB) undergoingthallium-201 exercise scintigraphy septal perfusion defectsare frequently observed irrespective of the presence or absenceof coronary artery disease. Consequently, in these patientsthe specificity for detecting stenoses in the left anteriordescending coronary artery (LAD) by thallium-201 scintigraphyis relatively low. It has been hypothesized that pharmacologicalvasodilation would result in higher specificity than conventionalexercise thallium-201 scintigraphy because of a more uniformexploitation of coronary flow reserve. Twenty-five consecutive patients with LBBB underwent dipyridamolethallium-201 imaging and coronary arteriography within 3 months.The prevalence of coronary artery disease was estimated at 48±19%.Sensitivity for detection of LAD lesions was 100% and specificitywas 88%. The positive predictive accuracy and the negative predictiveaccuracy were 80% and 100% respectively. The ‘false positive’septal defects were of the non-reversible type. The appearanceof septal perfusion defects was not dependent on changes inheart rate during dipyridamole infusion. This study indicatesthe value of dipyridamole thallium-201 imaging for non-invasivedetection of LAD stenosis in patients with LBBB.     

Coronary arteriograms and myocardial scintigrams in the electrocardiographic syndrome of septal fibrosis

Coronary artery disease (CAD) and myocardial perfusion were assessed by arteriograms and scintigrams (Technetium-99 microspheres alone or combined with Iodine-131 albumin macroaggregates) in 178 angina pectoris patients with and without the electrocardiographic (ECG) syndrome of septal fibrosis and with ≥70% obstruction in one or more coronary arteries. The ECGs of 96 patients without angiographic evidence of obstructive CAD were also examined for the ECG syndrome of septal fibrosis. Patients with the ECG syndrome of septal fibrosis have significantly higher incidences of positive exercise stress test, of ≥70% narrowing of the proximal left anterior descending (LAD) artery, of severe proximal LAD disease, and of more extensive left ventricular hypoperfusion than patients without the ECG syndrome. The fact that only 4% of patients without obstructive CAD have the ECG syndrome of septal fibrosis indicates the usefulness of the syndrome in identifying a subset of angina pectoris patients with advanced CAD of the proximal LAD and diffuse left ventricular hypoperfusion.     

Spectrum of exercise thallium-201 myocardial perfusion imaging in patients with chest pain and normal coronary angiograms.

Twenty-seven consecutive patients with chest pain and no significant obstructive coronary lesions on arteriography were studied with thallium-201 myocardial imaging during exercise and at rest. Fifteen of the patients had typical and 12 atypical angina pectoris. All underwent treadmill exercise electrocardiographic testing; the results were abnormal in 10 patients (37 percent), normal in 14 (52 percent) and uninterpretable in 3 (11 percent). The exercise and resting thallium-201 myocardial images were normal in 23 patients (85 percent); the results of exercise testing were normal in 12 of these patients, abnormal in 8 and uninterpretable in 3. Four patients had a perfusion defect on exercise thallium-201 myocardial imaging; the defect filled in by 4 hours in two patients but persisted in the other two. In contrast, when thallium-201 myocardial imaging was performed in 28 consecutive patients with angiographic coronary artery disease, only 5 patients (16 percent) had normal exercise and resting thallium-201 myocardial images. Therefore, thallium-201 myocardial imaging offers a more effective means of identifying patients with chest pain and no obstructive coronary artery disease than the clinical history or the exercise electrocardiographic test, or both. However, 15 percent of these patients will have abnormal exercise thallium-201 myocardial images because of factors that have not yet been identified.     

Myocardial contrast echocardiography in the evaluation of myocardial perfusion in patients with left bundle branch block and coronary artery disease.

BACKGROUND: In patients with left bundle branch block (LBBB), conventional tests such as electrocardiography and myocardial scintigraphy poorly evaluate coronary artery disease. It has been reported that myocardial contrast echocardiography (MCE) is capable of identifying patients with a postinfarction contractile reserve and myocardial functional recovery, also allowing the early identification of late left ventricular remodeling. The purpose of this study was to evaluate, retrospectively, myocardial perfusion in selected patients with LBBB. METHODS: Thirty patients (mean age 56 +/- 8 years) with LBBB, 15 with normal coronary arteries at angiography and 15 with a previous myocardial infarction and a critical one-vessel residual stenosis at angiography, underwent MCE from June 2000 to May 2001. MCE results were compared with rest thallium-201 myocardial scintigraphy. RESULTS: Among 15 LBBB patients with normal coronary arteries, MCE demonstrated normal perfusion in 14 patients, whereas 1 subject showed an impairment of septal perfusion. In the same group, rest thallium-201 myocardial scintigraphy showed an impaired septal perfusion in 14 patients, whereas 1 subject had a normal perfusion (MCE specificity 93% vs myocardial scintigraphy specificity 7%). Among 15 LBBB patients with coronary artery disease, MCE correctly identified a contrast defect in 14/15 patients, whereas rest thallium-201 myocardial scintigraphy demonstrated a perfusion defect in 15/15 patients (MCE sensitivity 93% vs scintigraphy sensitivity 100%). The two techniques showed a good agreement as for myocardial perfusion in the anterior wall (86.6% anterobasal; 86.6% mid-anterior; 80% distal anterior), the inferior wall (86.6%), the distal segment of the posterior lateral wall (83.3%), but a low concordance was found as for the basal septum (16.6%) and middistal septum (33.3%). CONCLUSIONS: MCE allows a diagnostic benefit in the detection of microvascular damage in patients with LBBB and unknown coronary artery disease, also in the presence of discordance with rest thallium-201 myocardial scintigraphy.     

Natural history of left anterior descending coronary artery obstruction: significance of location of stenoses in medically treated patients

We examined the prognostic significance of an obstructive lesion in the proximal left anterior descending (LAD) coronary artery. Five-year or longer follow-up data were examined from 311 patients with greater than 70% obstruction of the LAD treated without surgery. Mortality was compared in subsets with lesions proximal to and distal to the first septal perforating artery. Survival curves were worse in patients with proximal than with distal LAD disease (p less than 0.05); lesion location remained a significant determinant of survival when ejection fraction, age, and sex were controlled using a Cox regression model. However, when patient subsets were examined, survival with proximal LAD disease was worse than with distal obstruction only in the presence of an associated right coronary artery lesion and an ejection fraction of less than 40% (p less than 0.01). Patients with proximal LAD plus right coronary lesions had a 5-year mortality rate (34.08 +/- 8.9%) that was not significantly (p greater than 0.05) different from that of a group of 66 patients with greater than 50% narrowing of the left main coronary artery (24.02 +/- 4.3%). Thus, proximal LAD disease is more significant than is a distal lesion only in the presence of right coronary obstruction. This two-vessel combination results in a mortality rate as high as that associated with left main coronary artery obstruction.     

Myocardial perfusion in coronary disease: thallium-201 planar scintigraphy

This research evaluated the diagnostic and analytic effectiveness of 201-thallium imaging in a group of patients with coronary artery disease, each one of them with different localization, extent and number of coronary vessel obstructions. The thallium-201 imaging was performed immediately after ergometric test and repeated 4 hours later. In a large percentage of patients thallium-201 imaging of reversible and irreversible perfusion defects have been found; thallium-201 scintigraphy showed a greater sensitivity than exercise ECG. With particular evidence 201-Tl imaging showed perfusion defects in a high percentage of patients with obstruction of one and two coronary vessels; in these patients, in the former especially, the results of exercise ECGs showed a lower sensitivity. Both thallium-201 and exercise ECG had a similar sensitivity in patients with obstruction of three coronary vessels. In patients with obstruction of one or two vessels, thallium-201 imaging clearly showed a regional hypoperfusion corresponding to the specific perfusion coronary vessels, while exercise ECG gave aspecific topographic results. Irreversible perfusion defects resulted corresponding to the myocardial segments that were infarcted, but were also observed in patients without previous myocardial infarction.     

Noninvasive detection and localization of coronary stenoses in patients: Comparison of resting dipyridamole and exercise thallium-201 myocardial perfusion imaging

Two noninvasive tests to detect and localize coronary stenoses were compared in a fully blinded protocol. Thallium²⁰¹ myocardial perfusion imaging (MPI) following maximal treadmill exercise and pharmacologic coronary vasodilation with intravenous dipyridamole (DP) was performed in 33 patients. Thallium²⁰¹ imaging defects in six myocardial perfusion regions were correlated with stenoses in their respective vascular distributions. Disease severity was determined with coronary arteriograms using a computer-assisted method, 198 myocardial regions were evaluated; 101 were supplied by at least one major artery with a ≥ 50% stenosis (luminal diameter narrowing). The sensitivity and specificity for detecting a ≥50% stenosis were 85% and 64% (p < 0.005), respectively, for DP and 84% and 68% (p < 0.005) for exercise-thallium²⁰¹ imaging. A particular combination of anterior and septal imaging defects was useful in detecting left anterior descending artery stenoses proximal to its first septal branch. DP administration was safe in this group of patients; however, 42% experienced transient chest pain. Although the overall sensitivity and specificity of the two methods were not significantly different, DP-MPI appeared more sensitive than exercise-MPI (70% vs 52%, p < 0.01) in detecting coronary stenoses in the 40% to 60% range. DP-thallium²⁰¹ MPI provides a useful alternative test for potential coronary disease patients unable to perform maximal exercise.     

Clinical, angiographic, hemodynamic, perfusional and functional changes after one-vessel left anterior descending coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) was successfully performed in 20 patients with 1-vessel left anterior descending (LAD) coronary artery disease. Exercise capacity in terms of peak workload, heart rate and systolic blood pressure all increased significantly 1 week after PTCA. All patients had some decrease in stenosis size and gradient. All patients except 1 had an improvement in functional class. Eight of 12 patients with abnormal exercise electrocardiograms before PTCA had normal electrocardiograms after the procedure. Exercise thallium-201 (TI-201) myocardial perfusion images obtained in all 20 patients before and 1 week after PTCA were analyzed using a new computer method designed to quantitate regional myocardial TI-201 distribution, redistribution and clearance rate. Significant improvement in TI-201 activity was present in the anterior and septal segments of the left ventricle 1 week after PTCA. This increase in TI-201 uptake was associated with a significant reduction in the amount of TI-201 redistribution between initial and delayed postexercise images in the same regions. TI-201 clearance rate in the segments supplied by the dilated vessel also improved significantly. Abnormal TI-201 lung uptake was seen in 17 patients before and in 4 patients after PTCA. Exercise ejection fraction response and septal wall motion also improved after PTCA of the LAD stenosis in all 17 patients who had exercise radionuclide ventriculography. Improvement in clinical, angiographic and hemodynamic factors as well as in global and regional myocardial perfusion and function occurs after PTCA for 1-vessel LAD coronary artery disease.     

Comparison of exercise electrocardiography and quantitative thallium imaging for one-vessel coronary artery disease

The relative value of exercise electrocardiography and computer analyzed thallium-201 imaging was compared in 124 patients with 1-vessel coronary artery disease (CAD). Of these, 78 had left anterior descending (LAD), 32 right and 14 left circumflex (LC) CAD. In patients with no previous myocardial infarction (MI), thallium imaging was more sensitive than the electrocardiogram (78% vs 64%, p less than 0.01), but in patients with previous MI, sensitivity was similar. Further, thallium imaging was more sensitive only in LAD and LC disease. Redistribution was compared with ST-segment depression as a marker of ischemia. Only in patients with prior MI (76% vs 44%, p less than 0.01) and only in LC and right CAD did redistribution occur more often than ST depression. Thallium imaging was more accurate in localizing stenoses than the electrocardiogram (p less than 0.001), but did not always correctly predict coronary anatomy. Septal thallium defects were associated with LAD disease in 84%, inferior defects with right CAD in 40% and posterolateral lesion defects with LC CAD in 22%. The results indicate the overall superiority of thallium imaging in 1-vessel CAD compared with exercise electrocardiography; however, there is a wide spectrum of extent and location of perfusion defects associated with each coronary artery. Thallium imaging complements coronary angiography by demonstrating the functional impact of CAD on myocardial perfusion.     

Diagnostic value of exercise tomoscintigraphy with thallium 201 in patients with complete left branch block

Eighteen patients with rate-dependent (n = 5) or chronic (n = 13) left bundle branch block underwent thallium 201 exercise SPECT and selective coronary arteriography. 15 patients showed significant septal or anteroseptal perfusion defects on the exercise scintigrams, but in only 4 of them did the coronary disease involve the left anterior descending artery (LAD) (n = 3) or the left main coronary artery (n = 1). Among patients with normal scintigrams, one had right coronary artery stenosis. Test performance in detecting individual coronary artery stenosis greater than 70 p. 100 was: sensitivity 80 p. 100 (4/5) and specificity 15 p. 100. In patients with left bundle branch block, T1 201 SPECT was indeterminate for LAD disease due to reversible septal perfusion defect. We conclude that the usefulness of stress thallium 201 SPECT in patients with left bundle branch block is very limited.     

Thallium-201 myocardial perfusion imaging in patients with systemic lupus erythematosus

The cardiovascular system is frequently affected in systemic lupus erythematosus (SLE). The observation of clinical manifestations related to the presence of coronary artery disease has not been frequently documented in young SLE patients. In these patients, the presence of inflammatory or thrombotic vascular lesions is often documented by anatomo-histological studies in the absence of previous clinical manifestations. The purpose of this study was to evaluate the presence of myocardial perfusion defects in SLE patients. The study was carried out in 15 patients without clinical signs of myocardial ischemia, 1 male and 14 females, 24 to 64 years old, with a mean SLE duration of 10.2 +/- 7.5 years. All the patients had normal blood pressure; electrocardiogram and Doppler-echocardiographic analysis showed values in the normal range. All the patients underwent thallium-201 exercise stress imaging repeated 3 hours later at rest, with tomographic SPECT analysis. Exercise test was carried out until submaximal load, without induction of ST segment alterations or symptoms. Scintigraphic scan showed normal thallium-201 SPECT imaging in 11/15 patients, while the other 4 patients had a slight perfusion defect, 3 of them in the inferior segment, in 2 non reversible and in 1 reversible; 1 patient had a non reversible defect in the septal segment. These slight perfusion defects, prevalently non reversible, may sometimes be a false positive imaging. Our results are in contrast with the literature observations concerning the frequent incidence of thallium-201 perfusion defects in SLE patients. In young asymptomatic SLE patients, our study does not report very important data indicating myocardial ischemia and suggesting the presence of significant coronary obstruction or vasculitis.     

Influence of coronary artery disease on pulmonary uptake of thallium-201

An increased pulmonary thallium-201 concentration has been observed in exercise stress thallium perfusion imaging in patients with coronary artery disease. To understand the cause of this lung uptake, studies were performed in experimental animals and in patients undergoing stress thallium perfusion imaging. The extraction fraction of thallium-201 by the lungs was measured in a group of eight dogs using a dual isotope technique. Basal thallium-201 extraction fraction at rest was 0.09 ± 0.009. After administration of isoproterenol, it decreased to 0.06 ± 0.02 (difference not significant). After balloon obstruction of the left atrium (which increased mean left atrial pressure and pulmonary transit time) and after administration of acetylcholine as a bolus injection (which prolonged pulmonary transit time only) it increased to 0.19 ± 0.02 (p <0.01).Lung thallium-201 activity was measured in 86 patients who had undergone cardiac catheterization and stress-redistribution myocardial perfusion imaging. The initial/final lung activity ratio was 1.41 ± 0.03 in patients with no significant coronary artery disease, 1.52 ± 0.03 (difference not significant) in patients with single vessel coronary disease, 1.60 ± 0.05 (p <0.05) in those with two vessel disease and 1.59 ± 0.05 (p <0.05) in those with triple vessel disease. Quantitation of lung activity in 30 of these patients indicated that the increased ratio in patients with multivessel coronary artery disease was due to a transient absolute increase in the thallium-201 concentration immediately after maximal exercise. The data imply that increased pulmonary concentration of thallium-201 during exercise is a consequence of left ventricular failure.     

Thallium-201 exercise scintigraphy in patients having complete left bundle branch block with normal coronary arteries

Eleven patients with left bundle branch block and chest pain suggestive of coronary arterial disease were analyzed using thallium-201 exercise scintigraphy, M-mode echocardiography and coronary arteriography. The coronary arteries were shown to be normal in all patients. A reversible anteroseptal defect on thallium-201 scintigraphy and an asynchronous septal motion on echocardiography were evident in eight patients. Thus, symptomatic patients with left bundle branch block may have reversible anteroseptal defects on thallium-201 scintigraphy which do not indicate coronary artery disease. Rather, they may be due to functional ischemia secondary to abnormal septal motion.     

Detection of left anterior descending coronary artery disease in patients with left bundle branch block.

The detection of coronary artery disease is difficult if a patient has electrocardiographic evidence of left bundle branch block (BBB). Septal blood flow may be reduced in patients with left BBB, despite no angiographic evidence of left anterior descending (LAD) coronary artery disease. We have developed a new method of quantification of Thallium-201 single-photon emission computed tomographic (SPECT) images with the aim of better separating patients with left BBB and LAD disease from those with left BBB alone. The study cohort comprised 8 normal subjects (group I) and 20 patients with left BBB and chest pain who underwent thallium-201 SPECT imaging and coronary angiography. Eight patients (group II) had < or = 50% LAD stenosis, and 12 (group III) had > or = 70% LAD stenosis. Septal abnormality scores on the second short-axis slice from the base were computed, based on comparison of each subject's short-axis circumferential profile with a normal reference curve. This followed a procedure in which each profile was scaled to minimize differences in its absolute level in relation to the reference curve. Septal abnormality scores on stress images were 0.8 +/- 22 for group I, 27 +/- 43 for group II, and 165 +/- 67 for group III (p = 0.15 for group I vs II, and p < 0.0001 between groups I and III, and II and III).(ABSTRACT TRUNCATED AT 250 WORDS)     

Initial and delayed right ventricular thallium-201 rest-imaging following dipyridamole-induced coronary vasodilation: Relationship to right coronary artery pathoanatomy

The relationship of coronary anatomy to right ventricular (RV) appearance on serial thallium-201 myocardial imaging (TI) following dipyridamole (DP)-induced coronary vasodilation was examined in 71 consecutive patients undergoing coronary angiography for the evaluation of chest pain. Transient defects of the RV were found in 18 patients. All 18 had significant (≥ 50%) stenosis of the proximal right coronary artery (RCA). Nonvisualization of RV activity occurred in 13 patients. Six of these 13 (46%) had proximal RCA disease (p < 0.05 compared to transient defects). Normal RV appearance was seen in 40 patients, of whom only six (15%) had proximal RCA disease (p < 0.001 compared to transient defects). RV appearance was not affected by left anterior descending or left circumflex artery disease or by the thallium-201 uptake in the left ventricle. Thus with serial (initial and delayed) TI following DP (1) a transient RV defect appears to indicate significant proximal RCA disease; (2) normal RV appearance suggests the absence of proximal RCA disease; and (3) however, nonvisualization of the RV appears to be nondiagnostic.     

Reverse redistribution of thallium-201 detected by SPECT imaging after dipyridamole in angina pectoris

Reverse redistribution refers to a thallium-201 perfusion defect that develops or becomes more evident on delayed imaging compared with the initial image immediately after stress. To determine the diagnostic importance of reverse redistribution after intravenous dipyridamole, thallium-201 single photon emission computed tomography and quantitative coronary arteriography were performed in 90 men with angina pectoris. Of the 250 myocardial segments analyzed, reverse redistribution was present in 17 (7%). Minimal coronary cross-sectional area in proximal vessel segments was less than or equal to 2.0 mm2 more often in regions with transient perfusion abnormalities than in regions with reverse redistribution (66 vs 29%, p less than 0.05). Compared with regions exhibiting transient perfusion abnormalities, regions with reverse redistribution had larger proximal arterial diameters (1.9 +/- 1.1 vs 1.3 +/- 1.1 mm, p less than 0.001) and cross-sectional areas (3.9 +/- 3.1 vs 2.2 +/- 2.6 mm2, p less than 0.001). Coronary artery dimensions and relative stenosis severity did not differ between those regions with normal perfusion and those with reverse redistribution. Reverse redistribution detected by thallium-201 single photon emission computed tomographic imaging after dipyridamole is uncommon, appears to occur as frequently in normal subjects as in patients undergoing coronary arteriography and does not indicate the presence of severe coronary artery disease.     

The variable extent of jeopardized myocardium in patients with single vessel coronary artery disease: quantification by thallium-201 single photon emission computed tomography

To assess the extent of jeopardized myocardium in patients with single vessel coronary artery disease of variable severity and location, quantitative exercise thallium-201 single photon emission computed tomography was performed in 158 consecutive patients with angiographically proved single vessel coronary artery disease. The extent of abnormal left ventricular perfusion was quantified from computer-generated polar maps of three-dimensional myocardial radioactivity. Patients with only a moderate (51% to 69%) stenosis tended to have a small perfusion defect irrespective of the coronary artery involved. Whereas a perfusion defect measuring greater than or equal to 10% of the left ventricle was found in 78% of patients with no prior infarction and severe (greater than or equal to 70%) stenosis, this was observed in only 24% of patients with moderate stenosis. Perfusion defect size increased with increasing severity of stenosis for the entire group without infarction and for those with left anterior descending, right and circumflex coronary artery stenosis. However, the correlation between stenosis severity and perfusion defect size was at best only modest (r = 0.38, p = 0.0001). The left anterior descending artery was shown to be the most important of the three coronary arteries for providing left ventricular perfusion. Proximal stenosis of this artery produced a perfusion defect approximately twice as large as that found in patients with a proximal right or circumflex artery stenosis. However, marked heterogeneity in perfusion defect size existed among all three vessels despite comparable stenosis severity. This was most apparent for the left anterior descending coronary artery, where mid vessel stenosis commonly produced a perfusion defect similar in size to that found in proximally stenosed vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serial right ventricular thallium-201 imaging after exercise: Relation to anatomy of the right coronary artery

The relation of the appearance of the right ventricle on serium thallium-201 myocardial imaging to coronary artery anatomy was examined in 88 consecutive patients undergoing exercise thallium-201 testing and coronary angiography for the evaluation of chest pain. Transient defects in the right ventricle were found in 8 patients. All had high grade (≥ 90 %) stenosis of the proximal right coronary artery. Nonvisualization of right ventricular (RV) activity occurred in 10 patients. Nine of the 10 (90%) had significant (>- 50% stenosis) disease of the proximal right coronary artery and 7 (70%) had high grade stenosis. The right ventricle appeared normal in 70 patients. Twenty-nine (41 %) of these patients had significant proximal right coronary artery disease. Right ventricular appearance was not affected by the presence or absence of disease of the left anterior descending or left circumflex artery or by the appearance of the left ventricle.

Thus, with serial RV thallium-201 myocardial imaging after exercise, we found that (1) RV transient defects suggest the presence of high grade proximal right coronary artery stenosis, (2) nonvisualization of RV activity also predicts significant proximal right coronary disease, and (3) the right ventricle frequently appears normal despite proximal right coronary artery disease and therefore this finding does not exclude such disease.     

Adenosine Thallium-201 Tomography in Evaluation of Graft Patency Late After Coronary Artery Bypass Graft Surgery

Objectives. We sought to ascertain the utility of adenosine thallium-201 tomography for assessing graft stenoses late after coronary artery bypass graft surgery.Background. Although pharmacologic perfusion imaging has been increasingly used in the assessment of patients with coronary artery disease, the value of this stress modality for detecting coronary artery bypass graft stenosis late after surgery is unknown.Methods. We studied 109 patients who underwent both adenosine thallium-201 tomography and coronary angiography at 6.7 ± 4.8 (mean ± SD) years after coronary artery bypass graft surgery. Adenosine thallium-201 tomography was assessed quantitatively by computer-generated polar maps of the myocardial thallium-201 activity.Results. On coronary angiography, significant graft stenoses were present in 68 patients, 65 of whom had a corresponding perfusion defect as shown by thallium-201 tomography (sensitivity 96%). Significant stenoses were present in 107 (37.8%) of 283 grafts. The overall specificity by quantitative tomography was 61%. Seventy percent of the apparently false positive perfusion defects could be explained on the basis of unbypassed native disease or by the presence of fixed defects in patients with previous myocardial infarction.Conclusions. Thus, results of adenosine thallium-201 tomography are nearly always abnormal in patients with late coronary graft stenosis. Most of the false positive defects appear to be due to either unbypassed native disease or a previous myocardial infarction.(J Am Coll Cardiol 1997;29:1290–5)     

Atrial pacing with two-dimensional echocardiography for evaluation of chest pain: comparison with thallium 201 scintigraphy

Atrial pacing was performed with two-dimensional (2-D) echocardiography and thallium 201 scintigraphy in 40 men with stable chest pain. Coronary angiography showed significant (one or more lesions greater than or equal to 50%) coronary artery disease (CAD) in 36 patients and no or insignificant CAD in 4. Two dimensional echocardiography showed a left ventricular wall motion abnormality (WMA) either at rest or with pacing in 28 (78%) patients with CAD, with 17 (47%) showing a new or worsened WMA with pacing. A thallium scan showing abnormality (reversible or fixed perfusion defect) was seen in 26 (72%) patients with CAD; 18 (50%) had a reversible defect. In all, 34 of the 36 patients with CAD (94%) had a WMA, a perfusion defect, or both (specificity 50%). Occurrence of both a WMA and a perfusion defect in individual segments ranged from 10 of 25 patients with septal abnormalities to 0 of 12 with abnormalities of the lateral segment. Sensitivity of 2-D echocardiography for identifying CAD in specific vessels was 81% for the left anterior descending (LAD) artery, 30% for the right coronary artery, and 20% for the circumflex artery (both p less than .001 compared with the LAD artery). Corresponding sensitivities for thallium 201 imaging were 54% (p less than .05 compared with 2-D echocardiography), 27%, and 8% (both p less than .05 compared with the LAD artery). When combined with atrial pacing, 2-D echocardiography and thallium 201 perfusion imaging are of similar value for diagnosing the presence of CAD in patients with stable chest pain. Two-dimensional echocardiography is superior to thallium 201 imaging for identifying the presence of significant CAD in the LAD artery, but both tests are limited in their ability to detect lesions of the right coronary or circumflex arteries.