• Clinical Abstracts

    Clinical Abstracts on Transesophageal Atrial Pacing during Scintigraphic Tomography Exams

    Diagnosis of coronary artery disease with Tc 99m-methoxy isobutyl isonitrile and transesophageal pacing. Santomauro M, Cuocolo A, Celentano L, Ferraro S, Pace L, Pappone C, Maddalena G, Salvatore M, Chiariello M. Federico II University, Naples. Angiology 1992;43(10):818-25   Recently the use of a new radioactive agent with physical and biological properties more favorable than those of thallium 201, methoxy-isobutyl-isonitrile (MIBI) labeled with technetium 99m (Tc 99m), has permitted simultaneous performance of perfusion and function studies in ischemic cardiopathy. Transesophageal atrial pacing (TAP) technique has evolved as an alternative provocative test of ischemia. The authors compared the capability of Tc 99m-MIBI myocardial scintigraphy, combined with TAP, with that of Tc 99m-MIBI, combined with maximal stress test, in the diagnosis of ischemic cardiopathy. They studied 11 patients with a clinical history of angina pectoris. Myocardial scintigraphy was performed at rest, after stress test, and after TAP. Finally, all the patients underwent coronary angiography. The analysis of myocardial perfusion images on both Tc 99m-MIBI associated with TAP and with stress demonstrated, in 165 myocardial segments examined: 143 normal, 20 reversible defects, 2 irreversible defects. The concordance of localization between coronarographic data and scintigraphic reversible and irreversible defects was 85%. In conclusion TAP proves to be a valid and sensitive provocative test of ischemia when combined with myocardial scintigraphy and with Tc 99m-MIBI.

    Value of thallium 201 myocardial scintigraphy under transesophageal atrial stimulation for the diagnosis of coronary disease. Le Feuvre C; Vacheron A; Metzger JP; Berdah J; Etienne D; Albarede P; De Vernejoul P. Ann Med Interne (Paris) (France), 1991, 142(5) p325-9.   Fifty patients hospitalized for chest pain underwent coronary angiography, and thallium-201 myocardial scintigraphy after exercise (TE) and under transesophageal atrial stimulation (TST). The double product mean during exercise was 2,223 +/- 579 beats x cmHg/min and 2,313 +/- 420 beats x cmHg/min under TST (NS). The criterion of positivity was early hypofixation. Thallium redistribution 4 hours after administration is indicative of reversible ischemia. Thirty-six patients had more than 50% narrowing in at least one of the three principle coronary arteries. The predictive sensitivity for coronary stenosis was 83% for TE and 94% for TST. The respective specificities were 71 and 78%. The comparison of segmental hypoperfusion after exercise and under TST gave similar results in 230 of the 250 segments studied (92%). Thus, TST provides and alternative diagnostic method to TE for the detection of coronary artery disease and can be performed in patients for whom the usual stress test is not possible, most particularly when dipyridamole is counter indicated because of a bronchospastic factor.

    Usefulness of radionuclide ventriculography during transesophageal atrial pacing in the diagnosis of coronary artery disease. Le Feuvre C, Georges JL, Metzger JP, Etienne D, Albarede P, de Vernejoul P, Vacheron A. Necker Hospital, Paris, France. Angiology 1994 Jul;45(7):621-8. Radionuclide ventriculography before, during, and after atrial transesophageal pacing was carried out in 15 patients with suspected coronary artery disease (CAD) and without myocardial infarction. All patients underwent coronary angiography. Ten patients (group 1) had a coronary lesion > 50% on at least one of the main coronary arteries. Five patients (group 2) had normal coronary arteries. Radionuclide left ventricular ejection fraction (LVEF) before pacing was 56 +/- 3% in group 1 and 59 +/- 3% in group 2 (NS). Radionuclide ventriculography during pacing was 45 +/- 4% in group 1 (P < 0.0001 vs basal in group 1) and 45 +/- 6% in group 2 (P < 0.01 vs basal in group 2, NS vs group 1 during pacing). Immediate postpacing ejection fraction did not differ in the two groups and was identical to the prepacing value. A quantitative regional wall motion analysis was performed in 105 segments. Regional radionuclide ventriculography was calculated in each segment as follows: end-diastolic counts-end-systolic counts/end-diastolic counts. The relative decrease in regional LVEF during pacing was more important in the 39 segments related to a narrowed vessel than in the 66 segments related to normal coronary artery (32 +/- 13% vs 13 +/- 10%, P < 0.0001). A more than 20% relative decrease in at least one segment during pacing occurred in 10 patients in group 1 (sensitivity 100%) and in 2 patients in group 2 (specificity 60%). In conclusion, global radionuclide ventriculography during transesophageal atrial pacing decreases in patients with and without CAD.

    Technetium 99m SESTAMIBI myocardial perfusion imaging: comparison between treadmill, dipyridamole and trans-oesophageal atrial pacing "stress" tests in normal subjects. Primeau M, Taillefer R, Essiambre R, Lambert R, Honos G. Department of Nuclear Medicine, Hotel-Dieu de Montreal Hospital, University of Montreal, Quebec, Canada. Eur J Nucl Med 18(4):247-51, 1991. The purpose of this study was to determine the blood clearance, myocardial uptake and heart/lung and heart/liver ratios of technetium 99m methoxyisobutylisonitrile (99mTc-SESTAMIBI) following 3 different types of cardiac stimulation in normal subjects: treadmill stress (STRESS), intravenous administration of dipyridamole (DIP) and trans-oesophageal atrial pacing (TAP). Ten normal volunteers were submitted to 3 injections of 99mTc-SESTAMIBI (10 mCi/70 kg, separated by an interval of 7 days) following STRESS (standard Bruce protocol), DIP (0.142 mg/kg.min during 4 min) and TAP procedures. Blood samples were collected from 1 to 60 min after each 99mTc-SESTAMIBI injection. Planar imaging was performed at 5, 30 and 60 min. Blood retention (percentage of injected dose at 1 min) was 56% +/- 4%, 24% +/- 4% and 38% +/- 6% for STRESS, DIP and TAP, respectively (P less than 0.001). Myocardial uptake was similar for the 3 procedures while the heart lung ratio at 60 min was 3.1 +/- 0.5, 3.8 +/- 0.6 and 3.2 +/- 0.5 for STRESS, DIP and TAP, respectively. Heart/liver ratio at 60 min was 1.9 +/- 0.5, 1.3 +/- 0.3 and 1.1 +/- 0.2 for STRESS, DIP and TAP, respectively (P less than 0.001). These results demonstrated that the 3 types of cardiac stimulation show good imaging parameters with 99mTc-SESTA-MIBI. 

    The significance of scintigraphic, echocardiographic and electrocardiographic left atrial transesophageal pacing in diagnosis of ischemic heart disease. Kowalczyk R, Gawor Z, Maziarz Z, Goch A, Drobinski R, Malkowski B, Grycewicz T, Goch JH, Kosmider M, Adamus J. Klinika Kardiologii SK WAM w Lodzi. Pol Arch Med Wewn 1998 Mar;99(3):186-94. The aim of the study was to compare the perfusion scintigraphy (using SPECT method with Tc-99-MIBI) during left atrial transoesophageal pacing test (LAPT) with pacing electrocardiography (ECG), echocardiography (ECHO) and electrocardiography exercise test (ExT) in ischaemic heart disease (IHD) diagnostics. The effect of LATP on heart haemodynamic parameters and the correlation between scintigraphic, echocardiographic and electrocardiographic parameters during LAPT test have been also assessed. Investigations were carried out in 55 subjects (Group I: 36 patients with effort angina pectoris; group II: controls: 19 clinically healthy subjects). Coronarography was performed in 24 patients 6 weeks before or after examinations. LATP test was analyzed with ECG, ECHO and SPECT. Echocardiography did not increase significantly the LATP test diagnostic value. Perfusion scintigraphy enhanced sensitivity and predictive excluding value LATP test. These values were 93.3% v 62.9% and 90% v 59.3% respectively. LATP test assessed with ECG, ECHO and perfusion scintigraphy expressed significantly higher sensitivity and predicting excluding value in comparison to ExT. LATP test analyzed in such way was characterized by 100% sensitivity and 100% predicting excluding value. CONCLUSION: Combination of LATP with electrocardiography, echocardiography and SPECT is a non-invasive high quality method for ischaemic heart disease diagnostics.

    Comparison between exercise and trans-oesophageal atrial pacing in patients with coronary artery disease: technetium-99m methoxy isobutyl isonitrile simultaneous evaluation of ventricular function and myocardial perfusion. Cuocolo A, Santomauro M, Pace L, Celentano L, Nappi A, Nicolai E, Chiariello M, Salvatore M. Department of Nuclear Medicine, Second Medical School, Universita Federico II, Naples, Italy.  Eur J Nucl Med19(2):119-24, 1992. In this study we compared the results of exercise and trans-oesophageal atrial pacing (TAP) technetium-99m methoxyisobutyl isonitrile (99mTc-SESTAMIBI) cardiac imaging in the evaluation of left ventricular (LV) function and myocardial perfusion in patients with angiographically proven coronary artery disease. Ten patients (8 men and 2 women, mean age 59 +/- 6 years) were submitted to 3 separate injections of 99mTc-SESTAMIBI, one under control conditions, one after exercise and one after TAP. LV ejection fraction, as measured by electrocardiogram (ECG) gated first pass, decreased from 49 +/- 5% under control conditions to 42 +/- 6% during exercise (P less than 0.05 versus control) and to 43 +/- 8% during TAP (P less than 0.05 versus control and insignificant change versus exercise). Segmental myocardial perfusion analysis was performed on a total of 150 myocardial segments. On both exercise and TAP 99mTc-SESTAMIBI studies, 103 segmengts (69% of the total) were normal, 32 (21%) had reversible, and 15 (10%) irreversible, perfusion defects. Relative regional tracer uptake was not statistically different between exercise and TAP in normal regions (91.1 +/- 9.1% versus 90.7 +/- 8.5%, respectively), in regions with reversible (61.9 +/- 12% versus 62.4 +/- 10.4%, respectively) and irreversible perfusion defects (55.8 +/- 7.8% versus 58.8 +/- 9.5%, respectively). Our results demonstrated that 99mTc-SESTAMIBI TAP cardiac imaging shows similar results to 99mTc-SESTAMIBI exercise myocardial scintigraphy in the assessment of LV function and myocardial perfusion in patients with coronary artery disease. 

    Diagnostic value of the transesophageal atrial pacing stress for Tl-201 myocardial SPECT. Mashima Y, Ishinaga T, Komatsu C, Kawakami K. Department of Nuclear Medicine and Radiological Sciences, Tokyo Metropolitan Geriatric Hospital. Kaku Igaku 1990 Aug;27(8):877-81. The stress study for Tl-201 myocardial SPECT (single photon emission computed tomography) of a patient with old myocardial infarction, who had occasionally felt a chest pain for the last 8 months was performed with the transesophageal atrial pacing. The examination was fastly started and regular pacing rates were completely obtained for every pacing rate (50-100/min). In spite of a little amount of the pacing stress, the finding of stress induced ischemia and MI were obtained on this patient. This result suggests that the transesophageal atrial pacing stress might be useful for the evaluation of ischemic heart disease by Tl-201 myocardial SPECT, and is easily applied to the old and the patient with disorder of leg movement. 

    The pacing stress test: thallium-201 myocardial imaging after atrial pacing. Diagnostic value in detecting coronary artery disease compared with exercise testing. Heller GV; Aroesty JM; Parker JA; McKay RG; Silverman KJ; Als AV; Come PC; Kolodny GM; Grossman W.  J Am Coll Cardiol 1984, 3(5) p1197-204. Many patients suspected of having coronary artery disease are unable to undergo adequate exercise testing. An alternate stress, pacing tachycardia, has been shown to produce electrocardiographic changes that are as sensitive and specific as those observed during exercise testing. To compare thallium-201 imaging after atrial pacing stress with thallium imaging after exercise stress, 22 patients undergoing cardiac catheterization were studied with both standard exercise thallium imaging and pacing thallium imaging. Positive ischemic electrocardiographic changes (greater than 1 mm ST segment depression) were noted in 11 of 16 patients with coronary artery disease during exercise, and in 15 of the 16 patients during atrial pacing. One of six patients with normal or trivial coronary artery disease had a positive electrocardiogram with each test. Exercise thallium imaging was positive in 13 of 16 patients with coronary artery disease compared with 15 of 16 patients during atrial pacing. Three of six patients without coronary artery disease had a positive scan with exercise testing, and two of these same patients developed a positive scan with atrial pacing. Of those patients with coronary artery disease and an abnormal scan, 85% showed redistribution with exercise testing compared with 87% during atrial pacing. Segment by segment comparison of thallium imaging after either atrial pacing or exercise showed that there was a good correlation of the location and severity of the thallium defects (r = 0.83, p = 0.0001, Spearman rank correlation). It is concluded that the location and presence of both fixed and transient thallium defects after atrial pacing are closely correlated with the findings after exercise testing.

    Topography of preemptying ventricular segments in patients with Wolff-Parkinson-White syndrome using scintigraphic phase mapping and esophageal pacing. Chan WW, Kalff V, Dick M 2d, Rabinovitch MA, Jenkins J, Thrall JH, Pitt B. Circulation 1983 May;67(5):1139-46. We analyzed the sequence of ventricular emptying using the phase image in 10 patients with accessory pathways and in 15 normal subjects. In normal subjects, the earliest emptying occurred in ventricular septal, apical and left basal segments. Eight patients had manifest preexcitation; the earliest emptying occurred ectopically in the right ventricle in one of these patients and in the left ventricle in five. The remaining two patients had normal phase maps. Two patients had concealed left-sided pathways. Their phase maps showed earliest emptying in left basal segments. Six of the 10 patients underwent electrophysiologic mapping. There was complete agreement between phase and electrophysiologic maps. Transesophageal atrial pacing increased preexcitation in one patient, normalized the ECG in another and precipitated narrow QRS tachycardia in four patients. Phase maps then showed enlargement, reduction and loss of the ectopic earliest emptying segments, respectively. We conclude that this technique in conjunction with pacing is successful in lateralizing accessory pathways. 

    Comparison of the influence of stress exercise test and transesophageal cardiac pacing on polymorphonuclear neutrophils functions. Wysocki H, Minczykowski A, Wykretowicz A, Juniczak G; Smielecki J. Medical Academy, Poland. Arch Immunol Ther Exp (Warsz) 1995;43(3-4):187-90    Peripheral polymorphonuclear neutrophils (PMN) number, percent of PMN bearing IgG Fc receptors as well as PMN adherence were evaluated in 29 patients submitted to an exercise test. The peripheral PMN count significantly increased at the maximal work load. The increase in number of neutrophils bearing IgG Fc receptors was also noticed at that point, while PMN adherence to nylon wool columns did not change significantly. Nine subjects were additionally submitted to diagnostic transesophageal atrial pacing with a rate similar to maximal heart rate observed during the exercise test. It was revealed that atrial pacing in these patients had no influence on the peripheral PMN count, PMN adherence as well as number of neutrophils bearing IgG Fc receptors. We conclude, that granulocytosis observed during exercise can not be solely attributed to the increased heart rate and increased cardiac output but other mechanisms like muscle work play a significant role in this process.

    Atrial pacing with two-dimensional echocardiography for evaluation of chest pain: comparison with thallium 201 scintigraphy. Stratmann HG; Janosik DL; Mezei LE; Mark AL; Williams GA. St. Louis VA Med Ctr, Missouri. Angiology 1991, 42(11) p855-65. 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.

    Prognostic value of atrial pacing and thallium-201 scintigraphy in patients with stable chest pain. Stratmann HG; Mark AL; Walter KE; Williams GA. St. Louis VA Med Ctr. Am J Cardiol 1989, 64(16) p985-90. The value of atrial pacing and thallium-201 scintigraphy for assessing risk of subsequent cardiac events was examined in 210 patients with stable chest pain. Follow-up information was complete in 195 patients (mean age 61 years). Over an average follow-up of 19 months, cardiac events occurred in 38 patients--unstable angina in 20, nonfatal acute myocardial infarction in 6 and death from cardiac causes in 12. A history of previous myocardial infarction, diabetes mellitus, systemic hypertension or peripheral vascular disease at the time of pacing was not associated with an increased frequency of subsequent cardiac events. Six of 38 patients with later cardiac events had a history of congestive heart failure, compared with 8 of 157 without cardiac events (p less than 0.05). Neither pacing-induced angina, ST depression, nor the presence of a fixed perfusion defect was significantly more frequent in patients with cardiac events as a whole compared with patients without such events. Reversible defects and abnormal scans (reversible or fixed defects) were present, respectively, in 19 and 31 of 38 patients with cardiac events, compared with 42 and 79 patients, respectively, of the 157 patients without cardiac events (both p less than 0.01). In patients who developed unstable angina, a reversible defect was seen in 13 and an abnormal scan in 16 (both p less than 0.01 compared with patients without cardiac events). In 12 patients who died from a primary cardiac event, fixed defects were present in 8 and an abnormal scan in 11 (p less than 0.05 and p less than 0.01, respectively, compared with patients without cardiac events).

    Diagnostic value of atrial pacing and thallium-201 scintigraphy for the assessment of patients with chest pain. Stratmann HG; Mark AL; Walter KE; Williams GA. St. Louis VA Med Ctr. Clin Cardiol 1989, 12(4) p193-201. Atrial pacing was performed either alone (n = 23) or in combination with thallium-201 scintigraphy (n = 113) in 136 patients referred for evaluation of chest pain. The presence of coronary artery disease (CAD) was excluded by cardiac catheterization in 12 patients and confirmed in 124. Both pacing-induced ST depression and angina had sensitivities of 48% for CAD; specificities were 75% and 83%, respectively. An abnormal thallium-201 scan (one or more reversible and/or fixed perfusion defects) was seen in 72% of patients with CAD (specificity 83%). Reversible perfusion defects were present in 47% of patients with CAD (specificity 83%), and fixed defects in 36% (specificity 100%). Pacing was associated with either ST depression or an abnormal perfusion scan in 81% of patients (specificity 67%). There were no significant differences in the results of atria pacing or thallium-201 scintigraphy in patients with or without a history of myocardial infarction, or in those with or without previous coronary artery bypass surgery. Pacing-induced ST depression, or both ST depression and a reversible perfusion defect occurred significantly less frequently in patients with peripheral vascular disease than in those without this diagnosis (p less than .05). With only one exception, there were no significant differences in the sensitivities of any indicators of ischemia (ST depression, angina, or perfusion scans), either individually or in combination, as the peak pacing rate or double product achieved increased.

    Atrial pacing and thallium-201 scintigraphy in patients with chest pain: correlation with coronary anatomy. Stratmann HG; Mark AL; Walter KE; Williams GA. St. Louis VA Med Ctr. Clin Cardiol 1989, 12(4) p185-92.   Atrial pacing and thallium-201 scintigraphy were performed in 72 patients referred for evaluation of chest pain. Coronary artery disease (CAD) was present in 63 patients, as documented by cardiac catheterization performed at the same time or within 2 months of atrial pacing. Nine patients had no or insignificant (less than 50% stenosis) CAD. The sensitivity of pacing-induced angina for CAD was 51%, and was 49% for ST depression. Specificities were 89% and 78%, respectively. A reversible perfusion defect was seen in 54% of patients with CAD (specificity 89%), and a fixed defect in 29% (specificity 100%). The sensitivity of an abnormal thallium-201 scan (one or more reversible or fixed defects) was 79% (p less than 0.05 compared to angina or ST depression). Combined sensitivity of ST depression and/or an abnormal thallium-201 scan was 87%. There were no significant changes in any of these sensitivities as the number of vessels with CAD increased. Thallium-201 scintigraphy correctly identified 11 of 19 (58%) patients with single-vessel disease as having CAD in only one vessel, but underestimated the extent of disease in all but a few patients with multivessel disease. The sensitivity of perfusion imaging to identify lesions in specific vessels ranged from 27% (circumflex) to 57% (right coronary artery). Specificities were 100% for circumflex, 78% for anterior descending, and 83% for right coronary artery lesions.

    Hemodynamic determinants of thallium-201 lung uptake in patients during atrial pacing stress. Brown KA; McKay R; Heller GV; Royal HD; Parker JA; Silverman KJ; Aroesty. J Am Heart 1986, 111(1) p103-7. The present investigation was undertaken to define the hemodynamic determinants of lung uptake of thallium-201 (TI-201) in man during stress. Graded tachycardia was induced by atrial pacing with continuous hemodynamic monitoring in 21 patients (6 normal, 15 with coronary artery disease). At peak pacing, 80 MEq (2.2 mCi) of TI-201 was injected intravenously and imaging commenced within 5 minutes. Lung activity was expressed as a percentage of peak myocardial activity on the anterior image (Lung TI-201 Index). The influence of rest, peak and post pacing hemodynamic parameters including cardiac index, pulmonary capillary wedge pressure, left ventricular end-diastolic pressure, pulmonary artery pressure, and heart rate on Lung TI-201 Index was examined using step-wise multiple regression. Change in cardiac index from rest to peak pacing was negatively correlated, while pulmonary capillary wedge pressure at peak pacing was positively correlated to Lung TI-201 Index (combined r value of 0.75). No other parameter had a significant correlation. In summary, lung uptake of TI-201 activity during atrial pacing stress appears to depend on: changes in cardiac output which may determine tissue contact time and thus influence extraction efficiency, and hydrostatic pressure in the pulmonary capillary bed.

    Accuracy and usefulness of atrial pacing in conjunction with transesophageal echocardiography in the detection of cardiac ischemia (a comparative study with scintigraphic tomography and coronary arteriography). Don Michael TA, Rao G, Balasingam S. Kern Medical Center, Los Angeles. Am J Cardiol 1995 Mar 15;75(8):563-7. A comparative study of transesophageal echocardiography with single-photon emission computed tomography (SPECT) and coronary arteriography was performed in a community outpatient setting to determine accuracy and feasibility of the technique. Forty-one of 55 patients underwent all 3 procedures within a 90-day period. Fourteen patients underwent only SPECT and were compared with transesophageal echocardiography with pacing (TEEP). Atrial esophageal pacing was performed with transesophageal echocardiography to increase double product and induce ischemia, which would manifest as abnormal wall motion. The results in these patients indicated a sensitivity and specificity of 92% and 87% for TEEP and 96% and 82% for SPECT, respectively, using angiography as the gold standard. In 14 patients, the sensitivity of TEEP using SPECT as standard was 80% and the specificity was 87%. The 1 view that appeared to pick up the highest yield of abnormalities was the transgastric short-axis view. Thus, TEEP is indicated in the detection of chronotropically incompetent patients and those unable to exercise whose transthoracic images are not optimal. It is highly accurate compared with angiography or SPECT.

    Biplane transesophageal pacing echocardiography compared with dipyridamole thallium-201 single-photon emission computed tomography in detecting coronary artery disease. Norris LP, Stewart RE, Jain A, Hibner CS, Chaudhuri TK, Zabalgoitia M. University of TX Health Sci Ctr at San Antonio. Am Heart J 1993;126(3 Pt 1):676-85  TPE is a new diagnostic technique that uses simultaneous graded transesophageal left atrial pacing and biplane transesophageal echocardiography for the detection of pacing-induced wall motion abnormalities. In a prospective study 30 patients underwent biplane TPE, dipyridamole thallium-201 single-photon emission computed tomography (SPECT), and coronary arteriography. The sensitivity (86% vs 95%, p = not significant [NS]), specificity (89% vs 56%, p = NS), positive predictive value (95% vs 73%, p = NS), and negative predictive value (83% vs 83%, p = NS) of biplane TPE and thallium-201 SPECT in identifying patients with significant coronary artery disease was similar. In the 90 vascular territories analyzed, the agreement between biplane TPE and thallium-201 SPECT for presence or absence of significant disease was 71%. Analysis of the three major vascular territories demonstrated that each imaging modality had a high sensitivity and specificity in the left anterior descending and right coronary artery segments. However, the two techniques demonstrated poorly sensitivity in the segmental distribution of the circumflex coronary artery. In conclusion, biplane TPE compared favorably with thallium-201 SPECT in terms of safety and accuracy for detecting significant coronary artery disease. Accordingly, biplane TPE may be a suitable alternative for those patients with nondiagnostic thallium-201 SPECT studies and in those with contraindications to adenosine or dipyridamole.