Validation of left ventricular volume measurements by gated SPECT 99mTc-labeled sestamibi imaging.

BACKGROUND: Previous studies have shown that gated single photon emission computed tomography (SPECT) technetium 99-labeled sestamibi imaging provides accurate and reproducible measurement of left ventricular (LV) ejection fraction (EF), wall motion, and thickening. This study examined the reliability of gated SPECT sestamibi imaging in measuring LV end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV). METHODS AND RESULTS: Gated SPECT measurements were compared with an independent nongeometric method based on thermodilution SV and first-pass radionuclide angiographic EF (using a multicrystal gamma camera). Twenty-four patients aged 58+/-11 years underwent cardiac catheterization and coronary angiography for evaluation of chest pain syndromes. None had primary valvular disease, intracardiac shunts, or atrial fibrillation. RESULTS: The correlation between the two methods were as follows: EDV: r = 0.89, P<.001; ESV: r = .938, P<.001; SV: r = 0.577, P<.001. Bland-Altman plots showed mean differences (+/-standard deviation [SD]) for EDV of -14.3+/-33.3 mL, for ESV of -0.4+/-23.7 mL, and for SV of -13.9+/-15.2 mL. The reproducibility of measuring EDV and ESV by gated SPECT was very high (r = 0.99 each). CONCLUSION: Gated 99mTc-labeled sestamibi SPECT provides reproducible LV volume measurements. With validation of volume measurement, gated SPECT provides comprehensive assessment of regional and global LV function. This information is important in many patient groups such as those with ischemic cardiomyopathy, concomitant coronary and valve disease, and those who have had myocardial infarction. It will also be useful to assess the incremental value of LV volumes in risk assessment.

Hemodynamic effects of arbutamine.

This study examined the hemodynamic effects of arbutamine, a synthetic catecholamine, in 12 patients with and 7 patients without coronary artery disease. Arbutamine produced a balanced positive inotropic (increase in left ventricular dp/dt) and chronotropic effect (increase in heart rate).

Correlation between hemodynamic changes and tomographic sestamibi imaging during dipyridamole-induced coronary hyperemia.

OBJECTIVES: The purposes of this study were to examine the effects of dipyridamole infusion on hemodynamic variables and to compare these changes with myocardial perfusion. BACKGROUND: Dipyridamole stress testing with myocardial perfusion imaging is widely used in the assessment of patients with known or suspected coronary artery disease (CAD). Few studies, however, have correlated the hemodynamic effects of dipyridamole using invasive monitoring with perfusion patterns in patients with chest pain syndromes. METHODS: Hemodynamic measurements were made in the cardiac catheterization laboratory with a Swan-Ganz thermodilution catheter before, during and after infusion of dipyridamole (142 microg/kg body weight per min for 4 min). Technetium-99m sestamibi was injected 3 min after the completion of the infusion. RESULTS: There were 20 patients with and 6 without CAD, as demonstrated by angiography. Compared with baseline values, dipyridamole resulted in an increase in pulmonary capillary wedge pressure (54 +/- 78% vs. 32 +/- 26%, p = NS), cardiac index (36 +/- 21% vs. 40 +/- 18%, p = NS) and stroke volume index (16 +/- 18% vs. 40 +/- 18%, p = NS) and a decrease in systemic vascular resistance (22 +/- 13% vs. 24 +/- 11%, p = NS), aortic pressure (2 +/- 9% vs. 0 +/- 6%, p = NS) and pulmonary vascular resistance (19 +/- 25% vs. 11 +/- 32%, p = NS) in patients with and without CAD. The peak effect of dipyridamole on heart rate, systemic vascular resistance and pulmonary capillary wedge pressure was evident at 3 min after infusion in 70% of patients. Aminophylline, given to 20 patients, improved hemodynamic variables within 2 min. The single-photon emission computed tomographic sestamibi images were normal in the 6 patients without and abnormal in the 18 patients with CAD. CONCLUSIONS: Dipyridamole-induced coronary hyperemia produces mild hemodynamic changes in patients with and without CAD; these changes are at or near peak effect at 3 min after infusion and are rapidly reversed by aminophylline.

Hemodynamic effects of intravenous sematilide in patients with congestive heart failure: a class III antiarrhythmic agent without cardiodepressant effects.

OBJECTIVES: This study sought to evaluate the hemodynamic effects of intravenous sematilide hydrochloride, a selective class III antiarrhythmic agent, in patients with heart failure and left ventricular systolic dysfunction. BACKGROUND: Class I antiarrhythmic agents, which primarily slow conduction, can depress ventricular function, particularly in patients with heart failure. In contrast, pure class III agents, which selectively prolong repolarization, do not adversely affect hemodynamic variables in animal models, but there are no data evaluating their hemodynamic effects in humans. METHODS: In 39 patients with congestive heart failure and a left ventricular ejection fraction < 40%, hemodynamic and electrocardiographic measurements were obtained at baseline, after a loading dose and during a maintenance infusion of intravenous sematilide using either a low (0.75 then 0.3 mg/min) or high dose (1.5 then 0.6 mg/min) regimen. The study had an 80% power to detect clinically meaningful differences in hemodynamic variables. RESULTS: Both low (n = 20) and high (n = 19) dose sematilide infusions produced dose-dependent increases in QT interval (5 +/- 8% [mean +/- SD] and 18 +/- 10%, respectively) and corrected QT interval (4 +/- 8% and 14 +/- 10%), and high dose sematilide decreased heart rate by 7 +/- 10% (all p < 0.025 vs. baseline). Neither dose regimen had a statistically significant effect on any other hemodynamic variable, including mean arterial, right atrial, pulmonary artery and pulmonary capillary wedge pressures; cardiac index, stroke volume, systemic and pulmonary vascular resistances; and left ventricular stroke work index. Sematilide showed no adverse hemodynamic effects in patients with left ventricular ejection fraction < or = 25% or > 25% and in patients with cardiac index < 2 or > or = 2 liters/min per m2. Sustained polymorphic ventricular tachycardia (n = 1) and excessive QT prolongation (n = 4) were seen during the high dose. CONCLUSIONS: Sematilide, in the doses administered, prolonged repolarization but did not alter hemodynamic variables in patients with heart failure. These data suggest that class III antiarrhythmic agents, which selectively prolong repolarization, are not cardiodepressant but may be proarrhythmic in humans, especially at high doses.

Use of a tantalum-178 generator and a multiwire gamma camera to study the effect of the Mueller maneuver on left ventricular performance: comparison to hemodynamics and single photon emission computed tomography perfusion patterns.

During the Mueller maneuver, there is a decrease in intrathoracic pressure and an increase in transmural left ventricular pressure. The changes in loading conditions cause transient left ventricular dysfunction. This study examined the effects of the Mueller maneuver on left ventricular performance using tantalum (Ta)-178 (half-life 9.3 min) and a multiwire gamma camera. First-pass radionuclide angiograms were obtained at baseline and during Mueller maneuver in 41 patients aged 58 +/- 10 years. In 34 patients, stress single photon emission computed tomography (SPECT) myocardial perfusion imaging with thallium-201 or sestamibi was also performed. Hemodynamic measurements during the Mueller maneuver (n = 10) showed a decrease in systemic pressure (139 +/- 25 mm Hg vs 123 +/- 24 mm Hg, p < 0.001) and pulmonary artery pressure (24 +/- 6 mm Hg vs 14 +/- 12 mm Hg, p = 0.01) and an increase in heart rate (67 +/- 10 bpm vs 75 +/- 14 beats/min, p = 0.001). Among the 34 patients who had perfusion imaging, the left ventricular ejection fraction remained unchanged or increased in 17 patients (group 1) (48% +/- 19% vs 49% +/- 21%, p not significant) and decreased (> or = 5%) in 17 patients (group 2) (55% +/- 13% vs 40% +/- 16%, p = 0.001). The stress SPECT images showed no or only fixed defects in 11 (65%) patients in group 1 and 3 (18%) patients in group 2 (p = 0.02), and reversible defects in 6 (35%) patients in group 1 and 14 (82%) patients in group 2 (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular applications of fluorocarbons: current status and future direction--a critical clinical appraisal.

Alteration of normal blood flow to the heart may result in myocardial ischemia or infarction. Perfluorochemical emulsions offer a potential means to improve oxygenation of the heart during periods of hypoxia. The small particle size and linear disassociation curve of perfluorochemicals may result in greater oxygen delivery than blood particularly in severely diseased or damaged atherosclerotic vessels. Intracoronary Fluosol given during PTCA reduces the myocardial ischemia which occurs during balloon inflation. Although Fluosol does not prevent myocardial dysfunction during prolonged balloon inflations, new concentrated perfluorochemicals have increased oxygen delivery capacity and may have greater benefit. Experimentally, during coronary occlusions, perfluorochemicals promote higher oxygen tension in areas of ischemia and result in infarct size reduction. Reduction of oxygen free radicals has been proposed as the mechanism by which Fluosol exerts its ability to reduce infarct size. Clinical studies with Fluosol and thrombolytic therapy for treatment of acute myocardial infarctions are ongoing to assess ability to preserve myocardial function. Perfluorochemical cardioplegia can deliver oxygen during periods of cardiac arrest and may improve immediate post CPB myocardial function particularly in those patients with pre-existing left ventricular dysfunction. The oxygen-carrying capacity of perfluorocarbons and its unique properties offer great advantages to improve the treatment of cardiovascular diseases.

Identification of high-risk patients with left main and three-vessel coronary artery disease by adenosine-single photon emission computed tomographic thallium imaging.

The purpose of this study was to examine the ability of SPECT imaging with thallium-201 during adenosine-induced coronary hyperemia to detect high-risk patients with left main or three-vessel CAD. There were 339 patients: 102 with either left main or three-vessel CAD (group 1) and 237 with no CAD, one-, or two-vessel disease (group 2). By means of univariate analysis, several variables were found to differ between groups 1 and 2: Q wave myocardial infarction (35% vs 25%, p < 0.05), ST segment depression (35% vs 19%, p < 0.001), age (67 +/- 9 vs 62 +/- 10 years, p < 0.001), resting systolic blood pressure (142 +/- 22 vs 135 +/- 20 mm Hg, p < 0.01), abnormal thallium images (95% vs 74%, p < 0.0001), multivessel thallium abnormality (76% vs 39%, p < 0.0001), extent of thallium abnormality (24 +/- 11% vs 19 +/- 13%, p < 0.0001), and increased lung thallium uptake (39% vs 15%, p < 0.01). According to stepwise discriminant analysis, only three variables were predictors of high risk: multivessel thallium abnormality (chi 2 = 27), increased lung thallium uptake (chi 2 = 10), and ST depression (chi 2 = 5). On the basis of these variables, patients were divided into three groups with different prevalence rates for left main and three-vessel CAD: 63% in 68 patients, 30% in 137 patients, and 13% in 137 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of adenosine on coronary blood flow and its use as a diagnostic test for coronary artery disease.

Myocardial perfusion imaging during adenosine induced coronary hyperaemia is a highly sensitive method for diagnosing coronary artery disease. Most perfusion defects reflect heterogeneity in coronary blood flow in the territories of normal and diseased coronary arteries. Myocardial ischaemia can occur, however, due to subendocardial hypoperfusion and coronary artery steal. Evidence for myocardial ischaemia is more difficult to document in clinical than in experimental studies, and includes abnormalities in the ST segment, wall motion, haemodynamic variables, metabolism, and coronary blood flow responses. Using these indices, myocardial ischaemia may occur in some patients with coronary artery disease but it is not a prerequisite for the development of perfusion abnormalities and for the diagnosis of coronary artery during adenosine stress testing.

Identification of high-risk patients with left main and three-vessel coronary artery disease using stepwise discriminant analysis of clinical, exercise, and tomographic thallium data.

This large-scale study examined the ability of stepwise discriminant analysis of clinical, exercise, and thallium tomographic data to detect high-risk patients with three-vessel or left main disease. There were 834 patients, 229 with three-vessel or left main disease (group 1) and 605 (group 2) with either two-vessel disease (n = 236), one-vessel disease (n = 195), or no coronary artery disease (n = 174). The two groups were different in age, exercise heart rate, ST segment depression during exercise, exercise systolic blood pressure, abnormal thallium scans, reversible perfusion defects, extent of thallium abnormality, number of vascular territories with perfusion abnormalities, left ventricular cavity dilatation, and increased lung thallium uptake. On multivariate stepwise discriminant analysis, only three variables were independent predictors of high risk. These included multivessel thallium abnormality (F = 107, p < 0.001), exercise heart rate (F = 27, p < 0.001), and ST segment depression (F = 8, p < 0.01). Based on these three variables, patients could be stratified into three categories with different prevalences of left main or three-vessel disease; the prevalence was 53% in 239 patients, 24% in 271 patients, and 12% in 324 patients. Thus high-risk patients with left main or three-vessel disease can be identified by exercise thallium tomographic imaging that uses a model based on stepwise discriminant analysis. The thallium data are far more powerful than the clinical or treadmill exercise data.

Early thallium imaging after percutaneous transluminal coronary angioplasty: tomographic evaluation during adenosine-induced coronary hyperemia.

This study examined the immediate results of 201Tl imaging during adenosine-induced coronary hyperemia in 25 patients with one-vessel coronary artery disease, 4 +/- 3 days after percutaneous transluminal coronary angioplasty (PTCA). There were special features in our study: use of quantitative angiography and single-photon emission computed tomography (SPECT); a homogeneous group of patients (one-vessel disease) and a uniform stress (adenosine infusion). As a group, quantitative coronary angiography showed a decrease in percent diameter stenosis from 72% +/- 12% to 23% +/- 14%, p < 0.001. The thallium images were normal in 17 patients and abnormal in eight patients. However, of the eight patients, four had residual stenosis either in a secondary branch or downstream; one patient had local dissection (the residual stenosis could not be assessed reliably), two patients had > 50% residual diameter stenosis, and one patient had previous Q-wave myocardial infarction with a corresponding fixed thallium defect. In each of the eight patients with an abnormal image, a logical explanation could be identified. Thus, our results suggest that maximum reactive coronary hyperemia returns to normal immediately after PTCA, and that abnormal thallium results are due to inadequate dilatation or associated lesions.

The perfusion pattern in coronary artery occlusion: comparison of exercise and adenosine.p6.

This study compared exercise to adenosine thallium-201 single photon emission computed tomography in detecting occlusion of left anterior descending or right coronary arteries in patients with no previous myocardial infarction. There were 41 patients who underwent adenosine thallium imaging (adenosine infusion at a rate of 140 micrograms/kg/min for 6 min), and 143 patients who underwent exercise thallium imaging. There were more patients with right coronary than left anterior descending coronary artery occlusion. Thus, in the adenosine group, there were 15 patients with left anterior descending artery occlusion, and 26 with right coronary artery occlusion, and in the exercise group, there were 46 patients with left anterior descending artery occlusion, and 97 patients with right coronary artery occlusion. In the adenosine group, the thallium images were abnormal in 41 patients (100%), while in the exercise group, the thallium images were abnormal in 125 patients (87%, P < 0.02) in the territories of the occluded arteries. ST segment depression was noted in 19 patients (46%) in the adenosine group, and 69 patients (48%) in the exercise group (P:NS). In patients with isolated single vessel occlusion, the size of the perfusion abnormality was 28 +/- 9% with adenosine, and 21 +/- 12% with exercise (P:NS). Thus, most patients with occlusion of the left anterior descending or right coronary artery have regional perfusion abnormality during stress; the different role of collaterals with each type of stress may explain the higher percentage of abnormal results with adenosine than exercise.

Effect of intravenous adenosine infusion on myocardial perfusion and function. Hemodynamic/angiographic and scintigraphic study.

BACKGROUND: Myocardial perfusion imaging during adenosine-induced hyperemia with dipyridamole or adenosine is an accepted method to diagnose coronary artery disease (CAD) and risk assessment. The mechanism of perfusion abnormality may be caused by disparate flow responses or coronary steal. This study examined the relation between 201Tl perfusion pattern and hemodynamic/angiographic changes during intravenous adenosine infusion. METHODS AND RESULTS: Patients with suspected CAD underwent sequential hemodynamic, coronary arteriographic, and left ventriculographic studies simultaneously with 201Tl imaging during adenosine infusion (140 micrograms.kg-1.min-1 for 6 minutes). There were 33 patients with CAD and 12 patients without CAD. The 201Tl images (using single-photon emission computed tomography) were abnormal in 31 patients with CAD (sensitivity, 94%) and normal in the patients without CAD (specificity, 100%). In patients with and without CAD, there were significant increases in heart rate and cardiac output (p less than 0.0001) and decreases in systemic vascular resistance and blood pressure (p less than 0.0001). There was a 77 +/- 38% increase in pulmonary capillary wedge pressure in normal subjects and a 125 +/- 83% increase in patients with CAD (p = 0.02). ST segment depression was observed in 11 patients with CAD (33%). In CAD patients, there was no change in percent diameter or area stenosis measured quantitatively during adenosine infusion. In 15 patients, contrast left ventriculography was repeated during adenosine infusion. In these patients, 201Tl perfusion defects were seen in 31 of 75 segments (41%) whereas only six of 75 segments (8%) developed regional wall motion abnormality (p less than 0.001); the remaining segments showed either no change or improved function. The left ventricular ejection fraction did not change significantly (73% versus 75%). CONCLUSIONS: There is a disparity between the effects of adenosine on left ventricular perfusion and function; most patients with CAD have perfusion defects whereas the global and regional systolic function remains unchanged or improves. Diastolic left ventricular dysfunction is a probable mechanism of the increase in pulmonary capillary wedge pressure.

Atrioventricular block during adenosine thallium imaging.

Transient atrioventricular (AV) block has been reported during adenosine thallium imaging. This study examined the predictors and hemodynamic implications in 55 patients who had second- or third-degree AV block (group 1) and compared the results with those in 803 patients who did not have AV block (group 2). There were no significant differences in age, sex, or heart rate at baseline between the two groups. ST segment depression was observed in 25% of patients in group 1 and 16% in group 2 (p = NS). Chest pain occurred in 56% in group 1 and 44% in group 2 (p = NS). Preexisting conduction abnormalities (17% vs 16%) and treatment with digitalis (15% vs 15%) and beta-blockers (31% vs 36%) were similar in the two groups. The results of thallium imaging were abnormal in 66% in group 1 and 67% in group 2 (p = NS). Reversible thallium defects were seen in 51% in group 1 and 52% in group 2 (p = NS). The AV block appeared during the first 2 minutes of infusion in 40 patients (73%) and disappeared despite continuation of infusion in 43 (78%). The heart rate during AV block was 79 +/- 18 beats/min, and the systolic blood pressure was 127 +/- 27 mm Hg. Premature termination of adenosine infusion was required in one patient (2%). Aminophylline was used in 5% in group 1 and 2% in group 2 (p = NS). Thus AV block is transient, occurs during the early minutes of infusion, is not aggravated by digitalis or beta-blocker therapy, can be seen in patients with normal perfusion images, and is often well tolerated.

Delayed resolution of obstructing thrombus following acute closure.

A case of acute thrombotic closure following percutaneous coronary angioplasty demonstrating delayed clearance of obstructing thrombus is reported. Although common in other clinical scenarios this has not been reported following coronary angioplasty.

Preservation of myocardial function during ischemia with intracoronary perfluoroocytlbromide (Oxygent).

UNLABELLED: The effects of intracoronary infusion (24 ml/min) of oxygenated perfluoroocytlbromide (PFOB) or autologous blood on regional myocardial function and hemodynamics were studied during a 2 min perfused occlusion in nine open chest dogs to determine if a PFOB infusion could prevent the myocardial dysfunction observed during the balloon occlusion of percutaneous transluminal coronary angioplasty (PTCA). Regional myocardial function was measured with sonomicrometers in the ischemic and non-ischemic zone to determine segment length and percent of systolic shortening (% delta L). Without infusion, the ischemic zone in each animal developed akinesis during a 20 sec coronary occlusion. Each animal underwent a 2 min infusion of blood and PFOB at 24 ml/min. During the 2 min perfused occlusion, the blood ischemic zone % delta L of 14.4 +/- 3.1 versus a PFOB % delta L of 23.4 +/- 2.9. % delta L of blood and PFOB were not as significantly different from control (P less than .05 PFOB vs. blood). The bromine ion in PFOB results in a radiodense compound. Adequate images of the canine left ventricle and coronaries were obtained using DSA. CONCLUSION: (1) PFOB infusion maintains normal myocardial function during perfused coronary inclusion. (2) PFOB may be used as an oxygen carrying contrast agent to obtain DSA images.

Dynamics of coronary occlusion in the pathogenesis of myocardial infarction.

In most coronary artery stenoses in humans, lumen size decreases in response to acute vasoconstriction, reduced aortic pressure or passive collapse. Because the effects of vasoconstriction and plaque rupture with thrombus formation are additive, in some cases total cessation of flow may result from only minimal obstruction by thrombus. This hypothesis was investigated with use of a previously developed model of the coronary circulation in which the pressure drop across and flow through an arterial stenosis were determined by standard hemodynamic equations. The vessel wall was assumed to be composed of pliable and rigid sections, as is the case in most arterial stenoses in humans. The computer analysis was conducted for a rigid stenosis and for a dynamic stenosis in which proximal artery constriction and distal collapse were simulated. Plaque rupture with subsequent thrombus formation was simulated as a decrease in lumen area without effect on the arterial wall. Compared with a dynamic stenosis, a rigid stenosis required a significantly larger thrombus for vessel occlusion. Thrombus formation equal to the nonobstructed area of the lumen was required to occlude a rigid vessel; a 60% stenotic vessel required a 40% plaque rupture with thrombus formation for occlusion. However, for a dynamic stenosis, if vasoconstriction and passive collapse were simulated, small plaque ruptures led to vessel occlusion: a 60% stenotic vessel required only a 12% plaque rupture with thrombus formation for occlusion. This analysis indicates that even mild coronary lesions may be responsible for myocardial infarction, suggesting that vasomotion may be a very important element in the pathogenesis of most myocardial infarcts.

Assessment of coronary artery disease using single-photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia.

Thallium-201 myocardial imaging during dipyridamole-induced coronary hyperemia has been an accepted method for diagnosing coronary artery disease (CAD) and risk stratification. Adenosine is a powerful short-acting coronary vasodilator. Initial results of thallium imaging during adenosine infusion have been encouraging. In 132 patients with CAD and in 16 patients with normal coronary angiograms, adenosine was given intravenously at a dose of 0.14 mg/kg/min for 6 minutes and thallium-201 was injected at 3 minutes. The thallium images using single-photon emission computed tomography were abnormal in 47 of the 54 patients (87%) with 1-vessel, in 34 of 37 patients (92%) with 2-vessel and in 40 of 41 patients (98%) with 3-vessel CAD. The sensitivity was 92% in the 132 patients with CAD (95% confidence intervals, 86 to 96%). In patients with normal coronary angiograms, 14 of 16 patients had normal thallium images (specificity, 88%; 95% confidence intervals, 59 to 100%). The results were very similar when subgroups of patients were analyzed: those without prior myocardial infarction, elderly patients and women. The nature of the perfusion defects (fixed or reversible) was assessed in relation to whether the 4-hour delayed images were obtained with or without the reinjection technique. In patients who underwent conventional delayed imaging, there were more fixed perfusion defects than in patients with reinjection delayed imaging (16 vs 0%, p less than 0.0001). The adverse effects were mild, transient and well tolerated. Thus, adenosine thallium tomographic imaging provides a high degree of accuracy in the diagnosis of CAD. The use of the reinjection technique enhances the ability to detect reversible defects.

Single photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia: correlation with coronary arteriography, exercise thallium imaging and two-dimensional echocardiography.

The feasibility, safety and diagnostic accuracy of single photon emission computed tomography (SPECT) with thallium-201 imaging during adenosine-induced coronary hyperemia were evaluated in 53 patients with and 7 without coronary artery disease proved by coronary angiography. Adenosine was infused intravenously at a dose of 0.14 mg/kg body weight per min for 6 min and thallium was injected at 3 min. Adenosine caused an increase in heart rate (68 +/- 12 at baseline versus 87 +/- 18 beats/min at peak effect, p less than 0.0001) but no change in blood pressure. The sensitivity and specificity were 92% (95% confidence intervals 81% to 98%) and 100% (95% confidence intervals 59% to 100%), respectively; 20 (61%) of 33 patients with multivessel coronary artery disease were also correctly identified. In 30 patients, the predictive accuracy of adenosine thallium imaging was slightly higher than that of exercise SPECT thallium imaging (90% versus 80%, p = NS) (95% confidence intervals 72% to 97% and 61% to 92%, respectively). In 25 patients, two-dimensional echocardiography during adenosine infusion disclosed a new wall motion abnormality in 2 (10%) of 20 patients with coronary artery disease; 80% of these patients had reversible thallium defects (p less than 0.001). Side effects were mild and transient; aminophylline was used in only three patients. Thus, adenosine SPECT thallium imaging provides a high degree of accuracy in the diagnosis of coronary artery disease. The results are comparable with those of exercise SPECT thallium imaging. Most reversible defects in the adenosine study are not associated with any transient wall motion abnormality.