Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Computer-enhanced thallium scintigrams in asymptomatic men with abnormal exercise tests

The use of treadmill testing in asymptomatic patients and those with an atypical chest pain syndrome is increasing, yet the proportion of false positive stress electrocardiograms increases as the prevalence of disease decreases. To determine the diagnostic accuracy of computer-enhanced thallium perfusion scintigraphy in this subgroup of patients, multigated thallium scans were obtained after peak exercise and 3 or 4 hours after exercise and the raw images enhanced by a computer before interpretations were made. The patient group consisted of 191 asymptomatic U.S. Air Force aircrewmen who had an abnormal exercise electrocardiogram. Of these, 135 had normal coronary angiographic findings, 15 had sub-critical coronary stenosis (less than 50 percent diameter narrowing) and 41 had significant coronary artery disease.

Use of computer-enhancement resulted in only four false positive and two false negative scintigrams. The small subgroup with subcritical coronary disease had equivocal results on thallium scintigraphy, 10 men having abnormal scans and 5 showing no defects. The clinical significance of such subcritical disease is unclear, but it can be detected with thallium scintigraphy.

Thallium scintigrams that have been enhanced by readily available computer techniques are an accurate diagnostic tool even in asymptomatic patients with an easily interpretable abnormal maximal stress electrocardiogram. Thallium scans can be effectively used in counseling asymptomatic patients on the likelihood of their having coronary artery disease.     

Evaluation of aortocoronary bypass using exercise myocardial thallium 201 scintigraphy

The surveillance of aortocoronary bypass grafts is a difficult problem. Clinical examination and exercise testing are unable to give a complete evaluation of the operative results and cardiac catheterisation with radiological opacification of the grafts are not without risk and cannot be repeated periodically. Therefore, radioisotopic methods have been proposed as a means of assessing aortocoronary bypass grafts. The aim of this study was to evaluate postoperative myocardial perfusion by Thallium 201 scintigraphy. The authors compared pre and postoperative scintigraphies in 37 patients undergoing aortocoronary bypass surgery (36 men and 1 woman, average age: 53.9 years). Preoperative coronary angiography showed 9 cases of single vessel disease, 11 cases of double vessel diseases and 17 cases of triple vessel disease. Seventy one bypass grafts were performed (average 1.92 grafts/patient): 37 on the LAD, 15 on the circumflex, 10 on the diagonal and 9 on the right coronary. All patients were submitted to the same protocol before surgery and during the third postoperative month; Clinical examination, ECG, exercise stress testing and Thallium 201 myocardial scintigraphy. The results confirm the improvement in myocardial perfusion after coronary bypass surgery. The percentage of pathological scintigraphic segments fell from 42 per cent before surgery to 27 per cent after surgery (p less than 0.01). The total Thallium perfusion index improved significantly after surgery from 9.3 +/- 2 to 7.7 +/- 1.9 (p less than 0.01). Thallium 201 scintigraphy was superior to clinical examination and exercise testing in the assessment of graft patency, identifying 2 postoperative infarctions inapparent on clinical examination, excluding postoperative non-anginal chest pain and evaluating myocardial perfusion in patients who had sub maximal postoperative exercise stress tests. The relatively non traumatic character of Thallium 201 scintigraphy makes it the best non-invasive method of assessing aortocoronary bypass graft patency.     

Use of dobutamine stress echocardiography in detecting silent myocardial ischaemia in asymptomatic diabetic patients: a comparison with thallium scintigraphy and exercise testing.

AIMS: Silent myocardial ischaemia is frequent in diabetic patients. The aim of this study was to compare the efficacy of thallium-201 single-photon emission computed tomography (201Tl SPECT) coupled with exercise stress testing (EST), and dobutamine stress echocardiography (DSE) in the detection of asymptomatic coronary artery disease. METHODS: Fifty-six asymptomatic diabetic patients, with a known duration of diabetes > 15 years for Type 1 and > 5 years for Type 2, having at least three added risk factors, but without rest ECG abnormalities, were enrolled in this prospective study. All of them were submitted to DSE with a maximum infusion rate of 40 microg/kg per min dobutamine +/- i.v. atropine, and to 201Tl SPECT coupled with EST. Coronary angiography was performed if at least one test was abnormal. RESULTS: Diabetic patients were 37 males and 19 females, aged mean (sd) 60 +/- 10 years, 10 Type 1 and 46 Type 2, with a known duration of disease of mean (sd) 17 +/- 9 years. Feasibility of DSE was 91%. No serious complication occurred during the test. Coronary angiography was performed in 26 patients (47%); 17 were abnormal (30% of the whole group): six patients had a one-vessel, six a two-vessel and five a three-vessel disease. Predictive positive value was 69% for DSE, 75% for 201Tl SPECT and 60% for EST. DSE was falsely negative in four cases vs. eight for 201Tl SPECT and nine for EST. CONCLUSIONS: Asymptomatic coronary disease is common in diabetes associated with other risk factors. DSE appears useful in its detection and a good alternative to 201Tl SPECT.     

Prevalence and prognostic significance of silent myocardial ischaemia detected by exercise test and continuous ECG monitoring after acute myocardial infarction

The incidence and prognostic significance of silent myocardial ischaemia in 165 patients who survived a first acute myocardial infarction were assessed by means of maximal exercise stress test and 24 h continuous ECG monitoring performed before discharge. During the 1 year follow-up period 10 cardiac deaths occurred; moreover seven patients suffered a fatal myocardial re-infarction and 14 developed unstable angina. Cardiac death occurred in five of 40 patients (12.5%) with ST segment depression on stress test by in only three of 117 (2.6%) without ST segment changes (P less than 0.01). One-hundred-and-three of 117 patients (88.0%) without angina or ST segment depression on stress testing survived 1 year without cardiac events, compared with 24 of 40 patients (60.0%) with ST segment depression whether or not associated with angina (P less than 0.001). Cardiac death occurred in five of 25 patients (20.0%) with ST segment depression on continuous ECG monitoring, compared with five of 140 (3.6%) without (P less than 0.01). One-hundred-and-seventeen out of 140 patients (83.6%) without angina or ST segment depression survived 1 year follow-up without cardiac events, compared with 13 of 25 (52.0%) with ST segment depression with or without angina (P less than 0.01). Classifying patients in a 2 x 5 contingency table according to the occurrence of ST segment depression on exercise testing and/or ECG ambulatory monitoring, the Yates corrected chi-square test showed a significant pattern when cardiac deaths and cardiac events were considered together (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of thallium myocardial scintigraphy after exercise and transoesophageal atrial pacing in the diagnosis of coronary artery disease.

Forty-nine patients admitted for assessment of chest pain underwent coronary angiography, planar Thallium 201 myocardial scintigraphy after submaximal exercise (TE) and transoesophageal atrial pacing (TAP). Early hypofixation with redistribution after 4 h indicated ischaemia. The criterion for a myocardial infarction (MI) was a fixed perfusion defect. Coronary angiography was carried out in all patients. Sixteen patients (group 1) had no MI and over 50% narrowing of at least one main coronary vessel. Ischaemia was noted in 10 of the 16 patients during exercise, and in 14 of the 16 patients during atrial pacing. The sensitivity for the prediction of coronary stenosis was 62% for TE and 87% for TAP. Nineteen patients (group 2) had had a previous MI. Reversible ischaemia was noted in 10 of the 19 patients during exercise, and in 11 of the 19 patients during TAP. Four of 14 patients with normal coronary arteries (group 3) had a reversible ischaemia with TE, and three of these same patients developed a positive scan with TAP. The respective specificities were 71% and 78%. Comparison of segmental hypoperfusion after TE and TAP gave identical results in 72 of the 80 segments studied in group I (90%), and in 88 of the 95 segments studied in group 2 (92%). The localizing value of TAP was good in left anterior descending (12 out of 18) and right coronary disease (16 out of 19), but poor in left circumflex stenosis (3 out of 9) misclassified as right coronary disease in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence and significance of an abnormal S-T segment response to exercise in a young athletic population

Treadmill stress electrocardiography is employed widely to detect underlying cardiovascular disease in asymptomatic persons. To determine the frequency and significance of an abnormal S-T segment response to exercise in young athletes with increased left ventricular (LV) mass induced by physical conditioning, 75 male isometrically trained athletes without evidence of heart disease (mean age 21 years) and 48 nonathletic young normal subjects were studied by M-mode echocardiography and exercise electrocardiography. Ventricular septal and posterior free wall thicknesses and calculated LV mass were significantly greater in athletes than in control subjects.

An abnormal S-T segment response to exercise was present in 7 (9%) of the 75 athletes, all of whom had a LV mass > 275 g and in 5 the LV mass was above the 95th percentile of that of the control subjects. An abnormal treadmill exercise test result also was present in 3 (6%) of 48 control subjects. Seven of the 10 subjects with abnormal exercise test results had radionuclide angiograms at rest and with exercise, each of which was normal. It is concluded, therefore, that (1) abnormal exercise test results occur commonly in both athletes and nonathletes; (2) almost 10% of isometrically trained athletes have “false-positive” exercise electrocardiograms, suggesting that this test has major limitations in screening for underlying cardiovascular disease in athletes; and (3) in athletes, a relation was present between “physiologically” increased LV mass and false-positive exercise test results.     

Prognostic value of exercise thallium scintigraphy in patients with good exercise tolerance and a normal or abnormal exercise electrocardiogram and suspected or confirmed coronary artery disease.

Exercise thallium scintigraphy is widely used to assess prognosis in patients with suspected or proven coronary artery disease. The incremental prognostic value of this technique in patients who have good exercise tolerance has not been well studied. Two hundred ninety-nine patients with known or suspected coronary artery disease without prior myocardial infarction or revascularization procedure referred for exercise myocardial perfusion imaging and able to exercise to greater than or equal to stage III of the Bruce protocol were included. After a mean follow-up of 50 +/- 10 months, there were 15 cardiac events (5%). The incidence of cardiac events was 10 versus 3% (p less than 0.001) in patients with an abnormal versus normal thallium-201 scan, and 9 versus 3% (p = 0.03) for an abnormal versus normal exercise electrocardiogram. When the 185 patients with a normal exercise electrocardiogram were examined, the incidence of cardiac events was 3% (5 of 150) in patients with a normal scan versus 0% (0 of 35) in patients with an abnormal scan. In the 114 patients with an abnormal exercise electrocardiogram, an abnormal thallium-201 scan was predictive of cardiac events (18% [8 of 44] versus 3% [2 of 70]; p = 0.006). Stepwise logistic regression analysis selected an abnormal thallium-201 scan and abnormal exercise electrocardiogram, low peak exercise heart rate, and male gender as independent variables associated with a significant increased risk of cardiac events. Thus, in patients with known or suspected coronary artery disease and good exercise tolerance, the addition of thallium-201 imaging in patients with an abnormal exercise electrocardiogram provides useful prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reverse redistribution on exercise thallium scintigraphy: relationship to coronary patency and ventricular function after myocardial infarction.

OBJECTIVE: To define prevalence, pathophysiology and relation to thrombolytic therapy of reverse redistribution (appearance of a new, or worsening of an existing, scintigraphic defect on 4 h delayed images compared with the stress thallium image). DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Referral centre. PATIENTS: Sixty-three patients with acute myocardial infarction. INTERVENTIONS: Tomographic exercise thallium scintigraphy, radionuclide angiography, and quantitative coronary angiography. MAIN RESULTS: Tomographic exercise thallium scintigraphy performed at day 10 revealed fixed defects in 15 patients, reversible defects in 22 patients and reverse redistribution in 26 patients; no difference in treatment assignment (tissue plasminogen activator versus placebo) was found among the three groups. Left ventricular function was similar in patients with fixed or reversible defects and reverse redistribution; global ejection fraction was 48 +/- 14, 51 +/- 10 and 48 +/- 5%, respectively, and regional infarct ejection fraction was 36 +/- 15, 40 +/- 13 and 37 +/- 18%, respectively. However, nitroglycerin administration resulted in a significantly greater improvement in regional ejection fraction in reverse redistribution patients (5 +/- 4%) than that in patients with fixed defect (2 +/- 5%, P < 0.05) or reversible defects (3 +/- 5%, P < 0.05). The infarct-related artery had a greater cross-sectional area in reverse redistribution patients (1.5 +/- 1.42 mm2) compared with those with reversible defects (0.50 +/- 0.26 mm2, P < 0.05), but was similar to fixed defect patients (1.04 +/- 0.88). CONCLUSIONS: Reverse redistribution on tomographic thallium scintigraphy is a frequent phenomenon (occurring in 40% of patients following acute myocardial infarction) and is independent of thrombolytic therapy. Patients with reverse redistribution have a more widely patent infarct-related artery and similar ventricular function, but significantly greater functional improvement following nitroglycerin administration compared with those with reversible or fixed defects. These data suggest myocardial salvage within the infarct zone in some patients with reverse redistribution.     

Prevalence and clinical significance of silent myocardial ischemia in exercise test

Prevalence of silent myocardial ischemia in exercise test was retrospectively reviewed from 749 tests performed for 513 patients with definite evidence of ischemic heart disease. The clinical significance was studied and absence of transient ischemia, occurrence of transient ischemia with and without pain were observed in 48%, 30% and 22% of the tests, respectively. Anginal pain was frequently observed in exercise tests for patients with severe coronary artery disease and low exercise tolerance. A large number of tests showing ischemic response were discontinued due to symptoms other than anginal pain and hence silent myocardial ischemia could be thought to be a result of ischemic state which does not reach the angina threshold. Silent myocardial ischemia was frequently observed during usual daily life. However, a definite correlation between severity of transient ischemia and presence or absence of chest pain in the same individuals was not obtained from the study. A day to day variation in the angina threshold might be responsible. In general, silent myocardial ischemia was not rare. However, the consistent condition was very unusual. In angina of effort (EA) and old myocardial infarction (OMI), 3.7% and 12.3% were silent, respectively. A higher incidence was obtained in OMI than in EA. This is important for the management of these patients. The mechanism of silent myocardial ischemia and the cause of the different incidence of this state between EA and OMI were not defined and remained to be further studied.     

The significance of repeated exercise testing with thallium-201 scanning in asymptomatic diabetic males

This study was conducted with asymptomatic middle-aged male subjects with diabetes mellitus to detect latent cardiac disease using noninvasive techniques. One group of 38 diabetic males (mean age 50.5 +/- 10.2 years) and a group of 15 normal males (mean age 46.9 +/- 10.0 years) participated in the initial trial; 13 diabetic patients and 7 control subjects were restudied 1-2 years later. Maximal treadmill exercise with a Bruce protocol and myocardial scintigraphy with thallium-201(201Tl) were used. Diabetic subjects on initial examination and retesting achieved a lower maximal heart rate and duration of exercise than control subjects. Abnormal electrocardiographic changes, thallium defects, or both were observed in 23/38 diabetic males (60.5%) on the first study and only one 65-year-old control subject had such findings. On retesting, the control subjects had no abnormalities while 76.9% of diabetic subjects had either 201Tl defects or ECG changes. We conclude that despite the fact that none of diabetic males had any clinical evidence or symptoms of heart disease, this high-risk group demonstrated abnormalities on exercise testing that merit careful subsequent evaluation and followup and could be an effective method of detecting early cardiac disease.     

Noninvasive prediction of restenosis after coronary angioplasty: a head to head comparison among exercise ECG, dipyridamole and exercise thallium scintigraphy

Restenosis remains the main limitation of percutaneous transluminal coronary angioplasty (PTCA). Since it seems likely that restenosis not severe enough to induce ischemia may be better detected with pharmacological testing than with exercise, we investigated whether dipyridamole thallium scintigraphy is better than exercise-electrocardiogram and exercise-thallium in predicting restenosis after PTCA. Noninvasive tests and re-angiography were performed in 61 consecutive patients, 5-6 months after successful single vessel PTCA. Detection of vessel stenosis greater than or equal to 50% was used as angiographic criteria for restenosis. Exercise-induced angina, ST segment depression greater than or equal to 1 mm at exercise-electrocardiogram and reversible perfusion defects in the area supplied by the dilated vessel, during either dipyridamole and exercise-thallium, were considered noninvasive abnormal responses. The overall restenosis rate was 41% (25/61). Angina was the most specific (97%) of all criteria for restenosis, but also one of the least sensitive (40%), slightly better than exercise-ECG (24%). Exercise-thallium had lower sensitivity (72% vs 88%, p less than 0.05) and negative predictive value (82% vs 91%, p less than 0.05) than dipyridamole-thallium. In patients positive at both exercise-thallium and dipyridamole-thallium testing, mean stenosis at follow-up was more severe (73 +/- 23%) than in patients with positive dipyridamole-thallium and negative exercise-thallium (55 +/- 26%) results, but the difference did not reach statistically significant levels. For these reasons, dipyridamole-thallium seems to be an acceptable alternative to exercise thallium to follow patients after initially successful PTCA.     

Comparison of optimised planar scintigraphy with SPECT thallium, exercise ECG and angiography in the detection of coronary artery disease

Background: Thallium SPECT has been shown to be more sensitive than planar imaging in the detection of coronary heart disease (CAD) in a number of reported series. Early (< 10 minutes) redistribution on planar imaging has been demonstrated in clinical studies and this may partly contribute to its lower sensitivity. Aim: To determine whether thallium SPECT is superior to planar scintigraphy (with the timing of imaging performed optimally so that it was commenced within five minutes of injection) in the detection of CAD. Methods: Planar and SPECT studies were performed in 44 patients with significant (>70% stenosis) CAD, seven patients with borderline stenoses (50–69%) and in 18 patients with no significant CAD. Results: The sensitivity of planar imaging was 66% which was higher than exercise ECG 54% (ns) but significantly lower than SPECT 86% (ρ<0.005). The specificity of planar thallium scintigraphy was 100% which was higher than SPECT (83%) and significantly higher than exercise ECG 72% (ρ<0.05). SPECT had a significantly higher sensitivity for LAD and single vessel disease than planar imaging and this was unrelated to a history of prior myocardial infarction. Conclusion: Even when planar imaging is timed optimally to minimise the impact of early redistribution, SPECT is more sensitive than either planar imaging or exercise ECG in the detection of CAD, but its specificity is lower.     

Determinants of an abnormal response to exercise in patients with asymptomatic valvular aortic stenosis.

AIM: Patients with asymptomatic aortic stenosis (AS) and abnormal haemodynamic responses to exercise testing are at increased risk of cardiac events. This study assesses the Doppler echocardiographic determinants of a positive exercise test in a cohort of asymptomatic patients with AS. METHODS AND RESULTS: One hundred and twenty-eight patients with AS underwent quantitative Doppler echocardiographic measurements at rest and during exercise test. Of these patients, 60 had an abnormal response to exercise. Two independent determinants of an abnormal exercise response were selected in multivariate analysis: a larger increase in mean transaortic pressure gradient (P = 0.00014) and a limited contractile reserve-latent left ventricular dysfunction-as indicated by smaller changes in ejection fraction (P = 0.0002). Limiting symptoms were associated with greater increase in mean transaortic pressure gradient, smaller changes in systolic blood pressure and a lower ejection fraction at peak exercise. The increase in pressure gradient was associated with smaller exercise-induced changes in aortic valve area and in ejection fraction and new or worsening mitral regurgitation during exercise. CONCLUSION: Abnormal responses to exercise in asymptomatic AS patients are mediated by a larger increase in mean transaortic pressure gradient and/or a limited contractile reserve characterized by an inadequate increase in ejection fraction at exercise.     

Prognostic value of intravenous dipyridamole thallium scintigraphy after an acute myocardial ischemic event

Seventy-seven patients recovering from an acute coronary event were studied by intravenous dipyridamole thallium scintigraphy to evaluate the prognostic value and safety of the test in this patient subset. Forty-four patients (58%) had unstable angina and 33 (42%) had an acute myocardial infarction. One death occurred within 24 hours of testing. Sixty-eight patients were followed for an average of 12 months; 25, 31 and 23% had a fixed, reversible or combined thallium defect on their predischarge thallium scan. During follow-up, 10 patients died or had a nonfatal myocardial infarction; in each case, a reversible or combined myocardial thallium defect was present. Univariate analysis of 17 clinical, scintigraphic and angiographic variables showed that a reversible thallium defect and the angiographically determined extent of coronary artery disease were predictors of future cardiac events. The extent of coronary disease and global left ventricular ejection fraction were predictors of subsequent reinfarction or death. Logistic regression analyses revealed that a reversible thallium defect (p less than 0.001) and the extent of coronary disease (p less than 0.009) were the only significant predictors of a cardiac event. When death or reinfarction were the outcome variables, the extent of coronary disease (p less than 0.02) and left ventricular ejection fraction (p less than 0.06) were the only variables selected. Thus, intravenous dipyridamole thallium scintigraphy after an acute coronary ischemic syndrome is a useful and relatively safe noninvasive test to predict subsequent cardiac events.     

Quantification of myocardial ischemia and infarction with 201thallium scintigraphy

A quantitative method for the analysis of 201thallium myocardial scintigrams, developed in an experimental infarcted dog heart model, has been compared with two nonquantitative methods for interpretation of stress myocardial scintigrams in two groups of patients studied with coronary angiography: 11 with normal coronary arteries and 14 with coronary artery disease. Three independent observers interpreted scintigrams which were 1) not computer processed; 2) corrected for background activity in lungs and chest wall; and 3) processed by a computer method which uses a uniform threshold of counts determined from the dog model to define perfusion defects. Interobserver variability as well as sensitivity and specificity of detecting coronary disease were examined. In patients with coronary artery disease interobserver variability was improved by using the computer technique: observers agreed as to the existence of a perfusion defect in 93% of the scintigrams as compared to 55% and 81% for the unprocessed and background-subtracted images respectively. No false positive indications of coronary disease were obtained by any of the three techniques. Use of the computer method did not improve the sensitivity of detecting coronary disease, however--71% compared to 64% for unprocessed images and 79% for background-substracted images. The advantages of this quantitative computer method are increased consistency of interpretation and lack of false positive diagnoses of coronary disease. An improved sensitivity of detection may be gained by varying thallium count thresholds according to anatomic location in the heart.     

Diagnostic and prognostic value of vasodilator stress echocardiography in asymptomatic Type 2 diabetic patients with positive exercise thallium scintigraphy: a pilot study.

AIM: To assess the diagnostic and prognostic value of vasodilator stress echocardiography in Type 2 diabetic patients with positive exercise perfusion scintigraphy. METHODS: Of an initial cohort of 50 asymptomatic Type 2 diabetic patients undergoing exercise single photon emission computed tomography (SPECT) thallium scintigraphy, 24 had a positive thallium scan, with a reversible perfusion defect. All these 24 underwent high dose (up to 0.84 mg/kg in 10 min) dipyridamole echocardiography and coronary angiography independently of stress echocardiography results. All patients were then followed for 61+/-22 months. RESULTS: Coronary angiography showed normal coronary arteries in 11 patients and significant (> 50% visually assessed diameter reduction in a major vessel) coronary artery disease in 13. Stress echocardiography showed 92% sensitivity and 100% specificity for non-invasive detection of coronary artery disease. During follow-up, five patients experienced cardiac events: heart failure in one, angina with subsequent revascularization in two, and myocardial infarction in two. Event-free survival was 100% in the 12 patients with negative and 58% in the 12 patients with positive stress echocardiography (P = 0.08 by Mantel-Cox test). CONCLUSIONS: In asymptomatic Type 2 diabetic patients with stress-induced perfusion defects, vasodilator stress echocardiography is an excellent diagnostic and prognostic tool proven with long-term follow-up.