Effect of prior myocardial infarction and extent and location of coronary disease on accuracy of exercise echocardiography

Supine bicycle stress echocardiography: peak exercise imaging is superior to postexercise imaging

The abilities of peak exercise (PEAK) stress echocardiography versus postexercise (POST) stress echocardiography to detect coronary artery disease were evaluated in 136 consecutive patients undergoing supine bicycle stress echocardiography and coronary arteriography: 42 (31%) had normal coronary vessels, 38 (28%) had single-vessel disease, 34 (25%) had double-vessel disease, and 22 (16%) had triple-vessel disease. The results were as follows: (1) For detection of disease in the group of patients, sensitivity of PEAK versus POST was 94% versus 83% (p < 0.01) and specificity was 88% versus 90%. (2) For detection of disease in specific vessels, sensitivity of PEAK versus POST was 90% versus 72% (p < 0.0001) and specificity was 89% versus 92%. (3) For evaluation of the three major coronary arteries, sensitivity of PEAK versus POST was 96% versus 85% (p < 0.05) for the left anterior descending artery, 90% versus 65% (p < 0.01) for the right coronary artery, and 79% versus 60% (p < 0.05) for the left circumflex coronary artery. There were no differences in specificity. (4) The percent diameter stenosis of vessels normalizing from PEAK to POST versus vessels abnormal at PEAK and POST was 80.6% +/- 16% versus 85.9% +/- 14%, p = 0.07. There were no differences in exercise parameters between patients with and without resolution from PEAK to POST. (5) PEAK versus POST accuracy for identification of patients with multivessel disease was 93% versus 68% (p < 0.001). We conclude that stress echocardiography performed during peak exercise is superior to postexercise stress echocardiography.

Paradoxic hypotension during dobutamine stress echocardiography: clinical and diagnostic implications

OBJECTIVES

The purpose of this study was to elucidate the prevalence, magnitude and clinical implications of a hypotensive response during dobutamine stress echocardiography.

BACKGROUND

Dobutamine stress echocardiography is an accurate noninvasive method for detecting coronary artery disease. It has been associated with unexpected hypotension in a proportion of patients. Hypotension occurring during exercise testing has been associated with an increased prevalence of multivessel coronary artery disease and a poor prognosis. The clinical significance of hypotension when seen during dobutamine infusion for diagnostic testing is unknown.

METHODS

Clinical characteristics, coronary artery anatomy (n = 41), ventricular function at rest and during dobutamine infusion and prognosis were evaluated in 115 patients experiencing hypotension during dobutamine stress echocardiography and compared with data in 59 nonhypotensive catheterized patients for comparison of coronary anatomy and in 239 nonhypotensive patients for prognostic purposes.

RESULTS

Hypotension occurred in 115 (20%) of 568 consecutive patients studied with dobutamine stress echocardiography. It was gradual in 73 and precipitous in 42 patients. There were no statistical differences among the hypotensive groups and the index group in prevalence or severity of coronary disease or in prognosis during 15 months compared with findings in nonhypotensive patients.

CONCLUSIONS

Hypotension occurs commonly during dobutamine stress echocardiography, and patients with dobutamine-induced hypotension constitute a heterogeneous group. Unlike hypotension occurring with exercise testing, dopamine-induced hypotension is not invariably associated with advanced coronary disease or an adverse prognosis.

Digital supine bicycle stress echocardiography: a new technique for evaluating coronary artery disease

OBJECTIVES

The objective of this study was to determine the accuracy of digital supine bicycle stress echocardiography, a new technique for evaluating coronary artery disease during peak exercise.

BACKGROUND

Prior stress echocardiographic techniques have not utilized peak exercise imaging to determine the extent and location of coronary artery disease.

METHODS

Two-hundred twenty-two patients were studied: 180 underwent both supine bicycle stress echocardiography and coronary arteriography; 42 had a < 5% likelihood of disease. Forty-three patients had normal coronary arteries, 55 had single-vessel, 42 had double-vessel and 40 had triple-vessel coronary artery disease.

RESULTS

Supine bicycle stress echocardiography was 93% sensitive, 86% specific and 92% accurate for identifying patients with coronary artery disease irrespective of prior myocardial infarction or achievement of > or = 85% maximal predicted heart rate. The "normalcy" rate in the low probability group was 100%. Supine bicycle stress echocardiography was 87% sensitive, 89% specific and 88% accurate for specific vessel identification. The sensitivity was greatest for the left anterior descending compared with the right coronary artery and the left circumflex coronary artery (95% vs. 81% vs. 78%, p < 0.01) and for vessels in patients with double- and triple-vessel compared with single-vessel disease (90% vs. 89% vs. 78%, p < 0.05). The procedure was significantly more sensitive for detection of vessels with 90% to 100% compared with 50% to 70% diameter stenosis (91% vs. 81%, p < 0.05) and was 88% correct in the prediction of multivessel disease.

CONCLUSIONS

Supine bicycle stress echocardiography is a highly accurate tool for evaluating coronary artery disease, identifying both the patient with coronary artery disease and the location and extent of disease.

Prognostic usefulness of positive or negative exercise stress echocardiography for predicting coronary events in ensuing twelve months

Stress echocardiography is useful in diagnosing myocardial ischemia in patients with significant coronary artery disease. This study examines the correlation between the results of exercise stress echocardiography and cardiac event rates within 12 months after testing in patients referred for evaluation of possible myocardial ischemia. Cardiac events, defined as myocardial infarction, coronary artery bypass surgery, percutaneous transluminal coronary angioplasty or death, were tabulated for 360 patients with > or = 12 months of follow-up, or a cardiac event within 12 months of follow-up, or both. Wall motion abnormalities at rest were present in 60% of patients. A positive stress echocardiogram, defined as the development of new or worsened wall motion abnormalities, was obtained in 18% of patients (65 of 360), and > or = 1 cardiac event during follow-up was present in 14% (n = 49). A cardiac event occurred in 34% of patients (22 of 65) with a positive stress echocardiogram and in 9% (27 of 295) with a negative one. Myocardial infarctions occurred in 9% of patients with a positive stress echocardiogram compared with 2% with a negative test. An insufficient exercise capacity to reliably exclude ischemia was present in 63% of patients (17 of 27) with a cardiac event despite a negative stress echocardiogram. The predictive value of the stress echocardiographic results was enhanced by combining these results with the electrocardiographic results. In summary, a positive stress echocardiogram was associated with a threefold increased incidence of any cardiac event, and a fourfold increased incidence of myocardial infarction within 12 months of follow-up compared with a negative stress echocardiogram.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of coronary artery disease with upright bicycle exercise echocardiography

This study examined the advantages and limitations of upright bicycle exercise echocardiography in the evaluation of a large series of patients with known or suspected coronary artery disease. The study population consisted of 309 patients (231 men, mean age 57 +/- 11 years) who underwent exercise echocardiography within 8.5 +/- 16.1 days of coronary angiography. All stress electrocardiographic, echocardiographic, and angiographic data were reinterpreted in a blinded manner by the investigators. No patient was excluded because of poor echocardiographic image quality. Wall motion was analyzed at baseline, peak exercise, and immediately after exercise with a 16-segment model, and a regional wall motion score index was calculated at each stage. Abnormalities were ascribed to the distribution of the three coronary arteries and correlated with qualitative angiography. There were 126 patients with wall motion abnormalities at rest and 211 (75%) with coronary artery disease. The stress electrocardiogram (ECG) was negative in 61, positive in 144, and nondiagnostic in 104, yielding a sensitivity of 40% and a specificity of 89%. Echocardiography was normal in 76 of 98 patients without coronary disease (78% specificity) and abnormal in 193 of 211 patients with disease (91% sensitivity). Sensitivity was higher among patients with multivessel disease compared with those with single vessel disease (95% versus 86%, respectively, p = 0.03). Among patients with normal wall motion at rest (n = 183), sensitivity was 83% and specificity was 84%. Of the 104 patients with a nondiagnostic stress ECG, echocardiography correctly identified 95% of those with coronary disease and 75% of those without disease. Among 82 patients with a wall motion abnormality at rest, an additional exercise-induced wall motion abnormality developed in 32 of 46 patients (70%) with multivessel disease and seven of 32 (22%) with single-vessel disease. Overall, echocardiography detected 258 of 392 (66%) individual coronary lesions. Accuracy was higher for lesions in the left anterior descending and right coronary arteries (both 79%) compared with the left circumflex artery (36%, p < 0.001). In conclusion, upright bicycle exercise echocardiography is an accurate technique for the evaluation of patients with known or suspected coronary artery disease and is especially valuable in patients with a nondiagnostic stress ECG. The test provides supplemental information on the extent and location of coronary lesions and is useful in patients with and without prior myocardial infarction.

Ischemia-induced regional wall motion abnormality is improved after coronary angioplasty: demonstration by dobutamine stress echocardiography

OBJECTIVES

The purpose of this study was to examine whether dobutamine stress echocardiography can detect reversal of ischemia-induced left ventricular regional wall motion abnormality immediately after percutaneous transluminal coronary angioplasty.

BACKGROUND

Although angioplasty is routinely performed as a means of coronary revascularization, at present there is a question whether this results in an immediate improvement in ischemia-induced left ventricular regional function.

METHODS

Thirty-five patients underwent dobutamine stress echocardiography 24 h before and 24 to 48 h after angiographically successful coronary angioplasty. Only patients with normal wall motion at rest were included. Dobutamine infusion was begun at 5 micrograms/kg per min and increased at 5-min intervals (10, 20, 30, 40 micrograms/kg per min). Echocardiographic images were stored into cine loops and analyzed off line with simultaneous comparison of images acquired at baseline, 5 micrograms/kg per min, peak infusion and recovery. Echocardiographic images were interpreted independently, without knowledge of other data, by two experienced cardiologists using the 16-myocardial segment model.

RESULTS

Before angioplasty, dobutamine stress echocardiography induced wall motion abnormalities in 31 patients (88%). Wall motion score at peak dobutamine infusion improved in 28 (90%) of the 31 patients after angioplasty. Wall motion score at peak dobutamine infusion for the group improved from 20 +/- 3 before angioplasty to 17 +/- 2 after angioplasty (p < 0.001). There was no change in the rate-pressure product achieved for the group before and after angioplasty (20,038 +/- 6,415 beats/min x mm Hg before versus 20,775 +/- 5,435 after angioplasty, p = NS). Before angioplasty, dobutamine stress echocardiography induced angina in 13 patients (37%), whereas angina occurred only once after angioplasty. Electrocardiographic changes diagnostic of ischemia occurred seven times, all before angioplasty.

CONCLUSIONS

We conclude that dobutamine stress echocardiography is an excellent method to demonstrate an immediate improvement in stress-induced regional left ventricular dysfunction in the distribution of the vessel undergoing successful angioplasty.

Supine bicycle stress echocardiography versus tomographic thallium-201 exercise imaging for the detection of coronary artery disease

To compare the accuracy of supine bicycle stress echocardiography (SBSE), a new technique for evaluating coronary disease during peak exercise, with tomographic thallium-201 exercise imaging (SPECT), 71 patients were evaluated by SBSE, SPECT, and coronary arteriography. Twenty patients had normal coronary vessels; 22 had single-vessel, 14 had double-vessel, and 15 had triple-vessel disease. There were no differences in sensitivity (90% vs 92%), specificity (80% vs 65%), and accuracy (87% vs 85%) between SBSE and SPECT for the group of 71 patients. The results were similar in patients with and without prior myocardial infarction and with single-, double-, or triple-vessel disease. There were no differences between SBSE and SPECT for disease detection for the group of 213 individual vessels in sensitivity (88% vs 80%), specificity (87% vs 84%), and accuracy (88% vs 82%), but SBSE was more sensitive for the left anterior descending artery (97% vs 82%, p < 0.005) and for arteries involved in triple-vessel disease (93% vs 69%, p < 0.01) and more specific for the right coronary artery (88% vs 66%, p < 0.01). Supine bicycle exercise was associated with significantly lower maximal heart rates than treadmill exercise but with significantly higher systolic and diastolic blood pressures. There were no differences in heart rate x systolic blood pressure. We conclude that SBSE and SPECT are equally reliable for coronary disease detection in patients and for evaluation of disease in specific arteries with the exception of SBSE's higher sensitivity for the left anterior descending artery and arteries involved in triple-vessel disease and higher specificity for the right coronary artery.

Selection of the optimal nonexercise stress for the evaluation of ischemic regional myocardial dysfunction and malperfusion. Comparison of dobutamine and adenosine using echocardiography and 99mTc-MIBI single photon emission computed tomography

BACKGROUND

The mechanisms of action of exercise-simulating and vasodilator stressors support their combination with imaging techniques that evaluate left ventricular function and perfusion, respectively. However, reported accuracies of either pharmacological stress together with two-dimensional echocardiography (2DE) or single photon emission computed tomography (SPECT) of myocardial perfusion are similar. The purpose of this study was to establish the optimal stress for each imaging technique by comparing the results of digitized 2DE and 99mTc-methoxyisobutyl isonitrile (MIBI) SPECT using both dobutamine and adenosine stresses in the same patients and conditions.

METHODS AND RESULTS

Ninety-seven consecutive patients without evidence of previous infarction undergoing coronary angiography for clinical indications were studied prospectively. Dobutamine was infused during clinical, ECG, and echocardiographic monitoring in dose increments from 5 to 40 micrograms.kg-1.min-1. Adenosine was infused under the same conditions in doses of 0.10, 0.14, and 0.18 mg.kg-1.min-1. For each protocol, the end points were achievement of peak dose, development of severe ischemia, or intolerable side effects. At peak stress, 20 mCi of MIBI was injected, and SPECT imaging was performed 2 hours later; abnormal poststress images were compared with resting SPECT: Digitized 2DE images were compared qualitatively before, during, and after stress in a cine-loop display. Significant coronary disease (n = 59 patients) was defined by the quantification of > 50% stenosis in a major epicardial vessel. The sensitivity of adenosine 2DE was 58%, less than those of adenosine MIBI (86%, p = 0.001), dobutamine 2DE (85%, p = 0.001), and dobutamine MIBI (80%, p = 0.01). Their respective specificities were 87%, 71%, 82%, and 74% (p = NS). The accuracy of adenosine 2DE was 69%, compared with 80% for adenosine MIBI (p < 0.001), 84% for dobutamine 2DE (p = 0.001), and 77% for dobutamine MIBI (p = 0.005); the latter three did not differ significantly in either sensitivity or accuracy.

CONCLUSIONS

This prospective, direct comparison of alternative pharmacological stresses in patients without myocardial infarction shows vasodilator stress scintigraphy and dobutamine stress echocardiography and scintigraphy to share equivalent levels of sensitivity. All three are significantly more sensitive than adenosine stress echocardiography. Dobutamine stress may be used for wall motion or perfusion imaging, but adenosine stress is best combined with perfusion scintigraphy.

Usefulness of supine bicycle stress echocardiography for detection of restenosis after percutaneous transluminal coronary angioplasty

The role of supine bicycle stress echocardiography (SBSE) for detecting restenosis after percutaneous transluminal coronary angioplasty (PTCA) was evaluated in 80 patients: 41 (51%) with single and 39 (49%) with multivessel PTCA (total 129 dilated vessels). Total revascularization was performed in 54 (68%) and partial revascularization in 26 (32%) patients. Restenosis was angiographically demonstrated in 60 patients (75%) and in 72 vessels (56%) 6.1 +/- 2.9 months after PTCA. The results for detecting restenosis were: (1) SBSE versus exercise electrocardiographic sensitivity, 87 versus 55% (p < 0.001); (2) specificity, 95 versus 79%; and (3) accuracy, 89 versus 61% (p < 0.001). SBSE was 83% sensitive, 95% specific and 88% accurate for restenosis detection in specific vessels with comparable results for single versus multivessel PTCA and total versus partial revascularization. Sensitivity, specificity and accuracy were: 91, 93 and 91% for the left anterior descending coronary artery; 77, 94 and 85% for the right coronary artery; and 76, 96 and 88% for the left circumflex coronary artery. Ninety-four percent of the nondilated diseased vessels were correctly identified. It is concluded that SBSE is an excellent tool for identifying restenosis after PTCA.

Usefulness of heavy isometric exercise echocardiography for assessing left ventricular wall motion patterns late (> or = 6 months) after acute myocardial infarction

The aim of this prospective study was to determine the effects of heavy isometric exercise on left ventricular (LV) wall motion patterns in patients who have had myocardial infarction, and to compare heavy isometric exercise with dynamic exercise for competence in eliciting LV wall motion abnormalities at equivalent rate-pressure products. Echocardiography was performed in 42 patients during supine bicycle ergometry and during heavy dynamometer stretching at 50% of maximal voluntary contraction. Systemic vascular resistance increased from 1,484 to 1,649 dynes s cm-5 (p < 0.05) during isometric exercise, and decreased significantly during dynamic exercise. Wall motion abnormalities or new asynergy were induced by isometric exercise in 120 segments, 107 of which (89%) showed significant stenosis of the perfusing coronary artery. Hypokinesia was the dominant pattern in the range of 76 to 90% narrowing; akinesia was dominant at 91 to 100% narrowing. Wall motion abnormalities were also documented in 13 segments (11%) assumed to be supplied by vessels with nonsignificant stenosis. Dyskinesia, seen in 7% of the segments, was equally distributed between both groups with significant stenosis. Sensitivity and positive predictive value in identifying specific coronary vessel disease was similar for both isometric and dynamic exercise. In conclusion, heavy isometric exercise in patients who have had myocardial infarction induces wall motion abnormalities of a severity proportional to the degree of coronary narrowing. This exercise method is similar to dynamic exercise for ability in identifying obstructions in a specific vessel. Furthermore, when compared at near-equal rate-pressure products, heavy isometric exercise is far superior in sensitivity to dynamic exercise.

Exercise echocardiography: a methodological study comparing peak-exercise and post-exercise image information

It is unclear whether echocardiography at peak bicycle exercise adds information to registrations obtained recumbent immediately after the test and what factors influence image quality. Therefore, exercise echocardiography was performed consecutively and prospectively in 66 men, unselected with regard to echocardiography, one month after an episode of unstable coronary artery disease. Of 594 segments (9 x 66), 569 (96%) were adequately visualized recumbent at rest. The corresponding figures recumbent directly after exercise, seated before exercise, and seated at peak exercise were 544 (92%), 474 (80%), and 428 (72%), respectively. In the majority of our patients, acceptable images at peak exercise were obtained for the septal region, while for the anterior, lateral, and inferior segments the success rate varied from 50 to 70%. Recumbent after exercise, the success rate was acceptable for most segments, possibly with the exception of the apical and lateral segments. Fifty-five patients developed new wall motion abnormalities or worsening of wall motion in connection with exercise. Echocardiography at peak exercise provided more information than afterwards in patients with images of good quality. However, in patients with inferior image quality, the registrations obtained recumbent after the test revealed wall motion abnormalities which were not obtained seated at peak exercise. Patients with worse image quality had significantly higher respiratory rate and weight, and rated a higher degree of dyspnoea at peak exercise than those with good quality. We conclude that in middle aged men with coronary artery disease, image acquisition at peak bicycle exercise and immediately after exercise are of complementary value.

Exercise echocardiography after coronary artery bypass grafting

Exercise echocardiography was used to assess the adequacy of regional myocardial perfusion in 125 patients who had undergone coronary artery bypass grafting. There were 108 men and 17 women (mean age 65 years) evaluated from 6 weeks to 16 years (mean 7 years) after surgery. Resting parasternal long- and short-axis and apical 4- and 2-chamber echocardiograms were recorded, digitized and stored. Maximal, symptom-limited upright treadmill exercise was then performed with continuous electrocardiographic monitoring. Repeat echocardiographic imaging and digitization were repeated within 1 minute of exercise termination. Resting and postexercise digitized echocardiograms were compared. A normal regional wall motion response to exercise consisted of improved segmental contraction and was used to predict uncompromised regional vascular supply. Unimproved or worsened segmental contraction after exercise was abnormal and was used as a predictor of regional vascular insufficiency. All patients underwent cardiac catheterization within 1 month after exercise testing. Regional coronary insufficiency was considered to exist when a segment's major vascular conduit exhibited greater than or equal to 50% luminal diameter reduction. Compared with the simultaneously acquired stress electrocardiogram, exercise echocardiography had superior sensitivity (98 vs 41%), specificity (92 vs 67%), positive predictive value (99 vs 91%), and negative predictive value (86 vs 12%) (p less than 0.001, 0.1, 0.01 and less than 0.001, respectively). In addition, exercise echocardiography correlated closely with the extent and regional distribution of compromised vascular supply. Exercise echocardiography is a highly sensitive, specific and accurate screening test for abnormal global and regional myocardial vascular supply in patients who have undergone coronary artery bypass grafting.

Relationship between exercise echocardiography and perfusion single-photon emission computed tomography in patients with single-vessel coronary artery disease

The aim of this study was to assess the relative value of exercise echocardiography and perfusion single-photon emission computed tomography (SPECT) in identifying the presence and severity of coronary artery stenosis. Accordingly, 44 consecutive patients with stenosis in one vessel performed simultaneous postexercise echocardiography and perfusion SPECT (with either thallium-201 [n = 19] or 99m-Tc-methoxyisobutyl isonitrile [n = 25]) in conjunction with symptom-limited bicycle exercise testing. Positive test results were based on the presence of new or worsened exercise-induced wall motion abnormalities and transient perfusion defects, respectively. Moreover, an "ischemic" score index was derived for semiquantitative assessment of both echocardiography (with a 14-segment model of left ventricular wall on a 4-point scale) and SPECT (47-segment model on a 5-point scale). All patients underwent correlative coronary arteriography, assessed by digital caliper. Significant coronary artery disease (diameter stenosis greater than or equal to 50%) was present in 30 patients. There was a good overall concordance between the two tests in terms of result (79%); compared with patients with positive results of both tests, in the seven patients with positive SPECT and negative echocardiography the time of recording echocardiographic images was longer (p = 0.05). When analyzing patients according to the percent diameter stenosis (greater than 70%, 50% to 70%, and less than 50%) for both echocardiography and SPECT, the prevalence of an ischemic response was directly related to the severity of the coronary stenosis (p less than 0.001); moreover, a negative test result was highly predictive of a diameter coronary stenosis less than 70%.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise echocardiography

Exercise echocardiography is a versatile, noninvasive diagnostic test that involves the recording and interpretation of 2-dimensional echocardiograms prior to, during, and after exercise. By analyzing and comparing wall motion at each stage, a prediction about the presence or absence of coronary artery disease can be made. The development of a wall motion abnormality is both sensitive and specific for the presence of a significant coronary stenosis. Changes in regional systolic function during exercise enable the clinician to distinguish between infarction and ischemia. Thus, the test yields information on the presence, extent, severity, and location of coronary artery disease. Echocardiography can be adapted to almost any form of stress, although treadmill or bicycle exercise are most commonly employed. An advantage of bicycle stress echocardiography is the opportunity to image during exercise, rather than relying on postexercise recording. This contributes to enhanced sensitivity, although false-positive results may increase due to the difficulties of analyzing wall motion during strenuous exercise. Exercise echocardiography increases the diagnostic accuracy of stress testing in a manner similar to radionuclide perfusion imaging. It is particularly useful in the setting of an ambiguous stress electrocardiography (ECG) or when a false-negative or false-positive result is suspected. It has been successfully applied to patients following revascularization and yields useful prognostic data in a variety of clinical situations. Exercise echocardiography is being increasingly utilized as a safe and accurate test in patients with known or suspected coronary artery disease.

Dobutamine stress echocardiography

Two-dimensional echocardiography is a versatile, accurate, and readily available method for the assessment of cardiac anatomy and function, and extensive experience has been gained in the analysis of left ventricular wall motion. Using modern imaging techniques, regional as well as global wall motion analysis can be performed. Echocardiography can be used in conjunction with a protocol for either exercise or pharmacologic cardiovascular stress in order to identify the distribution and severity of coronary artery disease, with the induction of a regional wall motion abnormality being a sign of myocardial ischemia. The use of dobutamine infusion to accomplish stress echocardiography is a safe, accurate, and practical method for the diagnosis of coronary artery disease in patients unable to exercise. In addition to the evaluation of inducible ischemia, preliminary work is being performed with dobutamine stress echocardiography for the assessment of risk and patient prognosis following acute myocardial infarction and as an indication of tissue viability for myocardium that remains dysfunctional at rest following thrombolytic therapy.

The value and promise of echocardiography in acute myocardial infarction and coronary artery disease

Two-dimensional and Doppler echocardiography have become extremely useful in the management of patients with acute myocardial infarction (AMI). Echocardiography is noninvasive, relatively inexpensive, and has no known biohazards. It offers unequaled information about cardiac anatomy and function. In the acute setting it is useful in the diagnosis of AMI and its complications. It is an excellent tool for monitoring therapy. Echocardiography has been shown to be useful in risk stratification upon presentation to the emergency ward and prior to hospital discharge. Stress echocardiography has broadened and sharpened the diagnostic and prognostic information. Contrast echocardiography has promise for demonstrating coronary artery flow. Research in ultrasonic myocardial tissue characterization shows potential for differentiating ischemic myocardium from infarcted myocardium. Thus, echocardiography is likely to become increasingly important in the future management of patients with AMI.

Accuracy of dobutamine stress echocardiography in detecting coronary artery disease

The diagnostic accuracy of dobutamine stress echocardiography (DSE) (incremental infused doses of 5, 10, 20 and 30 micrograms/kg/min) was evaluated in 141 patients who underwent coronary arteriography within 2 weeks of DSE. All patients were being evaluated for known or suspected coronary artery disease (CAD). DSE was interpreted blindly as normal or showing evidence of CAD, depending on the presence of resting or inducible wall motion abnormalities. Coronary arteriograms were reviewed in a blinded, quantitative fashion. DSE had a sensitivity of 96% for detecting patients with CAD, and a specificity of 66%. For the 53 patients with normal resting wall motion, sensitivity was 87% and specificity 91%. The protocol was well-tolerated by all patients. In comparison with wall motion analysis, 12-lead electrocardiograms during dobutamine infusion revealed ischemic changes in only 17% of patients with CAD. It is concluded that DSE is a clinically useful and accurate means for detecting CAD, its specificity is hindered in patients with resting wall motion abnormalities, and it can safely be used in patients with known cardiac disease.

Diagnosis of coronary artery disease using exercise echocardiography and positron emission tomography: comparison and analysis of discrepant results

Both exercise echocardiography and rubidium-82 positron emission tomography are used in the detection and characterization of coronary artery disease. This study compared results of both in 74 patients with known coronary anatomy, by use of exercise echocardiography before and after treadmill exercise and positron emission tomography with intravenous dipyridamole-handgrip stress. Significant (greater than 50%) coronary stenoses were present in 70 patients; exercise echocardiography and positron emission tomography each identified 63 patients (sensitivity 90%). Significant stenoses without previous myocardial infarction were present in 34 patients; 29 (85%) were identified by exercise echocardiography and 28 by positron emission tomography (82%, p = NS). Four patients had no significant coronary disease, and were all identified as normal by both methods. Segments were classified as either normal or showing stress or resting abnormalities, and the diagnoses were compared in the territories of the three major coronary arteries. Results were concordant with respect to the presence or absence of coronary disease in 185 of 222 territories (83%). The remaining 37 regions had abnormalities by exercise echocardiography or positron emission tomography but not both. Stress defects were identified by only one of the tests in 24 areas (in 12 [50%], angiographic findings correlated with positron emission tomography). Resting defects were diagnosed by only one modality in 13 regions (angiographic findings correlated with the results of positron emission tomography in 9 [69%] of these). Both exercise echocardiography and positron emission tomography are sensitive for the identification of coronary artery disease, although on a regional basis, positron emission tomography appears to be more specific for the diagnosis of resting perfusion defects.

Dobutamine stress echocardiography: correlation with coronary lesion severity as determined by quantitative angiography

This study was performed 1) to determine the ability of dobutamine stress echocardiography to detect stenoses in individual coronary arteries by utilizing a new model of coronary artery distribution; 2) to evaluate its ability to detect coronary artery stenosis with a minimal lumen diameter less than 1 mm; and 3) to correlate the heart rate at which a positive test result occurs with the severity of coronary artery disease. Eighty-five patients were identified who underwent both dobutamine stress echocardiography and quantitative coronary angiography. During incremental infusion of dobutamine, two-dimensional echocardiograms were obtained at rest, during low and peak stress and after stress. Echocardiograms were interpreted with use of a modified 16-segment model with an anteroinferior overlap scheme. The overall sensitivity of the technique for the detection of significant coronary artery disease (diameter stenosis greater than or equal to 50%) was 95%; specificity was 82% and accuracy 92%. The sensitivity for detection of individual coronary artery lesions did not differ significantly (p greater than 0.05) in the three major coronary artery distributions (79% left anterior descending, 70% left circumflex, 77% right coronary artery). Among 35 stenoses with a minimal lumen diameter less than 1 mm, the test result was positive in 30 (86%). Test results were correctly positive for 88%, 82% and 86% of stenoses in the left anterior descending, left circumflex and right coronary artery distributions, respectively. Multivessel disease was present in 11 of 16 patients with normal wall motion at rest who developed a wall motion abnormality at a heart rate less than 125 beats/min. The incidence of multivessel disease was statistically higher in patients with positive findings on a dobutamine stress echocardiogram at a heart rate less than or equal to 125/min. In conclusion, dobutamine stress echocardiography has high sensitivity and specificity for the detection and localization of coronary artery disease. Detection of stenosis in individual coronary arteries is improved in those lesions with a minimal lumen diameter less than 1 mm. Patients with a positive test result at a heart rate less than or equal to 125 beats/min have a high likelihood of multivessel coronary artery disease.

Bicycle stress echocardiography

Bicycle stress echocardiography involves the recording and interpretation of two-dimensional echocardiographic information before, during, and after bicycle exercise. The exercise test can be performed in the supine or upright posture. While there are important physiological differences between these two positions, they appear to provide similar diagnostic information on the presence or absence of coronary artery disease. A major advantage of bicycle stress echocardiography compared to treadmill exercise is the ability to image at peak exercise, rather than relying solely on pre- and postexercise imaging. This contributes to the greater sensitivity of the test for the detection of ischemia. The recent application of digital processing techniques may also improve sensitivity by permitting side-by-side comparison of rest and stress images. In summary, bicycle stress echocardiography is a useful tool in the management of patients with known or suspected coronary artery disease. It is a versatile and accurate technique, which competes favorably with other imaging modalities and provides information on regional and global left ventricular function.

Utility of stress echocardiography for postinfarct prognosis

Although high-risk patients following myocardial infarct are usually identified in the acute stage by clinical assessment and determination of left ventricular function at rest, a significant percentage of infarct patients with increased risks, i.e., presence of residual myocardial ischemia, remain undetected at discharge. Since the yield of adequate images for interpretation stress echocardiograms has been significantly improved with digital technology, stress echocardiography has become a truly practical technique to identify these patients. Presence of remote asynergy, i.e., asynergy not directly adjacent to the infarcted area and supposed to be related to another vascular region, directly following cessation of dynamic exercise appears to be highly related to multivessel disease and an unfavorable follow-up period. Treadmill electrocardiographic findings, however, appeared to be of limited value in this respect. Furthermore, the echocardiographic ejection fraction was also a poor predictor. The versatility of the technique, lack of injections, or radiation hazard, and the relatively low cost will undoubtedly increase the application of stress echocardiography for postinfarct stratification.

Exercise echocardiography versus 201Tl single-photon emission computed tomography in evaluation of coronary artery disease. Analysis of 292 patients

BACKGROUND

Exercise echocardiography (digital cine-loop technique) and 201Tl single-photon emission computed tomography (SPECT) were performed simultaneously in 292 patients being evaluated for coronary artery disease.

METHODS AND RESULTS

Pretreadmill and posttreadmill echocardiographic images of diagnostic quality were obtained in 289 patients, and the left ventricle was divided into anterior, inferior, and lateral regions. Any wall motion or perfusion abnormality observed within each region was classified as totally reversible, fixed, or partially reversible. Exercise echocardiography and SPECT were normal in 137 patients and abnormal in 118 (88% agreement). Equal numbers of regional abnormalities were detected by one test when missed by the other. The two tests had an 82% agreement in detecting the same type of finding within the regions analyzed. SPECT detected more reversible abnormalities than echocardiography, whereas echocardiography detected more fixed abnormalities than SPECT: Regions with a fixed abnormality by echocardiography frequently showed partial reversibility of a perfusion defect by SPECT: Nearly one third of regions with fixed perfusion defects by SPECT demonstrated normal resting function or reversible abnormalities by echocardiography. Sensitivity for coronary artery disease by angiography (greater than or equal to 50% diameter stenosis) in 112 patients was similar for the two tests, ranging from 58% and 61% (echocardiography and SPECT, respectively) for one-vessel disease to 94% for three-vessel disease. The specificities for echocardiography and SPECT were 88% and 81%, respectively.

CONCLUSIONS

Exercise echocardiography had a diagnostic accuracy comparable to that of SPECT for the detection of regional abnormalities produced by significant coronary artery disease. A greater number of abnormal regions were detected with the combined use of both tests.

Stress echocardiographic techniques. An overview

The choice of upright or supine exercise, pharmacological agents, or atrial pacing for the induction of ischemia depends on the goals and the imaging modality. Dynamic stress echocardiography has improved diagnostic accuracy over and above the stress electrocardiogram. Indications include patients with atypical symptoms, prior nondiagnostic stress electrocardiograms, or baseline electrocardiographic abnormalities. Pharmacological agents coupled with echocardiography do well in the high-risk preoperative patient (e.g., abdominal aneurysmectomy) or in those unable to walk due to orthopedic, neurological, or peripheral vascular disease. When there is uncertainty as to the physiological significance of anatomical (angiographic) stenosis, dynamic stress echocardiography in the ambulatory patient or atrial pacing (or beta-agonist pharmacological stressors) in the catheterization laboratory are useful. The accuracy of stress echocardiography for detection of ischemia in the follow-up of interventional procedures or for postmyocardial infarction risk stratification is superior to standard stress electrocardiography alone.

Accuracy and limitations of exercise echocardiography in a routine clinical setting

Despite the high reported accuracy of exercise echocardiography in the detection of coronary artery disease, factors that compromise its sensitivity and specificity are less clear. This study examined the results of 179 post-treadmill stress echocardiograms in 150 consecutive patients who also underwent cardiac catheterization and in 29 normal persons at low risk for coronary artery disease. Of 114 patients who had significant coronary stenoses at angiography, 96 had an abnormal exercise echocardiogram (overall sensitivity 84%). False negative results correlated with the performance of submaximal exercise, single-vessel disease and moderate (50% to 70% diameter) stenoses. After the exclusion of seven patients performing submaximal exercise, the sensitivity was 90%. In 54 patients without previous infarction performing maximal exercise, the sensitivity was 87%, higher in patients with multivessel coronary disease (96%) than in those with single-vessel disease (79%). After the exclusion of patients with nondiagnostic results, due either to the performance of submaximal stress or the presence of electrocardiographic (ECG) changes at rest, exercise echocardiography had a higher sensitivity than did exercise electrocardiography (87% vs. 63%, p = 0.01). In 36 patients without significant coronary disease, exercise echocardiography had an overall specificity of 86%. After the exclusion of patients with a nondiagnostic test, exercise echocardiography had a specificity of 82% compared with 74% specificity for exercise electrocardiography (p = NS). Similarly, of the 29 normal subjects, 93% had a normal exercise echocardiogram and 97% had a normal exercise ECG (p = NS). Similarly, of the 29 normal subjects, 93% had a normal exercise echocardiogram and 97% had a normal exercise ECG (p = NS). Age, gender, body weight and image quality did not significantly influence the accuracy of exercise echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole echocardiography

Intravenous dipyridamole is a potent coronary vasodilator that has been extensively investigated over the past several years in the noninvasive assessment of patients with suspected coronary artery disease when exercise cannot be performed or is suboptimal. As an alternative to exercise studies, dipyridamole has been used in combination with different cardiac imaging techniques such as echocardiography, thallium scintigraphy, and radionuclide ventriculography. Extensive experience has been obtained with dipyridamole thallium-201 imaging for coronary artery disease screening, risk stratification, and prognosis after an acute coronary event. However, experience with the use of dipyridamole in combination with two-dimensional echocardiography has been limited. Dipyridamole increases coronary blood flow in nondiseased coronary vessels relative to coronary vessels with significant luminal narrowings. These provide the basis for detecting regional differences in flow by using different cardiac imaging techniques. Two-dimensional echocardiography would show regional wall-motion abnormalities in response to those regional differences in coronary blood flow. In this article, the most commonly used protocols, safety, and practicability of dipyridamole echocardiography are reviewed. As an alternative to exercise, dipyridamole echocardiography shares all the indications of a standard exercise test. Clinical applications of dipyridamole echocardiography include coronary artery disease screening, suspected coronary artery spasm, postmyocardial infarction risk stratification, evaluation of percutaneous transluminal coronary angioplasty results, and prognosis following an acute coronary event. Compared to conventional (ECG) exercise testing, dipyridamole echocardiography appears to be equally sensitive but more specific. Compared to atrial pacing, dipyridamole provokes ischemia at a lower rate pressure product and results in a greater ST segment depression suggesting that dipyridamole induces more profound myocardial ischemia than atrial pacing. Dipyridamole thallium and exercise thallium have shown to be equally sensitive and specific in the assessment of coronary artery disease. High dose dipyridamole echocardiography appeared to be equally sensitive and more specific. Experimental studies have demonstrated that dobutamine appears to be a more powerful pharmacological agent in inducing wall-motion abnormalities. Dipyridamole echocardiography as compared to stress echocardiography offers the advantage of obtaining better quality postintervention images. With regard to sensitivity and for coronary artery disease diagnosis, both techniques appear to render similar results. Although further studies are needed, the available data indicates that cardiac ultrasound imaging prior to and following the intravenous administration of dipyridamole may be an attractive alternative to thallium perfusion imaging in the clinical setting, particularly when radionuclide capabilities are not present.

Feasibility of high-dose dipyridamole-magnetic resonance imaging for detection of coronary artery disease and comparison with coronary angiography

To assess the feasibility, safety and usefulness of gradient-echo magnetic resonance imaging (MRI) combined with pharmacologic stress testing for the detection of coronary artery disease, 23 patients without previous myocardial infarction but with significant stenosis (greater than 70% diameter stenosis) of greater than or equal to 1 major coronary artery were selected for dipyridamole-MRI stress testing. Each patient underwent MRI at rest, and high-dose dipyridamole-MRI (0.75 mg/kg over 10 minutes) of corresponding basal and midventricular short-axis tomograms. Additionally, these patients performed symptom-limited exercise stress tests. All short-axis tomograms were evaluated on a standardized segmental basis by grading each segment as normal, hypokinetic, akinetic or dyskinetic. Dipyridamole-MRI was considered pathologic if segmental wall motion deteriorated by greater than or equal to 1 grade after dipyridamole. For comparison with coronary angiography, segmental wall motion gradings were related to the respective coronary artery territories in the short-axis plane. Pathologic dipyridamole-MRI was obtained in 18 of 23 (78%) patients. For 1- and 2-vessel diseases, sensitivity was 69 and 90%, respectively. Exercise stress tests were pathologic in 14 of 23 (66%) patients. For 1- and 2-vessel diseases, sensitivity of exercise stress test was 58% (7 of 12 patients) and 77% (7 of 9), respectively. Sensitivity/specificity of dipyridamole-MRI for the localization of the stenosed coronary artery was 78/100% for left anterior descending, 73/100% for left circumflex, and 88/87% for right coronary artery stenoses. It is concluded that dipyridamole-MRI is a feasible nonexercise-dependent test for detection and localization of functionally significant coronary artery disease.

Clinical applicability of echocardiographically detected regional wall-motion abnormalities provoked by upright treadmill exercise

Exercise electrocardiography is the time-honored screening test for coronary artery disease but has serious limitations in many patient subgroups. A number of adjunctive modalities have been coupled to exercise ECG to increase the diagnostic accuracy of noninvasive testing, including thallium scintigraphy and gated blood pool radioventriculography. Exercise echocardiography has more recently emerged as a tool that can detect exercise-induced regional wall-motion abnormalities as an indicator of provoked myocardial ischemia. While there are conceptual advantages to performing echocardiography during maximal exercise, we have found that regional wall-motion analysis performed with echocardiograms obtained before and immediately after upright treadmill exercise allows highly accurate prediction of the extent and distribution of coronary artery disease as detected by angiography. This monograph summarizes our experience with this form of exercise echocardiography in three important patient groups: (1) patients being screened for the presence or absence of coronary artery disease; (2) patients who have undergone previous coronary artery bypass surgery and who are being evaluated for graft failure and/or progression of native-vessel disease; and (3) patients who have undergone coronary angioplasty and are at risk for restenosis and/or progression of disease. We believe, based on our experience and that of other investigators, that exercise echocardiography is a uniquely valuable tool in these and other patients for assessing the status of the coronary vascular anatomy. Not only can the presence or absence of obstructive disease be assessed, but the extent and distribution of disease can be accurately predicted, and other, noncoronary causes of chest pain such as aortic stenosis, mitral valve prolapse, hypertrophic cardiomyopathy, and pericardial disease can readily be identified.

Quantitative stress echocardiography

Dramatic improvements in our ability to treat coronary artery disease have created the need to develop sensitive and specific noninvasive tests for diagnosing and assessing the severity of ischemic disease. The purpose of this review is to examine stress echocardiography and, in particular, quantitative stress echocardiography in this context. Methodology and technical aspects of performing and interpreting stress echocardiography are discussed, including the type of exercise performed, imaging and recording techniques, and methods for on-line and off-line analysis. Qualitative, semiquantitative, and quantitative approaches are compared and contrasted. In assessing quantitative stress echocardiography, the role of global measurements of left ventricular function including ejection fraction, peak systolic pressure to end-systolic volume index ratio, as well as regional measurements including wall-motion analysis and wall stress, are discussed. Pertinent literature using quantitative approaches is reviewed including those comparing quantitative stress echocardiography with other noninvasive modalities. Future directions for study are also addressed. We concluded that quantitative stress echocardiography has excellent sensitivity and specificity for diagnosing ischemic heart disease. It was useful in localizing lesions, defining multivessel disease, and predicting patients with poor prognosis postmyocardial infarction. Its reproducibility makes it a valuable technique in following patients noninvasively over time.

Diagnostic accuracy of peak exercise echocardiography in coronary artery disease: comparison with thallium-201 myocardial scintigraphy

To evaluate the accuracy of exercise two-dimensional echocardiography for the recognition of coronary artery disease, 53 patients (46 men and 7 women, age range 35 to 69 years) without either previous myocardial infarction or resting wall motion abnormalities, were studied. According to coronary angiography 26 had normal coronary arteries, 14 had one-vessel, seven had two-vessel, and six had three-vessel disease. After withdrawal of any therapy, all patients underwent a single exercise stress test with a stress table during which cine-loop digitized echocardiography was acquired and 74 MBq of thallium-201 (TI-201) were injected. Echocardiographic images were evaluated at rest and at peak exercise. Three-view planar scintigraphic images were collected immediately after exercise and 4 hours later. For the overall recognition of coronary artery disease, exercise electrocardiography had 77.8% sensitivity and 65.4% specificity; myocardial scintigraphy had 100% sensitivity and 92.3% specificity; and exercise echocardiography had 92.6% sensitivity and 96.2% specificity (both NS versus myocardial scintigraphy). Global accuracy was 71.7% for exercise electrocardiography, 94.3% for stress echocardiography, and 96.2% for myocardial scintigraphy. For the classification of the individual involved coronary arteries, the sensitivity of myocardial scintigraphy was 84.8% and that of exercise echocardiography was 63% (p less than 0.01); the related specificities were 98% and 98.2% respectively (NS). It may be concluded that exercise echocardiography is highly accurate for the recognition of coronary artery disease, whereas it appears less sensitive in the identification of the involved vessels, particularly in patients with multivessel disease.

Absence of myocardial dysfunction during stress in patients with syndrome X

Stress two-dimensional echocardiographic studies were performed in 18 patients with angina, a positive exercise test and normal findings on coronary angiography (syndrome X). Rest and immediate posttreadmill exercise two-dimensional echocardiograms were performed with a digitized cine loop and side by side visual analysis in all patients. In 16 of these patients, right atrial pacing up to 160 beats/min was also performed and percent systolic wall thickening was calculated at five equally spaced segments around the left ventricle, each corresponding to an anterior, lateral and inferior wall and the posterior and the anterior ventricular septum. Measurements of percent systolic wall thickening were established in 10 age- and gender-matched normal persons for comparison. ST segment depression occurred in all patients during exercise and persisted for 42.1 s (range 18 to 75) into the recovery period. Immediate postexercise echocardiography was started within 20.1 +/- 5.4 s and completed in 54.1 +/- 11.3 s. No patient had regional wall motion abnormalities seen on two-dimensional imaging of any myocardial segment. Thirteen patients (72%) reported reproduction of their usual chest pain, which led to termination of the test. During rapid right atrial pacing, nine patients (56%) developed ST segment depression that was associated with angina in seven. In all 16 patients, percent systolic wall thickening increased over values at rest in each myocardial segment. Percent systolic wall thickening averaged 47.1 +/- 6.1% at rest and increased to 74 +/- 8% during right atrial pacing (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal stress echocardiography: detection of coronary artery disease in patients with normal resting left ventricular contractility

A new nonexercise test to detect significant coronary disease was prospectively evaluated in 36 patients with chest pain syndrome and normal left ventricular contractility. Transesophageal atrial pacing was used to provoke ischemia during monitoring of left ventricular contractility by transesophageal echocardiography. A 12-lead ECG was recorded. A TSE was abnormal if new segmental wall motion abnormalities developed. On the basis of the TSE results, patients were separated into normal (group 1, n = 16) and abnormal response (group 2, n = 20). Arteriography revealed significant disease in 21 patients, 19 from group 2 and two from group 1. Sensitivity and specificity of TSE were 90% and 93%, respectively, and those for pacing ECG were 43% and 100%, respectively. In addition, TSE accurately predicted the coronary artery perfusion bed involved. In 10 patients, Wenckebach AV block developed during pacing and resolved immediately by the administration of atropine sulfate. No serious complications were seen. Thus TSE is a highly sensitive and specific novel technique to detect significant coronary disease in patients with chest pain syndrome and normal resting left ventricular contractility.

Trends in use of coronary angiography in subacute phase of myocardial infarction

BACKGROUND

Most patients do not undergo acute reperfusion after myocardial infarction, and which of these patients should undergo coronary angiography is still debated.

METHODS AND RESULTS

We analyzed the 1-year clinical outcomes and rates of coronary angiography performed as late as 60 days after myocardial infarction in 3,804 patients admitted between 1979 and 1988 and followed in six different centers. Patients less than 75 years old were classified into low-, medium-, and high-risk groups using a multivariate analysis of historical and clinical variables gathered during the first 8 hospital days. Patients who underwent early reperfusion (17%, all after 1984) were analyzed separately. To analyze time trends, patients were compared before and after mid-1984. Mortalities from day 9 through 1 year were similar for the two time periods in the low- (3.3% versus 2.5%) and medium-risk (7.4% versus 5.6%) groups, but mortality was lower for the high-risk group after 1984 (31.6% versus 20.0%). The proportion of patients undergoing coronary angiography increased dramatically in each group after 1984 (low risk, 18% versus 48%; medium risk, 23% versus 49%; high risk, 10% versus 32%, before and after 1984, respectively). Furthermore, a large percentage of patients (more than 40%) in the low-risk group did not have at least one of the indications for coronary angiography recently recommended by a joint task force. Among patients undergoing coronary angiography, the proportion of patients with three-vessel coronary artery disease decreased after 1984, whereas the proportion undergoing mechanical revascularization in the year after infarction increased in all risk groups.

CONCLUSIONS

Despite the recent development of noninvasive techniques with high sensitivity for detecting high-risk patients after myocardial infarction, coronary angiography is being performed increasingly in all patients, including those determined to be at low risk for complications based on clinical data. The economic consequences of such a trend could be considerable, and its impact requires careful analysis.

Stunned left ventricular myocardium after exercise treadmill testing in coronary artery disease

Myocardial stunning (postischemic ventricular dysfunction) occurs in dogs after coronary stenosis following treadmill exercise. Less data are available in humans regarding development of stunned myocardium after exercise. Regional wall motion changes were evaluated in 22 patients with known coronary artery disease using 2-dimensional echocardiography and exercise treadmill testing. Wall motion was scored as 1 = normal, 2 = hypokinetic, 3 = akinetic, 4 = dyskinetic. At least 1 left ventricular segment with normal resting function developed an increase in wall motion score at 15 or 30 minutes compared with values at rest. The wall motion score in the midportion of the ventricular septum increased from 1.0 at rest to 1.6 (p less than 0.004) at 30 minutes after exercise; the basal inferior wall score worsened from 1.0 at rest to 1.9 (p less than 0.01) at 30 minutes after exercise. Coronary angiographic data in these patients revealed that left anterior descending narrowing correlated best with left ventricular septal wall motion abnormalities, whereas right coronary artery and circumflex narrowing best correlated with inferior and posterior wall motion abnormalities. Eight normal adult volunteers with no history of myocardial ischemia also underwent 2-dimensional echocardiography and exercise testing. No wall motion abnormalities were observed at any time after exercise. The present study suggests that in patients with coronary artery disease, exercise treadmill testing may induce regional wall motion abnormalities of the left ventricle that persist greater than or equal to 30 minutes after exercise, an observation consistent with the phenomenon of stunned myocardium.

Dobutamine digital echocardiography for detecting coronary artery disease

To assess the value of dobutamine echocardiography for detecting coronary artery disease (CAD), 70 men (mean age 62 +/- 8 years) presenting for coronary angiography were prospectively studied. Dobutamine (2.5 to 40 micrograms/kg/min) was infused in 3-minute stages. Digital echocardiograms were recorded on-line at baseline, during low- and high-dose dobutamine infusion, and at recovery. An echocardiogram positive for CAD was defined as one showing a new wall motion abnormality induced by dobutamine. Compared with coronary angiography, the overall sensitivity of dobutamine echocardiography for detecting CAD was 86%, specificity 95% and accuracy 89%. The sensitivity for detecting 3-vessel CAD was 100%, 89% for 2-vessel and 69% for 1-vessel CAD. The accuracy of predicting multivessel disease by 2 methods was 71% and 84%, respectively. Heart rate at the echocardiographic ischemic threshold was lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (89 +/- 17, 95 +/- 18 and 118 +/- 18 beats/min, respectively, p less than 0.01); rate-pressure product was also lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (12.7 +/- 3.6, 13.7 +/- 2.8 and 18.9 +/- 44 x 10(3) beats/min x mm Hg, respectively, p less than 0.01). Heart rate was the most important physiologic determinant of ischemia induced by dobutamine. There were no major complications during the study. Thus, dobutamine digital echocardiography is an excellent test for identifying CAD and should be beneficial in patients unable to exercise.

Exercise echocardiography as a screening test for coronary artery disease and correlation with coronary arteriography

We evaluated exercise echocardiography as a screening test for coronary artery disease in 228 patients, all of whom underwent subsequent coronary angiography. After an echocardiogram at rest was obtained, each patient performed maximal, symptom-limited, upright treadmill exercise, immediately after which repeat imaging was performed. The exercise echocardiogram was abnormal if any segment failed to become hypercontractile with exercise, and these regional wall motion abnormalities were used to predict the extent and distribution of coronary disease. At subsequent angiography, coronary stenosis was defined as significant if luminal diameter was reduced greater than or equal to 50%. Compared with electrocardiography, exercise echocardiography was more sensitive (97 vs 51%) and specific (64 vs 62%), and had higher positive (90 vs 82%) and negative (87 vs 28%) predictive accuracies. Exercise echocardiography was also highly predictive of the extent (no, 1-, 2- or 3-vessel disease) and distribution (which vessel) of coronary stenoses. It is concluded that exercise echocardiography is an excellent screening test for the presence, extent and distribution of coronary artery disease.

Echocardiographic detection of coronary artery disease during dobutamine infusion

BACKGROUND

Two-dimensional echocardiography performed during dobutamine infusion has been proposed as a potentially useful method for detecting coronary artery disease. However, the safety and diagnostic value of dobutamine stress echocardiography has not been established.

METHODS AND RESULTS

In this study, echocardiograms were recorded during step-wise infusion of dobutamine to a maximum dose of 30 micrograms/kg/min in 103 patients who also underwent quantitative coronary angiography. The echocardiograms were digitally stored and displayed in a format that allowed simultaneous analysis of rest and stress images. Development of a new abnormality in regional function was used as an early end point for the dobutamine infusion. No patient had a symptomatic arrhythmia or complications from stress-induced ischemia. Significant coronary artery disease (greater than or equal to 50% diameter stenosis) was present in 35 of 55 patients who had normal echocardiograms at rest. The sensitivity and specificity of dobutamine-induced wall motion abnormalities for coronary artery disease was 89% (31 of 35) and 85% (17 of 20), respectively. The sensitivity was 81% (17 of 21) in those with one-vessel disease and 100% (14 of 14) in those with multivessel or left main disease. Forty-one of 48 patients with abnormal echocardiograms at baseline had localized rest wall motion abnormalities. Fifteen had coronary artery disease confined to regions that had abnormal rest wall motion, and 26 had disease remote from these regions. Thirteen of 15 patients (87%) without remote disease did not develop remote stress-induced abnormalities, and 21 of 26 (81%) who had remote disease developed corresponding abnormalities.

CONCLUSIONS

Echocardiography combined with dobutamine infusion is a safe and accurate method for detecting coronary artery disease and for predicting the extent of disease in those who have localized rest wall motion abnormalities.

Simultaneous transesophageal atrial pacing and transesophageal two-dimensional echocardiography: a new method of stress echocardiography

The diagnostic use of exercise echocardiography has been widely reported. However, transthoracic exercise echocardiography is inadequate in up to 20% of patients because of poor image quality related to exercise. In an attempt to overcome these limitations, a system was developed in which transesophageal echocardiography is combined with simultaneous transesophageal atrial pacing by means of the same probe. In a prospective study, transesophageal echocardiography was performed before, during and immediately after maximal atrial pacing in 50 patients with suspected coronary artery disease. Results of transesophageal stress echocardiography were considered abnormal when new pacing-induced regional wall motion abnormalities were observed. Correlative routine bicycle exercise testing was carried out in 44 patients. Cardiac catheterization was performed in all patients. The success rate in obtaining high quality diagnostic images was 100% by transesophageal echocardiography. All nine patients without angiographic evidence of coronary artery disease had a normal result on the transesophageal stress echocardiogram (100% specificity). Thirty-eight of 41 patients with coronary artery disease (defined as greater than or equal to 50% luminal diameter narrowing of at least one major vessel) had an abnormal result on the transesophageal stress echocardiogram (93% sensitivity). The sensitivity of the technique for one, two or three vessel disease was 85%, 100% and 100%, respectively, compared with 44%, 50% and 83%, respectively, for bicycle exercise testing; the 12 lead electrocardiogram (ECG) during rapid atrial pacing showed a sensitivity of 25%, 64% and 86%, respectively. Thus, rapid atrial pacing combined with simultaneous transesophageal echocardiography is a highly specific and sensitive technique for the detection of coronary artery disease. Ischemia-induced wall motion abnormalities were detected earlier than observed ECG changes. The technique appears to be particularly suited to patients who are unable to perform an active stress test or those with poor quality transthoracic echocardiograms.

Prediction of cardiac events after uncomplicated myocardial infarction by cross-sectional echocardiography during transesophageal atrial pacing

Atrial pacing can safely be utilized shortly after myocardial infarction. To evaluate the prognostic value of wall motion abnormalities induced by such pacing 83 consecutive patients with recent uncomplicated myocardial infarction underwent transthoracic cross-sectional echocardiography during transesophageal atrial pacing and upright bicycle exercise stress test. Patients were followed-up for 14 +/- 5 months. During the atrial pacing and the echocardiography, patients were defined at high risk if abnormalities of wall motion were detected in left ventricular regions remote from the infarcted area. Then, during the exercise stress test, high risk patients were those with ST segment depression greater than or equal to 1 mm. On the other hand, patients were considered to be at low risk if they had no abnormalities of wall motion during atrial pacing in remote regions or, in the case of the stress test, if they did not develop ST depression greater than or equal to 1 mm. Of the 83 patients, 21 had major cardiac events during the period of follow-up. Cardiac events occurred in 15/23 (65%) and 5/60 (8%, P less than 0.001) patients assigned to the groups adjudged to be at high and low risk, respectively, on the basis of echocardiographic results. Exercise testing was less reliable in identifying patients at risk of future cardiac events. Major events occurred in only 6 of the 19 patients with a positive stress test (32%, P less than 0.05 vs positive stress echocardiography) and in 14 of the 64 patients with a negative exercise stress test (22%, P = NS vs positive exercise stress test, P less than 0.05 vs negative atrial pacing echocardiography).

Relation of quantitative coronary lesion measurements to the development of exercise-induced ischemia assessed by exercise echocardiography

To assess the relation of quantitative measures of coronary stenoses to the development of exercise-induced regional wall motion abnormalities, 34 patients with isolated, single vessel coronary artery lesions and normal wall motion at rest underwent exercise echocardiography and quantitative angiography on the same day. Although all 11 patients with a visually estimated stenosis greater than or equal to 75% had an ischemic response and 10 (91%) of 11 patients with a less than or equal to 25% visually estimated stenosis had a normal response by exercise echocardiography, among 12 patients with a visually estimated stenosis of 50%, 6 (50%) had an ischemic response and 6 (50%) had a normal exercise echocardiogram. Quantitative measurements of stenosis severity distinguished patients with ischemic (group 1) from normal (group 2) exercise echocardiographic responses as follows: minimal luminal diameter (mm), group 1 1.0 +/- 0.4 versus group 2 1.7 +/- 0.4, p less than 0.0001; minimal cross-sectional area (mm2), group 1 0.9 +/- 0.6 versus group 2 2.5 +/- 1.1, p less than 0.0001; percent diameter stenosis, group 1 68.3 +/- 14.2 versus group 2 42.2 +/- 12.1, p less than 0.0001; and percent area stenosis, group 1 87.5 +/- 7.8 versus group 2 64.8 +/- 15.9, p less than 0.0001. These data validate the utility of exercise echocardiography by demonstrating that 1) coronary stenosis severity measured by quantitative angiography is closely related to wall motion abnormalities detected by exercise echocardiography, and 2) exercise echocardiography can be used as a noninvasive means to assess the physiologic significance of coronary artery lesions.

Cardiac evaluation of the patient with stroke

Coronary artery disease and ischemic cerebrovascular disease are leading causes of morbidity and mortality in the United States. Coronary artery disease often coexists with asymptomatic carotid artery atherosclerosis, transient ischemic attacks, or ischemic stroke. Numerous studies have shown that mortality from all forms of ischemic cerebrovascular disease is primarily due to coronary artery disease. Thus, there is increasing interest in identifying coronary artery disease in patients with cerebrovascular disease, including those without clinical manifestations of heart disease. We review the use of current noninvasive techniques to detect coronary artery disease and present practical approaches to screen for ischemic heart disease. Current diagnostic imaging methods for potential cardioembolic sources of cerebral infarction are also discussed.

Upright bicycle exercise echocardiography after coronary artery bypass grafting

Upright bicycle exercise echocardiography and coronary angiography were performed in 42 patients from 1 month to 15 years (mean 6.3 years) after coronary artery bypass grafting (CABG) to determine if exercise-induced wall motion abnormalities could be correlated with the presence and location of nonrevascularized vessels. Nonrevascularized vessels were defined as obstructed vessels without grafts, obstructed grafts or native vessels obstructed distal to bypass graft insertion. Adequate quality echocardiograms were recorded at rest, peak exercise and after exercise in 38 patients (90%). Rest and postexercise echocardiograms were adequate in 3 others. Only 1 patient was excluded from analysis for inadequate peak and postexercise echocardiograms. Exercise-induced wall motion abnormalities were present in 33 of 35 patients (94%) who had 1 or more nonrevascularized vessels and these abnormalities were absent in 5 of 6 (83%) who had all vessels revascularized. Wall motion abnormalities were localized to the territory of the left anterior descending (LAD) artery or to a combined right (R) coronary-left circumflex (LC) region of circulation. Exercise-induced wall motion abnormalities were present in 24 of 27 LAD artery regions (89%) and 23 of 26 R-LC regions (88%) that had nonrevascularized vessels. These abnormalities were absent in 13 of 14 LAD regions (93%) and in 12 of 15 R-LC regions (80%) that had only revascularized vessels. Upright bicycle exercise echocardiography was successfully performed after CABG. The technique detected and accurately localized nonrevascularized and revascularized vessels.

Exercise echocardiographic detection of coronary artery disease in women

The utility of exercise echocardiography for the diagnosis of coronary artery disease has been demonstrated in populations consisting largely of men with a high prevalence of disease. To determine the diagnostic value of exercise echocardiography in women, 57 women who presented with chest pain were studied with coronary cineangiography and echocardiography combined with either treadmill (n = 38) or bicycle exercise (n = 19). Significant coronary artery disease (greater than or equal to 50% reduction in luminal diameter) was present in 28 (49%) of 57 patients, including 16 (84%) of 19 who had typical angina, and 12 (32%) of 38 who had atypical chest pain. The overall sensitivity and specificity of echocardiography were both 86%. Exercise echocardiography correctly determined the presence or absence of coronary artery disease in 32 (84%) of 38 patients who had atypical chest pain and in 17 (89%) of 19 who had typical angina (p = NS). The exercise electrocardiogram (ECG) was nondiagnostic in 17 patients (30%) who had rest ST segment depression or ST depression with exercise that could also be induced by hyperventilation or changes in position. The correct diagnosis was made by echocardiography in 14 (82%) of 17 patients with a nondiagnostic exercise ECG. In conclusion, exercise echocardiography has a clinically useful level of sensitivity and specificity for the detection of coronary artery disease in women. The technique provides diagnostic information in women presenting with atypical chest pain and in those who have a nondiagnostic exercise ECG.