Detection of coronary artery disease by digital stress echocardiography: comparison of exercise, transesophageal atrial pacing and dipyridamole echocardiography

Stress echocardiography in heart failure patients: additive value and caveats

Heart failure (HF) is a clinical syndrome characterized by well-defined signs and symptoms due to structural and/or myocardial functional impairment, resulting in raised intracardiac pressures and/or inadequate cardiac stroke volume at rest or during exercise. This could derive from direct ischemic myocardial injury or other chronic pathological conditions, including valvular heart disease (VHD) and primary myocardial disease. Early identification of HF etiology is essential for accurate diagnosis and initiation of early and appropriate treatment. Thus, the presence of accurate means for early diagnosis of HF symptoms or subclinical phases is fundamental, among which echocardiography being the first line diagnostic investigation. Echocardiography could be performed at rest, to identify overt structural and functional abnormalities or during physical or pharmacological stress, in order to elicit subclinical myocardial function impairment e.g. wall motion abnormalities and raised ventricular filling pressures. Beyond diagnosis of ischemic heart disease, stress echocardiography (SE) has recently shown its unique value for the evaluation of diastolic heart failure, VHD, non-ischemic cardiomyopathies and pulmonary hypertension, with recommendations from international societies in several clinical settings. All these features make SE an important additional tool, not only for diagnostic assessment, but also for prognostic stratification and therapeutic management of patients with HF. In this review, the unique value of SE in the evaluation of HF patients will be described, with the objective to provide an overview of the validated methods for each setting, particularly for HF management.

Tipping the scales of understanding: An engineering approach to design and implement whole-body cardiac electrophysiology experimental models

The study of cardiac electrophysiology is built on experimental models that span all scales, from ion channels to whole-body preparations. Novel discoveries made at each scale have contributed to our fundamental understanding of human cardiac electrophysiology, which informs clinicians as they detect, diagnose, and treat complex cardiac pathologies. This expert review describes an engineering approach to developing experimental models that is applicable across scales. The review also outlines how we applied the approach to create a set of multiscale whole-body experimental models of cardiac electrophysiology, models that are driving new insights into the response of the myocardium to acute ischemia. Specifically, we propose that researchers must address three critical requirements to develop an effective experimental model: 1) how the experimental model replicates and maintains human physiological conditions, 2) how the interventions possible with the experimental model capture human pathophysiology, and 3) what signals need to be measured, at which levels of resolution and fidelity, and what are the resulting requirements of the measurement system and the access to the organs of interest. We will discuss these requirements in the context of two examples of whole-body experimental models, a closed chest in situ model of cardiac ischemia and an isolated-heart, torso-tank preparation, both of which we have developed over decades and used to gather valuable insights from hundreds of experiments.

Left Ventricular Myocardial and Cavity Velocity Disturbances Are Powerful Predictors of Significant Coronary Artery Stenosis

Background and Aim: Dobutamine stress echocardiography (DSE) is a well-established noninvasive investigation for significant coronary artery disease (CAD). The aim of this study was to evaluate the accuracy of cardiac Doppler parameters in predicting CAD. Methods: We prospectively studied 103 consecutive patients with suspected CAD based on typical symptoms; 59 proved to have CAD, and 44 patients proved to have no-CAD (n = 44). All patients underwent a complete stress Doppler echocardiographic examination. Total isovolumic time (T-IVT) as a marker of cavity dyssynchrony and wall motion score index (WMSI) were also calculated. Results: At peak dobutamine stress, the compromised LV longitudinal excursion (MAPSE), systolic septal and lateral velocities (s’), and diastolic indices were more pronounced in the CAD patients compared with those without CAD, but LV dimension did not differ between groups (p > 0.05). The WMSI was higher and t-IVT more prolonged in patients with CAD (p < 0.01 for both). Similarly, the changes were more pronounced in patients with significant CAD compared with insignificant CAD. On multivariate model, Δ mean s’, OR 2.016 (1.610 to 3.190; p < 0.001), Δ E velocity OR 2.502 (1.179 to 1.108; p < 0.001), Δ t-IVT 2.206 (1.180 to 2.780; p < 0.001) and Δ WMSI OR 1.911 (1.401 to 3.001; p = 0.001) were the most powerful independent predictors of the presence of CAD, particularly when significant (>75%). Δ mean s’ < 5.0 was 85% sensitive, 89% specific with AUC 0.92. Respective values for Δ E velocity <6.0 cm/s were 82%, 90% and 0.91; for Δ t-IVT > 4.5, 78%, 77% and 0.81 and for Δ FT ≥ 150 ms, 76%, 78% and 0.84 in predicating significant CAD. WMSI ≥ 0.7 was 75% sensitive, 77% specific with AUC of 0.81 in predicting significant CAD. The accuracy of DSE was higher in significant CAD compared to insignificant CAD (80% vs. 74%; p = 0.03). Conclusions: Compromised LV longitudinal systolic function, lower delta E wave, prolonged t-IVT, and increased WMSI were the most powerful independent predictors of the presence and significance of CAD. These finding strengthen the role of comprehensive DSE analysis in diagnosing ischemic disturbances secondary to significant CAD.

Pharmacological and simulated exercise cardiac stress tests produce different ischemic signatures in high-resolution experimental mapping studies

OBJECTIVE

Test the hypothesis that exercise and pharmacological cardiac stressors create different electrical ischemic signatures.

INTRODUCTION

Current clinical stress tests for detecting ischemia lack sensitivity and specificity. One unexplored source of the poor detection is whether pharmacological stimulation and regulated exercise produce identical cardiac stress.

METHODS

We used a porcine model of acute myocardial ischemia in which animals were instrumented with transmural plunge-needle electrodes, an epicardial sock array, and torso arrays to simultaneously measure cardiac electrical signals within the heart wall, the epicardial surface, and the torso surface, respectively. Ischemic stress via simulated exercise and pharmacological stimulation were created with rapid electrical pacing and dobutamine infusion, respectively, and mimicked clinical stress tests of five 3-minute stages. Perfusion to the myocardium was regulated by a hydraulic occluder around the left anterior descending coronary artery. Ischemia was measured as deflections to the ST-segment on ECGs and electrograms.

RESULTS

Across eight experiments with 30 (14 simulated exercise and 16 dobutamine) ischemic interventions, the spatial correlations between exercise and pharmacological stress diverged at stage three or four during interventions (p<0.05). We found more detectable ST-segment changes on the epicardial surface during simulated exercise than with dobutamine (p<0.05). The intramyocardial ischemia formed during simulated exercise had larger ST40 potential gradient magnitudes (p<0.05).

CONCLUSION

We found significant differences on the epicardium between cardiac stress types using our experimental model, which became more pronounced at the end stages of each test. A possible mechanism for these differences was the larger ST40 potential gradient magnitudes within the myocardium during exercise. The presence of microvascular dysfunction during exercise and its absence during dobutamine stress may explain these differences.

The modified protocol of transesophageal atrial pacing in stress echocardiography as an alternative way to increase the information value of the method for detection of ischemic wall motion abnormalities

Aim    To develop a new, modified protocol for transesophageal atrial electric stimulation (TEAES), which would significantly enhance the diagnostic value of stress echocardiography and reduce the duration of the test in patients with ischemic heart disease (IHD).Material and methods    This study included 101 patients (80 men and 21 women aged 55±9 years) with suspected or documented diagnosis of IHD who were divided into two homogenous groups. Group 1 (51 patients) underwent stress echocardiography (stress-EchoCG) according to a standard protocol (SP) for TEAES and group 2 (50 patients), underwent stress-EchoCG according to a modified protocol (MP). In addition to stress-EchoCG with TEAES, selective coronary angiography was performed for all patients. The development of the new method for evaluating occult coronary insufficiency was based on comparison of SP and MP for TEAES with stress-EchoCG with data of coronary angiography.Results    In both groups, significant differences in values of systolic and diastolic blood pressure were absent. However, the values of achieved heart rate were significantly different: 141±11 (TEAES SP) and 155±10 (TEAES MP) bpm (p=0.01). There was also a difference in the duration of the TEAES protocols: 15±3 and 5±2 min, respectively (p=0.006). The use of the modified TEAES protocol for detecting transient disorders of left ventricular myocardial local contractility increased the sensitivity, specificity and accuracy of the test from 76 %, 87 %, and 80 % to 83 %, 92 %, and 86 %, respectively. The most significant differences were found in the area supplied by the circumflex artery: the SP and MP sensitivities were 63 % and 75 %, respectively (p&lt;0.05) and the SP and MP accuracies were 81 % and 90 %, respectively (p&lt;0.05).Conclusion    Evaluation of occult coronary insufficiency by stress-EchoCG with the TEAES MP as compared to the TEAES SP provides a gentler procedure regimen for the patient due to a shorter duration of the test and at the same time improves the diagnostic significance of this method in IHD patients.

Value of exercise echocardiography for predicting mortality in elderly patients

BACKGROUND

Elderly patients with suspected or known coronary artery disease are often referred for pharmacological stress testing. Data on the value of exercise echocardiography (ExEcho) for predicting outcome (particularly all-cause mortality) in these patients are scarce.

METHODS

Peak treadmill ExEcho was performed in 2159 patients ≥ 70 years of age with known or suspected coronary artery disease. Left ventricular wall motion was evaluated at baseline and with exercise, and the increase in wall motion score index from rest to peak exercise (ΔWMSI) was calculated. Ischaemia was diagnosed when new or worsening wall motion abnormalities developed with exercise. The end points were all-cause mortality and major cardiac events (cardiac death or myocardial infarction).

RESULTS

Ischaemia developed in 844 patients (38·6%) during exercise. Over a mean follow-up of 3·5 ± 3·1 years, 439 deaths occurred. The cumulative 5-year mortality rate was 29·3% in patients with ischaemia versus 16·8% in those without ischaemia (P < 0·001). After covariate adjustment, ΔWMSI remained an independent predictor of mortality [hazard ratio (HR) 2·37, 95% confidence interval (CI) 1·66-3·39, P < 0·001] and major cardiac events (HR 3·48, 95% CI 2·11-5·74, P < 0·001). These results remained significant even in patients with chronotropic incompetence. When added to a model with clinical, resting echocardiographic and exercise electrocardiogram variables, ExEcho results provided incremental value for the prediction of both end points (P < 0·001).

CONCLUSIONS

ExEcho is feasible in elderly patients with suspected or known coronary artery disease and provides useful information for risk stratification in these patients.

Comparison of exercise electrocardiography, technetium-99m sestamibi single photon emission computed tomography, and dobutamine and dipyridamole echocardiography for detection of coronary artery disease in hypertensive women

To assess the performance of currently used stress tests for the detection of coronary artery disease (CAD) in a series of female hypertensive patients. We performed exercise electrocardiography (ECG), technetium-99m sestamibi (MIBI) single photon emission computed tomography, dobutamine and dipyridamole echocardiography, and coronary angiography in 76 hypertensive women. Of the 76 study patients, 31 (41%) had significant CAD. The sensitivity of exercise ECG (81%), MIBI scanning (90%), and dobutamine echocardiography (87%) was greater than that of dipyridamole echocardiography (61%). This finding resulted from the lower sensitivity of dipyridamole echocardiography in the detection of single-vessel CAD (47% vs 76%, 88%, and 82% for the other 3 methods). In contrast, the sensitivity of the 4 tests was similar in the detection of multivessel CAD. The specificity of exercise ECG (56%) and MIBI scanning (53%) was less than that of dobutamine (82%, both p <0.01) and dipyridamole (91%, both p <0.001) echocardiography. This finding related to the lower specificity of exercise ECG in patients with either left ventricular hypertrophy or ST-T abnormalities at rest compared to the specificity in patients without these disorders (33% vs 89%, p <0.01). A lower MIBI scan specificity was found only in patients with left ventricular hypertrophy (31% vs 66%, p <0.05). The overall accuracy of dobutamine echocardiography reached 84% compared to exercise ECG (66%, p <0.01), MIBI scan (68%, p <0.05), and dipyridamole echocardiography (79%, p <0.05). In conclusion, dobutamine echocardiography yielded satisfactory diagnostic accuracy for identifying CAD in hypertensive women. Although dipyridamole echocardiography had the greatest specificity, it might be limited in detecting mild CAD. Both exercise ECG and MIBI scanning had fare sensitivity; however, our findings limit the usefulness of these 2 tests in unselected patients.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Systematic overview and clinical applications of pacing atrial stress echocardiography

Pacing atrial stress echocardiography (PASE) has been studied over the past 3 decades for the evaluation of myocardial ischemia. Published studies suggest that PASE may be used as an alternative to exercise or pharmacologic stress imaging. The recent introduction of improved pacing electrodes, together with use of accelerated and shortened pacing protocols and improvements in transthoracic echocardiographic imaging techniques, makes PASE an appealing stress imaging method. A critical analysis of the diagnostic accuracy of PASE shows equivalence with other imaging stress modalities. PASE has been found to be highly feasible and accurate technique that may expedite the diagnosis and risk stratification of patients with coronary artery disease. This review addresses the history, hemodynamics, protocols, accuracy, clinical utility, and cost-effectiveness of PASE as well as elucidating its place among other stress modalities.

Stress Echocardiography in Octogenarians: Transesophageal Atrial Pacing is Accurate, Safe, and Well Tolerated

The feasibility and diagnostic accuracy of transesophageal pacing stress echocardiography for detection of inducible myocardial ischemia were evaluated in 161 patients 80 years of age or older (mean 84 +/- 3.9, range 80-97). The pacing time was 5.5 +/- 2.5 minutes with a total test time of 37 +/- 7 minutes. The mean achieved heart rate was 96 +/- 7% (83%-121%) of maximum predicted with an average rate pressure product of 21,560 +/- 5175 beats/min x mm Hg. There were minor adverse events in 8% of cases and no major complications occurred. Patient acceptance was high. When compared with myocardial single photon emission computed tomography, pacing stress echocardiography had a sensitivity of 89% and a specificity of 93% for the detection of myocardial ischemia, and 91% agreement (kappa = 0.80, P < .001). We demonstrate that pacing stress echocardiography is safe and accurate for detection of myocardial ischemia and, thus, a reliable substitute to exercise and pharmacologic stress testing in octogenarians.

A meta-analytic comparison of echocardiographic stressors

BACKGROUND

The relative performance of alternative stressors for stress echocardiography for the diagnosis of coronary artery disease (CAD) is not well established.

METHODS

All studies published between 1981 to December 2001 who met inclusion criteria were included in this analysis. We performed a summary receiver operator characteristic (SROC) analysis and calculated weighted mean of the likelihood ratio and sensitivity/specificity. A covariate analysis using meta-regression methods was also performed.

RESULTS

Forty-four studies presented data on Exercise, 11 on Adenosine, 80 on Dobutamine, 40 on Dipyridamole, 16 on transatrial pacing transesophageal echocardiography (Tap-TEE), and 7 on transatrial pacing transthorasic echocardiography (Tap-TTE). SROC analysis showed that the following order of most discriminatory to least: Tap-TEE, Exercise, Dipyridamole, Dobutamine and Adenosine. Weighted means sensitivity/specificity were Exercise: 82.6/84.4%, Adenosine: 68.4/80.9%, Dobutamine: 79.6/85.1%, Dipyridamole: 71.0/92.2%, Tap-TTE: 90.7/86.1%, and Tap-TEE: 86.2/91.3%. Covariate analysis showed that the discriminatory power of Exercise decreased with increasing mean age.

CONCLUSIONS

Tap-TEE is a very accurate test for both ruling in and ruling out CAD although its invasiveness may limit its clinical acceptability. Exercise is a well-balanced satisfactory test for both ruling in and ruling out but performance might be lower for the elderly. Dobutamine offers a reasonable compromise for Exercise. Dipyridamole might be good for ruling in but not for ruling out CAD. The incapability in ruling-out CAD was a major problem in clinical application of the stress. Adenosine was the least useful stressor in diagnosing CAD.

Pacing stress echocardiography

Background

High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility.

Methods

The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG.

Conclusion

Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker.

The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an initial up- sloping followed by a later down-sloping trend, or flat or negative when peak stress pacing systolic pressure/end-systolic volume index is equal or lower than baseline stress values. This approach is certainly highly feasible and allows a conceptually immaculate definition of contractility with prognostic usefulness, but its therapeutic implications remains to be established. Bowditch treppe, assessed with pacing stress, can be used to assess the optimal stimulation frequency and to optimise the patient's chronotropic response in programming rate-adaptive pacemakers.

Pacemaker stress echocardiography predicts cardiac events in patients with permanent pacemaker

PURPOSE

Noninvasive pacemaker stress echocardiography is a newly introduced method for the diagnosis of coronary artery disease in patients with a permanent pacemaker. The prognostic value of pacemaker stress echocardiography has not been studied.

SUBJECTS AND METHODS

We studied 136 patients (mean age 64+/-12 years) with a permanent pacemaker who underwent pacemaker stress echocardiography for evaluation of coronary artery disease. All patients underwent pacemaker stress echocardiography by external programming (pacing heart rate up to ischemia or target heart rate).

RESULTS

Thirty-one patients (23%) had normal study results. Ischemia was detected in 75 patients (55%). During a mean follow-up of 3.5+/-2.4 years, 35 deaths (26%) (20 the result of cardiac causes) and 2 nonfatal myocardial infarctions (1%) occurred. The annual cardiac death rate was 1.3% in patients without ischemia and 4.6% in patients with ischemia (P=.01). The annual all-cause mortality rate was 3.1% in patients without ischemia and 7% in patients with ischemia (P=.004). The presence of ischemia during pacemaker stress echocardiography was the strongest independent predictor of cardiac death (hazard ratio 4.1, confidence interval 1.2-14.5) and all-cause mortality (hazard ratio 2.7, confidence interval 1.2-6.0) in a multivariable model.

CONCLUSION

Myocardial ischemia during pacemaker stress echocardiography is an independent predictor of cardiac death and all-cause mortality in patients with a permanent pacemaker.

Relationship between the ischemic threshold at the onset of wall-motion abnormality on semisupine exercise echocardiography and the extent of coronary artery disease

Semisupine exercise echocardiography (SSEE) provides the unique opportunity of continuous monitoring of segmental wall motion during physiologic stress. We evaluated the relationship between the ischemic threshold at the onset of wall-motion abnormality on SSEE and the extent of coronary artery disease (CAD) in a consecutive series of 224 patients who underwent coronary angiography. Ischemic threshold was significantly lower for patients with multivessel disease compared with single-vessel disease: maximal workload was 102 versus 135 W (P = 1.3.10(-6)); percentage of maximal predicted heart rate achieved was 64 versus 70% (P =.004); and double product was 21,335 versus 23,389 (P =.03), respectively. Sensitivity, specificity, and positive and negative predictive values of SSEE for the detection of significant CAD (> or =60% diameter stenosis) were 81%, 74%, 90%, and 56%, respectively. SSEE is an accurate tool to diagnose CAD and the ischemic threshold at the onset of wall-motion abnormality is inversely related to the extent of CAD.

Prognostic value of contrast stress echocardiography in patients with image quality too limited for traditional noncontrast harmonic echocardiography

Clinical data and contrast stress echocardiography (CSE) results were analyzed in 283 patients to establish the prognostic value of CSE for patients with limited echocardiogram image quality at baseline. The mean follow-up period was 736 +/- 337 days. Only 7 patients (2.5%) had nondiagnostic image quality with contrast enhancement. During follow-up, 24 cardiac events (8.5%) occurred (5 cardiac-related deaths, 2 nonfatal myocardial infarction, 17 coronary revascularizations). Overall sensitivity, specificity, and positive and negative predictive values were 60.9%, 76.8%, 19.7%, and 95.5%, respectively. Kaplan-Meier event-free survival was higher for patients with a negative CSE result as compared with those with a positive CSE finding (P <.0001). In a multivariate Cox proportional hazards model, positive CSE was the strongest predictor of cardiac events (risk ratio 3.7; 95% confidence interval 1.6-8.7). CSE can successfully predict cardiac events for patients with limited noncontrast echocardiographic image quality. A negative CSE result conferred a good prognosis.

Feasibility and safety of transeophageal atrial pacing stress echocardiography in patients with known or suspected coronary artery disease

To investigate the feasibility and safety of the transesophageal atrial pacing stress test combined with echocardiography (TAPSE) 1,727 TAPSE tests were performed on 1,641 patients consecutively referred to our echocardiographic laboratory for nonexercise stress testing (1,319 men; mean age 60 +/- 9 years; 34% of whom were outpatients). Wall motion abnormalities were present at baseline echocardiography in 975 cases (56%). TAPSE was feasible in 1,648 cases (95.4%). It was not feasible in 79 patients due to failure of positioning the transnasal catheter (n=11), the patient's intolerance of esophageal stimulation (n=24), failure to obtain any or stable atrial capture (n=36), or because the echocardiogram could not be evaluated at the peak of the test (n=8). TAPSE was diagnostic in 1,584 cases (96% of the feasible tests, 92% of all attempts). TAPSE was nondiagnostic in 64 cases (4% of the feasible tests) due to second-degree atrioventricular type I block resistance to atropine administration with failure to achieve 85% of the age-predicted maximum heart rate (n=59) or due to side effects, such as arrhythmias (n=3) or hypertension (n=2), which required premature interruption of the test. There were no major complications (death, myocardial infarction, or life-threatening arrhythmias). There were 28 instances of minor complications that comprised transient arrhythmias, including atrial fibrillation (n=8), paroxysmal supraventricular tachycardia (n=6), automatic atrial tachycardia (n=1), sinus arrest (n=1), atrioventricular junctional rhythm (n=2), ectopic atrial rhythm (n=2), nonsustained ventricular tachycardia (maximum 6 beats, n=3), hypotension (n=1), and hypertension (n=4) leading to interruption of the test. Only 5 complications hampered a diagnostic result, whereas 18 occurred during or after a positive test and 5 during a negative, but diagnostic, test. Thus, TAPSE is a highly feasible and very safe stress test. It gives high percentage of diagnostic tests and may represent a valid alternative to pharmacologic stressors.

Interpretation of Left Ventricular Wall Motion During Stress Testing

This article describes the obstacles to stress echocardiographic interpretation, and reviews the techniques currently available that offer a more objective approach to stress wall motion analysis than the conventional visual methodology. These techniques include Doppler-based methods, such as myocardial Doppler velocity and strain rate imaging, as well as automated border detection techniques, such as acoustic quantification and color kinesis.

Noninvasive pacemaker stress echocardiography for diagnosis of coronary artery disease: a multicenter study

OBJECTIVE

We evaluated the feasibility, safety, and diagnostic accuracy of noninvasive pacemaker stress echocardiography (PASE) test as a potential alternative to exercise or pharmacologic stress in patients with suspected or known coronary artery disease (CAD).

BACKGROUND

Transesophageal atrial pacing echocardiography is an accurate test for detection of CAD, but its practical impact has been blunted by semi-invasiveness. In the expanding population of patients with permanent pacemakers (PMs), a pacing stress test can be administered noninvasively by external programming of the PM.

METHODS

In a prospective, multicenter, international study design, transthoracic stress-pacing echocardiography was performed in 46 consecutive patients with a permanent PM (33 men, 13 women; age 66.6 +/- 11.1 years) with suspected or known CAD. All patients underwent noninvasive PM-stress test by external programming (10 beats/min increments up to ischemia or target heart rate). Coronary angiography was performed in all patients independently of test results. Significant CAD was defined as >/=50% visually assessed diameter reduction in at least one major epicardial coronary artery. All coronary angiograms were scored by Duke prognostic weight values.

RESULTS

Fifteen patients were stimulated in atrial, and the remaining 31 in ventricular mode during stress. No significant side effects were observed. Echocardiographic images were interpretable in all patients. The average duration of stress was 8.9 +/- 3.5 min. Significant CAD was found in 27 patients. Sensitivity of PASE for identifying patients with significant CAD was 70%, specificity was 90%, and accuracy was 78%. When any abnormal wall motion at rest that remained unchanged at peak stress was regarded as a positive result of PASE, then the sensitivity, specificity, and accuracy levels for identifying patients with significant CAD were 85%, 84%, and 85%, respectively. Four of the eight patients with a false negative did not reach the target heart rate. The Duke values had significant correlation with values of wall motion score index at peak stress (r = 0.67) and with peak heart rate (r = -0.3).

CONCLUSIONS

Noninvasive PASE is a simple, rapid, safe, and diagnostically efficient option for patients with permanent PM and suspected or known CAD.

Pharmacological stress agents for evaluation of ischemic heart disease

Ischemic heart disease is the leading cause of death in the developed countries for those older than 65 years of age. In patients suspected to have coronary artery disease a stress test should be performed to identify the vulnerability of the myocardium to ischemia. As a rule of thumb, the evaluation of coronary artery disease is best done by exercise stress test. In patients who are not able to exercise adequately, pharmacological stress agents are used. The commonly used agents are the coronary vasodilators, adenosine and dipyridamole and the catecholamines, dobutamine and arbutamine. These agents are combined with imaging techniques to increase the sensitivity and specificity of the test. These agents have been widely used and have an excellent safety profile. Another advantage in using pharmacological stress agents is that they do not affect the image quality, especially with echocardiography and magnetic resonance imaging. Ongoing developments hold promise for safer and more reliable pharmacological stress agents in the future.

Pharmacologic stress testing for coronary disease diagnosis: A meta-analysis

BACKGROUND

Although noninvasive pharmacologic stress tests are widely used, their relative performance is not clear. We compared the performance of pharmacologic stress tests combined with echocardiography or nuclear imaging for the diagnosis of coronary disease.

METHODS

We performed a regression meta-analysis of published data. We included studies published between January 1975 and June 1999 in which subjects underwent echocardiographic or single-photon emission computed tomography (SPECT) stress testing with adenosine, dipyridamole, or dobutamine for diagnosis of coronary artery disease. All subjects also underwent coronary angiography. Two independent reviewers abstracted population characteristics, technical factors, methodologic factors, and results and calculated test sensitivity and specificity.

RESULTS

Eighty-two studies met the inclusion criteria. The sensitivity of dipyridamole SPECT imaging, 89% (95% CI, 84%-93%), was higher than that of dipyridamole echocardiography, but the specificity of dipyridamole SPECT imaging, 65% (95% CI, 54%-74%), was lower than that of dipyridamole echocardiography. Dipyridamole and adenosine tests had similar sensitivities and specificities. The sensitivity of dobutamine echocardiography, 80% (95% CI, 77%-83%) was similar to that of dobutamine SPECT imaging, but dobutamine echocardiography had a higher specificity, 84% (95% CI, 80%-86%) than dobutamine SPECT imaging did.

CONCLUSIONS

The findings of our study can be used to guide the selection of the optimal pharmacologic stress test for each patient. Maximum sensitivity can be attained by use of a vasodilator combined with SPECT imaging. Maximum specificity can be attained by use of a vasodilator with echocardiography. The highest combination of sensitivity and specificity can be attained with dobutamine echocardiography.

Stress echocardiography: technical considerations

Stress echocardiography has evolved into a widely practiced and accepted method for the noninvasive assessment of the status of the coronary anatomy. Furthermore, this modality incorporates the ability to assess left ventricular function, valvular structure and function, intracardiac masses, the pericardium, and hemodynamics. The extent to which this tool can reliably provide useful clinical information is dependent, in part, on optimal performance. The purpose of this report is to provide an overview of those technical considerations that can contribute to the successful operation of a stress echocardiography laboratory. Consideration is given to personnel qualifications, functional requirements of the digital acquisition/storage/replay system, functional integration of the various hardware components, characteristics of the software, physical layout of the facility, and alternatives to treadmill exercise as the stressor. A thorough understanding of the physiologic basis of stress echocardiography, coupled with optimization of resources used in its performance, enable this tool to be an extraordinarily useful and cost-efficient method for comprehensive cardiovascular assessment.

Pacing stress echocardiography: an alternative to pharmacologic stress testing

OBJECTIVES

We sought to evaluate the diagnostic accuracy and feasibility of bedside pacing stress echocardiography (PASE) as a potential substitute for pharmacologic stress echocardiography in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

BACKGROUND

Accurate and rapid noninvasive identification and evaluation of the extent of coronary artery disease (CAD) is essential for optimal management of these patients.

METHODS

Bedside transthoracic stress echocardiography was performed in 54 consecutive patients admitted to a community hospital with new-onset chest pain, after acute myocardial infarction had been excluded. We used 10F transesophageal pacing catheters and a rapid and modified pacing protocol. The PASE results were validated in all patients by coronary angiography performed within 24 h of the test. Significant CAD was defined as > or =75% stenosis in at least one major epicardial coronary artery.

RESULTS

The sensitivity of PASE for identifying patients with significant CAD was 95%, specificity was 87% and accuracy was 92%. The extent of significant CAD (single- or multivessel disease) was highly concordant with coronary angiography (kappa = 0.73, p<0.001). Pacing stress echocardiography was well tolerated, and only 4% of the patients had minor adverse events. The mean rate-pressure product at peak pacing was 22,313+/-5,357 beats/min per mm Hg, and heart rate >85% of the age-predicted target was achieved in 94% of patients. The average duration of the bedside PASE test, including image interpretation, was 38+/-6 min.

CONCLUSIONS

Bedside PASE is rapid, tolerable and accurate for identification of significant CAD in patients admitted to the hospital with new-onset chest pain or worsening angina pectoris.

Anatomy of a meta-analysis: a critical review of "exercise echocardiography or exercise SPECT imaging? A meta-analysis of diagnostic test performance"

BACKGROUND

Accurate diagnosis of coronary heart disease has the potential to contribute substantially to cost-effective delivery of health services. Recent work by Fleischmann et al (JAMA 1998;280:913-20) represents an effort to summarize the accuracy of exercise echocardiography and exercise single photon emission computed tomography (SPECT).

METHODS AND RESULTS

A critique of the previous work was constructed, obtaining the 44 articles used. These articles were reviewed and summarized with established techniques for meta-analysis. The studies summarized by Fleischmann et al were found to be significantly heterogeneous (echocardiography and SPECT, both P<.001). In the SPECT cohort, combination of different radioisotopes and reading techniques, and inclusion of reports using experimental techniques, were sources of heterogeneity. In the echocardiography cohort, experimental techniques and an individual series were identified. When the sample was stratified for sources of heterogeneity, it was found that there was no significant difference in diagnostic accuracy between the echocardiography and SPECT techniques used in current clinical practice. Meta-regression with summary receiver operating characteristic curve techniques, after adjustment of the model for multicolinearity and outliers, revealed that there were no significant differences between SPECT as used in current clinical practice and echocardiography.

CONCLUSION

The report by Fleischmann et al contains serious flaws that limit its validity and generalizability.

Diagnostic and prognostic use of stress echocardiography in stable patients

Stress echocardiography is an effective diagnostic and prognostic technique in stable patients with known or suspected coronary artery disease (CAD), myocardial infarction, or chronic left ventricular dysfunction and those undergoing noncardiac surgery. Stress echocardiography is sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events regardless of the clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Stress echocardiography provides incremental prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable to that from radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for one-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

Exercise echocardiography versus exercise electrocardiography in the diagnosis of coronary artery disease in hypertension

In hypertension, coronary artery disease (CAD) can be overestimated by stress electrocardiography (ECG) and scintigraphy due to frequent false-positive results. Exercise tests are also limited by an excessive blood pressure increase, and pharmacologic pressure normalization decreases the accuracy of the test. The aim of this study was to assess the accuracy of exercise echocardiography as an alternative test for CAD detection in hypertension, both before and after adequate blood pressure control. We studied 59 hypertensive and 59 normotensive patients undergoing coronary angiography for chest pain. Upright bicycle exercise ECG and echocardiographic tests were performed in each group in the absence of therapy; in hypertensives, the tests were repeated a day apart after blood pressure normalization with sublingual nifedipine. Significant CAD (lumen narrowing >50%) was detected in 22 hypertensive and 41 normotensive patients. In the two groups, sensitivity, specificity, and diagnostic accuracy of exercise echocardiography performed before treatment were not statistically different (95%, 94%, 94% in hypertensives and 82%, 77%, 83% in normotensives, respectively), but were significantly higher than for the exercise ECG test (68%, 70%, and 69%, respectively). After blood pressure lowering, exercise echocardiography sensitivity slightly decreased (91%), whereas specificity (100%) and diagnostic accuracy (96%) did not vary; on the contrary, exercise ECG sensitivity decreased to 45%. Therefore, according to our data, exercise echocardiography can be an accurate test and more reliable than exercise ECG to detect CAD in normotensives as well as in hypertensives. Normalization of blood pressure with nifedipine does not affect its accuracy, but markedly reduces the sensitivity of exercise ECG.

Transthoracic stress echocardiography with transesophageal atrial pacing for bedside evaluation of inducible myocardial ischemia in patients with new-onset chest pain

To date, there are no data on the feasibility and accuracy of bedside pacing stress echocardiography in patients admitted to the hospital with new-onset chest pain or unstable angina. We evaluated the feasibility of pacing stress echocardiography and examined its correlation with myocardial perfusion stress scintigraphy (rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion single-photon emission computerized tomography) performed within 24 hours of the pacing stress echocardiography test. We studied 70 consecutive patients after acute myocardial infarction had been excluded. The bedside pacing stress echocardiography test was performed with 10Fr transesophageal pacing catheters. We found pacing stress echocardiography to be feasible and safe (3% minor adverse event rate) at the patients' bedside. Target heart rate of >85% of the age-predicted heart rate was achieved in 96% of patients, and the mean rate-pressure product was 22,644 +/- 4,520 beats/min/mm Hg. The mean duration of the bedside pacing stress echocardiography test including technical preparations and image interpretation was 41 +/- 7 minutes. Pacing stress echocardiography and myocardial perfusion stress scintigraphy correlated well for identification or exclusion of inducible myocardial ischemia in 63 of 70 patients (90%) (kappa 0.81, p <0.001). The extent of inducible myocardial ischemia by vascular territories correlated with myocardial perfusion stress scintigraphy in 52 of 70 patients (74%) (kappa 0.6, p <0.001). We conclude that bedside pacing stress echocardiography is feasible and safe, and highly correlates with myocardial perfusion stress scintigraphy for identifying inducible myocardial ischemia in patients with new onset of chest pain or unstable angina.

The comparable diagnostic accuracies of dobutamine-stress and dipyridamole-stress echocardiographies: a meta-analysis

BACKGROUND

Dobutamine-stress and dipyridamole-stress echocardiographies are widely used for pharmacological stress echocardiography, with wide geographical variations.

OBJECTIVE

To assess whether evidence derived from the literature indicates or disapproves that either stress modality confers diagnostic superiority.

METHODS

We performed a meta-analysis of peer-reviewed literature of published trials with head-to-head comparison, on the same population, of high-dose (0.84 mg/kg) dipyridamole-stress versus high-dose (up to 40 micrograms/kg per min) dobutamine-stress echocardiography. Data from 12 studies performed in 12 institutions in seven countries were analysed. Angiographic information about 818 patients was considered.

RESULTS

The diagnostic accuracies of the two tests were similar (631 of 818, 77%, for dipyridamole versus 654 of 818, 80%, for dobutamine, NS). Overall sensitivities were 403 of 568 (71%) for dipyridamole and 437 of 568 (77%) for dobutamine (P < 0.05). Sensitivities for patients with single-vessel disease were 177 of 275 (64%) for dipyridamole and 203 of 275 (74%) for dobutamine (P < 0.05). Sensitivities for patients with multivessel disease were 162 of 203 (80%) for dipyridamole and 163 of 203 (80%) for dobutamine (NS). Specificities were 232 of 250 (93%) for dipyridamole and 217 of 250 (87%) for dobutamine (P < 0.05). Data from an additional 26 studies with dipyridamole alone and 47 studies with dobutamine alone were analysed. The diagnostic accuracies were 80% for dipyridamole (n = 2038 patients; 95% confidence interval 75-82%) and 82% for dobutamine (n = 4264 patients; 95% confidence interval 79-84%).

CONCLUSION

High-dose dobutamine-stress and high-dose dipyridamole-stress echocardiographies have comparable diagnostic accuracies, with a slightly higher sensitivity with dobutamine and a slightly higher specificity with dipyridamole.

Comparison of bicycle, heavy isometric, dipyridamole-atropine and dobutamine stress echocardiography for diagnosis of myocardial ischemia

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are considered to have better diagnostic accuracy than vasodilator or isometric SE, but there are no studies in a single group of patients comparing these 3 tests with heavy 2-arm isometric SE. The purpose of this study was to determine the diagnostic characteristics of 4 SE methods in patients with chest pain. Altogether, 60 patients (age +/- SD 55.1 +/- 2.1 years) were tested with bicycle, heavy 2-arm isometric, dipyridamole-atropine and dobutamine SE. CAD (>50% stenosis) was present in 44 patients; 26 patients had 1-vessel disease. During bicycle SE, the double product at peak stress was higher than during dobutamine and dipyridamole-atropine SE (26.5 x 10(3), p <0.005 vs dobutamine and dipyridamole-atropine SE), and peak wall motion score index (1.40) was higher than during dipyridamole-atropine and isometric SE (1.26 and 1.07, respectively, p <0.05 vs bicycle SE). Bicycle, dipyridamole-atropine, and dobutamine SE had higher sensitivity than isometric SE (90%, 93%, 95%, and 30%, respectively, p <0.05 isometric SE vs others). There were no statistically significant differences with regard to specificity. Similarly, bicycle, dipyridamole-atropine, and dobutamine SE had a higher diagnostic accuracy than isometric SE (78%, 88%, 87% and 47%, respectively, p <0.05 isometric SE vs others). We conclude that bicycle, dipyridamole-atropine, and dobutamine SE have an equal diagnostic accuracy in detecting CAD despite higher double product and ischemic burden at peak stress during bicycle and dobutamine SE over dipyridamole-atropine SE. Heavy isometric SE is inaccurate.

Gated Tc-99m sestamibi SPECT versus stress-rest SPECT in detecting coronary artery disease: correlation with coronary angiography in patients without myocardial infarction

PURPOSE

It is possible to simultaneously evaluate wall thickening and perfusion abnormalities with radionuclide techniques that use tracers such as Tc-99m MIBI. We presumed that detection of wall thickening by gated MIBI SPECT imaging in the presence of a stress-induced perfusion defect correlates with reversibility of that defect on resting images. Therefore, the aim of our study was to analyze, in patients without myocardial infarction, resting wall thickening and stress perfusion imaging as an alternative to conventional stress-rest imaging.

METHODS AND RESULTS

The patients (n = 44) underwent an exercise (n = 37) or pharmacologic (n = 7) stress protocol. All patients had previous coronary angiography within 3 months. Stress-rest MIBI SPECT and gated MIBI SPECT studies were analyzed by visual scoring. The sensitivity and specificity of segmental analysis of both stress-rest MIBI SPECT perfusion and gated MIBI SPECT studies for the overall detection of coronary artery disease were, respectively, 71% and 96%. For patient evaluation for detection of coronary artery disease, stress-rest MIBI SPECT perfusion and gated MIBI SPECT studies showed a sensitivity rate of 96% for both and specificity rates of 84% and 79%, respectively.

CONCLUSIONS

Our data revealed close agreement between reversible perfusion defects on stress-rest MIBI SPECT scans and significant wall thickening on gated MIBI SPECT stress images in patients without previous myocardial infarction (95%). Gated MIBI SPECT stress, without resting studies, which provide an assessment of wall motion and wall thickening, potentially allows stress defect reversibility to be evaluated in patients without previous myocardial infarction.

Diagnostic and Prognostic Use of Stress Echocardiography and Radionuclide Scintigraphy

Stress echocardiography and radionuclide scintigraphy are effective diagnostic and prognostic techniques in patients with known or suspected coronary artery disease (CAD), myocardial infarction (MI), chronic left ventricular dysfunction (LVD), and those undergoing noncardiac surgery. Both are sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events irrespective of clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Both provide incremental diagnostic and prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable with radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for single-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

Overall and Segmental Agreement of Stress Echocardiography

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are commonly considered to have a better diagnostic accuracy than vasodilator SE. The purpose of this study was to assess the agreement between the test results and the segmental concordance between three SE tests in patients with chest pain. A total of 60 patients (mean age, 55.1 years; SD, 2.1) were tested by symptom-limited bicycle (BSE), dipyridamole-atropine (DiASE), and dobutamine (DSE) tests. CAD (50% stenosis) was present in 44 patients, and 26 patients had one-vessel disease. In BSE and DSE, the double product at peak stress (26.5 and 16.1 vs 13.3 x 10(3), respectively, P < 0.005 vs DiASE) and the peak wall motion score index were higher than in DiASE (1.40 and 1.35 vs 1.26, respectively, P < 0.05 vs DiASE). BSE, DiASE, and DSE did not differ in sensitivity in diagnosing CAD (90%, 93%, and 95%, respectively). Similarly, there were no statistically significant differences in the diagnostic accuracy of BSE, DiASE, and DSE (78%, 88%, and 87%, respectively). The intermethod agreement was moderate between BSE and DiASE (kappa = 0.51), good between BSE and DSE (kappa = 0.62), and moderate between DiASE and DSE (kappa = 0.57). The segmental agreement between BSE, DiASE, and DSE was mostly moderate. Agreement was best between the pharmacologic tests due to test protocols, especially the anterior wall (kappa > 0.60). Also, the basal segments showed good agreement. In conclusion, BSE, DiASE, and DSE have a similar diagnostic accuracy in detecting CAD. The overall agreement between the tests was good, and the assessment of wall motion was variable. Nevertheless, concordant diagnosis of a patient can be obtained by BSE, DiASE, and DSE without loss of diagnostic power.

Dipyridamole stress echocardiography

Dipyridamole stress is the forerunner and prototype of pharmacological stress echo tests in the diagnosis of coronary artery disease. The safety of this test has been conclusively demonstrated as a result of extensive experience in large-scale multicenter projects. The diagnostic accuracy of dipyridamole stress echo is comparable to dobutamine and largely a function of the employed dose. Higher dosages (up to 0.84 mg/kg) are being required to achieve good sensitivity. The prognostic value has been shown to be independent and additive to clinical, exercise echocardiogram, and angiographic data. The test positive response should be titrated on the basis of severity, extent, and timing of induced dyssynergy with low positivity being associated to more anatomically and functionally severe forms of disease. Multicenter, randomized, prospective, international studies on cost-effectiveness directly comparing a noninvasive strategy centered on stress echo versus an invasive strategy centered on coronary angiography are currently ongoing.

Exercise echocardiography. Principles, methods, and clinical use

Stress echocardiography is composed of a family of examinations in which various forms of cardiovascular stress are combined with echocardiographic imaging to assist in the diagnosis of coronary artery disease. Exercise cardiography has evolved over the past 20 years into a routinely available clinical tool employed in both university and community hospital settings. This article discusses advantages and disadvantages of using exercise echocardiography.

Assessment of flow mismatch with pharmacologic stress test on myocardial contrast echocardiography in a model of critical stenosis: adenosine triphosphate and dipyridamole

Although adenosine triphosphate (ATP) is a favorable vasodilator because of its short-acting duration, the agent's effectiveness in facilitating the diagnosis of myocardial ischemia with myocardial contrast echocardiography (MCE) is not fully understood. The goal of this study was to examine the efficacy of intravenous ATP administration (0.15 to 0.30 mg/kg/min for 5 minutes) in diagnosing the flow mismatch with MCE. To achieve this, a critical stenosis was produced in the left circumflex artery in 10 anesthetized dogs. The peak intensity ratio of risk area to control area was reduced by ATP from 0.51 +/- 0.19 to 0.31 +/- 0.12 (P <.05). Systolic wall thickening of the risk area did not change significantly (32.8% +/- 9.8% to 27.5% +/- 12.8%). These changes did not differ from those obtained after dipyridamole. We conclude that MCE with intravenous ATP administration is as useful as the dipyridamole method for diagnosing critical coronary stenosis.

Nonexercise stress transthoracic echocardiography: transesophageal atrial pacing versus dobutamine stress

OBJECTIVES

To compare transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography for feasibility, safety, duration, patient acceptance and concordance in inducing wall motion abnormalities.

BACKGROUND

Transesophageal atrial pacing is an effective method of increasing heart rate and has been used in the assessment of coronary artery disease.

METHODS

Both tests were performed in sequence on the same patients in random order. Transesophageal atrial pacing stress echocardiography began at a heart rate of 10 beats/min above the baseline value and was increased by 20 beats/min every two min until 85% of the age-predicted maximum heart rate or another end point was reached. Dobutamine echocardiography was performed using three-min stages and a maximum dose of 40 microg/kg per min. Atropine (total dose < or =2 mg) was administered at the start of the 40 microg/kg per min stage if needed to augment heart rate or during pacing if Wenckebach heart block occurred.

RESULTS

Transesophageal atrial pacing stress echocardiography was feasible in 100 of 104 patients (96%); the duration (8.6+/-3.6 min) was significantly shorter than that of dobutamine stress echocardiography (15.1+/-3.9 min) (p = 0.0001). With transesophageal atrial pacing stress echocardiography, the recovery period was shorter, symptoms and dysrhythmias were fewer, hypertension and hypotension were less common and target heart rate was more frequently achieved. No complications occurred with either test. Patient acceptance was satisfactory. Agreement between results of both tests was good for segmental wall motion scoring with a 16-segment model, scores 1 to 5 (kappa: rest, 0.79; peak, 0.57) and test interpretation (normal, ischemia, infarction or resting wall motion abnormality with ischemia) (kappa: 0.77).

CONCLUSIONS

Transesophageal atrial pacing stress echocardiography is a feasible, well-tolerated alternative to dobutamine stress echocardiography. It can be performed rapidly and shows good agreement with dobutamine stress echocardiography in the induction of myocardial ischemia.

Regional mean systolic myocardial velocity estimation by real-time color Doppler myocardial imaging: a new technique for quantifying regional systolic function

A new color Doppler myocardial imaging (CDMI) system with high spatial and temporal resolution and novel postprocessing modalities has been developed that could allow quantifiable stress echocardiography. The purpose of this study was to determine whether regional myocardial systolic velocities could be accurately and reproducibly measured both at rest and during bicycle ergometry by using CDMI. Thirty normal subjects were examined with CDMI at rest, and peak mean systolic myocardial velocities (MSV) were measured for 34 predetermined left ventricular myocardial segments. Interobserver variability and intraobserver variability were established for all segments. Submaximal bicycle ergometry was performed in 20 normal subjects by using standardized weight-related increases in workload. MSV were measured at each step of exercise for 16 left ventricular stress echo segments. At rest, a base-apex gradient in regional MSV was recorded with highest longitudinal shortening velocities at the base. A similar pattern was noted for circumferential shortening MSV. Measurements were predictable and highly reproducible with low interobserver and intraobserver variability for 26 of 34 segments. Reproducibility was poor for basal anteroseptal segments in all views and mid anterior, anteroseptal, and septal segments in the short-axis views. During exercise, mid and basal segments of all walls showed a significant increase of MSV between each workload step and for apical segments between alternate steps. The resting base-apex velocity gradient observed at rest remained in all walls throughout ergometry. Thus a CDMI system with improved spatial and temporal resolution and postprocessing analysis modalities provided reproducible and accurate quantification of segmental left ventricular circumferential and longitudinal contraction both at rest and during exercise.

Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography

Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

[II. Role of Doppler echocardiography in the management of chronic ischemic cardiopathy]

Doppler echocardiography is a simple, fast and non-invasive method to identify abnormal regional and global left ventricular function. One could consider this method the best application for this end within the techniques of imaging. This chapter reviews the role of Doppler echocardiography in the management of chronic coronary artery disease, as well as for studying the global and regional function at rest, as in the applications derived from their use during stress testing. Frequent techniques of stress echocardiography for the diagnosis of ischemic heart disease, their utility in the study of myocardial viability, and the establishment of recommendations for their use in clinical practice are analyzed.

Comparison of the diagnostic potential of four echocardiographic stress tests shortly after acute myocardial infarction: submaximal exercise, transesophageal atrial pacing, dipyridamole, and dobutamine-atropine

This study assessed and compared the diagnostic potential of submaximal exercise, transesophageal atrial pacing, dipyridamole, and dobutamine-atropine stress echocardiography tests shortly after acute myocardial infarction. In 121 study patients, 325 digital echocardiographic stress tests were attempted 10 to 11 days after acute myocardial infarction: 83 submaximal exercise tests, 121 high-dose dipyridamole echocardiography tests (DET), 69 transesophageal atrial pacing tests (< 150 beats/min), and 52 dobutamine tests, starting at 10 microgram/kg per minute, increasing stepwise to 40 microgram kg/min, and coadministering atropine in 12 patients (dobutamine-atropine stress echocardiography [DASE]). Results were correlated to a coronary artery diameter stenosis > or = 50% as determined by quantitative angiography. Feasibility to perform submaximal exercise echocardiography, atrial pacing echocardiography, DET, and DASE was 89%, 52%, 98%, and 88%, respectively. Atrial pacing was not tolerated by 18 patients and refused by 6 (9%). Severe but not life-threatening side effects were hypotension in DET (2%) and tachyarrhythmias in DASE (6%). Test positivity in multivessel disease with submaximal exercise, DET, and DASE was 55%, 93%, and 90%, respectively, and in 1-vessel disease 47%, 65%, 71%, and for atrial pacing, 82%, respectively. We conclude that submaximal exercise has limited sensitivity and atrial pacing limited feasibility. The pharmacologic stressors provide a useful, safe diagnostic approach: DET with slightly lower sensitivity in 1-vessel disease and DASE with insignificantly less feasibility.