Two-dimensional Stress Echocardiography Research Articles

Real Time Three‐Dimensional Stress Echocardiography Advantages and Limitations

The role of two-dimensional stress echocardiography (2D-SE) is well established for diagnosis and prognosis of patients with known or suspected coronary artery disease. 2D-SE has its limitations as multiple views of the left ventricle (LV) must be obtained within 90 seconds of peak stress from more than window to completely visualize all LV segments. 2D-SE is operator-dependent and requires advanced skills to match the same myocardial segments during stress. LV foreshortening is a frequently encountered problem in 2D-SE that may result in false negative studies. Real time three-dimensional SE (RT-3D-SE) can overcome many limitations of 2D-SE. In 3D-SE, overall wall motion of the entire LV is assessed simultaneously in different planes. 3D images can be displayed in multiplane or multislice views for ease of comparison with greater accuracy and interobserver agreement when compared to 2D. 3D-SE is quantitative, provides rapid image acquisition, requires lower level of operator skills, and avoids LV foreshortening by correct alignment of imaging planes. 3D-SE is easily applied during pharmacologic stress and is feasible during exercise-induced stress. Despite these advantages, 3D has lower temporal and spatial resolution than 2D and requires longer analysis time. With advances in transducer technology, smaller matrix footprints, and automated softwares, 3D full LV volume image acquisition can be obtained with a single beat that is less prone to artifacts. We will discuss the current application of RT-3D-SE, highlight the pros and cons of 3D-SE over conventional 2D-SE, and review major studies on 3D-SE and future implications.

Dobutamine Stress Echocardiography Assessment of Myocardial Contusion due to Blunt Impact in Dogs

We sought to investigate the role of two-dimensional stress echocardiography in the early assessment of myocardial contusion. For this purpose, 12 dogs, weighing 11.36 ± 1.50 kg, were selected and the myocardial contusion was experimentally induced. Two-dimensional dobutamine stress echocardiography (DSE) was used to detect abnormal myocardial motions segments at time phases of baseline and 0.5, 2, 4, and 8 h post-wounding. Finally, the above results were compared with pathological findings. The data show that after the dogs were induced to have severe myocardial contusion, 122 segments were found with abnormal myocardial wall motions at 0.5 h post-wounding, 133 segments at 2 h post-wounding, and 142 segments, each, at 4 h and 8 h post-wounding. The wall motion score (WMS) and wall motion score index (WMSI) increased (P < 0.001) as compared with the pre-impaction values. Considering the left ventricular axis view as the standard section, in the 60 segments examined by echocardiography, 54 segments were found to have wall motion abnormalities. Comparing with the results of pathological TTC staining, the sensitivity and specificity were found to be 100 and 66.6%, respectively. It was, therefore, concluded that two-dimensional DSE was a valuable technique in the early diagnosis of myocardial contusion due to its better sensitivity and specificity.

Automated analysis of three-dimensional stress echocardiography

Real-time three-dimensional (3D) ultrasound imaging has been proposed as an alternative for two-dimensional stress echocardiography for assessing myocardial dysfunction and underlying coronary artery disease. Analysis of 3D stress echocardiography is no simple task and requires considerable expertise. In this paper, we propose methods for automated analysis, which may provide a more objective and accurate diagnosis. Expert knowledge is incorporated via statistical modelling of patient data. Methods for identifying anatomical views, detecting endocardial borders, and classification of wall motion are described and shown to provide favourable results. We also present software developed especially for analysis of 3D stress echocardiography in clinical practice. Interobserver agreement in wall motion scoring is better using the dedicated software (96%) than commercially available software not dedicated for this purpose (79%). The developed tools may provide useful quantitative and objective parameters to assist the clinical expert in the diagnosis of left ventricular function.

Two-dimensional stress echocardiography in coronary artery disease.

Stress echocardiography done using various methods has become a primary way to assess and quantify the extent of myocardial ischemia. Although it is highly versatile, its use remains patchy, and in many centers it is simply considered a research technique. This review discusses some of the advantages of stress echocardiography in relation to recent publications, and it points to some areas for future research.

Does hypotension during dobutamine stress echocardiography correlate with anatomic or functional cardiac impairment?

The development of hypotension during various exercise stress tests has been correlated with the presence of multivessel coronary artery disease and impaired left ventricular contractility. Hypotension may also occur during dobutamine stress echocardiography; however, its anatomic and functional significance remains unknown. As part of an ongoing study of restenosis, dobutamine stress echocardiography and diagnostic cardiac catheterization were performed on the same day in 105 outpatients approximately 6 months after percutaneous coronary revascularization (balloon angioplasty or directional coronary atherectomy) to determine the anatomic and functional significance of dobutamine-induced hypotension. Dobutamine was infused in stepwise increments to a maximum rate of 30 μg/kg/min. Hypotension was defined as a reduction in systolic blood pressure of ≥ 15 mm Hg. Anatomic abnormalities were defined by quantitative coronary angiography and functional abnormalities by digitized two-dimensional stress echocardiography. Clinical, angiographic, hemodynamic, and electrocardiographic data underwent multivariable regression analysis to determine their ability to predict independently the development of dobutamine-induced hypotension. Dobutamine-induced hypotension was not associated with the presence or severity of coronary artery disease or with echocardiographic wall motion abnormalities. Univariable predictors of stress-induced hypotension included high baseline systolic blood pressure, advanced age, and high left ventricular ejection fraction. Only a high baseline systolic blood pressure contributed independent predictive information in multivariable stepwise logistic regression analysis. Therefore, the development of hypotension during dobutamine stress echocardiography, unlike that during traditional exercise stress tests, is not associated with the presence of significant coronary artery disease or left ventricular dysfunction.

Should all patients undergo cardiac catheterization after a myocardial infarction?

Between one half and two thirds of patients who survive an acute myocardial infarction (AMI) may be at low risk for future complications and hence can be managed with medical therapy. However, the remaining patients are prone to future complications, which by and large occur within the subsequent 3 months and include cardiac death, recurrent AMI, unstable angina, and congestive heart failure. Current available methods for risk stratification include a good clinical evaluation, rest and stress electrocardiograms (preferentially combined with radionuclide imaging), and possibly two-dimensional stress echocardiography. In patients unable to exercise, pharmacologic perfusion scintigraphy affords a powerful means to identify high-risk patients. Patients deemed to be at high risk should be referred for cardiac catheterization and myocardial revascularization. The practice of performing routine cardiac catheterization after an AMI has led to an over use of resources in the United States. Such a practice is not based on any scientific evidence of enhanced benefit. In fact, in other Western world countries where only selected patients are referred for cardiac catheterization, patient survival appears to be similar to that in the United States. In conclusion, most patients after AMI, whether treated with thrombolytic therapy or not, can be managed conservatively and risk stratified on the basis of noninvasive testing, after which patients deemed to be at high risk should undergo invasive evaluation.