Stress echocardiography is the combination of two-dimensional echocardiography with a physical, pharmacological, or less commonly, electrical stress with atrial pacing. Stress-induced ischemia generates new or worsening wall motion abnormalities in the segment supplied by the stenosed coronary artery. Stress echocardiography plays an important role in identifying these wall motion abnormalities in the assessment of ischemic heart disease, and also plays a vital role in the evaluation of systolic or diastolic heart failure, valvular pathologies, nonischemic cardiomyopathy, pulmonary hypertension, and congenital heart disease. 
Anatomy involves studying the various wall motion abnormalities and understanding the vascular territories associated with various segments. The segments are studied in six views: the parasternal long axis, the parasternal short axis at the levels of the mitral valve, papillary muscles, and apex, apical four chambers, apical two chambers. The scoring system is based on if the wall motion is normal, hypokinetic, akinetic or dyskinetic. Based on the wall motion, a score of 1 to 4 is assigned. The American Society of Echocardiography uses a 17-segment model for wall motion abnormalities.
Parasternal long axis (PLAX) view
Segments seen in parasternal long axis view:
Apical four chambers (A4C) view
Segments seen in apical four chamber view:
Apical two chambers (A2C) view
Segments seen in apical two chamber view:
Parasternal short axis (SAX) view
Segments seen in parasternal short axis view at the papillary muscle level:
The following are indications for stress echocardiography:
Contraindications to exercise/pharmacologic stress echocardiography:
Specific contraindications to dipyridamole (or adenosine) and dobutamine stress echocardiography include severe conduction abnormalities (high-degree AV block without pacemaker), active bronchospasm, Sick sinus syndrome without a pacemaker, systolic blood pressure less than 90 mmHg, and tachyarrhythmias such as atrial fibrillation.
Technical equipment for stress echocardiography includes:
Stress echocardiography equipment takes into consideration M-mode, two-dimensional, color and spectral (both flow and tissue) Doppler imaging for evaluation of ischemic heart disease.
Contrast agents are used as indicated for patients in whom at least two endocardial wall territories are not well visualized.
Tissue harmonic imaging is indicated in stress echocardiography. It improves resolution, reduces artifacts, improves signal-to-noise ratio, greater depth of penetration and improves myocardial signals. Tissue harmonic imaging increases the sensitivity of stress echocardiography as it improves endocardial delineation due to enhanced resolution.
Intravenous contrast agents in combination with harmonic imaging increase the accuracy of the procedure. Increased number of wall segment motion abnormalities can be studied when contrast agents are used.
Stress testing methods:
Exercise stress testing: This is indicated in patients who can exercise. Either treadmill or bicycle can be used for exercise.
Pacing stress testing: This is indicated in patients with a permanent pacemaker. Target heart rate can be achieved by increasing the pacing. This is indicated in patients who are unable to exercise. The pacing protocol consists of two-minute stages and increasing paced heart rate to levels of 85% and 100%, respectively, for pre-peak and peak stress information. Images are obtained at rest, the first stage, and pre-peak and peak heart rate. Termination of stress test occurs with the achievement of age-predicted maximal heart rate, new or worsening moderate regional wall motion abnormalities, greater than 2 mm horizontal or downsloping S-T depression or presence of intolerable symptoms.
Imaging obtained at resting and stress phase are compared for interpretation of left ventricular (LV) size, shape, and function. A normal response during stress involves LV size becoming smaller compared to rest, while the shape is maintained and there is increased endocardial excursion along with systolic wall thickening.
In a patient with multiple vessel diseases, exercise echocardiography demonstrates dilated LV cavity with changes in the shape and reduction of systolic wall thickening of the septum, anterior, and inferior wall. Prolonged systolic wall thickening may also indicate severe coronary artery disease.
The coronary arteriographic cut off of luminal diameter stenosis at which wall thickening abnormalities occur is 54% for exercise, 58% for dobutamine, and 60% for dipyridamole. The sensitivities for detection of coronary artery disease (CAD) are 85%, 80%, and 78% with specificities of 77%, 86%, and 91% for exercise, dobutamine, and dipyridamole stress results. However, diagnostic accuracy varies according to the pretest likelihood of CAD in the patient tested.
Dobutamine stress echocardiography: The most common cardiovascular side effects associated with dobutamine are angina, hypotension, and cardiac arrhythmias. Atrial fibrillation and nonsustained ventricular arrhythmias occur in about 3% patients. Sustained ventricular tachycardia is not common. Dobutamine can also induce left ventricular mid-cavity and outflow tract obstruction. Frequent premature atrial or ventricular contractions occur in about 10%.
Vasodilator stress echocardiography: Major adverse reactions include myocardial infarction, asystole, and ventricular tachycardia. Hypotension and bradycardia may occur but can be treated with aminophylline.
Pacing stress echocardiography: Wenckebach second-degree heart block may occur, requiring atropine administration.
In terms of clinical significance and diagnostic accuracy stress echocardiography has an advantage in terms of specificity over standard exxcercise electrocardiopgraphy. When compared to nuclear perfusion imaging studies, stress echocardiography has similar accuracy, with a moderate sensitivity gap that is well balanced by a higher specificity. Both dipyridamole and dobutamine have overall good tolerance and feasibility. The choice of one test over the other depends on patients clinical characteristics and the physician’s preference. Diagnostic accuracy can significantly be affected by antianginal medical therapy particularly beta-blocking agents and therefore, it is recommended, to withold medical therapy at the time of testing to avoid a flase-negative result.
Healthcare workers including nurse practitioners will frequently encounter patients with heart disease. One of the ways to investigate these patients is with stress echocardiography. Stress echocardiography is the combination of two-dimensional echocardiography with a physical, pharmacological, or less commonly, electrical stress with atrial pacing. Stress-induced ischemia generates new or worsening wall motion abnormalities in the segment supplied by the stenosed coronary artery. Stress echocardiography plays an important role in identifying these wall motion abnormalities in the assessment of ischemic heart disease, and also plays a vital role in the evaluation of systolic or diastolic heart failure, valvular pathologies, nonischemic cardiomyopathy, pulmonary hypertension, and congenital heart disease.
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