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Stress Echocardiography in Diagnosis of Coronary Artery Disease
hypertensive response occurs. Despite the different pathophysiological ischemia, non-ischemic cardiomyopathy, beta-blocker treatment, left
mechanisms, the vasodilator at appropriately high doses shows bundle branch block, or severe hypertension. An ischemic response is
ischemic stressor potency similar to exercise or dobutamine.
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recognized whenever a segment with normokinesis at rest becomes
Moreover, the lower peak heart rate in those protocols compared with hypokinetic, akinetic, or dyskinetic during stress. SEcho is considered
exercise or dobutamine facilitates the acquisition of images. positive if stress-induced abnormalities are found in at least two
adjacent segments.
The standard dipyridamole dose is 0.56mg/kg administered  over
four  minutes. If no ischemia is induced after  four minutes without Regarding regions with abnormal resting function, four possible
perfusion, an additional 0.28mg/kg is administered over  two minutes, responses during stress may be found:
followed if necessary by atropine (in doses of 0.25mg up to a maximum
of 1mg). The standard adenosine protocol consists of an intravenous • biphasic response—at low levels of stress, systolic wall thickening
infusion of 0.14mg/kg/minute over four to six minutes. increases and starts earlier, improving contractile function; at higher
levels, however,  the increase in myocardial demand cannot be
The safety of dipyridamole and adenosine SEcho is well established. The matched by further increases in blood flow, leading to ischemia and
risk of major adverse reactions is lower than dobutamine SEcho, at systolic function deterioration;
approximately  one in 1,000.
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The most common side effects include • sustained functional improvement at low stress that persists or
headache and dyspnea. Since they have a bronchoconstrictor activity, is further improved until peak stress;
both techniques are contraindicated in patients with untreated • worsening of resting  wall motion  during stress without any
atrioventricular block and bronchospastic disorders. Abstinence from improvement; and
xanthene-containing foods and beverages is required before the test. • no change in function.
Aminophylline (240mg intravenously) reverses dipyridamole-related
adverse effects and should be available for immediate use during the The SEcho sign of myocardial viability is a stress-induced improvement
test. Although reversal of dipyridamole with aminophylline is not of contractile function during low levels of stress in a region that is
otherwise usually needed, some SEcho laboratories propose that
aminophylline  should be routinely given at the end of the test,
independent of the result.
The interpretation of stress
echocardiography is usually based on a
Interpretation of Stress Echocardiography
Standard SEcho protocol requires a full echocardiographic evaluation in
subjective assessment of regional wall
resting condition. After this, the echocardiogram is continuously
motion, comparing wall thickening and
monitored and a digital record is intermittently captured at each stage
of the protocol and during the recovery phase or administration of the
endocardial excursion in a side-by-side
antidote. Parasternal long-axis and short-axis views, as well as standard
display of baseline and stress images.
apical views (four-chamber,  two-chamber, and long-axis) are the
echocardiographic projections usually used. The interpretation of
SEcho is usually based on a subjective assessment of regional wall abnormal at rest. The pattern of response  is predictive of post-
motion, comparing wall thickening and endocardial excursion in a side- revascularization functional improvement. A biphasic response,
by-side display of baseline and stress images. Clear endocardial indicating that the tissue is not only viable but also supplied by a
definition is crucial for optimal regional function evaluation, which is stenosed artery, has greatest predictive accuracy for recovery. In a
performed using a five-point  wall-motion  scoring system (1 = recent study,
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72% of segments with biphasic response recovered
normokinesis; 2 = mild hypokenesis; 3 = moderate or severe function. A uniphasic response with sustained improvement has limited
hypokinesis; 4 = akynesis; and 5 = dyskenesis) for the 16- or 17- specificity to predict functional recovery, since augmentation alone
segment model of the left ventricle. may occur not only with non-jeopardized myocardium but also in areas
of non-transmural infarction without hibernating myocardium
As with rest echocardiography, patient-dependent factors such as (subendocardial scar) or in remodeled myocardium.
obesity and lung disease may lead to poor acoustic windows and
reduce diagnostic accuracy. In these patients, contrast-enhanced New Technologies Applied to Stress Echocardiography
endocardial border detection may be used to improve visualization. The state-of-the-art diagnosis of ischemia and myocardial viability in
Evaluation of wall motion abnormalities is also challenging in patients SEcho remains the qualitative analysis of regional wall motion. The major
with previous myocardial infarction, in whom passive tethering motion potential drawback for use of this index is semi-quantitative assessment
is a confounding variable. Finally, signal dropout can cause suboptimal of wall motion, which is limited by subjectivity and technical challenges.
images, leading to misdiagnosis in some patients. In fact, the clinical acuity of SEcho evaluation does not depend on the
stress modality used, since this is appropriate to patient characteristics,
Regardless of the form of stress, the normal response is a global but rather depends on the quality of the echocardiographic window and
increase in contractility leading to hyperdynamic wall motion. Lack of the experience of the echocardiographer. Considerable expertise is
hyperkynesis is abnormal and may be caused by regional myocardial required to interpret SEcho images accurately. This learning curve
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