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I./3.3.: Echocardiography
I./3.3.1.: Introduction
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The basic examinations in patients with acute coronary syndrome include transthoracic and, in certain special cases, transesophageal echocardiography. This latter is performed mainly when a complication is suspected, or occasionally in cases when no imaging of appropriate quality can be attained with the transthoracic method. The examination provides two- or more recently three-dimensional anatomic-structural recordings, it allows the assessment of wall movements, detection of the complications; color Doppler shows the laminar or turbulent nature of flows, and it detects shunts and regurgitations. The determination of the various pressure gradients is based on the measurement of flow velocity (by Doppler).
The most important issues which may be provided by echocardiography in patients with an acute myocardial infarction:
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(i) wall movement disorders,
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(ii) detection of mechanic complications,
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(iii) hemodynamic monitoring.
I./3.3.2.: Wall movement disorders
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Based on the extent of a segmental wall movement disorder, it is termed hypokinesis (decreased movement), akinesis (complete lack of movement), or dyskinesis (passive movement which suggests a certainly necrotic area). Based on this, the most important issue provided by echocardiography is the localization of ischemia or necrosis. In patients with non-ST elevation acute coronary syndrome, when the coronary angiography shows multiple-vessel disease, or occasionally multiple occlusions, the detection of a definitive old necrosis (akinesis or dyskinesis, thinning of the wall) that coronary branch can be identified, the revascularization of which would produce no benefit. In patients with multiple severe stenoses found in the coronary system, the viability of an area that is akinetic, but shows no thinning, no definitive necrosis, can be examined (of course not in the acute phase) with dobutamine stress echocardiography that shows if the given segment starts to contract on the effect of dobutamine.
I./3.3.3.: Detection of mechanical complications
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In case of a sudden deterioration of the patient’s state, failure of the left heart, development of shock or a new murmur, the transthoracic or, as required, transesophageal echocardiography, which helps to diagnose any pericardial fluid, tamponade, rupture of the mitral papillary muscle, or perforation of the ventricular septum, should be performed immediately. Detection and follow-up of the left ventricular function can also be performed with echocardiography.
I./3.3.4.: Hemodynamic monitoring
The up-to-date echocardiographic examination offers an excellent possibility for non-invasive hemodynamic monitoring: systolic function of the left ventricle, diastolic filling, pulmonary pressure, volume filling state, just to mention the most important ones. The examination is non-invasive, it can be repeated at any time, and the therapy can be controlled.
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