Final Feigenbaum’s Echocardiography DIGITAL

Feigenbaum’s Echocardiography

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Feigenbaum’s Echocardiography

virtually all regional wall motion abnormalities are initially associated with abnormalities of thickening as well as endocardial motion. Regional wall motion abnormalities should be described in a standardizedmanner. Figure 5.28 schematizes the 17-segment model for description of regional wall motion currently recommended by the American Society of Echocardiography. Previous schemes used a 16-segment model, which includes a portion of the true apex in each of the four distal segments. A shortcoming of the 16-segment model is that if an abnormality is isolated to the apex, it is represented in each of four separate segments, thus resulting in a disproportionate contribution to the wall motion score, especially if the abnormality was limited to the “true” apex. „e 17th segment represents the true apex. Addition of the 17th segment allows more precise comparisons with other imaging modalities, such as cardiac magnetic resonance imaging, computed tomography, or radionuclide perfusion tech- niques. Depending on the size of an apical wall motion abnormality, it may either enhance the accuracy of the wall motion score, if the abnormality is con‡ned to the true apex, or result in overestimation if it involves portions of the four distal segments. When portions of the distal segments are involved, they will also be given an abnor- mal wall motion score, which again may result in disproportionate weighting of an apical wall motion abnormality. „e location of a wall motion abnormality is predictive of the location of the coronary “culprit” lesion in myocardial ischemia or infarction. Figure 5.28 also depicts the relationship of the prede‡ned segments of the le‰ ventricle to the traditional distributions of the le‰ anterior descending, circumŠex, and right coronary arteries. It should be emphasized that there can be substantial overlap in the

METHODS FOR EVALUATION OF REGIONAL WALL MOTION ABNORMALITIES

Table 5.5

Visual/subjective Descriptive: normal, hypokinetic, akinetic, dyskinetic Normal myocardial thickness versus scar Location: anterior, lateral, inferior, posterior, apex, basal, mid, apical segments Semi-quantitative WMS or WMSI Normal = 1 Hypokinetic = 2 Akinetic = 3 Dyskinetic = 4 Scored for each segment n = N WMSI = ∑ n = 1 WMS ÷ N Quantitative Anatomy based Radian change Regional area change Center-line chordal shortening Doppler tissue imaging or speckle tracking Local velocity Velocity gradient (endocardial – epicardial) Myocardial displacement Myocardial strain Strain rate imaging WMS, wall motion score; WMSI, wall motion score index.

FIGURE 5.28. Schematic representation of the 17-segment model of the left ventricle. Parasternal and apical views are depicted. For the 16-segment model, each of the distal segments (13 to 16) incorporates its adjacent portion of the apical segment. For each segment, the cor- onary distribution most likely responsible for wall motion abnormality in that area is noted. When more than one coronary territory is listed, overlap between coronary distributions is anticipated in that segment. The true apex is most often perfused by the left anterior descending cor- onary artery; however, in the presence of a dominant right or circumflex coronary artery, it may also be perfused by that artery. PW, posterior wall.

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