As discussed in Chapter 2, the coronary circulation normally arises as two separate vessels from the sinuses of Valsalva – the left coronary artery (LCA) from the left sinus, and the right coronary artery (RCA) from the right sinus (Fig. 2.5, p. 9). The initial portion of the LCA is the left main stem which soon divides into the left anterior descending (LAD) and circumflex (Cx) arteries. The LAD runs down the anterior interventricular groove and the Cx runs in the left atrioventricular groove. The RCA runs in the right atrioventricular groove, and in most people gives rise to the posterior descending artery which runs down the posterior interventricular groove.

All the arteries supply branches to the myocardium in their respective territories, and as there is some anatomical variation from one person to the next, there can be a little variability in which vessel is responsible for supplying blood to each territory. Nonetheless, each vessel’s territory is fairly well defined and so wall motion abnormalities in a particular region give an indication of the coronary vessel(s) likely to be involved.

The LV is conventionally split into 16 or 17 different regions or ‘segments’. In the 16-segment model the LV is sliced longitudinally into thirds (basal, mid-cavity and apical). The basal and mid-cavity slices each contain six segments and the apical slice contains four segments. The American Heart Association’s 17-segment model contains all these segments plus one more – an apical ‘cap’ (Fig. 16.1). The 16-segment model remains popular for echo purposes, but if you are going to compare echo findings with other modalities (e.g. nuclear cardiology) then it is better to use the more widely applicable 17-segment model. Whichever model you choose, ensure that your nomenclature is consistent.

In the 17-segment model, the six segments in each of the basal and mid-cavity slices are termed anterior, anteroseptal, inferoseptal, inferior, inferolateral (sometimes also called posterior) and anterolateral. The boundaries of the septum are defined by the attachment of the right ventricle (RV), and each of the six circumferential segments occupies 60° in the short axis view. As the LV narrows towards the apex, there are just four apical segments, termed anterior, septal, inferior and lateral. The apical cap is at the very tip of the ventricle, where there is no LV cavity.

Each segment is assigned to one of the coronary arteries (LAD, Cx or RCA), as indicated by the colour-coding in Fig. 16.1, although there can be some overlap depending on each individual’s coronary anatomy. Normal wall motion during systole is indicated by an endocardial excursion >5 mm and by wall thickening >50 per cent. Inspect each segment in turn, where possible in two separate views, and score it according to its motion:

Areas of myocardial ischaemia and infarction typically lead to hypokinetic, akinetic, dyskinetic or aneurysmal myocardial segments. By assessing wall motion in each of the LV segments a comprehensive picture of LV

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