PMC5808971_01
(a) Time-longitudinal global (dotted line) and segmental (coloured lines) longitudinal strain curve obtained from two-dimensional speckle tracking echocardiography (2D-STE; left apical four-chamber view) on day 0 in a young cat with hypertrophic cardiomyopathy (HCM). Six segmental curves are designated as the basal septum (yellow), middle septum (light blue), apical septum (green), apical lateral (purple), middle lateral (dark blue) and basal lateral (red) for speckle tracking analysis. Post-systolic shortening during the diastolic phase (arrow) can be observed. Note the lower and non-synchronous segmental strains (yellow and light-blue lines) corresponding to gradually hypertrophied segments on follow-up examinations (interventricular septum walls). All wall thicknesses on day 0, including the subaortic interventricular septum wall thickness on a long-axis view, were <6 mm, indicating the absence of left ventricular hypertrophy. (b) Time-longitudinal global (dotted line) and segmental (coloured lines, same as designated as above) longitudinal strain rate curve obtained from 2D-STE (left apical four-chamber view) on day 0 in a young cat with HCM. Note the small peak of systolic (S) and early diastolic (E) strain rate values. Global longitudinal strain rate E:A was 1.1. Conventional 2D and Doppler echocardiography did not reveal any sign of HCM on day 0. (c) Time-longitudinal global (dotted line) and segmental (coloured lines, same designated as above) longitudinal strain curve obtained from 2D-STE (left apical four-chamber view) for a healthy cat. Note the synchronous strains. (d) Time-longitudinal global (dotted line) and segmental (coloured lines, same designated as above) longitudinal strain rate curve obtained from 2D-STE (left apical four-chamber view) for a healthy cat. Note the strain rate E:A ratio of 1.9
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PMC5808971_01_10.1177_2055116918756219-fig1.jpg
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Although the global peak systolic 2D-STE variables on day 0 were within the healthy cats ranges (Table 3), post-systolic shortening during the diastolic phase (Figure 1) and lower and non-synchronous segmental strains (basal septum) corresponding to the gradually hypertrophied segments on follow-up examinations (subaortic interventricular septum) were observed (Table 4).