Spatial and Temporal Non-Uniform Changes in Left Ventricular Myocardial Strain in Dogs with Duchenne Muscular Dystrophy

Figures

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  Figure 1. Circumferential strain (CS) of left ventricular (LV) endocardial (ENDO), middle (MID) and epicardial (EPI) layers analyzed from the parasternal short-axis-apex view. Panels (A,B) show the values and curves of 6 segments (showed by different colors) analyzed in each LV wall layer obtained in a 2-month-old healthy control dog and in an age-matched GRMD (golden retriever muscular dystrophy) dog. The curve in dotted line in each part of the LV wall is the average of the 6 curves. Panels (C–E) compare the peak systolic circumferential strain values of ENDO, MID and EPI layers of healthy control and GRMD dogs at different ages. Data were expressed as mean ± SEM. The one-way ANOVA was performed to test the within-group differences. The two-tailed unpaired two-sample t-test was performed on data obtained in all dogs at each time point to determine the difference between GRMD and healthy control dogs. n = 22, 22, 17, 13, 8 and 8 for GRMD dogs, and 7, 7, 4, 4, 4 and 4 for healthy control dogs at 2, 6, 9, 12, 18 and 24 months of age, respectively. * p < 0.05 and † p < 0.01 versus healthy control dogs of the same age.

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  Figure 2. Longitudinal strain of left ventricular (LV) endocardial (ENDO), middle (MID) and epicardial (EPI) layers analyzed from the apical 4-chamber view. Panels (A,B) show the values and curves of 6 segments (showed by different colors) analyzed at each layer of the LV wall obtained in a 2-month-old healthy control dog and an age-matched GRMD (golden retriever muscular dystrophy) dog. The curve in dotted line in each part of the LV wall is the average of the 6 curves. Panels (C,D) are the bulls-eye presentations of segmental peak LS values obtained in each LV myocardial layer from 3 apical views of the above dogs. Panels (E–G) compare the longitudinal strain values of the ENDO, MID and EPI layers of healthy control and GRMD dogs at different ages. Data were expressed as mean ± SEM. The one-way ANOVA was performed to test within-group differences. The two-tailed unpaired two-sample t-test was performed on data obtained in all dogs at each time point to determine the differences between GRMD and healthy control dogs. n = 22, 22, 17, 13, 8 and 8 for GRMD dogs, and 7, 7, 4, 4, 4 and 4 for healthy control dogs at 2, 6, 9, 12, 18 and 24 months of age, respectively. * p < 0.05 and † p < 0.01…