Comparative analysis of myocardial function in young adult and old healthy dogs using two-dimensional speckle tracking echocardiography

초록

Age is a major risk factor for cardiovascular disease, yet quantitative data on age-related myocardial changes in dogs using two-dimensional speckle tracking echocardiography (2D-STE) remain limited. This study aimed to establish preliminary reference data for myocardial strain (St) and strain rate (SR) using 2D-STE in healthy dogs and to compare these parameters between young adult and old dogs. Ten young adult and ten old clinically healthy dogs underwent conventional echocardiography and 2D-STE. Peak systolic St, peak systolic SR, early diastolic SR, and late diastolic SR were measured in radial, circumferential, and global longitudinal directions. Standard echocardiographic parameters, including left ventricular dimensions, fractional shortening, and tissue Doppler-derived early diastolic velocity, did not differ significantly between groups. However, the E/A ratio and late diastolic tissue velocity (Am) were significantly lower in old dogs. In 2D-STE analysis, systolic St and SR across all directions did not differ between groups. In contrast, early diastolic radial, circumferential, and global longitudinal SR were significantly reduced in old dogs, while late diastolic radial SR was higher in selected segments. These findings indicate that while systolic myocardial deformation remains preserved with age, diastolic deformation parameters exhibit significant age-related alterations. This study provides age-specific preliminary reference data for left ventricular myocardial deformation using 2D-STE in healthy dogs.

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