Abstract
Enhanced sensitivity in echocardiographic analyses may allow for early detection of changes in cardiac function beyond the detection limits of conventional echocardiographic analyses, particularly in a small animal model. The goal of this study was to compare conventional echocardiographic measurements and speckle-tracking based strain imaging analyses in a small animal model of type 1 diabetes mellitus. Conventional analyses revealed differences in ejection fraction, fractional shortening, cardiac output, and stroke volume in diabetic animals relative to controls at 6-weeks post-diabetic onset. In contrast, when assessing short- and long-axis speckle-tracking based strain analyses, diabetic mice showed changes in average systolic radial strain, radial strain rate, radial displacement, and radial velocity, as well as decreased circumferential and longitudinal strain rate, as early as 1-week post-diabetic onset and persisting throughout the diabetic study. Further, we performed regional analyses for the LV and found that the free wall region was affected in both the short- and long-axis when assessing radial dimension parameters. These changes began 1-week post-diabetic onset and remained throughout the progression of the disease. These findings demonstrate the use of speckle-tracking based strain as an approach to elucidate cardiac dysfunction from a global perspective, identifying left ventricular cardiac regions affected during the progression of type 1 diabetes mellitus earlier than contractile changes detected by conventional echocardiographic measurements.