Assessment of left ventricular time-related deformations in post-infarction rats by ultrasound speckle tracking imaging

Abstract

Objective To evaluate left ventricular (LV) remodeling and function after acute myocardial infarction (MI) in rats using speckle tracking imaging (STI). Methods The left anterior descending coronary was ligated to induce MI in twenty normal rats. One day after creation of MI, fifty survivals based on the diagnostic criteria of MI were divided into 4 groups as follows:pre-infarction, 1 day,4weeks,and 8 weeks after MI. Echocardiography was performed to evaluate the changes of left ventricularfunction in rats. M-mode and two-dimensional cross-sectional echocardiography data were acquired at the papillary muscle level and digitally stored for further analysis. Circumferential strain rate(SRcir) and radial strain rate(SRrad) indexes were measured by STI software for each animal. Results One day after MI,indexes of SRcir and SRrad in anterior and lateral segments were significantly decreased (P ＜0.01, for both). Four weeks after MI,compared with baseline,SRrad and SRcir were decreased in all segments ( P ＜0.01). Eight weeks after MI, however, SRrad and SRcir showed no significant difference compared with 4weeks group. Conclusions STI can correctly identify LV dysfunction in rats and can be used for serial assessment of cardiac remodeling in rats models. Key words: Echocardiography; Myocardial infarction; Ventricular function, left ; Rats; Speckle tracking imaging