Backgrounds and Objectives Two-dimensional strain echocardiography (2DSE) technique has enabled accurate quantification of regional myocardial function. This experimental study was aimed to investigate the value of 2DSE in detection of segmental regional myocardial dysfunction induced by fibrosis following myocardial infarction in a small animal (rat) model.
Methods An rat model of myocardial infarction was established by ligation of the proximal left anterior descending coronary artery in 17 SD rats. Regional myocardial function was detected by 2DSE at baseline and 4-weeks post-infarction, including end-systolic radial strain and strain rate (SR and SrR) and end-systolic circumferential strain and strain rate (SC and SrC) of each of six segments. According to the size of scar found by histologic Masson staining, the optimal cutoff points of parameters for detecting scar area were analysed and the sensitivity and specificity of every parameter to detect myocardial scar were obtained using ROC.
Results (1) Comparing with parameters measured at baseline, there were significant decreases in SR, SrR, SC and SrC as well as WTF of each segment at papillary level at 4-weeks post-infarction, with the worst in the infarct area (anterior septal, anterior and lateral wall) and the mildest in distal area (mid-inferior wall), (p<0.05 for each); (2) Significant negative correlations were found between the size of segmental scar and 2DSE parameters (r-value 0.63–0.80, all p<0.05) with the strongest correlation in SR. SR less than 10% has 84% sensitivity and 98% specificity for detecting segments of scar area greater than 30% with AUC=0.97.
Conclusions 2DSE is able to assess regional myocardial dysfunction in a rat model of myocardial infarction and has high accuracy in detecting infarct segments with scar area greater than 30%.