RESUMO
Objective To discuss the significance and value of speckle tracking imaging (STI) technique for accurate evaluating different types myocardial systole. Methods Anterior interventricular branches of 11 healthy crossbreed dogs were separated and ligatured to establish acute myocardial infarction models. The short axle radial strain (RS), circumferential strain (CS) of ventricular sinister and long axle longitudinal (LS) of apex of experiment dogs were measured with STI technique before and after myocardial infarction. Results Before myocardial infarction, no statistical difference of RS, CS was detected among sections of left ventricle (P>0.05), and RS was greater than LS (P<0.05). When detector was at the apex of base, LS of middle, apex sections of left ventricle myocardium increased gradually (LS of base section was least and apex section was most) (P<0.05). RS, CS and LS of antetheca, forepart of interventricular septum of middle of left ventricle and antetheca, posterior and forepart septum of apex all became lower after myocardial infarction (P<0.05). Conclusion Strains caused by all types of myocardium action can be accurately evaluated with STI.