Assessing myocardial viability of acute myocardial infarction with quantitative tissue velocity imaging and low dose dobutamine stress echocardiography

AIM: To explore the value of combining quantitative tissue velocity imaging(QTVI) with low-dose dobutamine stress(LDDS) in evaluating myocardial viability.METHODS: The acute myocardial infarction(AMI) models were set up by ligating the LCX of dogs.After collecting the imaging information from the apical four chamber,long axis and two chamber views by using QTVI,the systolic velocity(Vs) of left ventricular(LV) wall was analyzed by tissue velocity and the systolic displacement(Ds) of LV wall was analyzed by tissue tracking(TT).The position and the range of the myocardial infarction areas were determined with TTC staining and myocardial contrast echocardiography.The surviving myocardium was determined by the change of QTVI which reflects the myocardial contractility reserve,and compared with TTC staining and myocardial contrast echocardiography.RESULTS: Before LDDS there was no significant difference of Vs and Ds between viable and unviable myocardium.The changes of Vs and Ds in the surviving myocardium segments were significant(P0.01),while no change was found in Vs and Ds in the segments of myocardium infarction(P0.05) after LDDS.When △Vs0.66 mm/s was used as a threshold to determine whether the myocardium survived or not,the sensitivity was 83% and the specificity was 87%.When △Ds0.61 mm was used as the standard,the sensitivity was 80% and specificity was 89%.CONCLUSION: Combined with the LDDS,QTVI can forecast the surviving possibility of myocardia.