Quantitative assessment of regional left ventricular contractile function during acute myocardial infarction using tissue tracking echocardiography:an experimental study

Objective To investigate the feasibility of quantitative evaluation for regional left ventricular contractile function during acute myocardial infarction(AMI) using tissue tracking(TT) echocardiography.Methods Nine open-chest mongrel healthy dogs were scanned from the apical four-chamber,two-chamber and long axis views before,and at 15 min,30 min,60 min and 120 min after left anterior decending coronary artery(LAD) ligation.The maximal longitudinal myocardial tracking values(displacements)of 18 segments of left ventricle from these views were measured by TT curves during offline quantitative analysis.The extent of ischemic myocardium was determined by dye-stained specimens.Results AMI modes of 8 dogs were successfully established from 9 dogs.Along the long-axis plane,all maximal longitudinal myocardial displacements decreased significantly from the basal segments to the middle and apical segments(P 0.01),while no significant differences were found between the walls at baseline.As compared with the data of the baseline,the basal-apical gradient of myocardial displacements was no longer evident in the acute myocardial ischemia situation.The maximal longitudinal myocardial displacements of the infarct walls decreased significantly after 15 min of coronary artery ligation and increased slightly after 30 min,but they were different from the baseline ones and there were significant differences between the two groups(P 0.01).Conclusions TT may be a promising new tool for the quantification of ischemia-induced regional myocardial dysfunction.