Clinical Study On Evaluation Of Myocardial Viability By Dot Tracing Technique

Objective: To evaluate whether myocardial strain under adenosine stress calculated from two dimensional echocardiography by automatic frame-by-frame tracking of natural acoustic markers enables objective description of myocardial viability in clinic.Methods:Two dimensional echocardiography and two dimensional speckle tracking imaging (2D-STE) at rest was performed firstly and once again after adenosine was infused at140ug kg-1min-1over a period of6min in39stable patients with previous myocardial infarction (MI). An automatic frame-by-frame tracking system of natural acoustic echocardiographic markers was used to calculate peak-systolic circumferential strain, radial strain and longitudinal strain, which were acquired at rest and at the stage during the adenosine stress study. Radionuclide myocardial perfusion/metabolic imaging were served as the "gold standard" to define the viable and nonviable myocardium.Results:①215regions were viable whereas153were non-viable among368abnormal motion segments in39patients according to radionuclide imaging.②At rest, there were no significant changes between viable and nonviable myocardium.③After adenosine administration, RSpeak-sys(37.98±5.45VS30.22±5.47), LSpeak-sys(-23.71±4.53VS-17.52±4.34) increased significantly (P<0.05) in viable group, and all parameters had no changes before and after adenosine administration (P>0.05) in nonviable group compared to rest. RSpeak-sys(37.98±5.45VS30.12±5.37) and LSpeak-sys(-23.71±4.53VS-16.95±4.62) in viable group increased significantly compared with nonviable group (P<0.05) while CSpeak-sys had no significant changes (P>0.05).④A change of radial strain more than9.8%has a sensitivity of82.3%and a specificity of81.1%for viable whereas a change of longitudinal strain more than16.5%allowed a sensitivity of83.5%and a specificity of92.3%.Conclusions:2D speckle tracking imaging combined with adenosine stress echocardiography (ATE) could provide a new and reliable method to identify myocardial viability. Objective: To investigate whether three dimensional speckle tracking echocardiography (3D-STE) could provide a new way to assess myocardial viability in patients with myocardial infarction(MI).Methods: A total of45patients with MI underwent routine echocardiography, two dimensional speckle tracking echocardiography(2D-STE) and3D-STE. Then, radionuclide myocardial perfusion/metabolic imaging served as the "gold standard" to define the viable and nonviable myocardium was given in each patient within one day.Results:368segments from720segments in45patients were observed motion abnormality by visual assessment. Furthermore,204segments were attributed to viable group by SPECT/PET whereas the rest164segments were defined as nonviable among368abnormal segments. There were no significant difference in circumferential peak-systolic strain (CSpeak-sys), radial peak-systolic strain;(RSpeak-sys) and longitudinal peak-systolic strain (LSpeak-sys) by2D-STE between viable and nonviable group. Compared with those in viable group, there wasn’t any significant difference in CSpeak-sys, but RSpeak-sys and LSpeak-sys decreased significantly by3D-STE in nonviable group.3D strain and area strain in absolute value decreased which compared nonviable to viable group. According to3D-STE, RSpeak-sys more than11.1%had a sensitivity of95.1%and a specificity of53.4%for viable whereas LSpeak-sys more than14.3%allowed a sensitivity of65.2%and a specificity of65.7%. Besides,3D strain more than17.4%had a sensitivity of70.6%and a specificity of77.2%for viable while area strain more than23.2%allowed a sensitivity of91.5%and a specificity of78.8%. Conclusions:3D-STE might have potential detection of myocardial viability in the patients with left ventricular (LV) dysfunction due to previous MI.