Abstract 2070: Transmural Strain Gradient of Normal, Hyperemic and Ischemic LV Walls Evaluated by New 2D Speckle Tracking System
PURPOSE: Currently available 2D echo speckle tracking system can track the endocardial and epicardial echo, but cannot reliably track the speckles from the myocardium. We assessed feasibility of newly developed prototype speckle tracking system in humans with normal, hyperemic and ischemic LV.
METHODS: LV short-axis images were obtained by 2D echo (Aplio, TOSHIBA) at rest in 46 normal subjects and 52 patients with clinically diagnosed myocardial infarction (28 with non-Q wave and 24 with Q wave infarction), and during ATP infusion (0.14mg/min/kg) in 21 normals. Using the new system which could track the “myocardial” speckle (Figure⇓), we measured circumferential strain of the LV endocardium (Endo), mid-wall (Mid) and epicardium (Epi).
RESULTS: In normal subjects, circumferential strain showed distinct transmural gradient (p<0.001, ANOVA) (Table⇓). ATP infusion increased Endo strain (p<0.001) and steepened the gradient. Strain of ischemic region was extremely reduced (p<0.001) in both non-Q and Q wave infarction group and the gradient was hardly recognized in the latter.
CONCLUSION: “Myocardial” speckle tracking was feasible and can be used to evaluate the effects of coronary flow on transmural strain gradient.