Abstract 2079: New Developed Powerful Tool for Detecting of Exercise Induced Myocardial Dysfunction: Assessment of Early Diastolic Strain Rate
We investigated whether new developed parametric imaging of strain rate (SR) by two-dimensional (2D) speckle tracking method is possible to detect persistent regional exercise-induced myocardial dysfunction. We examined 19 patients with suspected coronary artery disease who underwent exercise-stress Tc99m myocardial scintigraphy. During examination of scintigraphy, 2D images of LV wall were acquired in short axis view (Aplio 80 ™, Toshiba) at rest and 10 minutes after exercise. By using prototype software with 2D speckle tracking method, values of radial SR were obtained, and the peak early diastolic SR (max-SRe) and the change of max-SRe from rest to after exercise were displayed as parametric imaging on whole cardiac layer. In patametric imaging, the decrease of max-SRe after exercise was showed blue coded area. We divided the imaging into six segments, and compared to the finding of scintigraphy as reference. It is possible to assess the radial SR in 95 of 114 segments (83.3%), and 39 of 95 segments (33.7%) showed decrease of max-SRe after exercise. Nineteen segments were excluded because of poor image quality. This new method detected the myocardial ischemia or myocardial dysfunction diagnosed by scintigraphy with high sensitivity (87.5%), specificity (82.5%), and accuracy (84.2%). Positive and negative predictive values were 71.8% and 92.0%. The concordance rate between scintigraphy and 2D tracking method was 84.2% (κ=0.67). In conclusion, the decrease of max-SRe indicates persistent regional LV abnormal relaxation 10 minutes after exercise. It may be powerful tool for detecting the myocardial ischemia and/or myocardial dysfunction.