Background In acute myocardial ischemia, postsystolic shortening (PSS) and lengthening-shortening (LS) ratio are considered as a method evaluating myocardial viability. But in chronic total occlusion (CTO), the values of PSS and LS ratio are less well established. The purpose of this study was to assess myocardial function by 2-dimensional ultrasound speckle tracking imaging in patients with CTO and compared these parameters with stable angina and healthy subjects. Methods Standard echocardiography and speckle tracking imaging were performed in 25 patients with CTO (group 1) before electively primary coronary intervention and compared with 26 age, sex-matched patients with stable angina (group 2), and 23 controls (group 3) who confirmed angiographically no significant lesion. Results 1332 segments were completely analyzed, culprit segments in CTO were 169 segments, and culprit segments in stable angina were 176. In global strain analysis, there was no difference between group 1 and 2 in LS ratio, PSS, and peak systolic strain rate (S_SR). In culprit segments, LS ratio, and PSS of group 1 were higher than group 3, statistically significant (table). Conclusion There were significant difference of LS ratio, and PSS between CTO and stable angina in culprit lesion suggesting speckle tracking strain analysis could be a useful to assess myocardial function. This results may be due to the collateral flow of CTO.