Background: An accurate assessment of LV function by determining the LV volumes and the ejec- tion fraction (EF) is important in evaluating the prognoses of patients with CAD. Strain by speckle tracking is evaluated by frame-by-frame tracking of the individual speckles throughout the cardiac cycle. This imaging technique discriminates between active and passive myocardial motion and enables angle-independent quantification of myocardial deformation in two dimensions. In-hospital heart failure during acute myocardial infarction is associated with adverse outcome. However, rela- tionship between left ventricular longitudinal myocardial mechanics and in-hospital heart failure with normal or mildly reduced left ventricular ejection fraction in patients with acute myocardial infarction is unclear. We hypothesized that speckle-tracking derived global longitudinal strain parameter is independent associated with in-hospital heart failure clinical criteria. Aim: To assess left ventricular function after drug eluting stent placement therapy of PCI in patients with myocardial infarction by Strain Imaging after myocardial longitudinal strain in patients with acute myocardial infarction. Material and methods: We prospectively included patients who presented acute myocardial infarc- tion and treated by primary PCI. In-hospital heart failure is defined by Killip class during admission. Multiple logistic regression analysis was used to reveal relationship between left ventricular global longitudinal strain and in-hospital heart failure. Separate multiple logistic regression model con- structed for patients with preserved left ventricular ejection fraction (LVEF≥55%). The incremental value of global longitudinal strain was tested by assessment of model c-statistics. Results: Total drug eluting stents were placed in 414 patients (mean age 60±13, 84% male) were included and 93 patients (22.5%) presented in-hospital heart failure Left ventricular global longi- tudinal strain (GLS) was significantly impaired in patients with in-hospital heart failure compared patients without in-hospital heart failure (-16.1±3.7 vs. -11.6±3.1, p<0.001). After adjustment of pos- sible predictor of in-hospital heart failure such as age, clinical, biochemical and echocardiographic parameters, global longitudinal strain was independently associated with in-hospital heart failure (odds ratio 1.32, 95% CI 1.16-1.50, p<0.001). In-hospital heart failure presented in 21 patients with LVEF≥55% and GLS is also significantly impaired in this group (-17.7±3.2 vs. -12.7±2.2, p<0.001).