Ten patients in the treatment group and 10 patients in the control group were enrolled in this prospective, randomized, double blinded study. Two weeks after myocardial infarction that was accompanied by successful recanalization and stent implantation, the patients of the treatment group received 10 μg/kg body weight per day (divided BID) G-CSF subcutaneously for treatment duration of maximum 5.0 days. In both groups, ejection fraction was evaluated with echocardiography and cardiac scan (Gated SPECT method) 10 days after myocardial infarction and after 6 months. Tei index was measured by echocardiography.