Objective: 1/ Assessing the effectiveness of treatment myocardial reperfusion based on ST segment resolution. 2/ Prognosis of patients with myocardial infarction based on ST segment resolution. Subject and methods: 90 patients in Khanh Hoa Hospital from 01/01/2009 to 30/12/2010 was diagnosed as ST-elevation acute MI. Method: Prospective study. Results: ST segment resolution or = 50 percent after 1 hour treatment is highest in the PCI group 63.8 percent, 56.7 percent in thrombolytic group and 23.1 percent in rescue PCI, P 0.05. MI after treatment with the HPST or = 50 percent, the predicted survival was 16 times higher than HPST 50 percent (OR or = 50 percent after treatment is highest in the PCI group. The ST-segment resolution is independent prognostic factor for acute myocardial infarction.