Acute myocardial infarction (AMI ) is one of the most common cause of mortality in almost all countries of the world. According to this fact that thrombus formation and coronary obstruction are the basic pathophysiology of AMI , early
   thrombolysis and reperfusion of coronary artery have important role in the reduction of mortality rate and it’s complications. So , recognition of the preventive causes of thrombolytic therapy is very important.

This research was a cross sectional study which was performed on 166 patients with AMI who needed thrombolytic therapy and were admitted in CCU ward of Hamadan’s Ekbatan hospital. Duration time between the onset of symptoms and
   hospital admission , duration between admission and begining of thrombolytic thrapy (Enter to Needle time) and causes of omit doing thrombolytic thrapy were assessed.

45.8 % of these patients did not receive thrombolytic therapy: 12.7 % due to misdiagnosis, 16.3 % due to thrombolytic therapy contraindication and 16.8 % in consequence of late hospital admission. The average time between the onset of symptoms and hospital admission was 5.4 hours and mean enter to needle time
   was 45.22 minutes.

            Although the rate of patients with misdiagnosis and delayed hospital admission was acceptable, it is necessary to improve both of them. In our study the enter to needle time albeit acceptable but was 15 minutes longer than optimal time which mentioned in references that should be improved.