Background & Objectives: Myocardial infarction is one of the most common causes of mortality throughout the world. Utilization of thrombolytic drugs at the first hours upon MI leads to decrease in the rate of mortality. Streptokinase (SK) is commonly used because of its cost and availability. The golden time for maximum effect of SK appeared to be first hours after MI. The drug efficiency diminishes after 3 hours and it will be ineffective after 12 hours.

  This study was aimed to investigate interval between onset of the clinical symptoms and streptokinase receiving in patients with acute myocardial infarction�admitted for drug reception.

  Methods: This cross-sectional study was conducted in 150 patients with STEMI (ST elevation Myocardial Infarction ) who were attended to emergency room of Imam Khomeini hospital and fulfilled a questionnaire containing the data about age, sex, educational level, onset of symptoms, referring time to emergency room, SK utilization, past medical history of cardiac diseases, type and location of AMI, contraindications and side effects of SK.

  Results: In 111 men (74%) and 39 women (26%), the mean for interval between onset of symptoms and drug injection was 8 hour and 27 minutes ± 8 hour and 18 minutes .Only 41% of patients received streptokinase in less than 3 hours after chest pain. The main reasons for delaying in drug consumption were delayed decision to come to hospital in 61% of persons, long distance to hospital for 22% of individuals, delayed admission tor CCU for 13% of cases and delay in physician diagnosis for 0.043% of patients. To have a male sex and residency in city where the hospital was establilished were associated with less-delayed treatment start. However, the educational level, age and history of MI were not correlated with onset of treatment.

  Conclusions: Our results clearly show that the majority of patients receipt streptokinase more than 3 hours after chest pain. With considering the factors associated with delay to receive SK, teaching the patients with ischemic heart disease and giving information about golden time for thrombolytic therapy and its effect in prognosis as well as extending cardiac disease treatment centers in suburbs are recommended.