BACKGROUND AND OBJECTIVES: Most reports about coronary angiographic findings in acute myocardial infarction were done after thrombolytic therapy or several days after onset of symptom. The aim of this study is to evaluate coronary angiographic findings in patients with AMI within 24 hours after onset of symptoms and without thrombolytic therapy. Also we evaluated the correlation between the risk factors and severity of coronary artery disease. MATERIALS AND METHODS: We studied 70 patients with acute myocardial infarction admitted to Kyungpook National University Hospital (KNUH) from November 1997 to January 1999, and evaluated the clincial and coronary angiographic findings. We analyzed risk factors of coronary artery disease: age, total cholesterol, tiglyceride, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, hypertension, smoking, diabetes and family history of CAD. Coronary angiography was done immediately after the arrival at emergency room (door-to- angiography time). Exclusion criteria were delayed arrival (more than 24 hours after symptom onset), previous history of anticoagulation or medication of antiplatelet agents. RESULTS: 1) Among 70 patients (M/F: 53/17), 59 patients had Q wave myocardial infarction (QMI) (84%), 11 patients had non-Q wave-MI (NQMI) (16%). 2) The mean age was 61+/-12.2 years (range: 26 to 82 years). 3) The mean time from the onset of chest pain to angiography was 6.2+/-4.7 hours. 4) Twenty eight patients (40%) had one-vessel disease, 25 (36%) had two-vessel disease and 17 (24%) had three-vessel disease. 5) The location of infarct related arteries were as follows: LAD in 33 (47%), LCX in 13 (19%) and RCA in 24 (34%). 6) The mean diameter stenosis of infarct related artery (IRA) was 95+/-10.9%. According to the American College of Cardiology/American Heart Association (ACC/AHA) classification of IRA, type B lesion occurred most commonly in 56 patients (80%). 7) Thrombus was observed in 44 patients (63%) with QMI versus 3 patients (27%) with NQMI (p=0.006). 8) Calcifications of the wall of coronary arteries were observed in 28 patients (40%) and correlated with ages of patients. 9) History of cigarette smoking was present in 73%, hypertension in 31% and hypercholesterolemia in 15% of patients. The mean number of risk factor for each patient was 1.3. 10) Multivessel disease was significantly more frequent in patients who had two more risk factors. 11) The frequency of cigarette smoking was greater and the level of plasma triglyceride were higher in patients under 50 years of age. 12) One patient died during coronary angiography and another 2 patients died at 5 and 8 days after coronary angiography due to cardigenic shock. CONCLUSION: In immediate coronary angiographic findings in patients with AMI, multivessel disease and thrombus, and severe stenosis of IRA were observed more frequently than other studies after thrombolytic therapy or after several days of delay. Multivessel disease was significantly more frequent in the patients who had two or more risk factors of atherosclerosis.