The objective of the submitted work is to analyze in patients with acute myocardial infarction (AIM) local priority data on ECG markers after admission to hospital, data on some associations of ECG and thrombolytic treatment and to assess in patients with the first AMI data on hospital mortality in connection with some ECG markers. The project was implemented as a prospective multicentre study. An independent audit and collection of data was done in 3123 patients with AIM in 66 departments between Sept. 16 1997 and Sept. 15 1998. The group included patients admitted within 96 hours after development of complaints with the diagnosis or suspicion of AMI who were discharged with the diagnosis of a first/repeated AMI. Elevation of ST segments was recorded in 67.1%, a Q wave in 42.2% and left bundle branch block in 3.7% of the patients. Early diagnosis of AMI based on ECG and data on prolonged stenocardia was made in 55.6% patients. This is the maximal proportion of patients where thrombolytic treatment can be contemplated. Thrombolytic treatment was not administered to 54.9% patients with elevations of the ST segments and in as many as 81.2% patients with left bundle branch block. The hospital mortality in patients with a first AMI is significantly greater in patients with elevations of the ST segment, Q infarction, anterior wall infarction, combined infarction, right ventricular infarction and in patients with bundle branch and fascicular block. It was confirmed that in Slovakia in clinical practice thrombolytic treatment is not always administered consistent with criteria adopted from randomized studies. The result is underutilization or overutilization of thrombolytic treatment to patients with AIM in clinical practice. Underutilization of thrombolytic treatment is generally known. It was demonstrated that attention must be devoted also to overutilization of thrombolytic treatment. All patients where significantly higher hospital mortality was recorded must receive special care already on admission to hospital.