The objective of the trial was to study the efficacy and safety of Fragmin(R) (Pharmacia, Sweden) in prevention of left ventricular thrombus (LVT) formation and arterial embolism (AE) after acute anterior myocardial infarction (AMI). The trial design was placebo-controlled, randomised, double-blind and multicentral. Fragmin(R) (150 IU/kg BW b.i.d.) was given until pre-discharge echocardiography (2DE) at day 9 +/- 2. The 2DE recordings were centrally evaluated. AE, reinfarction, mortality and haemorrhages were recorded continuously throughout hospitalisation. Only aspirin was allowed as adjunctive antithrombotic treatment.Results: 776 patients were randomised in the trial. Streptokinase and aspirin were given to > 90 percent of the patients. Other important concomitant treatment as well as baseline characteristics did not differ between the groups. The results are based on intention-to-treat analyses.Conclusions: Fragmin(R) was associated with a significant reduction in LVT formation after AMI. The numbers of arterial embolism and reinfarctions were low with no difference between the treatment groups. Furthermore, there was no difference in mortality rates between the groups. However, Fragmin(R) was associated with a significant increase in major bleeding.