In this study we compared efficacy and safety of prehospital with in-hospital thrombolytic treatment with anistreplase in patients with acute myocardial infarction (AMI). Three-hundred and fifty patients with chest pain were screened for eligibility by the municipal ambulance staff and/or the general practitioner. Patients were included in the absence of contraindications and if the telephone-transmitted ECG showed AMI. In a 6 month period 16 patients (5%) were eligible, but only seven (2%) were randomized. Age over 70 years, duration of chest pain for longer than 4 h and logistic problems were the major factors responsible for the low inclusion rate. The mean time spent at home with and without the ECG procedure was 38 +/- 14 and 14 +/- 8 min, respectively (P less than 0.001). These results demonstrate that in a medium sized town prehospital delivery of intravenous thrombolytic therapy by paramedics and/or the general practitioner is not feasible, leads to unnecessary time delay and may therefore yield no clinical benefits.