To analyse the effect of a primary care consultation at a health centre or at home and to determine the effect of the use of the pre-hospital electrocardiogram on thrombolytic delay. Analytical cross-sectional study. La Safor county (136,000 inhabitants), Valencia, Spain. Sample of 137 patients from the area admitted for acute myocardial infarction. None. Multivariate analysis through Cox regression models of the thrombolytic delay, comparing the patients who attended a primary care centre (40, 29.2%) and those who called out a doctor to their home (26, 19.0%) with those who attended hospital (71, 51.8%). The thrombolysis proportions in the groups were analysed with logistic regression. Patients referred from primary care arrived at hospital later than those who attended directly, although a greater thrombolytic delay was only seen in those visited at home (RR 0.25, 95% CI 0.09-0.71). A primary care electrocardiogram (14 patients, 10.2%) reduced the thrombolytic delay (RR 8.81, 95% CI 1.20-64.91) by reducing intra-hospital delay. There were no differences between the groups for the thrombolysis proportion (67 patients, 48.9%). Patients with infarction seen in primary care reach hospital later. Calling and waiting for the doctor at home increases the thrombolytic delay. An electrocardiogram on the infarction patients who attend a health centre reduces thrombolytic delay by reducing intra-hospital delay.