EDITOR Owen's perception that intravenous β blockers are less commonly given after acute myocardial infarction in the United Kingdom than elsewhere1 is confirmed by data from the European secondary prevention study.2 Clinical management was examined in a representative sample of over 4000 patients admitted to hospital with confirmed acute myocardial infarction in 11 European regions. Intravenous β blockade was given to 13% of patients overall, but this proportion varied from 0.5% (United Kingdom) to 54% (Sweden) in the regional samples. This 100-fold range, larger than the range for any other treatment or procedure studied, is particularly striking for an aspect of management that has been subjected to at least 28 randomised trials in over 27 000 patients.

Variation in practice on this scale has important messages for proponents of evidence based medicine and cannot be explained by lack of awareness on the part of clinicians. The key issue is the generalisability of the evidence from trials in highly selected low risk patients. In the largest trial, the first international study of infarct survival, fewer …