How much is enough?

The guidelines for treatment after myocardial infarction (MI) with or without ST-segment elevation (STEMI or NSTEMI)1--3 recommend the use of beta-blockers for all patients without contraindication because, based on large observational studies and randomized clinical trials, they increase survival rates. These guidelines recommend high doses of beta-blockers, but this recommendation is not followed in clinical practice, in which about 25% of the recommended dose is prescribed. Although widely used, these lower doses have not been tested in controlled and randomized trials. The question thus arises as to whether smaller doses of beta-blockers achieve the same benefit in reducing mortality, since the increases in survival in the trials were proportional to the decreases in heart rate obtained with incremental doses. Studies designed to answer the question of the correct beta-blocker dose have provided important information for the follow-up of MI. The Outcomes of Beta-Blocker Therapy After Myocardial Infarction (OBTAIN) registry,4 of 6682 patients in centers in the USA and Canada from 2007 to 2009 with a mean follow-up of 2.1 years, used multivariate and propensity score analysis to assess the results. No improvement was observed in the survival of patients