A number of clinical trials have evaluated whether acute or chronic anti-arrhythmic drug therapy can reduce mortality in post-MI patients. Of these, only the use of acute intravenous and long-term beta-blockers, independently and in combination, had been shown to reduce mortality. However, beta-blockers have many actions in addition to being anti-arrhythmic agents and it is possible that these other effects may have been particularly important in prolonging life.