Secondary prevention after myocardial infarction: facts and fallacies.

Therapeutic research into secondary prevention after myocardial infarction has a disappointing cost-benefit record. Many unrecognised biological problems have complicated apparently simple clinical trials. Inadequacies in design have also contributed to the low rate of success in demonstrating a statistically convincing and clinically worthwhile prophylactic benefit of any of the drugs so far tested. The potential hazards of long-term preventive drug treatment have yet to be defined. The projected economic impact on the community of successful secondary prevention is not encouraging. In the present state of knowledge, arguments for the long-term prophylactic drug therapy of asymptomatic survivors of myocardial infarction are difficult to sustain.