Use of beta-adrenergic blocking agents after myocardial infarction

Long-term clinical trials have been carried out to evaluate the effectiveness of beta-adrenergic blocking agents in modifying the natural history of myocardial infarction (MI). In most of these studies, a lower mortality rate was documented in patients receiving a beta-blocker than in those receiving placebo. The drugs may have both antiarrhythmic and antiischemic effects. In patients without contraindications to beta-blocker treatment, a relative reduction in mortality of 25% can be expected for at least one to two years, with the reduction higher in older patients or patients having complications at infarction. Study results indicate benefit from starting beta-blocker therapy early after infarction, and some benefit from starting late seems a reasonable assumption. Evidence also points to a benefit from prolonged therapy. Beta-blockers are well tolerated in most patients; those major side effects that do occur are often cardiovascular.