Pharmacologic therapies after myocardial infarction

Despite the availability and use of effective methods for limiting infarct size with thrombolytic agents and primary angioplasty, patients experiencing a myocardial infarction (MI) are at increased risk for a second cardiac event in the post-MI period (e.g., reinfarction, heart failure, and sudden death). For this reason, postinfarction risk management is crucial. An extensive data base has firmly established the efficacy of beta blockers in reducing cardiovascular risk following acute MI. The full advantages of angiotensin-converting enzyme (ACE) inhibitors have only recently begun to emerge as the result of a growing understanding of the mechanisms of adverse outcomes following MI. The importance of lipid-lowering agents, in particular the "statins," should be considered in all post-MI patients, especially since recent studies have conclusively shown improved survival and reduced rates of MI and coronary artery bypass surgery in this population with this therapy. Aspirin is now considered a standard part of the early management of the acute infarct patient as well as for secondary prevention in post-MI patients. At present, chronic anticoagulation with warfarin should be reserved for selected patients. The nondihydropyridine calcium antagonists diltiazem and verapamil can be considered for post-MI use only in patients in whom beta blockers are contraindicated and who have preserved systolic function and/or those without clinical heart failure. In contrast, the dihydropyridine calcium antagonists, particularly nifedipine, have no role in secondary prevention. Although long-term benefits are minimal, nitrates continue to be useful in post-MI patients with residual ischemia (angina or silent ischemia), heart failure (systolic or diastolic), or postinfarction hypertension. Antiarrhythmic agents, except amiodarone, are relatively contraindicated in post-MI patients. Recent data show that vitamin E reduces the rate of nonfatal MI. Its role in cardiovascular death and overall mortality remains to be clarified. Despite their demonstrated value, agents used in secondary prevention generally appear to be underutilized. In addition, when pharmacologic therapies are administered for secondary prevention, they are often prescribed at lower doses than those tested and proved in trials. A greater appreciation for the efficacy and safety profiles of these agents could lead to more widespread use and more pronounced reductions in morbidity and mortality among post-MI patients.