Emerging options in the management of myocardial ischemia.

Improved understanding of the pathogenesis of symptomatic and silent myocardial ischemia has led to important advances in the prevention and treatment of these syndromes. For example, recognition of the role of platelets in the atherogenic process and of thrombosis in acute myocardial ischemia has led to extensive use of aspirin and thrombolytic therapy, with resultant decreases in mortality. Both nitrates and beta-adrenergic blockers effectively alleviate myocardial ischemia. However, long-term nitrate use is limited by the occurrence of tolerance. beta blockers have been shown to decrease subsequent cardiovascular events in patients with acute myocardial infarction; however, adverse effects are often associated with their use. Calcium antagonists have been shown to be effective in the treatment of stable and vasospastic angina. In patients with coronary artery disease and symptoms resulting from either fixed obstruction or vasospasm, these agents decrease the frequency of angina episodes. The 3 types of calcium antagonists currently available--phenylalkylamine, benzothiazepine, and dihydropyridine derivatives--while chemically a heterogeneous group, share the common property of decreasing depolarization of smooth muscle, albeit to varying degrees. Nonetheless, other characteristics, including varying electrophysiologic effects, distinguish these groups. The novel calcium antagonist amlodipine is effective and well tolerated as an antianginal agent, and offers the advantage of once-daily dosing. Calcium antagonists appear to be well tolerated in patients with concomitant conditions such as diabetes and are effective in commonly coexistent cardiovascular disorders such as hypertension.