Silent myocardial ischemia. Rationale for management.

Recent studies show that in many coronary artery disease patients with any form of angina, myocardial infarction, or positive exercise tests but no symptoms, most of the ischemic episodes are silent. Furthermore, evidence is building to suggest that in many patient groups, silent ischemia relates to prognosis. Numerous therapies, including nitroglycerin or isosorbide dinitrate, have been shown to modify silent ischemia and its associated risks. Studies indicate that frequency and perhaps duration of silent ischemic episodes can be modified by treatment with beta-adrenergic blockers or calcium antagonists alone or, even more effectively, with a combination of both types of agent. Many ischemic episodes persist, however, when therapy is directed only at reduction of angina. Evidence suggests that some characteristics of silent ischemia predict prognosis, whereas angina characteristics do not. Until additional data about prognosis and the influence of treatment on prognosis are available, the appropriate focus seems to be improvement of outcome in those patients who are at highest risk, rather than only reduction of chest pain.