Silent myocardial ischemia : the cardiologist's perspective on mechanisms, prevalence, and treatment

Summary Silent ischemia occurs frequently in patients with stable angina and acute coronary syndromes as well as in patients undergoing major operation. Although it has not yet been established fully, several recent reports indicate that the presence of silent myocardial ischemia is a predictor of adverse clinical outcome and poor prognosis in these patients. Whether treatment of silent ischemia can alter the associated adverse prognosis is not yet known. Furthermore, the effects of anti-ischemic therapy on silent ischemic events detected during the perioperative evaluation has not been evaluated systematically in a large prospective clinical trial. Although antianginal agents, such as nitrates, calcium-channel blockers, and β-blockers, have all been evaluated on an individual basis, large comparative trials are lacking. The results of ongoing studies should provide important information regarding the most appropriate anti-ischemic therapy for control of total ischemic activity. Patients undergoing major operation should be evaluated carefully for the risk of the development of episodes of transient ischemia. Although the benefits of therapy have not yet been proved, based on the associated adverse prognosis, it has been suggested that the high-risk patient with evidence of silent ischemia be treated aggressively in an attempt to reduce the risk of perioperative cardiac events. It seems logical to emphasize that it is the presence of recurrent episodes of myocardial ischemia and not the associated symptoms that determines the subsequent prognosis.