An update to silent myocardial ischemia: pathophysiological, diagnostic, and therapeutic approaches

Silent myocardial ischemia (SMI) is a common ischemia process which can be defined as objective evidence of myocardial ischemia without chest pain or other equivalent indications. SMI can occur in totally asymptomatic patients, as well as in patients who have documented coronary artery disease (CAD) and who, on exercise and/or during Holter monitoring, may show ischemic changes. The precise mechanism for pathogenesis and pathophysiology of SMI remains to be clarified. A great deal has been learned about the role of beta-adrenergic receptors, adenylyl cyclase, and guanine nucleotide binding proteins (G proteins) in the myocardial ischemic process of SMI. Moreover, standard exercise test and long-term ECG recordings have proved to be of great value, especially when performed jointly, however, in this field there is still room for expanded knowledge. Pharmacological interventions to date have demonstrated the beneficial effects of beta-adrenergic receptor antagonists and/or calcium antagonists as contributing substantially to reducing both frequency and duration of SMI episodes. However, therapeutic options to improve the prognosis of SMI appear to be limited.