Total ischemic burden. Implications for prognosis and therapy.

Patients with silent myocardial ischemia can be classified as one of three clinical types: those who are totally asymptomatic (type 1), those who are asymptomatic after a myocardial infarction (type 2), and those who demonstrate both asymptomatic and symptomatic episodes (type 3). Total ischemic activity may be similar in any given patient, but the ratio of symptomatic to asymptomatic episodes will differ. Prognosis appears dependent on the degree of total ischemic activity plus the extent of coronary artery disease and left ventricular dysfunction. The effects of therapy can be monitored with exercise testing and/or Holter monitoring. Using the latter technique, the largest multicenter study to date, the Nifedipine Total Ischemia Awareness Program, has demonstrated the advantages of adding a calcium antagonist to nitrate and/or beta-blocker therapy regimens in order to maximize the reduction in total ischemic activity in angina patients.