This study addresses the effect of the three major classes of antianginal agents on asymptomatic myocardial ischemia in patients with chronic stable angina pectoris. The authors found that each class (given as monotherapy) resulted in a 50% reduction in asymptomatic ischemia (both in the number of episodes and the ST product). Dual therapy resulted in an overall four fold reduction compared to placebo. Therapy also resulted in a beneficial alteration in the frequency distribution of asymptomatic ischemia. Stratification into three age groups demonstrated an equal prevalence of asymptomatic ischemia in each. All ages had nearly equivalent reductions in asymptomatic ischemia by monotherapy and dual therapy, but the youngest age group seemingly responded better to monotherapy than did the oldest age group.