716-4 Placebo Treatment Reduces Both the Number of Ischemic Episodes and Duration of Ambulatory Silent Myocardial ischemia in Patients with Stable Angina Pectoris

Abstract

Ambulatory silent myocardial ischemia occurs frequently in patients with stable exertional angina pectoris, It is widely accepted that a medication has antiischemic effects if it reduces either the number or the duration of silent myocardial ischemic episodes in comparison to pretreatment values. Effect of monotherapy with placebo on silent myocardial ischemia in 33 patients who took part in a parallel group investigational drug study and were assigned to the placebo arm of the study form the basis of this investigation. After discontinuation of all antianginal medications patients received two weeks of single blind placebo treatment followed by four weeks of double blind placebo treatment. Ambulatory holter monitoring was performed for 48 hours after two weeks of single blind placebo treatment and again after 4 weeks of double blind placebo treatment. The median value of silent myocardial ischemia attack rate during single blind placebo treatment was 7.2 episodes per 48 hours and decreased during double blind placebo treatment to a median rate of 3.1 episodes per 48 hours (P < 0.004; 95% CI, -5.41, -1.0). Similarly the duration of silent myocardial ischemic episodes decreased by a median of 16,1 minutes per 48 hours (P < 0,001; 95% CI. -35.7, -6.2 minutes) during double blind placebo treatment from a median value of 24.8 minutes per 48 hours during single blind placebo treatment. placebo monotherapy had a marked influence on ambulatory silent myocardial ischemia and reduced both the duration and number of silent myocardial ischemic episodes in patients with stable angina pectoris. These findings have important implications for interpretation of studies in which the effects of active treatment on silent myocardial ischemia are compared to baseline pretreatment values.