Characteristics of transient ischaemic episodes in patients with silent and symptomatic exercise-induced myocardial ischaemia

To evaluate transient ischaemic episodes during daily life inpatients with coronary artery disease and exercise-induced myocardialischaemia, 38 patients underwent ambulatory ST-segment monitoringover 48 h. Sixteen patients had painless ischaemia during exerciseand occasional angina, and 12 patients had symptomatic ischaemiaand frequent angina during daily life. Ten patients with provencoronary artery disease but normal exercise electrocardiogramsserved as controls. The extent of coronary artery lesions andthe prevalence of myocardial infarction were similar in allgroups. ST-segment monitoring revealed 817 min and 98 episodesof ST depression in 13/16 patients of the asymptomatic groupand 111 min and 21 episodes in 5/12 patients of the symptomaticgroup (P<0.03). Subjective scores for physical activity duringHolter monitoring were significantly higher in the first groupthan in the second. The majority of ischaemic episodes in bothgroups was asymptomatic. No ischaemic ST changes occurred incontrol patients. Results indicate a higher frequency of transientischaemic episodes related to a higher level of physical activityin patients with silent ischaemia than in patients with symptomaticexercise-induced ischaemia.