Characteristics and clinical significance of ambulatory myocardial ischemia in men and women in the general population presenting with angina pectoris
MM Gandhi,
DA Wood,
and
FC Lampe
Department of Medicine, University of Southampton, London, United Kingdom.
OBJECTIVES. The aim of this study was to determine the frequency and prognostic importance of ambulatory myocardial ischemia and its association with cardiovascular risk factors in men and women in the general population presenting for the first time with typical angina pectoris. BACKGROUND. Previous studies in selected "low" and "high" risk patients with stable coronary heart disease report a wide range in the frequency of ischemia (24% to 82%) and there is no agreement about whether ambulatory ischemia is of prognostic importance for the generality of patients with stable angina. METHODS. Consecutive patients < or = 70 years of age from a randomly selected population with no previous coronary heart disease were assessed prospectively, and 96 patients with typical angina and 95 age-, gender- and practice-matched asymptomatic control subjects underwent 24-h ambulatory ST segment monitoring before antianginal therapy. All recordings were analyzed in blinded fashion. Follow-up evaluation of patients with angina to assess for revascularization, myocardial infarction and death was undertaken at a mean of 15.8 months (range 7 to 30) after the initial evaluation. RESULTS. Transient episodes of ischemic ST segment depression were detected in 50 patients (52%) with angina and 9 control subjects (9%). In patients with angina, 159 episodes (71%) were silent, median duration of ischemia was 66 min (range 1 to 782) and mean +/- SD ST depression was 2.4 +/- 1.1 mm. In logistic regression analysis, serum cholesterol (p < 0.05) and ischemia on exercise (p < 0.01) were independently associated with the presence of ambulatory ischemia in men with angina, but only the latter was significant in women; this may reflect a different pathophysiologic basis for ambulatory ischemia in women. During follow-up, there were 29 events. Kaplan-Meier survival analysis revealed no significant difference in event-free survival between patients with angina who did and did not have ischemic episodes (66% vs. 72%, p = NS). CONCLUSIONS. This is the first study representative of new patients with angina pectoris in the general population and shows that ischemia during daily living activities is present in > 50% of these patients but appears to be of no prognostic value.
