Frequency of silent myocardial ischemia with 12-lead ST segment monitoringin the coronary care unit: Are there sex-related differences?

BACKGROUND: Ischemia that occurs in the coronary care unit (CCU), whether s ymptomatic or silent, is associated with significant in-hospital and out-of -hospital complications. Studies have reported that more than 90% of ischem ic episodes are silent in patients with unstable angina who are treated in the CCU with maximal medical therapy. Prior reports indicate that women com plained more frequently of chest pain than men did. PURPOSE: The aim of this study was to compare the frequency of silent myoca rdial ischemia in men versus women with use of continuous 12-lead ST segmen t monitoring in the CCU. A secondary goal was to determine whether silent i schemia was associated with less ST segment deviation as compared with symp tomatic ischemia. METHOD: Patients admitted for treatment of acute coronary syndrome in the C CU and who subsequently had 1 or more ischemic events during their monitori ng period were selected for this analysis. All patients were continuously m onitored (42.5 hours +/- 37.6) in the CCU with the EASI (Zymed Medical Inst ruments, Camarillo, Calif) 12-lead electrocardiogram (ECG) system that deri ves 12 leads with use of 3 information channels and 5; electrodes. RESULTS: Of 491 patients, 128 (91 men and 37 women) had at least 1 episode of transient myocardial ischemia. Men and women did not differ in their pro portion of chest pain during ischemia (men 27% and women 21%, NS). For both men and women, ST segment deviation was significantly,greater during sympt omatic ischemia compared with silent ischemia. CONCLUSION: There are no sex-related differences in ischemic events in the CCU in regards to the variables of chest pain and ST magnitude. Therefore, because chest pain is not a reliable indicator of myocardial ischemia in th e CCU, regardless of sex, patients should be adequately monitored for ische mic events.