Frequency and Outcomes of Transient Myocardial Ischemia in Critically Ill Adults Admitted for Noncardiac Conditions

BACKGROUND: Critically ill adults admitted for noncardiac conditions are at risk for acute myocardial ischemia. OBJECTIVES: To detect myocardial ischemia and injury in patients admitted for noncardiac conditions and to examine the relationship of myocardial ischemia, injury, and acuity to cardiac events. METHODS: Transient myocardial ischemia, acuity, elevations in serum troponin I, and in-hospital cardiac events were examined in 76 consecutive patients. Transient myocardial ischemia, determined by using continuous electrocardiography, was defined as a 1-mm (0.1-mV) change in ST level from baseline to event in 1 or more leads lasting 1 or more minutes. Acuity was determined by scores on Acute Physiology and Chronic Health Evaluation II. RESULTS: A total of 37 ischemic events were detected in 8 patients (10.5%); 32 (86%) were ST-segment depressions, and 35 (96%) were silent. Twelve patients (15.8%) had elevated levels of troponin I. Transient myocardial ischemia, elevated troponin I levels, and advanced age were significant predictors of cardiac complications (R2 = 0.387, F = 15.2, P < .001). Acuity correlated only modestly with increased length of stay in the intensive care unit (r = 0.26, P = .02) and elevated troponin I levels (r = 0.25, P = .03). Patients with transient myocardial ischemia had significantly higher rates of elevations in troponin I (P < .001) and cardiac events (P < .001) than did patients without. CONCLUSIONS: Transient myocardial ischemia and advanced age are predictors of cardiac events and may indicate patients at risk for cardiac events.