Recurrent ischaemia during continuous multilead ST-segment monitoring identifies patients with acute coronary syndromes at high risk of adverse cardiac events; meta-analysis of three studies involving 995 patients

AIMS: Recurrent ischaemia, detected by continuous ECG monitoring, in patients with unstable angina increases the risk of unfavourable outcome. Studies that evaluated this relationship have been limited by the small series of patients. By combining data from three studies, the present analysis aims to provide an accurate assessment of the impact of recurrent ischaemia detected by multilead ECG-ischaemia monitoring on the occurrence of death and myocardial infarction in patients with acute coronary syndromes. METHODS AND RESULTS: Data were obtained from CAPTURE, PURSUIT and FROST, three trials evaluating glycoprotein IIb/IIIa blockers in patients with non-ST-elevation acute coronary syndromes. Patients were monitored for 24 h after enrollment with a computer-assisted 12-lead or a vectorcardiographic ECG-ischaemia monitoring device. In a retrospective blinded analysis, recurrent ischaemic episodes were identified by a computer algorithm. The number of ischaemic episodes was normalized to 24 h. Ischaemic episodes were detected in 271 (27%) of 995 patients. There was a direct proportional relationship between the number of ischaemic episodes per 24 h and the probability of cardiac events at 5 and 30 days. The 30-day composite of death and myocardial infarction occurred in 5.7% of patients without episodes and increased to 19.7% in patients with >/=5 episodes. After adjustment for baseline predictors of adverse outcome, the relative risk of death or myocardial infarction at 5 and 30 days increased by 25% for each additional ischaemic episode per 24 h. CONCLUSIONS: This analysis emphasizes the need for integration of multilead ECG-ischaemia monitoring systems in coronary care units and emergency wards to improve early risk stratification in patients with acute coronary syndromes.