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.

Recurrent ischemia during continuous 12-lead ECG-ischemia monitoring in patients with acute coronary syndromes treated with eptifibatide: relation with death and myocardial infarction. PURSUIT ECG-Ischemia Monitoring Substudy Investigators. Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin Therapy

Computer-assisted continuous monitoring of the ST-segment allows detection and quantification of recurrent ischemia in patients with acute coronary syndromes. In a substudy of the PURSUIT (Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin Therapy) trial, this technique was used to evaluate the effects of the glycoprotein IIb/IIIa inhibitor eptifibatide on the incidence and severity of recurrent ischemia, and to investigate the relationship between recurrent ischemia and the occurrence of subsequent death or myocardial (re)infarction. A total of 258 patients with unstable angina or evolving myocardial infarction without ST elevation were monitored for 24 hours during infusion with either eptifibatide or placebo with a computer-assisted 12-lead ECG-ischemia monitoring device. Recurrent ischemic episodes were identified by an automated computer algorithm. Two hundred and sixteen patients (84%) had ECG recordings suitable for analysis. Ischemic episodes were detected in 35 (33%) of the 105 eptifibatide patients and in 32 (29%) of the 111 placebo patients (not significant). No difference in ischemic burden was apparent between both treatment groups. Patients who exhibited 2 or more episodes of recurrent ischemia more frequently died or suffered a myocardial infarction, both at 7 and 30 days, as well as through the 6-month follow-up. A greater ischemic burden was significantly related to adverse outcome during the 6-month follow-up period. Real-time computer-assisted continuous multilead ECG-ischemia monitoring may help to identify patients with unstable coronary syndromes at increased risk of adverse outcome and, thus, allow for better prognostic triage and more appropriate selection of therapeutic strategies. Integration of these systems in coronary care units and emergency wards should, therefore, be recommended.