ST-segment monitoring with continuous 12-lead ECG improves early risk stratification in patients with chest pain and ECG nondiagnostic of acute myocardial infarction

OBJECTIVES: The purpose of this study was to evaluate the prognostic import ance of ischemic episodes detected by ST-segment monitoring with continuous 12-lead electrocardiography (ECG) in a nonselected coronary care unit (CCU ) population with chest pain and ECG nondiagnostic of acute myocardial infa rction (AMI). BACKGROUND: Patients with chest pain and ECG nondiagnostic of AMI constitut e a heterogeneous group concerning both diagnosis and prognosis. Continuous 12-lead ECG is a rather new method not thoroughly studied in this populati on. METHODS: The ST-segment monitoring with continuous 12-lead ECG was performe d for 12 h in 630 consecutive patients admitted to CCU due to chest pain an d a nondiagnostic EGG, i.e., no ST-segment elevations. An ST-episode was de fined as a transient ST-segment depression or elevation of at least 0.10 mV . The median follow-up time was six months. RESULTS: A total of 176 ST-episodes occurred in 100 (15.9%) patients. The m edian duration and maximal ST-segment deviation in patients with ST-episode s were 80 min and 0.20 mV, respectively. Presence of ST-episodes predicted worse outcome concerning cardiac death and cardiac death or myocardial infa rction (MI) (log-rank p < 0.001). At 30 day follow-up procedure, 10% versus 1.5% died from cardiac causes or had an MI in the group with and without S T-episodes, respectively. In a multivariate analysis, only troponin T great er than or equal to 0.10 mu g/l and the presence of ST-episodes came out as independent predictors of cardiac death or MI. CONCLUSIONS: Continuous 12-lead ECG monitoring provides prognostic informat ion on-line and considerably improves early risk stratification in patients with ECG nondiagnostic of AMI and symptoms suggestive of acute coronary sy ndrome. (C) 1999 by the American College of Cardiology.