• chest pain;
  • electrocardiographic monitoring;
  • echocardiography;
  • acute myocardial infarction;
  • unstable angina


Background: Various strategies have been proposed to improve diagnosis and triage of patients with chest pain at low risk, but uncertainty still exists on the optimal combination of diagnostic tools that should be used in this subset of patients.

Hypothesis: The aim of this study was to evaluate the incremental benefit of continuous 12-lead ST-segment monitoring over that provided by conventional diagnostic tools in patients with chest pain.

Methods: Of 232 consecutive patients referred because of chest pain, 52 were classified as low-risk according to the Agency for Health Care Policy and Research unstable angina guidelines and observed for 12 h with serial cardiac enzymes and electrocardiograms (ECG) (every 3 h). All patients also underwent both echocardiography at entry and continuous 12-lead ST-segment monitoring during the observation period.

Results: During a mean hospital stay of 3.7 days (range 1-14 days), a benign outcome was observed in 37 patients (71%), whereas 15 patients (29%) had major cardiac events or recurrence of chest pain of ischemic origin. Addition of ST-segment monitoring findings to baseline clinical data as well as to serial enzymes and ECG features added significant incremental prognostic value (p < 0.001). Multivariate analysis showed reproduction of pain by chest pressure (p < 0.05) and presence of ST-segment changes (≥ 0.1 mV) during 12-lead ST-segment monitoring (p < 0.001) as independent predictors of a benign or unfavorable outcome.

Conclusions: In low-risk patients with chest pain, continuous 12-lead ST-segment monitoring provides significant incremental diagnostic and prognostic information to currently used clinical, enzymatic, and ECG data, and is helpful in identifying the subset of patients with a worse in-hospital outcome.