Article Text
Abstract
Objectives: To determine the incremental value of clinical data, troponin T, ST segment monitoring, and heart rate variability for predicting outcome in patients with non-ST elevation acute coronary syndromes.
Methods: Prospective cohort study of 304 consecutive patients. Baseline clinical and electrocardiographic data were recorded, serial blood samples were obtained for troponin T assay, and 48 hour Holter monitoring was performed for ST segment and heart rate variability analysis. End points were cardiac death and non-fatal myocardial infarction during 12 months’ follow up.
Results: After 12 months, 7 patients had died and 21 had had non-fatal myocardial infarction. The risk of an event was increased by troponin T > 0.1 μg/l, T wave inversion on the presenting ECG, Holter ST shift, and a decrease in the standard deviation of 5 minute mean RR intervals. Positive predictive values of individual multivariate risk were low; however, analysis of all multivariate risk markers permitted calculation of a cumulative risk score, which increased the positive predictive value to 46.9% while retaining a negative predictive value of 96.9%.
Conclusion: A cumulative approach to risk stratification in non-ST elevation coronary syndromes successfully identifies a group in whom the risk of cardiac death or non-fatal myocardial infarction approaches 50%.
- unstable angina
- risk stratification
- risk markers
- non-ST elevation acute coronary syndromes
- AUC, area under the receiver operating characteristic curve
- CABG, coronary artery bypass graft
- CKMB creatine kinase MB fraction
- ELISA, enzyme linked immunosorbent assay
- FRISC II, Fragmin and fast revascularization during instability in coronary artery disease
- PTCA, percutaneous transluminal coronary angioplasty
- SDANN, standard deviation of 5 minute mean RR intervals
- TIMI, thrombolysis in myocardial infarction