The role of cardiac troponin I in determining the necessity for exercise electrocardiography in low risk patients with chest pain

Background. Assessment of non-cardiac chest pain places a considerable burden on healthcare resources. The current practice of serial electrocardiographs (ECGs), serum creatinine phosphokinase and by pre-discharge exercise electrocardiography gives an average in-hospital stay of 3.7 days. Aims. This study assess the use of a sensitive assay for cardiac troponin I (cTnl) to identify a low risk group for whom exercise ECG may not be indicated. Method. Ninety-five patients with acute chest pain and with peak cTnl <0.1 ng/ml and a non-diagnostic resting ECG were studied. Patients were divided into two groups. Group one had normal range cTnl (<0.03 ng/ml). Group two had minimal elevation of cTnl (0.03 - 0.099 ng/ml). Average follow-up was 172 days. Results. Nineteen patients had minimal elevation in cTnl of whom five developed significant ST shift on exercise and five had adverse events. No patients with a normal range cTnl had a positive stress test and none suffered an adverse event (p<0.001). Conclusion. CTnl in the normal range can identify patients with acute chest pain who have a negligible event rate and for whom exercise electrocardiography is not required.