European Resuscitation Council Guidelines for Resuscitation 2010 Section 5. Initial management of acute coronary syndromes.

History, clinical examinations, biomarkers, ECG criteria and risk scores are unreliable for the identification of patients who may be safely discharged early. The role of chest pain observation units (CPUs) is to identify, by using repeated clinical examinations, ECG and biomarker testing, those patients who require admission for invasive procedures. This may include provocative testing and, in selected patients, imaging procedures as cardiac computed tomography, magnetic resonance imaging, etc.